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Статті в журналах з теми "Pressure resistance welding":
1
Vishwakarma, Shailesh Kumar, Anurag Shrivastava, and Sharmistha Singh. "Optimization of Resistance Spotwelding Parameters Using Taguchi Method." International Journal of Emerging Research in Management and Technology 6, no. 7 (June 29, 2018): 196. http://dx.doi.org/10.23956/ijermt.v6i7.211.
Анотація:
Resistance spot welding (RSW) is a major sheet metal joining process in many industries, such as the automobile, domestic appliances, and space craft fabrication. It is one of the oldest of the electric welding processes in use by industry today. Furthermore, other metal-to-metal connections, such as wire-to-wire joints in the electronics industry, are accomplished by resistance spot welding. Application-specific measures, such as the diameter of the welding spot, define the quality of the joint. The weld is made by a combination of heat, pressure, and time parameters. As the name implies, it uses the resistance of the materials to the flow of electric current that causes a localized heating in the parts to be joined. Understanding of physical mechanisms for easily manipulating and controlling weld qualities in advance is extremely important. This paper represents the optimization of various parameters of resistance spot welding. The experimental studies have been conducted under varying pressure, welding current, pressure, and welding time parameters. In this investigation the quality characteristic (tensile strength and nugget diameter) parameters have been considered using Taguchi Method. The experimental studies have been carried out by varying welding currents, welding pressure and weld times for joining two sheets. The results of the investigation indicate the welding current to be the most significant parameter controlling the weld tensile strength as well as the nugget diameter. The contribution of welding current, holding time and pressure to tensile strength are 61%, 29%, 4% respectively and the contribution of these parameters to nugget diameter are 81%, 1.7%, 17% respectively. Relationship graphs have been plotted between tensile strength and nugget diameter with parametric variations according to orthogonal array.
2
Chang, Xu, Jie Liu, Guang Wei Fan, and Ren Long Tao. "Study on Microstructure and Fracture Morphology of 2205 Duplex Stainless Steel Resistance Spot Welds." Materials Science Forum 804 (October 2014): 289–92. http://dx.doi.org/10.4028/www.scientific.net/msf.804.289.
Анотація:
Fracture morphologies, microstructures and mechanical properties of the spot welded joints on 2205 duplex stainless steel (2205DSS) were studied by using three-phase inverter resistance welding machine with the welding currents of 6.4kA, 7.4kA, 9.5kA and 11.6kA, the welding pressures of 0.5MPa, 0.6MPa and 0.7MPa, and the welding time of 200ms. The results show that the macroscopic fracture fashion of 2205DSS spot welding joints are mainly button fracture and joint fracture, and the microstructures and mechanical properties of 2205DSS spot welding joints have the best performance with the welding current of 9.5kA, the welding time of 200ms and the welding pressure of 0.6MPa.
3
Zhou, Wei Min. "The Electrical Contact Resistance in Resistance Welding Evaluated by Gleeble Testing Machine." Materials Science Forum 575-578 (April 2008): 753–56. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.753.
Анотація:
Electrical contact resistance is an important parameter in resistance welding. In this article, a Gleeble 3500 thermal-mechanical testing machine was employed to measure the contact resistance. The machine is equipped with a special electrical resistance measuring system. The contact resistance is experimentally investigated for welding low carbon steel to themselves. A detailed work was carried out to investigate the influence of pressure, temperature on the contact resistance of low carbon steel. The experimental results show that the contact resistance decreases when pressure or temperature increases.
4
Kajiwara, Ryoichi, Satoshi Kokura, Yuzo Kozono, Tomohiko Shida, and Takao Funamoto. "Investigation of welding phenomena in resistance pressure welding using insert material." QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY 3, no. 4 (1985): 683–90. http://dx.doi.org/10.2207/qjjws.3.683.
5
Yu, Yan, Feng Xue Wang, and Zai Dao Yang. "Study on Resistance Spot Welding Technology and Properties of TRIP800 High Strength Steel Sheet." Advanced Materials Research 391-392 (December 2011): 661–65. http://dx.doi.org/10.4028/www.scientific.net/amr.391-392.661.
