摘要
通过OM、SEM、EBSD、EPMA、TEM等分析手段和拉伸、冲击和硬度测试研究了固溶温度对LNG储罐用高锰钢显微组织和力学性能的影响。结果表明:试验钢在500℃固溶处理时,其组织性能与热轧钢板相比未发生明显变化;固溶温度为600~800℃时,奥氏体晶粒尺寸为10~15μm,晶界处析出大量碳化物,屈服强度由400 MPa降低至379 MPa,抗拉强度几乎无变化,为879~880 MPa,-196℃冲击吸收能量较差,仅50 J左右;当固溶温度升高至900~1000℃时,屈服强度和抗拉强度急剧降低,-196℃冲击吸收能量升高。当热轧钢板在600~800℃固溶处理时,沿晶界析出的(Cr,Mn)_(23)C_(6)型碳化物显著降低了奥氏体晶界间的结合力,降低了冲击裂纹形成功和裂纹扩展功,从而严重恶化试验钢的低温韧性。当固溶温度升高至1000℃后,试验钢的-196℃冲击吸收能量达180 J,晶界处的碳化物完全回溶,晶粒长大,在冲击载荷作用下产生大量机械孪晶,甚至激活二次孪晶系统,有效抑制裂纹的行核和扩展,是试验钢低温韧性优异的主要原因。
Effect of solution treatment temperature on microstructure and mechanical properties of a high manganese steel for LNG storage tanks was studied by means of OM,SEM,EBSD,EPMA,TEM and tensile,impact and hardness tests.The results show that compared with the hot-rolled steel plates,there is no significantly change in microstructure and properties of the steel after solution treatment at 500℃.When the solution treatment temperature is 600-800℃,the austenite grain size is 10-15μm,and a large amount of carbides precipitate at the austenite grain boundaries,so that the yield strength decreases from 400 MPa to 379 MPa,while the tensile strength remains almost unchanged(879-880 MPa),meanwhile,the impact absorbed energy at-196℃is poor,which is only about 50 J.When the solution treatment temperature rises to 900-1000℃,the yield strength and tensile strength decrease sharply,and the impact absorbed energy at-196℃increases.When the solution treatment temperature is 600-800℃,the(Cr,Mn)_(23)C_(6) carbides precipitated along the grain boundaries significantly reduce the bonding force of austenite grain boundaries,lower the impact crack formation energy and crack propagation energy,and thus seriously deteriorate the low-temperature impact toughness of the steel.When the solution treatment temperature rises to 1000℃,the impact absorbed energy at-196℃ is 180 J,the carbides at the grain boundaries completely dissolve back,the grains grow,and a large number of mechanical twins are generated under impact loads,even activating the secondary twin system,effectively suppressing the nucleation and propagation of cracks,which is the main reason for the excellent low-temperature toughness of the steel the impact abserbed energy at-196℃is 180 J.
作者
齐祥羽
刘攀
严玲
苏幼明
刘鹏程
刘粤龙
Qi Xiangyu;Liu Pan;Yan Ling;Su Youming;Liu Pengcheng;Liu Yuelong(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan Liaoning 114009,China;Iron and Steel Research Institute of ANGANG Group,Anshan Liaoning 114009,China;Construction Project Management Branch of China National Petroleum Pipeline Network Group Co.,Ltd.,Langfang Hebei 065001,China;Pipe China Fujian Investment Co.,Ltd.,Zhangzhou Fujian 363106,China)
出处
《金属热处理》
北大核心
2026年第1期124-132,共9页
Heat Treatment of Metals
