Abstract: The test ultra-low carbon austenite stainless steel 316L (/%: 0. 010 〜0. 013C, 17. 50 〜17. 67Cr, 10. 10-10. 60Ni, 1.89 〜2. 02Mo, 0. 020 - 0. 201 N) is melted by a 200 kg vacuum induction furnace and hot rolled to 15 mm steel plate by 550 mm mill. The structure and impact toughness of steel 316L heat treated at 1 050 T for 40 min, water cooling, then at 750℃ for 25 ~ 100 h, air cooling has been studied. Results show that with increasing ageing time the impact energy of steel 316L decreases ； with same ageing time the impact energy of 0. 201% N high nitrogen steel 316L is lower than that of 0. 020% N low nitrogen steel 316L, with ageing at 750 ℃ for 100 h, the impact energies of high and low nitrogen steel 316L are respectively 40 J and 150 J ； the main precipitates in low nitrogen steel 316L are 3 ~5 μm carbides dispersed distributed at grain boundary and in grain and the main precipitates in high nitrogen steel 316L are 100 〜200 μm carbo-nitride and σ- phase distributed along grain boundary.

摘要： 316L超低碳不锈钢(/%:0.010～0.013C、17.50～17.67Cr、10.10～10.60Ni、1.89～2.02Mo、0.020～0.201N)由200 kg真空感应炉冶炼,并经550 mm轧机热轧成15 mm钢板。研究了1 050℃40 min水冷,750℃25～100 h空冷后316L钢的组织和冲击韧性。结果表明,随时效时间增加,316L钢的冲击功下降;同样时效时间,0.201%N的高氮316L钢的冲击功低于0.020%N较低氮316L钢,750℃100 h时效后两者的冲击功分别为40 J和150 J。低氮316L钢主要析出物为碳化物,在晶界和晶内呈细小弥散分布,尺寸为3～5μm;高氮316L钢析出物为100～200μm氮碳化物和σ-相,沿晶界分布。