摘要
采用Gleeble1500热模拟试验机,研究不同热输入对Q890高强钢焊接热影响区粗晶区的微观组织和韧性影响规律.结果表明,随着热输入的增加,粗晶区的微观组织表现出从马氏体组织向马氏体、贝氏体的混合组织,再向贝氏体、粒状贝氏体的混合组织的转变.当热输入为19.7 k J/cm时,冲击吸收功最高为83 J,主要原因是由于先相贝氏体分割后相马氏体,大角度晶界密度最大,改善了冲击韧性.当热输入较高时,粗晶区脆化的原因是由于M-A组元呈链状分布,造成局部应力集中,成为裂纹起裂和扩展的主要通道.
The present study focuses on the relationship between microstructure and toughness property in the coarse grain heat affected zone (CGHAZ) of Q890 high-performance steel.The result show that,with the heat input increasing microstructure changes from martensite to martensite and bainitic ferrite and then to bainitic ferrite and granular bainite.The Charpy impact test results show that impact energy as high as 83 J attained in the CGHAZ with 19.7 kJ/cm,which related to the contribution of pre-phase bainitic ferrite segment martensite and leading to maximum density of high angle boundaries,which can improve toughness.When the heat input is 34.1 and 44 k J/cm,the impact energy reasons for the decline is due to catenulate distribution of embrittlement M-A constituents and local stress concentration,resulting in rapid crack initiation and propagation via the massive martensite – austenite (M-A) constituent.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2017年第8期63-67,共5页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(51375015)
国家国际科技合作专项资助项目(2015DFA51460)
关键词
组织演变
M-A组元
大小角晶界
裂纹扩展
冲击韧性
microstructure variation
M-A constituents
high angle grain boundaries
crack propagation
impact toughness
