Journal articles: 'P91 martensitic steel'

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Qadr, Hiwa Mohammad, and Ari Maghdid Hamad. "Mechanical Properties of Ferritic Martenstic Steels: A Review." Scientific Bulletin of Valahia University - Materials and Mechanics 17, no. 16 (May 1, 2019): 18–27. http://dx.doi.org/10.2478/bsmm-2019-0003.

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Abstract The word-wide demand for energy is constantly increasing, and therefore ideas around future energy-generation are also on the increase with the aim of meeting this demand. This includes designs for the next generation of nuclear power reactors, such as gas-cooled, liquid-metal-cooled and water-cooled reactors; the goal being to create smarter ways to produce more economical, environmentally-friendly energy. The conditions such reactors would need to meet, present significant design challenges for scientist and engineers, not least around the structural materials and components to use. Depending on the operational conditions, use of elevated- temperature ferritic/martensitic materials such as P91 and P92 steel are favoured by several of the designs for use with out-of-core and in-core applications. The main goal behind this review article is to explain mechanical properties of P91 and P92 steel; these are two types of ferritic/martensitic steels. This reviewer, highlight and discuss the development of ferritic/martenisitc steels for nuclear programmes and to explain the effect of irradiation on mechanical properties of P91 and P92.

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Golański, G., J. Jasak, A. Zieliński, C. Kolan, M. Urzynicok, and P. Wieczorek. "Quantitative analysis of stability of 9%Cr steel microstructure after long-term ageing." Archives of Metallurgy and Materials 62, no. 1 (March 1, 2017): 263–71. http://dx.doi.org/10.1515/amm-2017-0040.

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Abstract The paper presents the results of research on the microstructure of martensitic X10CrMoVNb9-1 (P91) and X13CrMoCo- VNbNB9-2-1 (PB2) steel subject to long-term ageing at the temperature of 620°C and holding times up to 30 000 hours. The microstructural tests of the examined steel types were performed using a scanning microscope Joel JSM - 6610LV and a transmission electron microscope TITAN 80 - 300. The stability of the microstructure of the investigated steels was analyzed using a quantitative analysis of an image, including measurements of the following: the density of dislocations inside martensite/subgrain laths, the width of martensite laths, and the mean diameter of precipitates. It has been concluded that during long-term ageing, the microaddition of boron in PB2 steel significantly influenced the slowing of the process of degradation of the martensitic steel microstructure, as a result of slowing the process of coagulation of M23C6 carbides and Laves phase. It had a favorable effect on the stabilization of lath microstructure as a result of retardation of the processes of recovery and polygonization of the matrix.

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Shi, L., SA Alexandratos, and NP O’Dowd. "Combined finite element and phase field method for simulation of austenite grain growth in the heat-affected zone of a martensitic steel weld." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 1 (January 17, 2018): 13–27. http://dx.doi.org/10.1177/1464420717750999.

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Engineering components operating at high temperature often fail due to the initiation and growth of cracks in the heat-affected zone adjacent to a weld. Understanding the effects of microstructural evolution in the heat-affected zone is important in order to predict and control the final properties of welded joints. This study presents a combined finite element method and phase field method for simulation of austenite grain growth in the heat-affected zone of a tempered martensite (P91) steel weld. The finite element method is used to determine the thermal history of the heat-affected zone during gas tungsten arc welding of a P91 steel plate. Then, the calculated thermal history is included in a phase field model to simulate grain growth at various positions in the heat-affected zone. The predicted mean grain size and grain distribution match well with experimental data for simulated welds from the literature. The work lays the foundation for optimising the process parameters in welding of P91 and other ferritic/martensitic steels in order to control the final heat-affected zone microstructure.

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Vlasák, Tomás, Jan Hakl, Pavel Novák, Jiří Sochor, and Jan Čech. "Creep of Cast Steel P91 with Weld Joint." Materials Science Forum 782 (April 2014): 331–34. http://dx.doi.org/10.4028/www.scientific.net/msf.782.331.

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High-temperature martensitic steel P91, internationally marked GX12CrMoVNbN91, is the material used in the energy industry. Creep and high-temperature corrosion resistances are important properties that affect the application of this material at higher temperatures. Weldment reduces creep properties. This work deals with the quantification of this decrease in the case of material P91. The main focus is except the evaluation of creep test results given to the mathematical description of the weld creep strength reduction. Further metallographic analyses of weld joint after creep exposures were performed.

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Velkavrh, Igor, Joël Voyer, Fevzi Kafexhiu, and Bojan Podgornik. "Creep Rate, Friction, and Wear of Two Heat-Affected Zone Regions of 9–12 wt.% Cr Steels." Metals 11, no. 4 (March 29, 2021): 558. http://dx.doi.org/10.3390/met11040558.

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Coarsening of precipitates can have a profound effect on the mechanical properties of martensitic 9–12 wt.% Cr steels, which are typically used in critical parts of fossil-fuel power plants such as turbines, headers, and main steam pipes. In the present study, changes in precipitates’ size and distribution in the simulated heat-affected zone of two different 9–12 wt.% Cr steels (X20 and P91) after different aging conditions were analyzed and correlated with their creep, friction, and wear behaviors. It was shown that prior to aging, the morphology of the steel matrix (prior austenite grain size and microstructure homogeneity) governed the creep rate and the tribological performance of both steels, while after aging their response was additionally determined by the combination of the number and the size of precipitates. For the selected samples (prepared under identical conditions), number of precipitates was found to be within a narrower range for the X20 steel as compared to the P91 steel. For both steels, aging for a shorter time at the higher temperature yielded significantly higher stationary creep rate values as compared to aging for longer time at the lower temperature. The increase was more pronounced in the P91 than in the X20 steel. Both prior to and after aging, the P91 steel typically provided slightly higher creep resistance than the X20 steel, while the latter provided slightly better tribological performance. Furthermore, as a function of the increasing number of precipitates, static coefficient of friction in air atmosphere was approximately linearly decreasing, while the wear rate initially decreased.