Анотація:
A series of spot welding technology, joint mechanical properties and microhardness test analysis of TRIP800 high strength steel were researched. Based on these experiments and analysis, effect of spot welding parameters such as welding current, welding time and electrode pressure on joint mechanical properties were explored. The relevant spot welding parameters of TRIP800 high strength steel of spot welding were recommended, such as welding current is7.5~8.0KA, electrode pressure is 450 kgf and welding time is 20cyc. Welding electrode should be to ensure that as much as possible and clean the surface,to avoid welding current and welding time is too high or too long, as well as forging lack of power, to prevent the occurrence of welding defects.
6
Han, Lijun, Wenchao Yu, and Lei Jia. "Study on Welding Parameter Model of Resistance Spot Welding of Body-in-white Al Alloy Plate." Journal of Physics: Conference Series 2706, no. 1 (February 1, 2024): 012020. http://dx.doi.org/10.1088/1742-6596/2706/1/012020.
Анотація:
Abstract In this paper, the welding parameter model of resistance spot welding (RSW) of body-in-white(BIW) Al alloy plate was studied in details, and the key welding parameters that influence the RSW quality are analysed in-depth. Based on the concept of equivalent plate thickness (SV ), simplification of nugget volume and thermodynamic theories, combined with the properties of Al alloy, the mathematical models of welding current, pressure, time were established through production data and test verification. These models reflect the relationship between key welding parameters and equivalent plate thickness. The welding current and pressure are linear with SV , and the expressions are different when SV is greater than 2. For welding pressure, there exist two critical curves according to the different yield strength of welding materials. The yield of the material lies in between and pressure can be chosen between two critical curves. The welding time is directly linear to the actual thickness of the plate. Actual welding parameters can be obtained by the models and least test, which is very important for decision of welding parameters rapidly.
7
Zhang, Jun Ping, Yi Feng, Lei Feng Song, Guang Yao Wang, and Qing Sheng Jin. "Research on Resistance Spot Welding Property of Hot-Stamping Quenched Steel Sheets." Advanced Materials Research 1063 (December 2014): 120–25. http://dx.doi.org/10.4028/www.scientific.net/amr.1063.120.
Анотація:
22MnMoB hot-stamping quenched steel sheets were well welded together by power frequency spot welder with optimization of relevant welding parameters in this paper. According to the experiment results of welding spatter, maximum shearing force and the size of nugget, the effects of welding current, welding time and electrode pressure on weld property were advanced. The results show that while welding current, welding time and electrode pressure are respectively set as 6.0~6.5kA, 0.5~0.7s and 4~7kN, the weld exhibits good mechanical property. The nugget diameter appears approximate linear relationship with mechanical property of weld and determines the fracture model of welds. The novel hot stamping steel sheets exhibit good welding property. The optimizing welding parameters can be used to instruct the practical production.
8
Zhang, Xiaoqi, Lingbo Wei, Guocheng Xu, and Chunsheng Wang. "Connection Status Research of the Resistance Spot Welding Joint Based on a Rectangular Terminal Electrode." Metals 9, no. 6 (June 5, 2019): 659. http://dx.doi.org/10.3390/met9060659.
Анотація:
Rectangular terminal electrode is adopted in this research to conduct a resistance spot welding (RSW) process on stainless steel plate. The connection status of RSW joints under different welding current, time, and pressure were studied, and revealed how the rectangular terminal electrode shape and its dimensions influence the RSW joint dimensions. The process analysis results showed that the RSW nuggets welded with rectangular terminal electrode are normally elliptical in shape, and the dimensions of the long axis direction and the short axis direction have a certain proportion. As the welding current increases, the nuggets dimensions in long direction increase first and then decrease, and the internal grain structure also varies. As the welding time increases, the nugget size in long direction increase first and then steady and rarely splash occurs. As the welding pressure increase, the nugget dimensions in long direction increase first and then decrease, and the splash easily occurs under large welding pressure. However, when the welding pressure is too small, the unique adjacent double fusion nugget formed. By adopting proper welding parameters, the nugget size and quality can be controlled. This provides an important basis for the application of rectangular terminal electrode in RSW welding process.
9
Georgescu, Bogdan, Dănuţ Mihăilescu, and Marius Cornel Gheonea. "Shear Resistance of Joints Spot Cold Pressure Welding." Applied Mechanics and Materials 657 (October 2014): 251–55. http://dx.doi.org/10.4028/www.scientific.net/amm.657.251.
