Journal articles on the topic 'Steel strip Testing'
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1
He, Zhi-Qi, Changxue Ou, Fei Tian, and Zhao Liu. "Experimental Behavior of Steel-Concrete Composite Girders with UHPC-Grout Strip Shear Connection." Buildings 11, no. 5 (April 24, 2021): 182. http://dx.doi.org/10.3390/buildings11050182.
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This paper develops a new type of shear connection for steel-concrete composite bridges using Ultra-High Performance Concrete (UHPC) as the connection grout. The UHPC-grout strip shear connection is fabricated by preforming a roughened slot in the concrete deck slab, welding an embossed steel rib longitudinally to the upper flange of the steel girder, and casting the strip void between the slot and the steel rib with UHPC grout. The structural performance of the new connection was validated by two sets of experimental tests, including push-out testing of shear connectors and static and fatigue testing of composite beams. The results of push-out testing indicate that the UHPC-grout strip shear connection exhibits a significant improvement of ductility, ultimate capacity, and fatigue performance. The interface shear strength of the UHPC-grout strip connection is beyond 15 MPa, which is about three times that of the strip connection using traditional cementitious grouts. The ultimate capacity of the connection is dominated by the interface failure between the embossed steel and the UHPC grout. The results of composite-beam testing indicate that full composite action is developed between the precast decks and the steel beams, and the composite action remained intact after testing for two million load cycles. Finally, the trail design of a prototype bridge shows that this new connection has the potential to meet the requirements for horizontal shear.
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Chavan, Mr Vivek Sarjerao. "Flexural Behaviour of RCC slab using Epoxy Coated Bamboo as Reinforcement." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 682–87. http://dx.doi.org/10.22214/ijraset.2022.45241.
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Abstract: Bamboo is one of the potential material as a substitute for steel reinforcement. Bamboo is very cheap, easily available, and available in ample quantity. Bamboo is cultivated in farm by farmers. Bamboo is having very good mechanical properties which attract many researchers to use it as reinforcing material in concrete. From bamboo small thin strips were prepared. These strips were tied together in two directions to form a bamboo-strip- mat. All these strips while making bamboo-strip-mat was tied together with small thin Mild Steel wire to ensure their position in mat formation. Testing is done using bamboo- strip-mat as reinforcement in cement concrete prismatic section at bottom side. Concrete slab thus produced in laboratory were tested in flexure; results obtained were presented in this project. Bamboo strips were prepared from old age bamboo. Researchers at the Future Cities Laboratory Singapore Zurich achieved the liaison of both the superior physical properties of the bamboo fiber and the extraordinary mechanical properties of polymer resins in a new green and sustainable material technology.
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Stockert, Sven, Matthias Wehr, Johannes Lohmar, Gerhard Hirt, and Dirk Abel. "Development of a Laser Triangulation Gauge for High Precision Strip Thickness Control." Advanced Materials Research 1140 (August 2016): 107–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1140.107.
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Almost all metal strips with thicknesses of < 2 mm are produced by cold rolling. Thickness variations of cold rolled strips are caused by various factors like fluctuation in strength of the material, the eccentricity of the rolls or thickness variation of the incoming strip. As the demands concerning the thickness variation are ever increasing the Institute of Automatic Control and the Institute of Metal Forming aim at reducing the thickness tolerance of thin, cold-rolled steel and copper strips to 1 μm. As high frequency disturbances are expected, it is assumed that this goal can only be achieved by using a predictive controller in combination with a high precision strip thickness gauge and, for roll adjustment, a piezoelectric actuator in addition to the existing electromechanical actuator. The objective of this work is the constructive implementation and the testing of a thickness gauge based on laser triangulation. The gauge includes guide rollers to prevent strip vibration, a C-frame to allow an inline calibration and mechanical adjustment of the measuring range so that even flexible strip thicknesses can be measured. The designed gauge showed a high repeat accuracy of 0.4 μm for two different metal strips. Furthermore the gauge was used to investigate the dynamics of the thickness change of a steel strip at maximum rolling speed of 5 m/s using a Fourier transformation. This frequency analysis supports the need for a piezoelectric actuator that can also subsequently be dimensioned based on the obtained frequency data.
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Li, Long, Xin Chen, De Jing Zhou, and Chao Lan Tang. "Evaluation on Interface Bonding of Thin Aluminum Clad Steel Strip." Advanced Materials Research 1120-1121 (July 2015): 967–72. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.967.
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The bond strength were comparatively measured by tensile test, tension shear test and compression shear test in order to evaluate bonding behavior of thin aluminum clad steel strips bonded by cold rolling, and furthermore determine minimum stable reduction of clad strips. The morphologies after fracture were observed and analyzed using SEM (scanning electron microscope) and EDS (energy dispersive spectrometer). The results show that it is lower for the bond strength obtained by shear test than one obtained by tensile test, which largely attributes to different stress states during testing. Minimum stable reduction can be defined as one beyond which the fracture would completely occur at aluminum component layer instead of interface between components, which is suggested as 40-45% based on fracture feature of Al clad steel strip.
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Smith, Ali, Florian Vercruysse, Roumen Petrov, Patricia Verleysen, and Bernd Linke. "Effect of Ti on the Microstructure and Mechanical Properties of a Hot Rolled Advanced High Strength Steel Strip." Materials Science Forum 941 (December 2018): 106–11. http://dx.doi.org/10.4028/www.scientific.net/msf.941.106.
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The addition of titanium is a well-known microalloying concept for hot rolled structural steels. Concerning advanced high strength steels for the automotive sector, the use of Ti microalloying (usually with Nb-V) has been an active research area. However, Ti addition has not been explored in depth. For the current contribution, a laboratory hot rolled 0.2C-2.4Mn-1.5Si steel with and without Ti addition was studied. Mechanical testing of the hot strip revealed a very high UTS (1GPa) for the Ti added steel, whilst for the unalloyed chemistry the UTS was some 300 MPa lower. Observation of the hot rolled microstructures via optical microscopy showed a significantly higher hardenability for the Ti added steel. Moreover, X-ray diffraction analysis indicated a significant amount of retained austenite in the Ti added strip, which transformed completely to martensite after the tensile test. Further analysis via TEM and chemical extraction indicated that Ti was present both as Ti (C,N) precipitates and in solution. Finally, in light of these observations, the possible mechanisms leading to the enhanced hardenability observed for the Ti added hot rolled strip steel were discussed.
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NEACȘU, Marian-Iulian. "Mathematical Modeling of the Cold Rolling Process and Heat Treatment for DC01 Steel." Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science 44, no. 2 (June 15, 2021): 35–38. http://dx.doi.org/10.35219/mms.2021.2.06.
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The paper presents the elaboration of a mathematical model of the cold strip rolling process combined with the recrystallization annealing after the rolling at LBR Liberty Galati.The elaborated mathematical model allows the prediction of the mechanical properties of cold rolled strips subsequently subjected to a heat treatment.The realization of this mathematical model was based on statistical measurements of the mechanical properties Rm, Rp0.2 (Rc) and A5 for the rolled steel strip DC01 from Liberty Steel Galati. To achieve this mathematical model, the active experiment method was used.With the help of this mathematical model, it is possible to optimize the rolling process by significant savings of time and materials in the process of testing the mechanical properties for cold rolled tape, but also by choosing the most appropriate process parameters.
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NEACȘU, Marian-Iulian. "Mathematical Modeling in View of Property Prediction of DD11 Steel Laminated in LBC Liberty Galati." Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science 44, no. 2 (June 15, 2021): 5–10. http://dx.doi.org/10.35219/mms.2021.2.01.