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Rhode, Michael, Tim Richter, Tobias Mente, Peter Mayr, and Alexander Nitsche. "Thickness and microstructure effect on hydrogen diffusion in creep-resistant 9% Cr P92 steel and P91 weld metal." Welding in the World 66, no. 2 (December 9, 2021): 325–40. http://dx.doi.org/10.1007/s40194-021-01218-9.

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Abstract Martensitic 9% Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. Limited data on room temperature diffusion coefficients reported in literature vary widely by several orders of magnitude (mostly attributed to variation in microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. From the results obtained, diffusion coefficients were calculated using to different methods, time-lag, and inflection point. Results show that, despite microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients.

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Elarbi, Y., and Béla Palotás. "Microstructural Changes due to Secondary Precipitation Hardening of Martensitic Creep Resistant Steel X20CrMoWV 12 1 (AISI 422)." Materials Science Forum 589 (June 2008): 197–202. http://dx.doi.org/10.4028/www.scientific.net/msf.589.197.

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After development of the well-known T/P91 steel grade in the early 80’s and its long industrial experience since early 90’s, it has been necessary to develop new martensitic creep resistant steels to answer the demand of the power generation industry. New USC (ultra-super critical) boilers require materials with advanced creep properties to reach severe steam parameters. Addition of W to the steel has been found by many researches to be effective to increase creep rupture strength at high temperatures and already used in some developed steel grades such as T/P92, T/P122 and AISI 422 for the USC boilers. Recently, long-term creep strength of the advanced high Cr ferritic steels has been argued regarding the instability of their microstructures at high temperatures over 600 °C. This microstructural instability seems to be enhanced with increasing Cr content or with substitution of Mo by W in the steels. The aim of this paper is concentrated on the investigation of the microstructural development of the studied steel using the Jominy end-face quench test. Different hardness profiles from this test were introduced.

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Ducháček, Petr, and Jiří Janovec. "Heterogeneous Welded Joints (T23-T92; 15CH1M1F-P91)." Key Engineering Materials 647 (May 2015): 147–52. http://dx.doi.org/10.4028/www.scientific.net/kem.647.147.

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The use of new construction materials is increasingly on demand for the construction of new power plants, and for the modernization of existing plants that are at the end of their service life span. Steels such as type P/T92 (modified martensitic 9-12% Cr), and low-alloy steels derived from modified steel 2.5Cr1Mo (ASTM marked P/T23) are considered promising alternatives. In the construction of power units, the so-called heterogeneous joints, which most often consist of a combination of low-alloyed materials and highly-alloyed ones, preferably need to be avoided. These welded joints are often the weak links in the overall construction. Knowledge of the behaviour of creep-resistant steel welded joints is very important for the subsequent evaluation of the life span of the units. This study deals with the degradation of heterogeneous welded joints of steel T23 - T92 and 15CH1M1F - P91, using the commercially available welding materials Thermanit MTS 616 (highly-alloyed), Union I P23; ThermanitP23, Böhler P23-IG and Thermanit (FOX) P23 (low-alloyed). In the heterogeneous welds examined, slight loss of strength of the base material was observed during isothermal heat exposure and extension of the diffusion active zones (i.e., Carbon Depleted Zone (CDZ) and Carbon Enriched Zone (CEZ)). These degradation processes caused structural instability of heterogeneous welds. It was found that the use of low-alloyed welding materials showed superior structural stability than highly-alloyed welds. Additional laboratory analyses are warranted due to the extreme service conditions and the high temperature loads in power units.

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Janulionis, Remigijus, Gintautas Dundulis, and Albertas Grybėnas. "Numerical Research of Fracture Toughness of Aged Ferritic-Martensitic Steel." Metals 10, no. 12 (December 17, 2020): 1686. http://dx.doi.org/10.3390/met10121686.

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Generally, material properties such as the modulus of elasticity, yield strength or fracture toughness are determined by conducting an experiment. Sometimes experimental determination cannot be done due to specific experimental conditions, lack of testing material and so on. Also, experiments are time consuming and costly. Therefore, there arises the need for alternative determination methods. A numerical method for the fracture toughness determination of steel P91 is suggested in this paper. For this purpose, the universal finite element software ABAQUS was used. The numerical simulation of the C(T) specimen tension test was carried out using non-linear simulation for a conditional load PQ determination, and linear simulation for fracture toughness value KQ determination. The suggested method is validated by comparing numerical and experimental tests results. The secondary aim of the paper is the evaluation of the ageing effect on the fracture toughness of steel P91. Thermal ageing of the steel was carried out in an electric furnace at 650 °C up to 11,000 h. As the numerical results had a good coincidence with experimental data at room temperature, the prediction of fracture toughness at elevated temperature, i.e., 550 °C, using numerical method was carried out.

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Yaghi, A. H., T. H. Hyde, A. A. Becker, and W. Sun. "Numerical simulation of P91 pipe welding including the effects of solid-state phase transformation on residual stresses." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 221, no. 4 (October 1, 2007): 213–24. http://dx.doi.org/10.1243/14644207jmda152.

