Abstract: The ultralow temperature impact tests for S31608 stainless steel(/%:0.065C,16.50Cr,11.80Ni,2.2Mo) Φ168 mm×13 mm extruded seamless pipe (solid-solution-treated at 1060- 1020 ℃ with grain size 50.2- 17.6 μm)at 20 ℃ and-40--269 ℃ are carried out, and the impact fracture is analyzed by scanning electron microscope. The results show that the S31608 steel has high impact energy i.e.290-360Jat-269-20 ℃,and only the grain size of steel has obvious effect on impact energy at -80℃ and- 120 ℃,the impact energy of steel with grain size 25.3-50.2 μm (solid-solution-treated at 1060- 1040℃)at-80℃ and- 120℃ is330-360J,but that of steel with grain size 17.6 μm(solid-solution-treated at1020℃)at-80℃ and- 120℃ is 320-360J.

Key words: S31608, Utra Low Temperature, Grain Size, Impact Energy, Fracture Morphology

摘要： 对1060～1020℃固溶、晶粒尺寸50.2～17.6μm的S31608不锈钢(/%:0.065C,16.50Cr, 11.80Ni, 2.2Mo)Φ168 mm×13 mm挤压无缝管进行了20℃和-40～-269℃超低温冲击试验。并用扫描电子显微镜进行冲击断口分析。结果表明，S31608钢在-296～20℃具有较高冲击功，即290～360 J,且晶粒尺寸只对-80℃和-120℃冲击功明显的影响，25.3～50.2μm晶粒钢(1060～1040℃固溶处理)的-80℃和-120℃冲击功为330～360 J,17.6μm晶粒钢(1020℃固溶处理)的-80℃和-120℃冲击功为320～360 J。

关键词: 31608, 超低温；晶粒尺寸；冲击功；断口形貌