应力腐蚀开裂是影响超深井承压件安全稳定运行的重要因素。本文借助慢应变速率拉伸机、电化学工作站、X射线衍射仪、扫描电镜、透射电镜等实验设备，研究了回火温度对超深井防喷器组承压件F22M钢耐应力腐蚀性能的影响。结果表明，当回火温度由610℃升高到670℃时，F22M钢中位错密度由6.29×1015 m-2降低至3.51×1015 m-2，针状碳化物转变为细小弥散的颗粒状碳化物，大角度晶界占比升高；与此对应，F22M钢的应力腐蚀敏感性指数由0.76降低至0.12，耐应力腐蚀性能大幅提升。随着回火温度的升高，晶界类型的变化影响氢的分布和裂纹扩展，能够小幅改善F22M钢的耐应力腐蚀性能；位错密度的降低和碳化物尺寸的减小，能够降低F22M钢中局部氢和应力双重富集的倾向性，显著减小应力腐蚀敏感性系数，大幅提升F22M钢的耐应力腐蚀性能。

Existing low-alloy Cr-Mo steels of 35CrMo, 20CrMoV, and 25CrNiMo, are inadequate to meet the requirements of heat resistance, corrosion resistance, strength and toughness necessary for the pressure components of blowout preventers (BOPs) with large and thick sections in ultra-deep wells. Recently, a novel F22M steel, synchronously micro-alloyed with vanadium, boron and rare earth elements, has been developed and applied in a test ultra-deep well. Under the extreme conditions about 200 °C and 140 MPa in ultra-deep wells, hydrogen atoms derived from H2S decomposition synergistically interact with tensile stress and corrosive environments, potentially inducing stress corrosion cracking (SCC). The resulting crack growth rate could reach up to 10-6 mm/s, severely compromising the service safety of critical pressure-bearing components such as blowout preventers. Tempering, as a critical post-quenching heat treatment for Cr-Mo steels, significantly modifies microstructure features including dislocation density, carbide morphology, and grain boundary characteristics, thereby directly governing the resistance to SCC. The present work systematically investigated the effects of tempering temperature on microstructure evolution and stress corrosion resistance of F22M steel, using the slow strain rate test, electrochemical analysis, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. As the tempering temperature elevated from 610°C to 670°C, the dislocation density in F22M steel decreased from 6.29 × 1015 m-2 to 3.51 × 1015 m-2, the morphology of carbides transitioned from needle shape to spherical particle, and the proportion of high-angle grain boundaries increased from 41.0% to 54.3%. The reduction in dislocation density and change of carbide morphologies could prominently diminish the potential for local hydrogen accumulation and stress concentration, while grain boundary characteristics improvement further influencing hydrogen distribution and crack propagation. As a result, the stress corrosion susceptibility index has been decreased by 84.21%, indicating that the stress corrosion cracking resistance was substantially enhanced.