摘要
运用拉伸、冲击、SEM、TEM和EDS等测试方法,对添加稀土镧和未添加稀土镧的Nb-Ti-Mo系管线钢进行研究,分析稀土元素和卷取温度对组织和性能的影响。结果表明:稀土元素镧能有效的改善夹杂物的形貌,在铸坯中形成由Al、Mn、O、S、La组成的复合夹杂物,并最终提高管线钢的低温冲击韧性;两种管线钢的强度均随着卷取温度的降低而升高,且添加稀土镧的Nb-Ti-Mo系管线钢的强度上升趋势更为显著;并且镧能够提高管线钢低温卷取时获得板条贝氏体的能力,精细结构中观察到有200～900 nm的亚板条结构,M/A组元中马氏体为孪晶结构。
Nb-Ti-Mo pipeline steels with or without La addition were fabricated. Effects of rare earth La and coiling temperature on microstructure and mechanical properties of the steels were investigated by means of TEM, SEM and EDS analysis, and tensile and impact tests. The results show that the morphology of inclusions in the La-added steel is effectively refined and spherical complex inclusions of A1, Mn, O and S containing La are formed, which improves the low-temperture impact toughness of the steels. With the decreasing of the coiling temperature, strength of both steels with and without La increases, but the trend of the steel with La is more obvious. The addition of lanthanum can improve the formation of lath bainite for the steel at lower coiling temperature. Sub-lath structure of 200 - 900 nm is observed in the fine structure, and M/A components have the twin martensite structure.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第12期82-87,共6页
Transactions of Materials and Heat Treatment
基金
国家"十一五"科技支撑计划(2006BAE03A06)
关键词
稀土元素
管线钢
高韧性
夹杂物
rare earth element
pipeline
high toughness
inclusion