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The methodology of numerically simulating residual stresses in a welded P91 pipe section is described. The finite element (FE) method has been applied to simulate residual axial and hoop stresses generated in the weld region and heat affected zone (HAZ) of an axisymmetric 50-bead circumferentially butt-welded P91 steel pipe, with outer diameter of 145 mm and wall thickness of 50mm. The FE simulation consists of a thermal analysis which is followed by a sequentially-coupled structural analysis. Solid-state phase transformation (SSPT), which is characteristic of P91 steel during welding thermal cycles, has been modelled in the FE analysis by allowing for volumetric changes in steel and associated changes in yield stress due to austenitic and martensitic transformations. Phase transformation plasticity has also been taken into account. Preheat and interpass temperature control has been included in the modelling process. Thermally-obtained temperature contours indicate the size of the weld region, parent metal penetration, and HAZ. Residual axial and hoop stresses have been depicted through the pipe wall thickness as well as along the outer surface of the pipe. The results indicate the importance of including SSPT in the simulation of stresses during the welding of P91 steel.

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Oskay, Ceyhun, Tobias M. Meißner, Carmen Dobler, Benjamin Grégoire, and Mathias C. Galetz. "Scale Formation and Degradation of Diffusion Coatings Deposited on 9% Cr Steel in Molten Solar Salt." Coatings 9, no. 10 (October 22, 2019): 687. http://dx.doi.org/10.3390/coatings9100687.

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The employment of ferritic-martensitic steels e.g., P91, as structural materials in concentrated solar power (CSP) plants can significantly increase cost-efficiency. However, their application is strongly restricted by their lower corrosion resistance in molten nitrates, compared to austenitic steels or Ni-based alloys. In this study, Cr-, Al-, and Cr/Al-diffusion coatings were deposited on P91 via pack cementation in order to improve its scaling behavior in molten solar salt (MSS). The corrosion behavior of coated specimens was investigated with respect to uncoated P91 in MSS at 600 °C for up to 1000 h. The exposure in MSS resulted in a thick, highly porous, and multi-layered oxide scale on uncoated P91 consisting of hematite, magnetite, and sodium ferrite. On the other hand, the scale grown on the chromized P91 comprised of a thin Cr-rich inner layer, which shifted breakaway to prolonged exposure durations. The aluminized specimens both formed very thin, highly protective alumina scales with localized protrusions.

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GOLAŃSKI, Grzegorz. "MECHANICAL PROPERTIES OF P91 AND PB2 STEEL AFTER LONG-TERM AGEING AT 620°C." Journal of Metallic Materials 73, no. 3 (March 21, 2022): 2–6. http://dx.doi.org/10.32730/imz.2657-747.21.3.1.

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The article presents the results of research on mechanical properties of martensitic steels, X10CrMoVNb9-1 (P91) and X13CrMo- CoVNbNB9-2-1 (PB2), as-received and after 50,000 hours of ageing at 620˚C. The scope of the tests of mechanical properties included a Vickers hardness test, Charpy impact test, and static tensile test. As received, the investigated steels were characterised by relatively high mechanical properties. The long-term effect of temperature and time contributed to a relatively slight decrease in the strength properties and hardness of the tested steels. However, a considerable decrease in the ductility of these alloys was observed. The decrease in mechanical properties after long-term ageing was smaller in the case of the PB2 steel, which was attributed to the beneficial effect of microalloying boron.

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Sarwar, Muhammad, and Mohd Amin bin Abd Majid. "Study of Hydrogen Cracking and PWHT of Dissimilar Materials for Elevated Temperature Application." Applied Mechanics and Materials 754-755 (April 2015): 797–801. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.797.

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s. On construction sites many challenges and premature failures are being encountered in welded joints of creep strength-enhanced ferritic (CSEF) steels. The primary reason of these premature failures is found to be the dissimilar material joints, having strength mismatch, or improper heat treatment that is mandatorily carried out to achieve the required weld hardness. This study aims at determining the impact of post welding heat treatment (PWHT) on dissimilar alloy steels joints, between ASTM A335 Gr. P-22 and ASTM A335 Gr. P-91 steels, welded by gas tungsten arc welding (GTAW) using ER 90S-B9 filler wire. The PWHT, at 745°C for 1hr., was applied to attain the required hardness. The effect of PWHT was investigated on the weld metal and the heat affected zones (HAZ) by hardness testing. Due to the martensitic microstructure, the hardness values of HAZ of P91 steel are over 350 HV. However, the hardness value of the P22 HAZ less than 350 HV. P91 HAZ has a higher hardness value than P22 HAZ because of its higher hardenability and due to phase transformation from martensite to ferrite. The interaction between the too high hardness microstructure with hydrogen can result in the hydrogen induced cracking (HIC) initiation in the HAZ. Therefore, the PWHT is needed to reduce this high hardness HAZ.

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O’Hara, EM, NM Harrison, BK Polomski, RA Barrett, and SB Leen. "Fatigue damage characterisation of MarBN steel for high temperature flexible operating conditions." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 231, no. 1-2 (September 25, 2016): 23–37. http://dx.doi.org/10.1177/1464420716667759.