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The paper presents a mathematical model for predicting the mechanical properties of hot rolled strips. The realization of this mathematical model relied on statistical measurements of the mechanical properties (Rm, Rp0,2 and A5) for the laminated strip in the LBC rolling mill from the Liberty Steel Galati steel plant. To achieve this mathematical model, there has been used the active experiment method.By means of this mathematical model, significant time and material savings can be made in the process of testing the mechanical properties for hot rolled tape.
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Mazur, Igor, Aleksandr P. Dolmatov, and Sergey S. Borisov. "Investigation and Numerical Modeling of the Process of Cold Rolling HSLA Steels." Materials Science Forum 704-705 (December 2011): 832–41. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.832.
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Considering the problems and details of modeling process of cold rolling, it was constructed a theoretical model of deformation area based on a set of equations, which were practical testing. The model is based on cold-rolled numerical solution of differential equations of forces equilibrium in the deformation area by Karman. In the model there are included modules for calculating strip temperature and strip gage at the exit from the stand, considering elastic recovery of the strip. For adaptation of the equations to the specific conditions of cold rolling of HSLA steels in the continuous five stand mill 2030 and assess the deviation of calculated data from the actual, a procedure of correction for hardening curve of rolled steel has been developed. The model allows defining the energy-power parameters of rolling: average unit rolling force, the full force of rolling, rolling moment, rolling force, an average temperature of strip at the inlet and outlet of each of the mill stands, steel hardening curve when rolling. The model is implemented as software using object-oriented approach in the language of C++ Builder.
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Kopineck, H. J., H. Otten, and G. Dobmann. "Non-destructive testing for characteristic parameters of rolled steel strip." NDT & E International 24, no. 1 (February 1991): 39. http://dx.doi.org/10.1016/0963-8695(91)90689-z.
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Yu, Yong Wei, Guo Fu Yin, and Liu Qing Du. "Image Classification for Steel Strip Surface Defects Based on Support Vector Machines." Advanced Materials Research 217-218 (March 2011): 336–40. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.336.
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In order to realize less time consuming and on-line image classification for steel strip surface defects, an improved multiclass support vector machine (SVM) was proposed. The SVM used a novel algorithm and only constructed (k-1) two-class SVMs where K is the number of classes. In the testing phase, to identify the surface defects it used a new unidirectional acyclic graph which had internal (k-1) nodes and k leaves. Its testing time is less than traditional multiclass SVM method. The experiment results shows that this method is simple and less time consuming while preserving generalization ability and recognition accuracy toward steel strip surface defects.
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Li, Jian, Yun Hui Yan, Xing Hui Guo, and Yan Qing Wang. "Real-Time Vibration Control of Steel Strip Immersed in Fluid for a Continuous Hot-Dip Galvanizing Line." Advanced Materials Research 314-316 (August 2011): 2375–80. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.2375.
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A method of combining theoretical analysis with numerical simulation is presented to achieve real-time vibration control of steel strip immersed in fluid during continuous hot-dip galvanizing process. Theoretical and numerical methods are employed to investigate inherent properties of strip and immersed strip, respectively. Multivariate quadratic regression is adopted to fit the ratio of natural frequencies. Keeping inherent frequencies far from excitations is taken as optimization objective, based upon field testing results. Real-time vibration control of immersed strip near the air knife box is carried out by varying production parameters. The results reveal that width, thickness, tension and molten zinc have noticeable and highly nonlinear effect on inherent properties of steel strip. Axial speed of strip is negligible in calculations of natural frequencies. Wind load of air knife moving relative to strip is the principal source of vibration. The approach of combining theory with numerical computation can meet the requirement of real-time vibration control of alloy strip.
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Peng, Qi Chun, Zhi Bo Tong, Liu Yang, Bing Yu Liu, Long Qian, and Jin Ping He. "The Study of Edge Crack on Hot Strip Steel for CSP." Advanced Materials Research 581-582 (October 2012): 533–39. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.533.
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By macroscopic observation, metallographic examination, scanning electron microscope and energy spectrum analysis, it is inferred that the steel flow bellows SEN is too strong that the heat delivering at steel top surface in the mould is not enough by taking sample on slab, F2 transition strip and hot strip steel with cracks, which causes insufficient mould powder melting, and hooked oscillation marks are formed. Since liquid steel liquidity is not good either, a part of powder can be caught by solidification front, and many fine cracks are generated on slab surface. This kind of hooked oscillation mark, subsurface fine crack and corner crack evolve into edge crack, and rolling simulation testing proved this inference. Moreover, Cu beneficiation is also one reason of edge crack. Edge crack of hot strip steel study can be used to guide actual production, and to avoid the generation of edge crack.
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Jingzhong, Hou, Xia Kewen, Yang Fan, and Zu Baokai. "Strip Steel Surface Defects Recognition Based on SOCP Optimized Multiple Kernel RVM." Mathematical Problems in Engineering 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/9298017.
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Strip steel surface defect recognition is a pattern recognition problem with wide applications. Previous works on strip surface defect recognition mainly focus on feature selection and dimension reduction. There are also approaches on real-time systems that mainly exploit the autocorrection within some given picture. However, the instances cannot be used in practical applications because of a bad recognition rate and low efficiency. In this paper, we study the intelligent algorithm of strip steel surface defect recognition, where the goal is to improve the accuracy and save running time. This problem is very important in various applications, especially the process testing of steel manufacturing. We propose an approach called the second-order cone programming (SOCP) optimized multiple kernel relevance vector machine (MKRVM), which can recognize strip surface defects much better than other methods. The method includes the model parameter estimation, training, and optimization of the model based on SOCP and the classification test. We compare our approach with existing methods on strip surface defect recognition. The results demonstrate that our proposed approach can improve the recognition accuracy and reduce the time costs of the strip surface defect.
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Janošec, Marcel, Ivo Schindler, Vlastimil Vodárek, Emerich Místecký, and Martin Růžička. "Evolution of Microstructure and Mechanical Properties of HSLA Strip Steel after Cold Rolling and Annealing." Materials Science Forum 567-568 (December 2007): 345–48. http://dx.doi.org/10.4028/www.scientific.net/msf.567-568.345.
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A large testing programme of a strip steel HSLA grade, microalloyed by vanadium, titanium and niobium, was conducted. The experiment was based on combination of cold rolling, recrystallization annealing, mechanical testing, metallographic examinations and TEM analysis. Flat samples with thickness 3.9 mm were rolled in several passes with the total height reduction 5 to 75 %. Afterwards the laboratory mill products were annealed in the vacuum furnace with the protective gas atmosphere consisting of N2+H2. The annealed samples underwent the mechanical testing. The gained results – hardness, yield stress, tensile strength and their ratio, as well as elongation, were summarized in graph in dependence on relative height reduction before annealing. It was confirmed that by a suitable combination of size of previous cold deformation and parameters of the following recrystallization annealing it is possible to influence a complex of mechanical properties of particular strips. Particular trends of strength and plastic properties correspond to each other and they may be utilized for optimization of terms of heat treatment of the investigated HSLA steel in a cold rolling mill. These trends are caused by structure-forming processes (recrystallization, grain coarsening, changes of the state of precipitates) which were documented by micrographs.
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Naipinij, Sun, Sasapan Sukieum, Ravinupha Namprai, and Thanasak Nilsonthi. "Formation of thermal oxide scale and its adhesion to hot-rolled low carbon steels with different final strip thicknesses." E3S Web of Conferences 355 (2022): 02008. http://dx.doi.org/10.1051/e3sconf/202235502008.
