摘要
由于沿厚度方向冷却速度不同,超厚板表层与1/4 H处(H为厚度)具有不同的微观组织。为了研究微观组织对超厚板不同部位强韧性能的影响,进行了室温拉伸、低温冲击等试验,并利用SEM、TEM、EBSD等技术手段对超厚板表层及1/4 H处微观组织及力学性能进行了表征分析。结果表明,试验钢表层较为细小的马氏体板条块(Block)及高于1/4 H处的位错密度导致表层屈服强度略高于1/4 H处。表层及1/4 H处低温冲击性能差异明显,-60℃冲击功较1/4 H处降幅约为12.6%,-80℃冲击功降幅约为24.7%,这是由于表层马氏体板条块界等大角度晶界(HAGB)数密度低于1/4 H处马氏体+贝氏体混合组织的大角度晶界数密度,同时过快的冷却速度使得表层马氏体组织中具有更大的内应力集中,增加了微裂纹萌生的可能性。
Due to the different cooling rates along the thickness direction,the surface and 1/4 H(Hrepresents thickness)of the ultra thick plate have different microstructures.In order to study the influence of microstructures on the strength and toughness of different parts of ultra thick plate,the tensile test at room temperature and impact test at low temperature were carried out.The microstructure and mechanical properties of the surface and 1/4 H were characterized by SEM、TEM、EBSD analysis as well as other technical means.The results show that yield strength at the surface is slightly higher than that at 1/4 Hdue to the small martensite block size and the higher dislocation density.The impact properties at low temperature of the surface and 1/4 H are obviously different.Compared with 1/4 H,-60℃ and-80℃low temperature impact energy at the surface is reduced by 12.6% and 24.7%,respectively,which is attributed to the lower number density of large angle grain boundary(HAGB)and the higher internal stress concentration induced by the larger cooling rate at the surface.
作者
尹朝朝
张莉芹
胡锋
周松波
周雯
吴开明
YIN Chao-chao;ZHANG Li-qin;HU Feng;ZHOU Song-bo;ZHOU Wen;WU Kai-ming(Collaborative Innovation Center for Advanced Steels,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Hubei Province Key Laboratory of Systems Science on Metallurgical Processing,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Metals Valley and Band Metallic(Foshan)Composite Materials Co.,Ltd.,Foshan 528000,Guangdong,China)
出处
《钢铁》
CAS
CSCD
北大核心
2021年第7期129-138,共10页
Iron and Steel
基金
国家自然科学基金联合基金重点资助项目(U20A20279)
高等学校学科创新引智计划(111计划)资助项目(D18018)。