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This article is concerned with the high temperature low cycle fatigue behaviour of a new nano-strengthened martensitic-ferritic steel, MarBN. A range of strain-controlled, low cycle fatigue tests are presented on MarBN at 600 ℃ and 650 ℃, and compared with previously published data for a current state-of-the-art material, P91 steel, including microstructural analysis of the fracture mechanisms. A modified Chaboche damage law, incorporating Coffin–Manson life prediction, is implemented within a hyperbolic sine unified cyclic viscoplastic constitutive model. Calibration and validation of the model with respect to the effects of strain-rate and strain-range is performed based on an optimisation procedure for identification of the material parameters. The cyclic viscoplasticity model with damage successfully predicts fatigue damage evolution and life in the cyclically softening materials, MarBN and P91.

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Siska, Filip, Ludek Stratil, Miroslav Smid, Natalia Luptakova, Tomas Zalezak, and Denisa Bartkova. "Deformation and fracture behavior of the P91 martensitic steel at high temperatures." Materials Science and Engineering: A 672 (August 2016): 1–6. http://dx.doi.org/10.1016/j.msea.2016.06.065.

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Yang, Kai, Yingjie Zhang, Zexun Hu, and Jianping Zhao. "Optimized welding process of residual stress control of P91 steel considering martensitic transformation." International Journal of Pressure Vessels and Piping 194 (December 2021): 104517. http://dx.doi.org/10.1016/j.ijpvp.2021.104517.

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Zhang, Kuo, and Jarir Aktaa. "Characterization and modeling of the ratcheting behavior of the ferritic–martensitic steel P91." Journal of Nuclear Materials 472 (April 2016): 227–39. http://dx.doi.org/10.1016/j.jnucmat.2015.10.050.

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Agostini, P., G. Barbieri, R. Coppola, M. Moncada, C. Ohms, and R. C. Wimpory. "Stress Distributions in P91 Martensitic Steel and in AISI 316LN Steel Welds for Gen IV Nuclear Applications." Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques 14, S1 (October 2020): S25—S30. http://dx.doi.org/10.1134/s1027451020070022.

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Fairushin, A. M., S. A. Kinev, and M. Z. Zaripov. "Effect of vibration treatment during welding on technological strength of chromium martensitic steel P91." IOP Conference Series: Materials Science and Engineering 1047, no. 1 (February 1, 2021): 012178. http://dx.doi.org/10.1088/1757-899x/1047/1/012178.

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Gutiérrez, Nilthon Zavaleta, Jorge Vera Alvarado, Hernán de Cicco, and Ariel Danón. "Microstructural Study of Welded Joints in a High Temperature Martensitic-ferritic ASTM A335 P91 Steel." Procedia Materials Science 8 (2015): 1140–49. http://dx.doi.org/10.1016/j.mspro.2015.04.178.

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Haribabu, S., C. Sudha, S. Raju, R. N. Hajra, R. Mythili, J. Jayaraj, S. Murugesan, and S. Saroja. "Effect of Al Addition on the Microstructure and Phase Stability of P91 Ferritic-Martensitic Steel." Metallurgical and Materials Transactions A 50, no. 3 (January 1, 2019): 1421–36. http://dx.doi.org/10.1007/s11661-018-5077-2.

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Sirohi, S., C. Pandey, and A. Goyal. "Characterization of structure-property relationship of martensitic P91 and high alloy ferritic austenitic F69 steel." International Journal of Pressure Vessels and Piping 188 (December 2020): 104179. http://dx.doi.org/10.1016/j.ijpvp.2020.104179.

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Chmielewski, Marek, and Leszek Piotrowski. "Application of the Barkhausen effect probe with adjustable magnetic field direction for stress state determination in the P91 steel pipe." Journal of Electrical Engineering 69, no. 6 (December 1, 2018): 497–501. http://dx.doi.org/10.2478/jee-2018-0085.

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Abstract The paper presents the results of application of a novel Barkhausen effect (BE) probe with adjustable magnetizing field direction for the stress level evaluation in ferromagnetic materials. The investigated sample was in a form of a pipe, made of P91 steel that was anisotropic due to the production process. The measurements were performed before and after welding, revealing the influence of welding process on the residual stress distribution. As was observed, the process introduced high tensile stresses in the normal to the weld direction (which can be interpreted as a decrease of strongly compressive residual stresses present in martensitic steels). In addition to that, the paper presents investigations of the measurement set performance corroborating its applicability for Barkhausen effect signal measurements in the magnetically anisotropic materials. The signals obtained during manual rotation of the probe (typical method of BE measurements) are very similar to those recorded during automatic field axis rotation.

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Saikumaran, A., R. Mythili, P. Magudapathy, and C. David. "Comparison of Irradiation-Induced Hardening Behavior of P91 Ferritic Martensitic Steel and CrFeMoV High-Entropy Alloy." Journal of Materials Engineering and Performance 30, no. 5 (April 19, 2021): 3547–55. http://dx.doi.org/10.1007/s11665-021-05661-z.

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Carrizo, Denise Alejandra, Jorge Ignacio Besoky, María Luppo, Claudio Danon, and Cinthia Paula Ramos. "Characterization of an ASTM A335 P91 ferritic-martensitic steel after continuous cooling cycles at moderate rates." Journal of Materials Research and Technology 8, no. 1 (January 2019): 923–34. http://dx.doi.org/10.1016/j.jmrt.2018.07.004.

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Christopher, J., and B. K. Choudhary. "Constitutive modelling of stress-relaxation behaviour of tempered martensitic P91 steel using sine hyperbolic rate law." Materials Chemistry and Physics 205 (February 2018): 442–51. http://dx.doi.org/10.1016/j.matchemphys.2017.11.053.