Анотація:
The statement from the specialty literature that with the increasing diameter of spot welded by cold pressure decreases the amount of resistance to shear force is due to reporting of the breaking by shear at the circular section of the point. Our experimental research shows that a welded cold joint in spots, correctly done, will be torn off near the weld spot by drawing the point from one of the tins. By reporting the force to the real section of breaking it resulted a constant shear resistance, no matter which the size of the welded point was. Therefore, the approximate theoretical calculation of the breaking force of a cold welded point, correctly executed, can be achieved by knowing the mechanical properties of the metal base and taking into account the real section of the breaking point given by points periphery and the thickness of the panel after deformation. The calculation is encompassing, because due to cold hardening, the real mechanical characteristics are higher.
10
Jin, Zhao, Yafeng Qiu, Hao Yan, Dingbang Xu, and Xiaoming Hou. "Research on the influence of Welding Head using the process on Welding Performance of Spot Welding Machine." Journal of Physics: Conference Series 2396, no. 1 (December 1, 2022): 012019. http://dx.doi.org/10.1088/1742-6596/2396/1/012019.
Анотація:
Abstract Aiming at alloys commonly used in terminals, this paper studies the method of improving the characterization performance of the spot welding section from the perspective of controlling spot welding process parameters. Using the control experiment, by controlling the welding current, energization time, electrode pressure, and using coolant during welding, the surface structure image and the maximum tensile-shear force curve were obtained, so as to obtain the optimal spot welding process parameters. Then use ANSYS finite element analysis software to simulate the resistance spot welding process, and use the model of the macro morphology, microstructure, hardness distribution, and shear resistance of the spot welding head to verify the optimal welding process parameters of resistance spot welding.
Дисертації з теми "Pressure resistance welding":
1
Mabrouki, Mohamed. "Caractérisation de la tenue mécanique des assemblages bouchon-gaine en acier ODS obtenus par soudage par résistance." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0044.
Анотація:
Les aciers ODS (Oxide Dispersion Strengthened) ferrito-martensitiques, font partie des matériaux candidats à la fabrication des pièces pour le gainage de combustible des réacteurs nucléaires de 4ième génération. L’assemblage type « bouchon-gaine » se fait par le procédé de soudage par résistance (SPR) en bout ; procédé de soudage en phase solide, connu pour avoir un impact limité sur la dispersion des nano-oxydes dans la zone soudée par rapport aux procédés de soudage par fusion. Un des objectifs de ces travaux est d’évaluer et de comprendre les effets du SPR sur la résistance mécanique finale de l’assemblage « bouchon-gaine » en acier 11Cr-ODS. Une approche couplant caractérisations microstructurales et mécaniques avec des simulations numériques (du procédé de SPR et des essais mécaniques) est adoptée. L’originalité de cette approche réside aussi dans le développement de deux géométries spécifiques d’éprouvettes de traction, permettant de localiser les sollicitations dans la zone soudée. En effet, les sollicitations thermomécaniques sévères induites par le SPR génèrent des hétérogénéités microstructurales au matériau avec des conséquences directes sur la résistance mécanique. Des microstructures complexes en termes de taille de grain, de texture locale, de phases en présence (ferrite, martensite, ferrite résiduelle) et de type de grain (recristallisé ou déformé) sont obtenues. Les essais mécaniques réalisés ont mis en évidence que la résistance mécanique de l’assemblage soudé peut être principalement associée à la zone interne du plan de joint, formant un angle d’environ 45° par rapport à l’axe de la gaine. Cette zone subit une déformation plastique significative, présente les valeurs de dureté les plus élevées et affiche un affinement plus prononcé de la microstructure. Un second objectif est l’évaluation des effets d’un traitement thermique post-soudage sur les propriétés microstructurales de la soudure et sur la résistance mécanique de l’assemblage soudé. Son effet est significatif s’il est réalisé au-dessus de la température de transformation de phase Ac3, tandis qu’il est limité, s’il est effectué en dessous d’Ac3. Lors d’essais de traction à température ambiante, la zone de rupture est déplacée de la zone soudée vers le métal à l’état de réception lorsque l’assemblage a subi un traitement thermique post-soudage adéquatOxide Dispersion-Strengthened (ODS) ferrito-martensitic alloys are among the candidate materials for the manufacture of fuel cladding parts for 4th generation nuclear reactors. The « plug-clad » assembly is carried out by the Pressure Resistance Welding (PRW) process; a solid phase welding process known to have a limited impact on the dispersion of nano-oxides in the welded zone compared