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Currently, the steelmaking industry produces iron oxide waste scale resulting in pollution to the environment. It was necessary to have a good understanding of the composition, characteristics and properties of the oxide scale. This study focused on the formation of scale and its adhesion to the hot-rolled steel strip with different thicknesses. The oxide scale formed on an as-received hot-rolled steel strip was investigated by X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive X-ray (SEM-EDS). Magnetite, hematite and iron were found from the XRD results of all samples, which had the thickness strip of 8, 10 and 12 mm. The scale was thinner for the thinner strip. The adhesion test was conducted by a tensile testing machine adapted with an observation set. The strain initiating the first spallation and mechanical adhesion energy was lowest for the sample with the highest thickness (12 mm). These results indicate that the waste scale produced by hot rolled steel industry can be controlled by the final strip thickness. There was a need to control the scale of waste in a reasonable way to protect the environment.
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Ilmola, Joonas, Oskari Seppälä, Olli Haapala, Esa Puukko, and Jari Larkiola. "Optimization of Slab Edge in Roughing of Stainless Steel." Materials Science Forum 1016 (January 2021): 598–604. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.598.
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To reach high demands of a stainless steel surface quality the location of a slab edge is optimized utilizing multiphysical finite element (FE) analysis. The slab edge forms in roughing process when the longitudinal edge of the stainless steel slab moves parallelly towards the center of a transfer strip surface due to several rough and edge rolling passes. Strip spreading and location of the slab edge are managed by edge rolling process which is accomplished concurrently with roughing. Deformation resistance has a significant role characterizing the strip spreading and material flow in the roll bite, thus experimental material compression testing was carried out and the results fitted to the Hensel-Spittel equation. Multiple edger roll profiles were designed, and the most feasible details of the roll profile were iteratively utilized for the new profiles. In this way the location of the slab edge was optimized closer to the edge of the transfer strip by developing a new edger roll profile and resetting edge rolling passes according to results of FE-simulations. To mimic an industrial-scale roughing process an automated pass schedule control was developed in the FE-model. Therefore, multipass simulations require only a pass schedule data to run simulation.
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Negi, B. S. "Case Studies on Field Repairs of Stainless Steel Components in Refinery." Advanced Materials Research 794 (September 2013): 375–79. http://dx.doi.org/10.4028/www.scientific.net/amr.794.375.
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Stainless steels (SS) possess excellent corrosion, creep and high temperature oxidation resistance and are invariably used in refinery for construction of heater tubes, tube supports, Heat exchanger bundles, piping and internal lining of pressure vessels. Ferritic stainless steel type 405 is used for column strip-lining, martensitic stainless steel type 410 is used for column trays and heater tubes and austenitic stainless steel family is used very extensively for lining, piping, heat exchanger, heater tubes and tube supports. On-stream and turnaround condition monitoring of plant and equipment are carried out for health assessment and mitigation of premature failure. However, catastrophic failures of stainless steel due to stress corrosion cracking, thermal fatigue and stress relaxation cracking are encountered in addition to bulging and cracking of strip-lining. Field repairs of these components are required to be done. Stainless steels are difficult to weld due to low thermal conductivity, higher coefficient of thermal expansion, fissuring and solidification cracking problem during welding. Lower heat input and fast cooling facilitate the welding process. Welding of service exposed stainless steels is more challenging, as it has already undergone metallurgical degradation. Welding of stainless steels is carried out using TIG and SMAW process with matching electrode after establishing the welding specification procedures and welders qualification. Field repairs of stainless steels components are also attempted with original procedures and in case of difficulties, a buttering layer of inconel (ERNiCr3) or ER 309Mo is provided on the welding surface before using matching electrodes. Quality assurance of weld joint is ensured by stage-wise inspection and non-destructive testing. Dye penetrant test of root run and radiographic examination of final weld joint are most common. Post weld heat treatment is done as per code requirement. This Paper highlights three case studies on field repairs of stainless steel components in refinery. 1. Welding procedure followed for repair of bulged and cracked SS 316 strip-lining and cladding on carbon steel backing material. It is a dissimilar welding of SS 316L with degraded carbon steel. 2. Field welding of SS 347 Piping components, which has undergone thermal relaxation cracking at fillet joints. 3. Welding repair of SS 310 cast heater tube support conforming to A 297 Gr HK 40. The Paper also presents brief failure analysis with reasons and remedies.
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Felker, Caleb A., John G. Speer, Emmanuel De Moor, and Kip O. Findley. "Hot Strip Mill Processing Simulations on a Ti-Mo Microalloyed Steel Using Hot Torsion Testing." Metals 10, no. 3 (March 3, 2020): 334. http://dx.doi.org/10.3390/met10030334.
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Precipitation strengthened, fully ferritic microstructures in low-carbon, microalloyed steels are used in applications requiring enhanced stretch-flange formability. This work assesses the influence of thermomechanical processing on the evolution of austenite and the associated final ferritic microstructures. Hot strip mill processing simulations were performed on a low-carbon, titanium-molybdenum microalloyed steel using hot torsion testing to investigate the effects of extensive differences in austenite strain accumulation on austenite morphology and microstructural development after isothermal transformation. The gradient of imposed shear strain with respect to radial position inherent to torsion testing was utilized to explore the influence of strain on microstructural development for a given simulation, and a tangential cross-section technique was employed to quantify the amount of shear strain that accumulated within the austenite during testing. Greater austenite shear strain accumulation resulted in greater refinement of both the prior austenite and polygonal ferrite grain sizes. Further, polygonal ferrite grain diameter distributions were narrowed, and the presence of hard, secondary phase constituents was minimized, with greater amounts of austenite strain accumulation. The results indicate that extensive austenite strain accumulation before decomposition is required to achieve desirable, ferritic microstructures.
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Wu, Hao, and Quanquan Lv. "Hot-Rolled Steel Strip Surface Inspection Based on Transfer Learning Model." Journal of Sensors 2021 (May 28, 2021): 1–8. http://dx.doi.org/10.1155/2021/6637252.
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In the production process of steel strips, the detection of surface defects is very important. However, traditional methods of defect detection bring problems of low detection accuracy and dependence on subjective judgment. In this study, the surface defects of steel strips are detected by a classic convolutional neural network method that is improved by the use of a transfer learning model. This model has the advantages of shorter training time, faster convergence, and more accurate weight parameters. The transfer learning model obtained through experiments secures better results in defect detection than the classic convolutional neural network method, as its accuracy of training and testing has reached about 98%. Finally, a model based on a full convolutional neural network (FCN) is proposed for segmenting the defective areas of steel strips.
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Song, Kai, Yihua Kang, Yanhua Sun, Chen Qiu, and Jianke Su. "MFL testing of omni-directional cracks in steel strip using strong longitudinal magnetization." International Journal of Applied Electromagnetics and Mechanics 33, no. 3-4 (October 8, 2010): 1231–36. http://dx.doi.org/10.3233/jae-2010-1243.
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Naumov, Anton A., Yuriy A. Bezobrazov, and Evgenii V. Chernikov. "Physical Simulation of Pipes Production Cycle for Lean Alloyed Pipeline Steel X80." Key Engineering Materials 651-653 (July 2015): 260–65. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.260.
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Lean alloyed pipeline steel X80 with experimental chemical composition was taken for the present research. Rolling schedules for researched steel were developed for continuous mill 2000 by means of numerical simulation using HSMM, AusEvol+ and AusEvol Pro software. Developed schedules were analyzed in order to choose several of them, which guarantee the required final mechanical properties. The chosen schedules were realized on Gleeble-3800 system by tension-compression tests for experimental chemical composition. Mechanical testing of received samples was made. After that physical simulation of strip flattening, forming, expanding and coating using Gleeble-3800 system was produced and mechanical testing of received samples was made to compare results with samples after rolling simulation and with requirements submitted to pipeline steel X80.