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Shibli, Ahmed, and Fred Starr. "Some aspects of plant and research experience in the use of new high strength martensitic steel P91." International Journal of Pressure Vessels and Piping 84, no. 1-2 (January 2007): 114–22. http://dx.doi.org/10.1016/j.ijpvp.2006.11.002.

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Bhanu, Vishwa, Dariusz Fydrych, Ankur Gupta, and Chandan Pandey. "Study on Microstructure and Mechanical Properties of Laser Welded Dissimilar Joint of P91 Steel and INCOLOY 800HT Nickel Alloy." Materials 14, no. 19 (October 7, 2021): 5876. http://dx.doi.org/10.3390/ma14195876.

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This investigation attempts to explore the weld characteristics of a laser welded dissimilar joint of ferritic/martensitic 9Cr-1Mo-V-Nb (P91) steel and Incoloy 800HT austenitic nickel alloy. This dissimilar joint is essential in power generating nuclear and thermal plants operating at 600–650 °C. In such critical operating conditions, it is essential for a dissimilar joint to preserve its characteristics and be free from any kind of defect. The difference between the physical properties of P91 and Incoloy 800HT makes their weldability challenging. Thus, the need for detailed characterization of this dissimilar weld arises. The present work intends to explore the usage of an unconventional welding process (i.e., laser beam welding) and its effect on the joint’s characteristics. The single-pass laser welding technique was employed to obtain maximum penetration through the keyhole mode. The welded joint morphology and mechanical properties were studied in as-welded (AW) and post-weld heat treatment (PWHT) conditions. The macro-optical examination shows the complete penetrations with no inclusion and porosities in the weld. The microstructural study was done in order to observe the precipitation and segregation of elements in dendritic and interface regions. Solidification cracks were observed in the weld fusion zone, confirming the susceptibility of Incoloy 800HT to such cracks due to a mismatch between the melting point and thermal conductivity of the base metals. Failure from base metal was observed in tensile test results of standard AW specimen with a yield stress of 265 MPa, and after PWHT, the value increased to 297 MPa. The peak hardness of 391 HV was observed in the P91 coarse grain heat-affected zone (CGHAZ), and PWHT confirmed the reduction in hardness. The impact toughness results that were obtained were inadequate, as the maximum value of impact toughness was obtained for AW P91 heat-affected zone (HAZ) 108 J and the minimum for PWHT Incoloy 800HT HAZ 45 J. Thus, difficulty in obtaining a dissimilar joint with Incoloy 800HT using the laser beam welding technique was observed due to its susceptibility to solidification cracking.

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Blinn, Bastian, David Görzen, Torsten Fischer, Bernd Kuhn, and Tilmann Beck. "Analysis of the Thermomechanical Fatigue Behavior of Fully Ferritic High Chromium Steel Crofer®22 H with Cyclic Indentation Testing." Applied Sciences 10, no. 18 (September 16, 2020): 6461. http://dx.doi.org/10.3390/app10186461.

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The 22 wt.% Cr, fully ferritic stainless steel Crofer®22 H has higher thermomechanical fatigue (TMF)- lifetime compared to advanced ferritic-martensitic P91, which is assumed to be caused by different damage tolerance, leading to differences in crack propagation and failure mechanisms. To analyze this, instrumented cyclic indentation tests (CITs) were used because the material’s cyclic hardening potential—which strongly correlates with damage tolerance, can be determined by analyzing the deformation behavior in CITs. In the presented work, CITs were performed for both materials at specimens loaded for different numbers of TMF-cycles. These investigations show higher damage tolerance for Crofer®22 H and demonstrate changes in damage tolerance during TMF-loading for both materials, which correlates with the cyclic deformation behavior observed in TMF-tests. Furthermore, the results obtained at Crofer®22 H indicate an increase of damage tolerance in the second half of TMF-lifetime, which cannot be observed for P91. Moreover, CITs were performed at Crofer®22 H in the vicinity of a fatigue crack, enabling to locally analyze the damage tolerance. These CITs show differences between crack edges and the crack tip. Conclusively, the presented results demonstrate that CITs can be utilized to analyze TMF-induced changes in damage tolerance.

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Naveed, N. "Characterisation of short-length scale residual stress variations within an electron beam welded P91 Ferritic–Martensitic steel plate." Heliyon 7, no. 5 (May 2021): e07045. http://dx.doi.org/10.1016/j.heliyon.2021.e07045.

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Rai, Arun Kumar, Ramakanta Biswal, Ram Kishor Gupta, Sanjay Kumar Rai, Rashmi Singh, Uttam Kumar Goutam, K. Ranganathan, P. Ganesh, Rakesh Kaul, and Kushvinder Singh Bindra. "Enhancement of oxidation resistance of modified P91 grade ferritic-martensitic steel by surface modification using laser shock peening." Applied Surface Science 495 (November 2019): 143611. http://dx.doi.org/10.1016/j.apsusc.2019.143611.

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Vidyarthy, R. S., and D. K. Dwivedi. "Effect of shielding gas composition and activating flux on the weld bead morphology of the P91 ferritic/martensitic steel." Materials Research Express 6, no. 8 (June 12, 2019): 0865f7. http://dx.doi.org/10.1088/2053-1591/ab2699.

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Piotrowski, Leszek, Marek Chmielewski, and Zbigniew Kowalewski. "On the application of magnetoelastic properties measurements for plastic level determination in martensitic steels." Journal of Electrical Engineering 69, no. 6 (December 1, 2018): 502–6. http://dx.doi.org/10.2478/jee-2018-0086.