with fusion welding processes. One of the aims of this work is to assess and understand the effects of PRW on the final mechanical strength of the 11Cr-ODS steel plug-clad assembly. An approach coupling microstructural and mechanical characterizations with numerical simulations (PRW process and mechanical tests) is adopted. The originality of this approach also lies in the development of two specific geometries for tensile samples, enabling the localization of stresses in the welded zone. Indeed, the severe thermomechanical loadings imposed on the material during the PWR process generate microstructural heterogeneities in the material with direct consequences on its mechanical resistance. Complex microstructures in terms of grain size, local texture, phases (ferrite, martensite, residual ferrite) and grain type (recrystallized or deformed) are obtained. The mechanical tests indicate that the mechanical resistance of the welded assembly is primarily associated with the internal zone of the joint plane, forming an angle of approximately 45° with respect to the axis of the clad. This area is submitted to significant plastic deformation, presents the highest hardness values, and exhibits a more pronounced refinement of the microstructure. A second objective is the evaluation of the effects of a post-welding heat treatment on the microstructural properties of the weld and on the mechanical strength of the welded assembly. Its effect is significant if it is carried out above the phase transformation temperature, Ac3, while it is limited if below Ac3. During tensile tests at room temperature, the fracture zone is moved from the welded area to the as-received metal when the assembly has undergone adequate heat treatments
Частини книг з теми "Pressure resistance welding":
1
Zhong, Hua, Xiaodong Wan, Yuanxun Wang, and Yiping Chen. "Contact Pressure and Residual Strain of Resistance Spot Welding on Mild Steel Sheet Metal." In Proceedings of the International Conference on Martensitic Transformations: Chicago, 235–43. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-76968-4_37.
2
Swezy, John P., and Joel G. Feldstein. "Welding, Brazing and Fusing Qualifications." In Companion Guide to the ASME Boiler & Pressure Vessel Codes, Volume 2, Sixth Edition, 25–1. ASME Press, 2023. http://dx.doi.org/10.1115/1.886526_ch25.
Анотація:
Abstract This chapter covers the qualification of welding, brazing, and plastic fusing procedures and the qualification of individuals performing these procedures as required by the Construction Codes of the ASME Boiler and Pressure Vessel and Piping Codes. It first traces the history of Section IX, outlines the organization of the Section, and reviews the scope of weld processes that Section IX addresses. Section IX contains rules for the qualification of the several weld processes such as oxyfuel welding, shielded metal arc welding, submerged arc welding, gas metal arc welding, gas tungsten arc welding, and plasma arc, among others. The chapter then describes the classification of ASME base materials as given in Section IX. It explains the general requirements for both the welding procedure and welder performance qualification as well as the variables applicable to the welding procedure and welder performance qualification. The chapter also discusses the requirements to perform Charpy V-notch impact testing of the weld procedure qualification. It outlines the requisites for conducting the following testing and examination methods for groove weld and pressure-retaining fillet weld procedure qualification: tension test, guided-bend test, visual examination, volumetric examination, macroexamination, and fracture test. The qualification rules for two special weld processes, corrosion-resistant weld metal overlay and hardfacing overlay, are also explained. General requirements for brazing procedure and brazer performance qualification and the variables applicable to brazing procedure and brazer performance qualification are subsequently addressed. Finally, the chapter summarizes the general requirements for fusing procedure and fusing machine operator performance qualifications and identifies the variables applicable to fusing procedure and fusing machine operator performance qualification.
Тези доповідей конференцій з теми "Pressure resistance welding":
1
Carlucci, Antonio, Kamel Mcirdi, Pierre-Louis Auvret, and Jun Li. "Simplified Toughness Resistance Curve." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28827.
Анотація:
This paper presents a method in order to plot a simplified toughness resistance curve (R-Curve) from three single conventional toughness tests. The simplified toughness resistance curve will be used to carry out a tearing assessment as part of Engineering Criticality Assessment (ECA) (ref. to Level 3B, [2]). This level of assessment takes into account of stable tearing in order to reduce over-conservatism, but it usually requires additional toughness tests to identify the toughness resistance curve. This present method allows to reach this assessment level without impacting the welding procedure qualification (WPQ).