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Biallas, Alina, Sophia Ohmayer, and Marion Merklein. "Fundamental Investigations to Evaluate the Influence of Notching Processes on a Subsequent Cyclic Bending Process for the Production of Wire Cores." Journal of Manufacturing and Materials Processing 7, no. 1 (January 17, 2023): 24. http://dx.doi.org/10.3390/jmmp7010024.
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The production of wire cores by notch rolling and cyclic bending promises an ecologically and economically efficient manufacturing option for steel fibers. The paper at hand evaluates the influence of wire strips on cyclic bending by applying rolled wire strips of DP600 sheet metal (t0 = 0.8 mm) and a new cyclic bending testing tool. Analysis of material separation with varying parameters, rolling gap d and bending angle β, proves the interdependency of both process step, but indicates reduced adjustability of the notch rolling process. To enable better adjustability of the wire strip’s characteristics and analysis of their effects, wire strip production in the laboratory by notch stamping instead of rolling is aspired. The prior interaction analysis states the web height b, the notch angle α, and the hardening distribution as relevant wire strip’s characteristics to be replicated. Based on experimental analysis, an equivalent of notch rolling by notch stamping is deduced by considering the web height b identical for stamping and rolling, by adjusting the tool’s notch angle αt based on an equation considering geometric evaluations of α, and by taking advantage of the asymmetric hardening distribution of the outer notch which is comparable to rolled wire strip.
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Petrík, A. "Experimental verification referring to the new shape of the perforated steel strip." IOP Conference Series: Materials Science and Engineering 1209, no. 1 (December 1, 2021): 012033. http://dx.doi.org/10.1088/1757-899x/1209/1/012033.
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Abstract Perforated steel strips are used as reliable shear connectors many years. During this time, many different shapes of the openings or recesses were developed to improve the durability and resistance of the shear connection. Behaviour of these strips were mainly verified by experimental research, but many parameters could not be measured. Numerical analysis provides not only easy and fast way of testing the behaviour of specimens, but also the possibility to improve the geometry of the strips. Modified steel strips can be deeply investigated in simulations and subsequently verified by push-out tests in laboratories. The combination of these two methods can bring the spectrum of the information that can complexly describe the behaviour, durability and also the weak points of the shear connection, especially in case of the new or modified shape.
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Crevello, Gina, Irene Matteini, and Paul Noyce. "A novel approach to in-depth façade assessments: Improved corrosion test methods for embedded steel framing in historic masonry clad buildings." MATEC Web of Conferences 289 (2019): 07002. http://dx.doi.org/10.1051/matecconf/201928907002.
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Corrosion of structural steel frames and associated steel assemblies within ‘vintage’ buildings circa 1880s to 1930s pose a health and safety risk to the public in major urban centers. The projecting masonry elements pose a particular concern when the underlying steel assemblies and anchorage begin to corrode. Failed masonry has fallen from buildings, leading to death in worst case scenarios. While some signs of masonry cracking or displacement are usually visible prior to failure, the level of degradation of the embedded steel is not. With the equipment available to test these unforeseen conditions, methodologies need to be shifted to understand unobservable conditions to assist in condition state ratings of embedded steel. In many cities, building owners are being faced with large expenditures to strip and replace terra cotta or stone elements where the underlying steel is in fair condition. This paper will discuss the field-testing programs where a building elevations' masonry clad, steel assemblies (outriggers, anchorage and cross bracing) were evaluated for corrosion. The testing program assessed various steel components which either projected from the structure or were embedded at great depth with a bespoke, in-depth advanced testing program geared towards the development of condition state ratings for the façade elements.
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Lawson, William D., Priyantha W. Jayawickrama, Timothy A. Wood, and James G. Surles. "Pullout Resistance Factors for Inextensible Mechanically Stabilized Earth Reinforcements in Sandy Backfill." Transportation Research Record: Journal of the Transportation Research Board 2363, no. 1 (January 2013): 21–29. http://dx.doi.org/10.3141/2363-03.
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This paper presents results from a laboratory program of 402 pullout tests of inextensible reinforcements used for walls of mechanically stabilized earth (MSE). Results focus on the evaluation of pullout resistance factors for ribbed-steel strip and welded-steel grid reinforcements embedded in sandy backfill that marginally met AASHTO requirements for select granular fill. This project used Texas Tech University's large-scale MSE test box with dimensions of 12 3 12 3 4 ft and an applied overburden capacity of 40 ft of backfill. This test box facilitated pullout testing at a scale not unlike typical field construction. The research design evaluated pullout resistance factors for both ribbed-strip and welded-grid reinforcements for a variety of independent variables, including overburden pressure, reinforcement length, level of compaction, grid wire size, and grid geometry, such as transverse and longitudinal wire spacing. Appropriate statistical analyses were used to interpret the data within the context of published AASHTO design guidance for inextensible MSE reinforcements. The results show that pullout behaviors of both ribbed strips and welded grids in properly compacted sandy backfill are conservative compared with the default pullout resistance factors provided by AASHTO. The data also suggest that the current AASHTO equations for pullout resistance factors for grid reinforcement do not accurately capture the influence of transverse and longitudinal bar spacings.
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Wang, Chaojun, and Fei He. "State Clustering of the Hot Strip Rolling Process via Kernel Entropy Component Analysis and Weighted Cosine Distance." Entropy 21, no. 10 (October 21, 2019): 1019. http://dx.doi.org/10.3390/e21101019.
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In the hot strip rolling process, many process parameters are related to the quality of the final products. Sometimes, the process parameters corresponding to different steel grades are close to, or even overlap, each other. In reality, locating overlap regions and detecting products with abnormal quality are crucial, yet challenging. To address this challenge, in this work, a novel method named kernel entropy component analysis (KECA)-weighted cosine distance is introduced for fault detection and overlap region locating. First, KECA is used to cluster the training samples of multiple steel grades, and the samples with incorrect classes are seen as the boundary of the sample distribution. Next, the concepts of recursive-based regional center and weighted cosine distance are introduced. For each steel grade, the regional center and the weight coefficients are determined. Finally, the weighted cosine distance between the testing sample and the regional center is chosen as the index to judge abnormal batches. The samples in the overlap region of multiple steel grades need to be focused on in the real production process, which is conducive to quality grade and combined production. The weighted cosine distances between the testing sample and different regional centers are used to locate the overlap region. A dataset from a hot steel rolling process is used to evaluate the performance of the proposed methods.
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Peng, Qi Chun, Jia Jie Wang, and Zhi Bo Tong. "Study on High-Temperature Mechanical Properties of SPHC Steel Produced by CSP Technology." Advanced Materials Research 1095 (March 2015): 188–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1095.188.
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The high-temperature mechanical properties of SPHC steel produced by compact strip production (CSP) process were tested on Gleeble thermal simulator under different temperature conditions. The results show that: at the strain rate of 1×10-3s-1,the SPHC steel has three brittleness temperature zones within the range from 650°C to 1200°C;the percentage reduction of area of the tested steel are all above 60% within the range from 950°C to 1150°C,thus the steel has good high temperature plasticity; the percentage reduction of area decreases rapidly when the testing temperature is under 900°C and the minimum percentage reduction of area is only about 41.78% at 800°C.
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Ogoltcov, Aleksei, and Artem V. Mitrofanov. "Steel Production Technology Development for the Manufacture of Pipes Used in the Extraction and Transportation of Petroleum Products." Materials Science Forum 1016 (January 2021): 1051–57. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1051.
