低温设备和管道用304不锈钢热诱发马氏体相变特征研究

Study of Thermally Induced Martensite Forming Characteristics of Stainless Steel 304 Used in Low Temperature Equipment and Piping

借助于X-射线衍射技术,研究了304亚稳奥氏体不锈钢热诱发马氏体相变倾向。研究结果表明:C、Mn、Cr和Ni接近下限,钢的稳定性严重下降,固溶态即形成少量α′马氏体,液氮内冷却后α′马氏体急剧增加,并伴随有ε马氏体形成,室温发生应变诱发ε和α′马氏体相变,而且室温预应变进一步增大低温热诱发马氏体相变倾向。ε马氏体的变化与α′马氏体的累积量有关,α′马氏体较小时,ε马氏体量增加,α′马氏体累积到一定程度后ε马氏体下降,直至消失。

With the technique of X-ray diffraction,the trend of martensite forming existed in sub-stable austenitic steel 304 was studied.It was shown that when the content of C,Mn,Cr and Ni reach the lowest limit,the stability of the steel decrease seriously,a fewαmartensite had been formed in solid fusion phase.When the steel was cooled with liquid nitrogen,the quantity ofαmartensite increase sharply and someεmartensite was formed in accompany.The strain produced in room temperature will induce the forming ofεandαmartensites,moreover,the pre-strain in room temperature will further increase the trend to formεandαmartensites.The change ofεmartensites is related to accumulated quantity ofαmartensites.With a few ofαmartensites,the quantity ofεmartensites will increase,however,with the accumulation ofαmartensites,εmartensites will decrease,and up to disappear finally.