2
Singh, Rupinder, and Sehijpal Singh. "Experimental Investigations for Reducing Effect of Sensitization in Tungsten Inert Gas Welding." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61078.
Анотація:
Stainless steels are considered to have very good resistance to general and localized corrosion due to their chromium content. This property of corrosion resistance constitutes the main criterion for selecting austenitic grades of steels for service in the chemical, nuclear and aerospace industries although their mechanical properties are relatively modest. However, this resistance can degrade when structural components manufactured from these steels are used in a chemically aggressive environment, especially when service involves exposure to high temperatures like in welding. This exposure gives rise to precipitation of chromium carbides producing chromium depletion at grain boundaries that brings about the inter-granular corrosion or sensitization of these materials. Austenitic stainless steel (316L) is one of the corrosion resistance material used extensively in the oil production, chemical and power generation industries for transportation and reservoir of corrosive products. In spite of its corrosion resistance property there exist severe problems of sensitization. In the present work an effort has been made to reduce the effect of sensitization in Tungsten Inert Gas welding of Austenitic stainless steel (316L). Three welding procedures (namely conventional, back step and skip welding) in Tungsten Inert Gas welding have been used to control exposure time of the weld pool to higher temperatures, in order to study the effect of sensitization on mechanical properties (such as tensile strength, yield strength, percentage elongation and hardness). The results of this study suggested that the better mechanical properties were attained by the skip welding procedure and recommended welding parameters are 90 Amp current and 10 L/min of gas flow rate for a 5 mm thick work piece. Noticeable change in amount/extent of sensitization was observed using a scanning electron microscope (SEM) analysis within the various welding specimens prepared using the various procedures. Further mechanical properties (like strength and hardness) have been correlated with the extent of sensitization, which show remarkable decreases when the amount/extent of sensitization increases.
3
Cary, Claire, Jorge Penso, Narasi Sridhar, and Carolin Fink. "Pitting Corrosion Resistance in the Heat-Affected Zone of No-Backing Gas (NBG) Austenitic Stainless Steel Welds." In ASME 2023 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/pvp2023-106333.
Анотація:
Abstract Stainless steel welds for service applications in corrosive environments are typically performed using gas tungsten arc welding (GTAW) with an inert backing gas in order to minimize or prevent root pass contamination and oxidation. Back purging adds significant cost and complexity to stainless steel pipe welding due to access restrictions, personnel safety, and/or economic factors. In this study, two no-backing gas welds (NBG) were made on Type 304L austenitic stainless steel pipe with Type 316 filler metal. Two different shielding gas mixtures were used (98% Ar-2% CO2 and 90% He-7.5% Ar-2.5% CO2) for the NBG welds. Open gap root pass welds were performed using modified short circuit gas metal arc welding (SC-GMAW) process. A hot pass was welded with pulsed GMAW process. Fill and cap passes were made with flux-cored arc welding (FCAW) process. Cyclic potentiodynamic polarization (CPP) measurements based on ASTM G61 were performed locally on the backside surface heat-affected zone as a function of distance from the fusion line. Electrochemical corrosion testing was done using a simple syringe cell setup. Pitting corrosion resistance of the NBG welds was compared to a reference weld made with 100% argon backing gas and conventional GTAW for the root and hot pass.
4
Xiang, Guangte, Yurui Hu, Sheng Zeng, Jianfeng Shi, and Jinyang Zheng. "Demonstration of Intelligent Welding Machine for Polyethylene Pipe." In ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-62014.
Анотація:
Abstract Electrofusion (EF) welding is one of the most common connection methods for polyethylene (PE) pipe, as well as thermoplastic pipe and reinforced composite pipe. Conventional EF welding generally adopts constant-voltage welding mode. The welding machine outputs a constant welding voltage to heat the resistance wire within specific welding time. In our previous study, intelligent welding machine was designed to ensure the quality of the EF joint, based on the study of the temperature field in EF joint. In this paper, three experiments were used to show the difference between the intelligent welding machine and traditional welding machine. The intelligent welding machine can actively adjust the welding parameters to ensure the quality of EF joint even it was given the wrong welding voltage and welding time. Compared with the traditional welding machine, the intelligent welding machine can automatically control the maximum temperature and the depth of melting region in EF joint during the welding process, and this method applies for EF joints with various diameters or design welding parameters.