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The technology has been developed for the production of low-carbon and microalloyed steel for the production of strips in order to manufacture small and medium-diameter pipes for the extraction and transportation of petroleum products. The developed technology allows to obtain stable corrosion properties, according to the NACE Standard TM 0284 technique, in a hot-rolled condition from slab with thickness more than 200 mm and with a content of more than 0.03% of carbon, which is very difficult in terms of ensuring the availability of inclusions and heterogeneity in the structure - as the main reasons for the reduced fracture toughness of steels working in acid media (in environments saturated with H2S). The obtained results allowed, with minimum costs, to prepare the previously developed integrated computer model (STAN 2000) for calculating the structure and mechanical properties. Calculations using the model made it possible to select such temperature-deformation regimes, which would be the minimum structural inhomogeneity over the section of the thickness of the hot-rolled strip. The results obtained: corrosion resistance repeatedly confirmed by the absence of cracks at the beginning after testing in accordance with the procedure Standard TM 0284.
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Kim, S. I., D. J. Paik, Young Seog Lee, and Shi Hoon Choi. "Influence of Boron on Dynamic Recrystallization and Continuous Cooling Transformation of High Strength Interstitial Free Steels." Materials Science Forum 500-501 (November 2005): 321–28. http://dx.doi.org/10.4028/www.scientific.net/msf.500-501.321.
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The paper examines the effect of boron (B) on the dynamic recrystallization and continuous cooling transformation (CCT) behavior in Nb-Ti microalloyed high strength interstitial free (IF) steels. For this purpose, two Nb-Ti microalloyed IF steels containing 0.003wt.% and 0.0005wt.% B, respectively, and one IF steel without B were chosen. The dynamic recrystallization behavior was investigated using hot compression testing. The character of the austenite to ferrite transformation during continuous cooling was studied by dilatometry test and CCT diagrams for the IF steels have been constructed. It was found that the initiation of dynamic recrystallization is delayed as the amount of boron increases. Addition of B retards the austenite to ferrite transformation as well. Under cooling rates of 0.5 and 1oC s-1, which correspond to slow cooling rates in the hot strip mill, the addition of B leads to the development of acicular ferrite and bainite phases. On the other hand, at similar cooling conditions the B free IF steel was observed to have a polygonal ferrite microstructure.
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Zhang, Feng Quan, and Zhong Han Luo. "Analysis of Processing Equipment for Near-Net Shape Manufacturing Technology of Materials." Advanced Materials Research 572 (October 2012): 390–99. http://dx.doi.org/10.4028/www.scientific.net/amr.572.390.
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The processing equipment for near-net shape technology of materials is introduced in the paper. According to analysis of industrialized processing equipment and technology testing equipment for difficult-to-cut alloy materials, combined with difficulties in strip casting and features of difficult-to-cut alloy materials, the processing equipment for difficult-to-cut alloy materials near-net shaping is developed, thus realized single machine-shaping from molten steel to cold rolling product, and improved near-net shape manufacturing technology of materials.
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Wang, Shang, Wenpei Li, Xiaochen Wang, Rui Ai, Quan Yang, and Zhongde Shan. "Impact tensile cracking behavior of oxide scale in Q235 strip iron." MATEC Web of Conferences 189 (2018): 08002. http://dx.doi.org/10.1051/matecconf/201818908002.
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Scanning electron microscopy (SEM) is used to observe the fracture surface morphology of Q235 steel. The cracking law/crack rule principle of strip surface under tension is studied via universal tensile testing machine. The results show that the thickness of the scale is relatively uniform, about 10 μm, and the structure is dense and well attached to the matrix. Tensile experiments show that as the strain increases, the cracks increase slowly in the initial stage, rapidly in the middle period, and slowly in the final period. When the strain exceeds 0.15%, the cracks are difficult to increase. In order to avoid direct erosion of the abrasive on the substrate, a reasonable range of tension setting should be 0.15%-0.18% in the pretreatment process without acid descaling.
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Plaichum, Songphop, Attaphon Kaewvilai, Thammaros Pantongsuk, Duangrudee Chaysuwan, and Chayanee Tippayasam. "A Novel Ceramic Backing Strip from Metakaolin-Based Geopolymer with Gas Flow Holes for Welding Application." Key Engineering Materials 856 (August 2020): 309–16. http://dx.doi.org/10.4028/www.scientific.net/kem.856.309.
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This research is firstly presented the thermal resistance of a ceramic backing made from metakaolin-based geopolymer for stainless steel welding. The general problems such as lack of fusion, hydrogen inclusion, porosity and corrosions of stainless steel welded specimens were found because, largely, stainless steel presents an affinity to gases as oxidation. Therefore, during welding, if these gases do not escape from the weld pool before solidification of weld metal, it results in porosities or hydrogen inclusions. In this case, it can be solved by properly using inert gas backing. The welder usually uses the steel backing plate with a gas release hole to support weld root and gas transmission for completed weld penetration and superior weld quality. Since the geopolymer shows a good property of thermal resistance, researchers are interested in using the ceramic backing made from geopolymer instead of the commercial ceramic backing. The ceramic backings from the geopolymer were designed merely in 3 types as follows: Narrow curved groove without gas release hole, narrow curved groove with gas release holes and wide curved groove with gas release holes. Consequently, two pieces of stainless steel were welded by gas tungsten arc welding and then the weld quality such as defects, porosity and root penetration of welded specimens was inspected. Moreover, the surface failure of ceramic backing after the welding process was also considered. The results revealed that ceramic backing from a geopolymer with wide curved groove and gas release holes gave completed penetration at the root when inspecting with non-destructive testing such as visual test, penetration test, and radiography test. It was concluded that the geopolymer could be used as ceramic backing in stainless steel welding by gas tungsten arc welding. Moreover, it could be used as backing for aluminum and steel welding as well.
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Wolter, Bernd, Yasmine Gabi, and Christian Conrad. "Nondestructive Testing with 3MA—An Overview of Principles and Applications." Applied Sciences 9, no. 6 (March 14, 2019): 1068. http://dx.doi.org/10.3390/app9061068.
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More than three decades ago, at Fraunhofer IZFP, research activities that were related to the application of micromagnetic methods for nondestructive testing (NDT) of the microstructure and the properties of ferrous materials commenced. Soon, it was observed that it is beneficial to combine the measuring information from several micromagnetic methods and measuring parameters. This was the birth of 3MA—the micromagnetic multi-parametric microstructure and stress analysis. Since then, 3MA has undergone a remarkable development. It has proven to be one of the most valuable testing techniques for the nondestructive characterization of metallic materials. Nowadays, 3MA is well accepted in industrial production and material research. Over the years, several equipment variants and a wide range of probe heads have been developed, ranging from magnetic microscopes with µm resolution up to large inspection systems for in-line strip steel inspection. 3MA is extremely versatile, as proved by a huge amount of reported applications, such as the quantitative determination of hardness, hardening depth, residual stress, and other material parameters. Today, specialized 3MA systems are available for manual or automated testing of various materials, semi-finished goods, and final products that are made of steel, cast iron, or other ferromagnetic materials. This paper will provide an overview of the historical development, the basic principles, and the main applications of 3MA.
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Klein, M., H. Spindler, A. Luger, R. Rauch, P. Stiaszny, and M. Eigelsberger. "Thermomechanically Hot Rolled High and Ultra High Strength Steel Grades - Processing, Properties and Application." Materials Science Forum 500-501 (November 2005): 543–50. http://dx.doi.org/10.4028/www.scientific.net/msf.500-501.543.