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Abstract The change in the dislocation density, induced by plastic deformation, influences strongly the magnetic domain structure inside the material. Being so, classic parameters, like the coercivity or magnetic permeability, can be a good measure of the deformation level, yet their reliable determination in a non-destructive way in industrial environment is problematic. The magnetoacoustic emission (MAE) which results from the non-180° domain walls (DW) movement in materials with non-zero magnetostriction can be used as an alternative. The intensity of the MAE signal changes strongly as a result of plastic deformation for both tensile and compressive deformation. It is however possible to discern those cases by analysing the changes in the shape of the MAE signal envelopes. The set of the martensitic steel samples (P91) deformed up to 10% (for both tension and compression) was investigated. Due to geometrical limitations imposed by the special mounting system, enabling compression without buckling, the sample had the shape resulting in low signal to noise (S/N) ratio. Being so the optimization of FFT filtering and wavelet analysis was performed in order to improve sensitivity of the proposed method of deformation level determination.

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Sklenička, Vàclav, Květa Kuchařová, Marie Kvapilová, Luboš Kloc, Jiří Dvořák, and Petr Král. "High-Temperature Creep Tests of Two Creep-Resistant Materials at Constant Stress and Constant Load." Key Engineering Materials 827 (December 2019): 246–51. http://dx.doi.org/10.4028/www.scientific.net/kem.827.246.

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Creep is defined as a time dependent component of plastic deformation. Creep tests can be performed either at constant load or at constant applied stress. Engineering creep tests carried out at constant load are aimed at determination of the creep strength or creep fracture strength, i.e. the data needed for design. The constant stress tests are important as a data source for fundamental investigations of creep deformation and fracture mechanisms and for finite element modelling of more complex stress situations. For some materials, the difference between the two type of testing can be very small, while for other materials is large, depending on the creep plasticity of the material under testing. The paper aims to compare the creep results of two different creep-resistant materials: the advanced 9%Cr martensitic steel (ASME Grade P91) and a Zr1%Nb alloy obtained by both testing methods and to clarify the decisive factors causing observed differences in their creep behaviour.

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Grégoire, B., C. Oskay, T. M. Meißner, and M. C. Galetz. "Corrosion mechanisms of ferritic-martensitic P91 steel and Inconel 600 nickel-based alloy in molten chlorides. Part I: NaCl–KCl binary system." Solar Energy Materials and Solar Cells 215 (September 2020): 110659. http://dx.doi.org/10.1016/j.solmat.2020.110659.

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Thakare, Jayant Gopal, Chandan Pandey, Manas Mohan Mahapatra, and Rahul S. Mulik. "An assessment for mechanical and microstructure behavior of dissimilar material welded joint between nuclear grade martensitic P91 and austenitic SS304 L steel." Journal of Manufacturing Processes 48 (December 2019): 249–59. http://dx.doi.org/10.1016/j.jmapro.2019.10.002.

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Pal, Vinay Kumar, and Lokendra Pal Singh. "Effect of Varying Heat Treatment Regimes on Microstructure and Mechanical Properties of P92 Steel Welds." Journal of Mechanical Engineering 25, no. 1 (June 30, 2022): 38–59. http://dx.doi.org/10.15407/pmach2022.02.038.

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Cr-Mo steels are well-known for their high temperature application in thermal power plants. P91, P911 and P92 are most commonly used Cr-Mo steels for high temperature application. The steels de-rived their strength from tempered martensite and precipitates of MX and M23C6 type. The normalizing and tempering of the steels are performed before putting them in service condition. The present manuscript describes the effect of the varying heat treatment regimes on microstructure and mechanical properties of the P92 steel. The normalizing effect on microstructure and mechanical properties has been studied. The normalizing was performed in the range of 950–1150 ºC. The effect of the varying tempering time on mechanical behavior of the P92 steel has also been studied and effort to develop relation between microstructure and mechanical properties was made. Optical microscope and scanning electron microscope have been utilized for microstructure study. To characterize the mechanical behavior, tensile, hardness and Charpy impact toughness tests were performed.

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Grégoire, B., C. Oskay, T. M. Meißner, and M. C. Galetz. "Corrosion mechanisms of ferritic-martensitic P91 steel and Inconel 600 nickel-based alloy in molten chlorides. Part II: NaCl-KCl-MgCl2 ternary system." Solar Energy Materials and Solar Cells 216 (October 2020): 110675. http://dx.doi.org/10.1016/j.solmat.2020.110675.

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Akanda, Sajedur R., Richard P. Oleksak, Reyixiati Repukaiti, Kyle A. Rozman, and Ömer N. Doğan. "Effect of Specimen Thickness on the Degradation of Mechanical Properties of Ferritic-Martensitic P91 Steel by Direct-fired Supercritical CO2 Power Cycle Environment." Metallurgical and Materials Transactions A 52, no. 1 (November 3, 2020): 82–93. http://dx.doi.org/10.1007/s11661-020-06065-9.

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Koo, Ja Min, Sung Yong Kim, Kee Sam Shin, Yeon Gil Jung, and Sung Kang Hur. "Embrittlement Behavior of Isothermally Heat-Treated T/P92 Steel at 350°C." Key Engineering Materials 345-346 (August 2007): 465–68. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.465.

