摘要
用Gleeble-3800热模拟机对Ni-Cr-Mo-B低合金高强度钢进行不同焊接热输入条件的下热模拟试验,研究了模拟焊接热影响区的组织和性能,探讨了不同热输入条件(对应不同的t8/5)对钢中微观组织及形态的影响以及组织与低温韧性的关系。结果表明:随着热输入能量的增加,此类钢焊接热影响区的低温韧性呈现先增后降的规律。当以中等焊接热输入施焊,在热影响区形成贝氏体/马氏体复相组织,先形成的贝氏体对原始奥氏体晶粒的分割作用,使后生成的板条马氏体具有更细的板条束,从而获得最佳的低温韧性。而低热输入时形成全马氏体组织,高热输入时获得一定量的粒状贝氏体,两种组织的低温韧性均低于贝氏体/马氏体的复相组织。
Mierostructure and properties of HAZ in a Ni-Cr-Mo-B HSLA steel were investigated by welding simulation on a Gleeble-3800 thermal simulator. The influence of ts/5 on morphology of microstructure and effect of the mierostructure on low temperature toughness were discussed. The results indicate that the low temperature toughness of HAZ is changed with ts/5 and cooling rate. When welding at medium heat input energy, better low temperature toughness could be obtained by bainite/martensite （B/M） duplex microstructure in which subsequent martensite is isolated by small amount of pre-formed bainite, resulting in a finer martensite packet. Whereas, both the low temperature toughness of full martensite mierostructure formed with lower heat input and that of microstrueture with some granular bainite formed with higher heat input are lower than that of B/M duplex microstructure by more or less degree.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第8期69-73,共5页
Transactions of Materials and Heat Treatment