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In all application fields for hot rolled strip products for direct processing, e.g. construction and engineering but also crane and truck industry, there is a strong customers demand for grades with increased strength levels and well balanced formability. At voestalpine Stahl GmbH these requirements were met with the development of the high strength microalloyed steel grade ALFORM700M and the ultra high strength steel grade ALFORM900M with a minimum yield strength (YS) of 700 MPa and 900 MPa, respectively. In the present paper investigations on the steel grades ALFORM700M and ALFORM900M are introduced. To explain the evolution of the obtained complex microstructures consisting of bainitic ferrite, bainite and martensite alloy design and industrial production process is discussed on the base of dilatometric experiments and TEM investigations. The formation of precipitates is studied by using a numerical model, chemical methods and mechanical testing after heat treatment. Mechanical and mechanic-technological properties of the two steel grades are compared. Furthermore, some processing aspects as weldability an bending behaviour are highlighted. Finally, some typical applications for this high and ultra high strength steel grades are presented.
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Cunha, R. P. "Lantern effects on pressuremeter shear modulus in sand." Canadian Geotechnical Journal 33, no. 3 (July 2, 1996): 482–87. http://dx.doi.org/10.1139/t96-069.
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Self-boring pressuremeter tests are presently used to assess in situ deformation characteristics of sand. To reach the desire testing depth with minimum disturbance, a consistent self-boring procedure is commonly adopted. High lateral stresses developed during insertion of the pressuremeter has led, in the past, to the adoption of a lantern to cover and protect the expandable rubber membrane section of the probe. This note summarizes an investigation of the influence of different lantern designs on the predicted shear modulus of the sand. Distinct steel strip lanterns were used and compared with the standard lantern used in the Camkometer. It is demonstrated that the interstrip friction of the steel lantern can affect the shear modulus from unloadreload loops of the test. The importance of this investigation is viewed as more practical than technical, since steel lanterns are less expensive, quicker, and simpler to construct than the standard Camkometer lantern. Key words: self-boring procedure, lanterns effect, unloadreload, interstrip friction, shear modulus, sand.
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Zhou, Wen Qiang, Li Bo Pan, Kuan Hui Hu, Wei Hua Sun, and Rong Dong Han. "Effect of Original Microstructure on Microstructure and Mechanical Properties of High Strength Steel WHF1500H during Hot Forming." Materials Science Forum 941 (December 2018): 206–11. http://dx.doi.org/10.4028/www.scientific.net/msf.941.206.
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The press hardening steel sheets WHF1500H with different original structures produced by compact strip production (CSP) line in Wuhan Iron and Steel Ltd. were austenitized at 950 °C for 5 min, and then hot stamped and quenched by using the flat die. The microstructure and mechanical properties were investigated by optical microscope, transmission electron microscope and universal testing machine. The results show that the microstructure after stamping and quenching is fully composed of lath martensite. The mechanical properties of the steel samples with different original structures are different after hot stamping and quenching, and this difference is smaller than that before hot stamping and quenching. When the original structure consists of ferrite and pearlite, the austenite grains after austenitization are fine and uniform. In addition, the martensite structure obtained after hot stamping and quenching is also uniform and fine, leading to higher mechanical properties. With the increase of the strength of the original steel, when the original structure is martensite, the austenite grains after austenitization are coarse, and the martensite structures obtained after quenching is also coarse, and thereby decreasing the strength.
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Mead, Loren Benjamin, Tanner Mathison, Garry Osborne, and Anne Marie Richards. "Decontamination of Geobacillus Stearothermophilus using the Arca Aerosolized Hydrogen Peroxide decontamination system." PLOS ONE 17, no. 9 (September 20, 2022): e0273937. http://dx.doi.org/10.1371/journal.pone.0273937.
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Introduction In response to the limited supply of personal protective equipment during the pandemic caused by SARS-CoV-2, recent studies demonstrate that gaseous H2O2 is an effective decontaminant of N95 filtering facepiece respirators to enable reuse of these items in a clinical setting. This paper evaluates the efficacy of the Arca Aerosolized Hydrogen Peroxide Decontamination System (Arca), a novel aerosolized H2O2 decontamination system, using biologic indicator testing. Materials and methods The Arca produces and circulates H2O2 aerosol inside of a sealed stainless steel chamber. The Arca’s decontamination efficacy was evaluated in 8 decontamination trials with 2 H2O2 concentrations (3% and 12%) and 4 decontamination cycle durations (45, 60, 90, and 120 minutes). Efficacy was evaluated by testing: 1) the concentration in parts per million (ppm) of H2O2 produced inside the chamber and the concentration in ppm of H2O2 vented from the chamber, and 2) the decontamination of Mesa Biologic Indicator filter strips (BI) inoculated with Geobacillus Stearothermophilus. Control tests were conducted by submerging BI strips in 3mL of 3% and 12% H2O2 for 120 minutes (negative controls) and by not exposing one BI strip to H2O2 (positive control). Results Greater than 5000 ppm of H2O2 was detected on the concentration strips inside the chamber for each of the eight decontamination trials. No vented H2O2 was detected on the external concentration strips after any decontamination trial. No growth was observed for any of the negative controls after seven days. The positive control was positive for growth. Conclusion The Arca Aerosolized Hydrogen Peroxide Decontamination System is effective at decontaminating bacterial G. Stearothermophilus at a cycle time of 45 minutes utilizing 6mL of 3% H2O2 solution.
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Zhou, Zhaoming, Mian Qin, Yuedong Xie, Jinsong Tan, and Hailong Bao. "Experimental Study of Microstructures in Bias Weld of Coiled Tubing Steel Strip With Multi-Frequency Eddy Current Testing." IEEE Access 8 (2020): 48241–51. http://dx.doi.org/10.1109/access.2020.2979414.
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Rauf, Ichsan, Tri Hrianto, and Kusnadi. "Laboratorium Experimental Of Cantilever Sheet Pile Behaviour On Soft Soil Induced By Strip Load." E3S Web of Conferences 328 (2021): 10020. http://dx.doi.org/10.1051/e3sconf/202132810020.
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This study aims to analyze the deflection behavior of the sheet pile through experimental testing and numerical analysis using the Finite Element Method (FEM). The Laboratorium scale test on a Tub with length of 1500 mm, width of 600 mm, and height of 1500 mm, and Steel Plate 3.2 mm with dimensions of 1400 mm x 590 mm was used as a model of the sheet pile wall. The subgrade material is clay soil and embankment material in the form of Sirtu which passes the No. sieve. 40. Physical and mechanical testing of soil and gravel materials is carried out with reference to ASTM standards. The measurement of the value of the strip load (q) and deflection was carried out using a load cell with a capacity of 100 kN and a linear variable differential transformer (LVDT). The deflection of the sheet pile was using was analyzed using Plaxis 8.2 software of the FEM method. The results of laboratory tests show that the pile wall collapses at a load of 74 kN/m2, with a deflection of 24.56 mm, while the FEM analysis shows that the pile wall collapses at a load of 71 kN/m2 with a deflection of 21.29 mm.
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Bogatu, A. M., C. Rontescu, R. C. Diacu, and D.-T. Cicic. "Research regarding strip cladding of heat-resistant SA 387 Gr.11Cl.2 steel type." IOP Conference Series: Materials Science and Engineering 1182, no. 1 (October 1, 2021): 012008. http://dx.doi.org/10.1088/1757-899x/1182/1/012008.
