Fatih Muhammad R R, Chen Hou-Jen, Lin Hsin-Chih
Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
Materials (Basel). 2025 Apr 14;18(8):1784. doi: 10.3390/ma18081784.
Martensitic stainless steel (MSS) is widely used in several parts of automobiles where high strength, hardness, and corrosion resistance are required. However, the metastability of retained austenite can transform into martensite under severe deformation, adversely affecting material properties. Cryogenic treatments (CTs) have been extensively employed in iron-based alloys for fastener application due to their advantageous effect. This study explores the heat treatment processes applied to 13Cr-2Ni-2Mo martensitic stainless steel (MSS), including austenitizing, cryogenic treatment, and tempering cycles. Cryogenic treatment at (-150 °C) for varying durations, followed by tempering at 200 °C for 2 h, and the impact of post-cryogenic tempering at 200 °C for different tempering duration on the microstructure and mechanical properties were evaluated. Experimental results indicate that the sample quenched at 1040 °C for 2 h (CHT) contains lath martensite, retained austenite, δ-ferrite, and undissolved carbide precipitation. Compared to as-quenched samples, hardness decreased by 5.04%, 7.24%, and 7.32% after tempering for 2 h, 5 h, and 10 h, respectively. Extending cryogenic durations to 2 h, 12 h, and 20 h promoted nucleation of a mixture of MC and MC small globular carbides (SGCs) and grain refinement but resulted in hardness reductions of 5.04%, 5.32%, and 8.36%, respectively. The reduction in hardness is primarily attributed to a decrease in solid solution strengthening and promoted carbide coarsening.
马氏体不锈钢（MSS）广泛应用于汽车的多个部件，这些部件需要高强度、硬度和耐腐蚀性。然而，残余奥氏体的亚稳定性在严重变形下会转变为马氏体，对材料性能产生不利影响。由于其有利效果，深冷处理（CTs）已广泛应用于铁基合金的紧固件应用中。本研究探索了应用于13Cr - 2Ni - 2Mo马氏体不锈钢（MSS）的热处理工艺，包括奥氏体化、深冷处理和回火循环。在（-150°C）下进行不同时长的深冷处理，随后在200°C回火2小时，并评估了在200°C下不同回火时长的深冷后回火对微观结构和力学性能的影响。实验结果表明，在1040°C淬火2小时（CHT）的样品包含板条马氏体、残余奥氏体、δ-铁素体和未溶解的碳化物析出。与淬火态样品相比，回火2小时、5小时和10小时后硬度分别降低了5.04%、7.24%和7.32%。将深冷时长延长至2小时、12小时和20小时促进了MC和MC小球状碳化物（SGCs）混合物的形核以及晶粒细化，但硬度分别降低了5.04%、5.32%和8.36%。硬度降低主要归因于固溶强化的降低和碳化物粗化的促进。