5
Sippy, Haresh K. "Welding Tube to Tubesheet Joints for Corrosion Resisting Applications." In ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-60974.
Анотація:
Abstract The work in this paper relates to an improved tube to tubesheet joint in a shell and tube type heat exchanger that have dissimilar metallurgies of tube and tubesheet. This improved tube to tubesheet joint configuration will not only impart reliability and strength to the mechanical integrity of the joint but also reduce the costs of the manufacturing without compromising the functional performance of the exchanger. In a shell and tube heat exchanger, generally the material of tubes may be similar to the tubesheet or of a higher corrosion resistant grade in comparison to that of the tubesheet. Conventionally, shell and tube heat exchangers that involve dissimilar materials of tube and tubesheet are either: i. Tubes welded directly to the tubesheet with matching grade weld metal or ii. The tubesheets are clad / weld overlaid with the higher corrosion resistant material or material similar to the tube material For purpose of this study, we have considered the material of tube as stainless steel type 304L and that of tubesheet as carbon steel. The above case 1 wherein the SS-304L tubes are directly welded to the CS tubesheet, may have the following advantages: i. Manufacturing time is less. ii. Tubes are attached to the base metal and hence free from defects of weld overlay or cladding, if any. In case 2, wherein the SS-304L tubes are welded to the SS-304L clad / weld overlaid portion of tubesheet, the advantages are: i. Welding takes place between two austenitic stainless steel grades, hence PWHT is not required. ii. The tube to tubesheet joint and adjacent material is of austenitic stainless steel grade, hence has better corrosion resistance. The main objective of the work done and reported in this paper is to combine the advantages of the above two cases thereby: i. Reducing the cost of manufacturing ii. Increasing the mechanical reliability of the tube to tubesheet joint. Extensive trials were carried out on sample tube to tube sheet joints, the results and conclusions of which are reported in this paper.
6
Watanabe, Hirohisa, Keisuke Shiga, and Atsushi Ohno. "Guideline for Repair Welding of Pressure Equipment in Refineries and Chemical Plants: Part 5—Repair Welding for Specific Materials - Heat Resistance Alloy and Non-Ferrous Metals." In ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57788.
Анотація:
It has been recognized that repair welding takes an important role in the long term, safe operation of pressure equipment. Responding to the needs in petroleum and chemical industries, the Japan Welding Engineering Society (JWES) published Guideline for repair welding of pressure equipment at 2009. This paper describes the key points of repair welding for heat resistance alloy and non-ferrous metals such as Nickel, Copper, Titanium and their alloys, based on JWES’s guidelines. Before implementing repair welding, it is important to understand the features of damaged materials, because these materials have been used at severe environment in plants.
7
Osuki, Takahiro, Masahiro Seto, Hirokazu Okada, Masayuki Sagara, Satoshi Matsumoto, and Toshihide Ono. "Development of Fit-for-Purpose Austenitic Stainless Steels With High Polythionic Acid Stress Corrosion Resistance." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65536.
Анотація:
In the process units with Polythionic Acid Stress Corrosion Cracking (PTA-SCC) such as hydrotreater or hydrocracker, the neutralization treatment like soda ash washing and/or PWHT, Post Weld Heat Treatment, are conducted for stabilized austenitic stainless steels of TP321H or TP347H to mitigate the potential of PTA-SCC. 347AP, the proprietary version of Type 347LN, is remarkable for the possibility to save the fabrication and turnaround cost by the elimination of the neutralization treatment and/or PWHT and its reliability to PTA-SCC resistance without PWHT and neutralization was proven by the long-term service experience. However it has not been investigated the difference between 347AP and TP347H for the Stress Relaxation (SR) cracking resistance of welded joint required for the long term operation at elevated temperature. On the other hand, in atmospheric distillation units and vacuum distillation units using the crude containing high Total Acid Number (TAN), the resistances to both Naphthenic Acid Corrosion (NAC) and PTA-SCC are required by elevating the design temperature. Therefore, Fit-for-purpose austenitic stainless steels with high PTA-SCC resistance without stabilization treatment are required for the complicated environment with the variation of temperature, pressure and fluid in petroleum refinery process using the crude containing high S content. In this study, SR cracking susceptibility of 347AP is investigated and it is found that 347AP has lower SR cracking susceptibility than TP347H without stabilization treatment. Next, in order to improve NAC resistance compared with 347AP, the effect of Mo, Cu and W contents to NAC are investigated based on 347AP, and it is clarified that the increase of Mo content greater than 3% is the most effective to improve NAC resistance. Moreover, the conventional welding filler with the similar NAC and PTA-SCC resistances to base metal is investigated, and it is reported that ER NiCrCoMo-1 filler was recommended for the welding fabrication of Fit-for-purpose austenitic stainless steels with high PTA-SCC resistance.