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Abstract The continuous development of industrial processes in the petrochemical field requires the use of materials with anticorrosive properties, able to withstand working conditions at high temperatures but also in highly corrosive environments. The basic materials with anticorrosive properties have a high cost price which leads to the need to find alternative manufacturing solutions. In such situations, the use of bimetal plates or the option of welding cladding with an anticorrosive layer of the base material is used. The paper analyses the possibility of strip cladding using the submerged arc welding process of a reactor made of SA 387Gr11Cl.2 basic material, a heat-resistant alloy steel. To achieve the deposition of the appropriate anticorrosive layer (stainless steel type AISI 347) it was necessary to use a buffer layer made of austenitic stainless-steel type 309L. In order to eliminate the internal tensions appeared after the cladding process, the sample was subjected to a stress relieving heat treatment. After the heat treatment, the sample was subjected to non-destructive examinations (visual and penetrant testing) but also to destructive examinations specific to the approval tests of cladding technology (Metallographic tests, Vickers hardness test, bend test, ferrite number, chemical composition). Metallographic tests of cross-sectional phase structures were carried out in macroscopic and microscopic terms. In the area of the deposited material can be observed a typical austenitic casting structure resulting from the use of a high linear energy, specific to the automatic submerged arc welding. Following the performance of hardness measurements made in the characteristic areas of the deposition, it can be seen that there was a slight increase in the values obtained in the heat affected zone, without exceeding the prescribed values for the materials used. Following the analysis of the results obtained from the specific examinations and tests to the plated samples, it can be seen that they are within the limits prescribed by the standards in force regarding the approval of the cladding technology used.
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Michałowska-Maziejuk, Dorota, Barbara Goszczyńska, and Wiesław Trąmpczyński. "Effectiveness of strengthening pre-loaded RC beams with CFRP strips in conventional and accelerated strengthening procedures." MATEC Web of Conferences 284 (2019): 06005. http://dx.doi.org/10.1051/matecconf/201928406005.
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This paper analyses the results obtained from the testing of reinforced concrete beams additionally strengthened with composite materials pressed into the concrete cover using the near-surface-mounted reinforcement (NSMR) method. The testing program comprised two series of beams with cross-sectional dimensions of 0.12 x 0.30 x 3.30 m. The series differed in the amount of longitudinal steel reinforcement, 0.51% and 1.00%. Three beams were cast in each series. One beam was assigned as the control beam, while two other beams were strengthened with carbon fibre strips. A two-component thixotropic epoxy resin was used as a bonding agent. One of the two beams was cured for 7 days (to the product information document). The bonding process in the other beam was accelerated to last 1.5 hours by heating the strip up to 70°C. As the strengthening of "new" elements is not an accepted practice in engineering, the beams were pre-loaded. The load was maintained during the strengthening procedure and curing period (for 7 days and 1.5 hours) and then the beams were monotonically loaded to failure. The comparison of load capacity results for the CFRP strengthened and control beams revealed the effectiveness of the strengthening method. The paper also presents the strengthening technique in the NSMR application with the prototype heating device.
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Xue, Jinxin, Hao Wu, Chilou Zhou, Yuanming Zhang, Mohan He, Xinrui Yan, Huiyu Xie, Rui Yan, and Yansheng Yin. "Effect of Heat Input on Hydrogen Embrittlement of TIG Welded 304 Austenitic Stainless Steel." Metals 12, no. 11 (November 13, 2022): 1943. http://dx.doi.org/10.3390/met12111943.
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Welds made with 304 austenitic stainless steel play an important role in high-pressure hydrogen storage systems. However, there are few investigations of the effect of heat input on the hydrogen embrittlement (HE) of tungsten inert gas (TIG) welded 304 austenitic stainless steel. In this study, the effect of heat input on the HE of TIG welded 304 austenitic stainless steel is investigated. It was found that with the increase in TIG welding heat input, the ferrite content in the weld shows a tendency to first increase and then decrease. From the perspective of morphology, it first changes from lathy ferrite and strip ferrite to dendritic ferrite, and then becomes reticular ferrite and lathy ferrite. Slow strain rate tensile (SSRT) testing shows that with the increase in heat input from TIG welding, the susceptibility of the weld to HE first increases and then decreases. Our study shows that TIG welds of 304 austenitic stainless steel exhibit the best HE resistance when the welding heat input is 0.778 kJ/mm, the relative elongation (RE) is 0.884, and the relative reduction of area (RRA) is 0.721. This work can provide a reference for the optimization of the 304 stainless steel TIG welding process.
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Surianinov, Mykola, Stepan Neutov, and Iryna Korneieva. "Comparative analysis of strength and deformation of reinforced concrete and steel fiber concrete slabs." E3S Web of Conferences 166 (2020): 06003. http://dx.doi.org/10.1051/e3sconf/202016606003.
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The results of experimental studies of the steel fiber influence on the bearing capacity, deformability and crack resistance of reinforced concrete multi-hollow plates are given. We investigated a serial floor slab and a similar one, but with the addition of steel fiber. Both plates are factory-made. For testing, the testing apparatus was designed and manufactured that made it possible to study full-size floor slabs in laboratory conditions. The tests were carried out according to a single-span scheme with the replacing equivalent load. The loading was carried out by applying two concentrated strip vertical loads along the plate width. The load was applied in steps of (0.04 ÷ 0.05) from the breaking load. Each stage ended with exposure lasting up to 10 minutes with fixing all the necessary parameters. Deformations were measured using dial gauges. From the moment the first crack appeared in the stretched zone of concrete, the process of crack formation and opening was monitored. At each level, using the Brunell tube, the width of their opening and height were measured. The moment of cracking in both slabs began at the same relative strain. It has been established that the bearing capacity and crack resistance of a slab of combined reinforcement using steel fiber are respectively 50 and 44% higher than that of a similar reinforced concrete slab. The maximum deflection of the slab of combined reinforcement is 37.5% lower than that of conventional reinforced concrete. The destruction of both slabs occurred under loads, when the relative deformations in the compressed zone of concrete reached 0.80×10-3 and 1.10×10-3 for reinforced concrete and steel-fiber concrete slabs, respectively, the difference is 37.5%.
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Holm, C., H. J. Gittel, R. Krieg, R. Theiß, and P. Dültgen. "Comparison of preparation techniques used for the identification of microstructural constituents in the microcrystalline structure of the eutectoid cold-work steel 80CrV2 (1.2235) after austempering." Practical Metallography 59, no. 8-9 (August 1, 2022): 488–99. http://dx.doi.org/10.1515/pm-2022-0051.
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Abstract Strip material made of 80CrV2 was bainitized for a further development of the master blade steels for thin-cutting circular and band saw blades. Severe distortion after tempering of the material led to the search for a metallographic preparation method to identify the microstructural constituents retained austenite and martensite. Mechanical preparation followed by chemical etching was unsuccessful because the surface was too rough to identify the targeted phases under SEM. Performing an electrolytic preparation produced a less rough surface with sharp phase boundaries, which allowed identification at high magnifications under the SEM. Microhardness testing was used to distinguish between the microstructural constituents of retained austenite and martensite.
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Üstünyagiz, Esmeray, Mohd Hafis Sulaiman, Peter Christiansen, Chris Valentin Nielsen, and Niels Bay. "A Study on DLC Tool Coating for Deep Drawing and Ironing of Stainless Steel." Key Engineering Materials 767 (April 2018): 181–88. http://dx.doi.org/10.4028/www.scientific.net/kem.767.181.
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The trend in metal forming tribology is to develop new tribo-systems including new lubricants, tool materials and tool coatings in order to substitute environmentally hazardous lubricants by environmentally friendly tribo-systems. In preliminary testing the limits of lubrication of new tribo-systems for sheet forming production, it is advantageous to use dedicated simulative tribo-tests. This paper studies the influence of tool coatings on deep drawing operations using the Bending Under Tension (BUT) test and also under more severe tribological conditions by adopting the Strip Reduction Test (SRT) to replicate industrial ironing of deep drawn, stainless steel parts. Non-hazardous tribo-systems in form of a double layer Diamond-like coated tool applied under dry condition or with an environmentally friendly lubricant were investigated via emulating industrial process conditions in laboratory tests. Experiments revealed that the double layer coating worked successfully, i.e. with no sign of galling, when it was used with environmentally friendly lubricants, whereas the results were more prone to galling under dry condition.
