典型Cr-Ni-Mo-N高合金双相不锈钢热加工性能研究

Study on Hot Working Performance to Typical Cr-Ni-Mo-N High Alloy Duplex Stainless Steel

试验钢的典型高合金双相不锈钢S32707(022Cr27Ni7Mo5N)、S32750(022Cr25Ni7Mo4N)、S32205(022Cr23Ni5Mo3N)、S31803(022Cr22Ni5Mo3N)在生产坯料上取样,采取了不同的热处理、热加工和热穿孔以及调整化学成分等方法,研究了组织及工艺对其热加工性能的影响。结果表明:两相比例和σ相的析出情况与热穿孔温度和冷变形的中间退火密切相关,S32707钢的二次相的析出速度和析出量远超过S32750、S32205及S31803双相不锈钢。对S32707双相不锈钢需适当降低Cr(Cr≤27%)、N(N≤0.4%)含量,提高Mo(4%~5%Mo)含量,合理控制加热速度(2~2.5℃/min)及终轧(锻)温度(≥1060℃),并注意回炉加热和圆管坯中心钻孔的影响,可提高热加工塑性,防止开裂。

Tested typical duplex stainless steel grades S32707(022Cr27Ni7Mo5N)、S32750(022Cr25Ni7Mo4N)、S32205(022 Cr23 Ni5 Mo3 N)and S31803(022 Cr22 Ni5 Mo3 N)are sampled from produced billet,and by various heat treatment,hot working and hot piercing process as well as chemical composition adjustment,the effect of microstructure and produced process on hot working performance has been studied.The results show that the phase ratio andσphase precipitation are closely related to the temperature of hot piercing and solution treatment and cold forming annealing,and the precipitation speed and amount of second phase in S32707 far exceed S32750,S32205 and S31803 duplex stainless steel grades.For S32707 duplex stainless grades,lowering Cr(Cr≤27%)and N(N≤0.4%)content,increasing Mo(4%~5%Mo)content,properly controlling the heating rate(2~2.5℃/min)and finishing rolling(forging)temperature(≥1060℃)and paying attention to the effect of reheating and tube billet drilling could improve hot working ductility and prevent cracking.