8
Almomani, Abdulla Fawzi, Hazem Alhaj, and Abdel-Hamid Ismail Mourad. "The Impact of Silicon Content on the Corrosion Resistance of Nickel-Molybdenum Alloy in High Concentration Sulfuric Acid Transport." In ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-62023.
Анотація:
Abstract This failure case analysis highlights the impact of silicon content on the corrosion resistance of Ni-Mo alloy piping welding joints, known as Hastelloy B-2 (UNS N10665), in high concentration sulfuric acid (98 wt. % H2SO4) medium. A damaged piping weld joint is analyzed against an accelerated corrosion mechanism which was found to shorten the joints lifetime drastically. Superiority of B-2 alloys is largely attributed to the high concentration of molybdenum (26–30 wt. %) that gives its corrosion resistance to highly reducing acidic environments. However, certain deficiencies, such as short-range ordering (SRO) and intermediate phases formations (Ni4Mo transformation) in its metallurgical structure, in the as-welded conditions, was found to hinder its thermal stability. In this piping failure case analysis, close examination including optical assessment, X-ray fluorescence (XRF) spectrometry, and in-situ replication metallography were performed on a defected weld neck butt-fusion welding joint. XRF revealed a silicon content of almost four times (0.38% against 0.1%) the ASTM maximum requirements, which appears to have lowered the alloy’s thermal stability and increased its kinetics to rapid phase transformation (from α to β) along the grain boundaries. Extensive second phase precipitates were observed along the domain boundary interfaces in the microstructure, which is suggested to have resulted in Mo-depleted zones in the matrix. In this case analysis, the welding temperature (650–750°C) of NiMo alloys butt-joints along with the silicon content (0.1% to 0.3%) present were found as main contributors to the reduction of the welding corrosion resistance and hence to the shortening of the piping lifetime.
9
Messer, Barry, Shawn Seitz, Charles Patrick, and Ken Armstrong. "A Novel Technological Assessment for Welding Heavy Wall Stainless Steel." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71412.
Анотація:
In an effort to maximize quality and production in both field and shop fabrication while minimizing cost, Fluor and PCL, in a joint venture, assessed new welding technology comparing power sources, arc transfer modes, and shielding gas mixtures using various semi-automatic welding processes. The results were combined with “No-Backing Gas” (NBG) root technique to provide ASME code acceptable welds with excellent corrosion and crack resistance for type 321 Stainless Steel [1]. Welds were deposited in approximately one third the time commonly demanded by conventional welding. The strategies for the selection of a welding power source, arc transfer modes, shielding gas mixtures, and the successful bridging from quality and integrity validation to shop and field implementation are discussed.
10
Jian-qun, Tang, and Jianming Gong. "Leakage of 316Ti SS Pipeline Transporting 98% H2SO4 due to CUI and Changed Microstructure From Welding." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63090.