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P92 steels as well as P91 are widely used as boiler tube materials of ultra super critical (USC) power plants these days. And thus embrittlement is very important for structural integrity of the USC plants. The embrittlement was observed when P92 (Modified 9Cr-1.8W-0.5Mo-V-Nb) steels were quenched to and held at the temperature of 320 to 350°C, which were the temperatures intermediate between Ms and Mf, and then air-cooled. Nearly same kind of the embrittlement had been observed with the T/P91 steels and a theory had been proposed to explain the mechanism of the embrittlement by us. From the theory, the embrittlement might be caused by the brittle martensite which is freshly formed during air-cooling. We tried to apply the theory for the embrittlement of the T/P92 steel. The behaviors of the embrittled T/P92 steel were explained well by the theory.

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Kumar, S., V. K. Yadav, S. K. Sharma, C. Pandey, A. Goyal, and P. Kumar. "Role of dissimilar Ni-based ERNiCrMo-3 filler on the microstructure, mechanical properties and weld induced residual stresses of the ferritic/martensitic P91 steel welds joint." International Journal of Pressure Vessels and Piping 193 (October 2021): 104443. http://dx.doi.org/10.1016/j.ijpvp.2021.104443.

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Hiwa, M. Q., and M. H. Ari. "INVESTIGATION OF LONG AND SHORT TERM IRRADIATION HARDENING OF P91 AND P92 FERRITIC/MARTENSITIC STEELS." Problems of Atomic Science and Technology, Ser. Thermonuclear Fusion 42, no. 2 (2019): 81–88. http://dx.doi.org/10.21517/0202-3822-2019-42-2-81-88.

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Jaremkiewicz, Magdalena. "Determination of transient fluid temperature using the inverse method." Archives of Thermodynamics 35, no. 1 (March 1, 2014): 61–76. http://dx.doi.org/10.2478/aoter-2014-0004.

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Abstract This paper proposes an inverse method to obtain accurate measurements of the transient temperature of fluid. A method for unit step and linear rise of temperature is presented. For this purpose, the thermometer housing is modelled as a full cylindrical element (with no inner hole), divided into four control volumes. Using the control volume method, the heat balance equations can be written for each of the nodes for each of the control volumes. Thus, for a known temperature in the middle of the cylindrical element, the distribution of temperature in three nodes and heat flux at the outer surface were obtained. For a known value of the heat transfer coefficient the temperature of the fluid can be calculated using the boundary condition. Additionally, results of experimental research are presented. The research was carried out during the start-up of an experimental installation, which comprises: a steam generator unit, an installation for boiler feed water treatment, a tray-type deaerator, a blow down flashvessel for heat recovery, a steam pressure reduction station, a boiler control system and a steam header made of martensitic high alloy P91 steel. Based on temperature measurements made in the steam header using the inverse method, accurate measurements of the transient temperature of the steam were obtained. The results of the calculations are compared with the real temperature of the steam, which can be determined for a known pressure and enthalpy.

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Zhu, Jun, and Yin Zhong Shen. "Irradiation Hardening in Ferritic/Martensitic Steel P92 during Ar-Ions Irradiation at Elevated Temperature." Applied Mechanics and Materials 378 (August 2013): 289–92. http://dx.doi.org/10.4028/www.scientific.net/amm.378.289.

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The irradiation hardening behavior in a commercial ferritic/martensitic steel P92 has been investigated through 250KeV Ar-ions irradiations to a dose of 10dpa at 473, 673 and 973K combined with nanoindentation techniques. The results show that irradiation-induced hardening was observed at the all irradiation temperatures. There appear to have no previous reports of the irradiation-induced hardening at the temperature higher than 873K in ferritic/martensitic steels. Irradiation-induced hardening at elevated temperature of 973K has been found, for the first time, in ferritic/martensitic steel. The irradiation-induced hardening at 973K in the ferritic/martensitic steel P92 may be ascribed to the defects in the steel generated by Ar-ions irradiation.

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Kolesnikov, Dmitro, Andrey Belyakov, Alla Kipelova, Valeriy Dudko, Rustam Kaibyshev, and Dmitri A. Molodov. "Zener Pinning Pressure in Tempered Martensite Lath Structure." Materials Science Forum 715-716 (April 2012): 745–50. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.745.

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The Zener drag force exerted by M23C6carbides, Fe2(W,Mo) Laves phase and M(C,N) particles for migration of different grain boundaries in P92-type and P911+3%Co heat-resistant steels was calculated. In particular, the prior austenite grain boundaries (PAGB), boundaries of packets and blocks, which are mainly high-angle boundaries (HAGB), were addressed. Zener pinning pressures were determined for each type of dispersoids separately taking into account that the M23C6carbides, Fe2(W,Mo) Laves phase are inhomogeneously distributed such that they are mainly located at the boundaries, and the M(C,N) dispersoids are uniformly distributed throughout the metallic matrix. In the both steels, the pinning pressure from the second phase particles located at grain boundaries is about an order of magnitude higher than that caused by homogeneously distributed MX precipitates. In spite of numerous second phase particles precipitated during tempering, grain growth (although rather moderate) occurred during the creep tests of the studied materials. The driving pressure for grain boundary motion might be mostly associated with high dislocation density retained in the tempered martensite structure. The resulting pressure for grain growth in the P92-type steel under creep conditions at 600 and 650°C is somewhat higher than that for the P911 steel.