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Al-Bazoon, Mustafa, Abdulkhaliq Jaafer, Haidar Haidar, and Abbas Dawood. "Shear Strengthening of Reinforced Concrete Beam Using Wire Mesh–Epoxy Composite." Civil Engineering Journal 8, no. 6 (June 1, 2022): 1205–26. http://dx.doi.org/10.28991/cej-2022-08-06-09.
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This experimental research aims to study the use of wire mesh–epoxy composite (WMEC) as a shear-strengthening technique for reinforced concrete (RC) beams by focusing on the following parameters: (1) presence of shear reinforcement in the shear span; (2) type of strengthening technique (U-jacketing, vertical U strip, or inclined strip); and (3) number of wire mesh layers (three or six layers). Nine simply supported rectangular RC beams were tested under two monotonic point loads. The testing specimens were divided into two groups: (1) five beams without shear reinforcement and (2) four beams with shear reinforcement. Load–deflection relationship, shear ductility index, beams’ stiffness, energy absorption, crack propagation, mode of failure, and strain were studied for all testing specimens and compared with those of the control beams to measure the improvement from WMEC addition. Results showed that all WMEC types enhanced the shear capacity. Among the three shear-strengthening types, the continuous U-jacket scheme had a higher effect, increasing the shear capacity between 33.4 and 95.9% and the shear ductility index by 23% relative to those of the reference specimens. The shear capacity improvement by WMEC for the beams without shear steel reinforcement was greater than that for the beams with shear reinforcement under the same shear-strengthening configuration. When the number of wire mesh layers was doubled, the ultimate load was further increased from 33.4 to 57.8%. This research showed that WMEC is a practical and excellent shear-strengthening technique for RC beams. Doi: 10.28991/CEJ-2022-08-06-09 Full Text: PDF
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Rešković, Stoja, Ljerka Slokar Benić, and Martina Lovrenić-Jugović. "The Interdependence of the Degree of Precipitation and Dislocation Density during the Thermomechanical Treatment of Microalloyed Niobium Steel." Metals 10, no. 2 (February 24, 2020): 294. http://dx.doi.org/10.3390/met10020294.
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In this paper, thermomechanical processing of niobium microalloyed steel was performed with the purpose of determining the interaction between niobium precipitates and dislocations, as well as determining the influence of the temperature of final deformation on the degree of precipitation and dislocation density. Two variants of thermomechanical processing with different final rolling temperatures were carried out. Samples were studied using electrochemical isolation with an atomic absorption spectrometer, transmission electron microscopy, X-ray diffraction analysis, and universal tensile testing with a thermographic camera. The results show that the increase in the density of dislocations before the onset of intense precipitation is insignificant because the recrystallization process takes place simultaneously. It increases with the onset of strain-induced precipitation. In this paper, it is shown that niobium precipitates determine the density of dislocations. The appearance of Lüders bands was noticed as a consequence of the interaction between niobium precipitates and dislocations during the subsequent cold deformation. In both variants of the industrial process performed on the cold deformed strip, Lüders bands appeared.
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Ivanov, Vitaliy, F. V. Morgay, Elena V. Lavrova, Dmitriy P. Il’yaschenko, and Elena Verkhoturova. "Investigation of the Nature of Damage to Welded Flexible Compensating Elements Made of Austenitic Stainless Steels." Solid State Phenomena 328 (February 10, 2022): 9–16. http://dx.doi.org/10.4028/p-8y4hve.
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Welded flexible compensating elements made of austenitic stainless steels, such as metal hoses and bellows expansion joints, operate in a complex stress state; therefore, almost all corrosion damage of these products occurs in a stressed state. In addition, in welded joints, defects are possible associated with elastic-plastic deformations and stresses arising in the manufacturing process. Paper considers the defects of welded joints of multilayer bellows expansion joints made of stainless steels AISI 304 and AISI 316 types. The influence of the parameters of the argon tungsten electrode welding mode, with or without filler wire, on the mechanical characteristics of welded joints was studied. Mechanical tests of samples of welded joints were carried out on a tensile testing machine. The optimal range of variation of the parameters of the welding mode has been established, in which the plastic characteristics of the welded joints have maximum values. A metallographic study of the microstructure of welded joints of metal hoses and bellows expansion joints was carried out. The influence of the content of nonmetallic inclusions in the material of products on the conditions of melting and crystallization of the weld pool, contributing to the appearance of pores and hot cracks in the metal of the weld and the heat affected zone, has been established. To reduce the influence of the content of non-metallic inclusions in the weld metal and the heat-affected zone on the conditions of melting and crystallization of the weld pool, it is recommended to carry out preliminary heat treatment of the austenitic steel strip.
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Nielsen, Peter Søe, Casper Alexander Ormstrup, Benjamin Arnold Krekeler Hartz, Morten Storgaard Nielsen, and Niels Bay. "Simulative Winding of Roll Formed Profile in Carcass Production for Flexible Pipes." Key Engineering Materials 639 (March 2015): 163–70. http://dx.doi.org/10.4028/www.scientific.net/kem.639.163.
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In carcass production for flexible pipe systems roll formed profiles are wound around a mandrel forming an interlocking, flexible structure able to withstand collapse from outside water pressure or mechanical crushing. Carcass is often produced in lengths of several kilometres, which implies numerous welds between coils of stainless steel, often duplex grades. The welds are a source of failure, since fracture from time to time occurs here in the winding stage. A simulative test in form of three-point-bending is developed, which shows promising results together with simplified air- and v-bent profiles allowing offline testing of welds for optimisation purposes. Comparative studies are shown possible but discrepancies in boundary conditions cause the maximum strains in the simulative test to differ from those in production. A study of weld failure is done applying the simulative test and tensile tests using GOM ARAMIS 4M system for strain measurements. The results show strain localization at the weld from onset of yielding caused by the soft, heat affected zone next to the weld seam resulting in a local thinning of the strip similar to what is observed in production.
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Trzepieciński, Tomasz, Marek Szewczyk, and Krzysztof Szwajka. "The Use of Non-Edible Green Oils to Lubricate DC04 Steel Sheets in Sheet Metal Forming Process." Lubricants 10, no. 9 (August 30, 2022): 210. http://dx.doi.org/10.3390/lubricants10090210.
Full textAbstract:
Lubrication is a basic and relatively effective way to reduce friction in sheet metal forming operations. The drive to eliminate synthetic and mineral oils, which are difficult to recycle, from the manufacturing process has opened up opportunities for the use of vegetable-based bio-lubricants. This article presents a comparison of the lubrication performance of two non-edible oils (karanja and moringa) with the most frequently tested edible oils (sunflower and rape-seed). Deep drawing quality low-carbon steel sheets DC04, commonly used in the automotive industry, were used as the test material. Friction tests were carried out under various lubricants and normal pressures in the range between 3 and 12 MPa using the strip drawing test. Furthermore, a study was also made of the effect of a change in the surface topography and the mechanical properties of the sheet metal due to plastic deformation resulting from friction. It was found that under the most favorable lubrication conditions (sample pre-strain 21%, nominal pressure 6 MPa), karanja oil reduced the coefficient of friction by approximately 33%. Both non-edible lubricants provided the best lubrication when testing samples pre-strained at 7% under the whole range of nominal pressures. It was also revealed that in the case of the smallest pre-straining of the specimens (7%), karanja oil was the most effective within nominal pressures of 3–6 MPa, while at higher pressures (9–12 MPa), the moringa oil lowered the value of the coefficient of friction to a greater extent.