Анотація:
With the properties of good mechanical strength, excellent resistance to uniform corrosion and superior weldability, austenitic stainless steels are widely used in petrochemical industries. Among them, 316Ti austenitic stainless steel is a titanium stabilized version of 316 molybdenum-bearing steel. The addition of titanium can greatly increase the resistance to sensitization and significantly reduces the susceptibility to the formation of chromium carbides. So, 316Ti stainless steel is more resistant to general corrosion and pitting/crevice corrosion as well as intergranular corrosion, it is even more resistant to sensitization as compared to low carbon 316L stainless steel. Based on these advantages, 316Ti stainless steel pipelines are chosen to transport 98% H2SO4 in one factory. The pipelines for transporting concentrated H2SO4 were manufactured by welding segments of 316Ti stainless steel pipes. The external surface of the pipelines was insulated to maintain heat and prevent crystallization as well as for safety and health reasons. After being in use for about two years, leakage occurred on one pipe and concentrated H2SO4 was seeping from the pits on the pipeline. The investigation about leakage was carried out. The results show that leakage was caused by corrosion under insulation (CUI) and the pits formed by CUI are just located on the welding arc contact zone (WACZ) of the base metal caused by the welder’s faulty operation during welding the joints. The external surface metal of the pipe contacted by the welding arc was partially re-melted by arc heat, which solidified in air and finally formed into another new microstructure that is completely different from that of 316Ti stainless steel. The microstructure in re-melting and solidification zone of the pipe is similar to that of cast metal and didn’t experience any heat treatments. This has less resistance than austenite in 316Ti stainless steel. As a result of the continuous rainy days in the summer, the insulation on the external surface of the pipe was dampened or wetted, which made moisture penetrate and accumulate between the insulation and the pipe, finally resulting in CUI. At the same time, the accumulation and concentration of chloride from the insulation as well as the relatively high temperature in summer, greatly increased the corrosion rate of metal under insulation. Therefore, the presence of the less resistant microstructure in the re-melting and solidification zone, together with the dampened or the wetted insulation, as well as existence of chloride, made the external surface metal of the pipe under the insulation suffer from corrosion, finally resulting in the occurrence of the leakage. The concentrated H2SO4 which was seeping from the pipeline was easily diluted by the moisture or water trapped in insulation. The diluted H2SO4 is a strong corrosive medium, which in turn made the metal around the pits heavily corroded.
Звіти організацій з теми "Pressure resistance welding":
1
Dinovitzer, Aaron, Sanjay Tiku, and Amin Eshraghi. PR-214-153739-R01 ERW Fatigue Life Integrity Management Improvement-Phase III. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 2019. http://dx.doi.org/10.55274/r0011574.
Анотація:
While the general fracture mechanics methodology for calculating fatigue lives is well documented and validated, its application in the definition of pipeline system fatigue lives have differed from field experience. The source and magnitude of the conservatism inherent in the calculated fatigue life estimates are a concern when establishing integrity management programs. Of particular interest, are the fatigue life estimates used in the integrity management programs for Electric resistance welding (ERW) pipeline systems that are primarily concerned with pipe wall anomalies oriented along the pipe axis. In this project, fatigue crack growth rate parameters were generated for pipe body and ERW. Axial flaws of different sizes were machined in pipe body and weld center line of two different pipe geometries and subjected to cyclic pressure tests. Fatigue crack growth rate of the flaws in the full-scale fatigue tests was monitored. The full-scale fatigue tests results were compared to existing codified treatments to quantify the level of conservatism inherent in the current state of practice. Recommendations were provided to enhance the precision and manage conservatism in fatigue crack growth rate calculations used in integrity management. This report has a related webinar.
2
Bruce. L51782 Guidelines for Weld Deposition Repair on Pipelines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), February 1998. http://dx.doi.org/10.55274/r0010120.
Анотація:
Pipeline repair by direct deposition of weld metal, or weld deposition repair, is an attractive alternative to the installation of full-encirclement sleeves for repair of wall loss on in-service pipelines. This is particularly true where the installation of full-encirclement sleeves is difficult or impossible, such as for wall loss in bend sections and fittings. The results of recently completed work at Edison Welding Institute and previous work by others has shown that weld deposition repairs have the ability to restore the static strength of a pipeline and are resistant to pressure cycles over a wide range of applications. Prior to the widespread use of this technique, it was necessary to establish guidelines for carrying out repairs using this technique These guidelines must address not only the welding issues, but issues pertaining to inspection following welding, acceptance standards for discontinuities detected during inspection, and other related issues The objective of this project was to provide a report that contains theseguidelines. The guidance provided in this report is contained in two basic parts. The main body of the report contains a review of the various technological factors pertinent to weld deposition repair, Including a review of recently-completed research projects. The second part is an example guideline for carrying out weld deposition repair in the field, which was developed using the information contained in the main body of the report. This example guideline is in the form of a generic company specification and is contained in an appendix to the report.