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Liu, Chen Xi, Ze Sheng Yan, Zhi Zhong Dong, Yong Chang Liu, and Bao Qun Ning. "Effects of Two-Step Tempering Treatment on the Microstructural Formation of T91 Ferritic Steels." Solid State Phenomena 172-174 (June 2011): 875–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.172-174.875.

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As a representative type of high Cr ferritic heat-resistant steels, T91 steels (ASME SA-213 T91/P91) has been recognized as the preferable materials and widely used in high-temperature structural components such as header and main steam pipe in advanced power plants. For the service condition is tempered martensites, its corresponding microstructure and mechanical performance are mainly adjusted by the tempering treatment. After exploring the size and number of MX and M23C6precipitating particles and the width of martensitic lath as a function of tempering temperature, it is recognized that the high tempering temperature leads to an increase of secondary hardening effect, while the low tempering temperature brings a high dislocation density and a small martensitic lath. Hence, a two-step tempering treatment was developed after the traditional normalizing process, in which the T91 steels sample was firstly tempered at a low temperature in order to form some precipitates and then tempered at a high temperature. Those firstly-formed precipitates would pin the dislocations and martensitic laths on the subsequent tempering process, which finally leads to more precipitates, higher dislocation density and smaller martensitic lath width than that obtained from the traditional tempering process.

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Sklenička, Vaclav, Květa Kuchařová, Milan Svoboda, and Ivan Saxl. "Creep Response and Microstructural Changes during Intermittent Heating of Advanced Tempered Martensitic 9-12%Cr Steels." Materials Science Forum 604-605 (October 2008): 367–77. http://dx.doi.org/10.4028/www.scientific.net/msf.604-605.367.

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Significant developments have been made in recent years in the description of microstructure evolution and its effects on the creep behaviour in advanced 9-12%Cr steels. However, data available for assessing the predictability of the creep behaviour are somewhat scarce since creep testing has generally been for constant temperature and load conditions. The present investigation was conducted on three advanced 9-12%Cr martensitic/ferritic steels (P91, P92 and E911) in an effort to obtain more complete description and understanding of the role of degradation processes in high temperature creep during intermittent heating. A comparison between the creep characteristics of non-steady and monotonously loaded creep specimens has revealed no significant deterioration of the creep strength and fracture resistance of the steels P91, P92 and E911 under non-steady loading in power-law (dislocation) creep. The final part of this paper deals with detailed experimental microstructural and fractographic investigations of crept specimens to explain the observed creep behaviour. Special attention is paid to the thermodynamic calculations using the software package Thermo-Calc, that have been used to predict precipitation reactions during intermittent heating of 9-12% chromium steels. The results of the thermodynamic calculations are in a good agreement with experimental data.

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Xu, Xue Xia, Jie Ouyang, Xiao Guang Niu, Yan Ting Feng, and Wen Peng Li. "Study on Relationship of Abnormal Heat Treatment, Microstructure and Properties of P91 Steel." Advanced Materials Research 311-313 (August 2011): 830–34. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.830.

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Improper heat treatment may result in unsatisfactory microstructure and mechanical properties for P91 steel. In this work, the effect of abnormal heat treatment on microstructure and properties of P91 steel were studied. Results showed that with the normalization temperature increased from 860°C to 1000°C, the microstructures of P91 steel are ferrite, mixture of ferrite and martensite, and tempered martensite correspondingly. Cooling rate after austenization has important influence on microstructure and properties. The tempered microstructure has a gradual transition from coarse inhomogeneous ferrite to finer martensite when the cooling rate increased from 1 to 3°C/min. The reduced temperature normalization has no significant effect on hardness even as low as 860°C under aircooling condition, whereas the hareness is inadequate when the cooling rate is too slow. Incomplete austenization and transformation in dual phase zone may account for the phenomenon.

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Sklenička, Vàclav, Květa Kuchařová, Milan Svoboda, and Ivan Saxl. "Effect of Intermittent Heating on Creep Behaviour of Advanced 9-12%Cr Power Plant Steels." Materials Science Forum 561-565 (October 2007): 81–84. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.81.

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Critical high temperature components of machines and structures are often subjected to complicated load and temperature histories. The closest laboratory simulation of service loading conditions involves creep under nonsteady temperatures and stresses. For example, the start up and shut down cycles can be well simulated by temperature variation by use of intermittent heating tests. Such approach is illustrated by recent experimental results on advanced high creep strength 9- 12%Cr ferritic-martensitic steels (P91, P92 and E911). A comparison between the creep characteristics of nonsteady and monotonously creep specimens has revealed no significant deterioration of the creep strength and fracture resistance of these steels in power-law (dislocation) creep.

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Skorobogatykh, Vladimir, Izabella Schenkova, Valeriy Dudko, Andrey Belyakov, and Rustam Kaibyshev. "Microstructure Evolution in a 9%Cr Heat Resistant Steel during Creep Tests." Materials Science Forum 638-642 (January 2010): 2315–20. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2315.

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Dynamic structural changes during creep tests for about 103 hours at 600 and 650oC were investigated in a P92-type 9%Cr martensitic heat resistant steel. The structural changes are characterised by the development of relatively large equiaxed subgrains with relatively low dislocation densities in place of initial martensite laths. The coarsening of substructure was accompanied by a growth of second phase precipitates. The final grain/subgrain sizes and dislocation densities evolved after the creep tests were in rough correlation with applied stresses, i.e. larger (sub)grains developed under lower stresses. The structural mechanism responsible for microstructure evolution was considered as a kind of continuous dynamic recrystallization.

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Journal articles on the topic 'P91 martensitic steel'

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