摘要
为了明确Mo元素对极地船舶用钢显微组织及低温韧性的影响,采用含Mo和不含Mo两种化学成分坯料进行轧制,并结合SEM、EBSD、系列低温冲击试验对其组织性能进行了研究。结果表明,在较大冷速和较低终冷温度条件下,Mo元素的添加,增加了奥氏体的淬透性、促进了贝氏体的形成,减少了铁素体含量,导致大角度晶界(HAGB)比例减小且有效晶粒分布不均匀;此外,使C元素只能进行短程扩散,最终导致大量带尖端或长条状渗碳体在贝氏体板条界富集,降低了晶界或亚晶界之间的界面结合力,增大了冲击过程中界面间的应力集中。HAGB比例减小、不规则渗碳体的富集是含Mo钢板低温冲击韧性恶化的重要原因。
In order to clarify the effect of Mo on the microstructure and low-temperature toughness of polar marine steel,two billets(containing Mo and without Mo)were rolled,and the experiments were carried out to study the microstructure and properties of plates by means of SEM,EBSD and low-temperature impact tests.The results showed that Mo promotes bainite formation and decreases ferrite content by increasing the hardenability of austenite at a higher cooling rate and low final cooling temperature,which ultimately leads to a decrease in the proportion of high angle grain boundary(HAGB)and an uneven distribution of effective grains.The addition of Mo decreases the diffusion of C element,so that C can only diffuse in a short range,and eventually leads to the enrichment of a large number of tapered or strip cementites at the bainite lath boundary,reduces the interfacial bonding force between grain boundaries or sub-grain boundaries,and enhances the stress concentration during impact test.The decrease of HAGB proportion and the enrichment of irregular cementite are the important reasons for deteriorating the impact toughness at low temperature.
作者
陈林恒
邱保文
赵晋斌
王红涛
田勇
屈智忠
CHEN Lin-heng;QIU Bao-wen;ZHAO Jin-bin;WANG Hong-tao;TIAN Yong;QU Zhi-zhong(Nanjing Iron and Steel Group Co.,Ltd.,Nanjing 210035,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)
出处
《轧钢》
2020年第5期1-5,共5页
Steel Rolling
基金
国家重点研发计划资助项目(2016YFB0300600)。
关键词
Mo元素
超高强极地船舶用钢
显微组织
低温韧性
Mo element
ultra-high strength polar marine steel
microstructure
low-temperature toughness
