Abstract: The effect of micro Zr on structure and mechanical properties of welding coarse grain heat affected zone (CGHAZ)of ≤0.18C-1.2～1.6Mn HSLA steel has been studied by welding thermal simulation method. The test results showed that with 30~ 100 kJ/cm heat input welding thermal simulation,the strength,plasticity and impact toughness at -50 ℃ of CGHAZ of steel containing 0.01%～0.03% Zr were higher than that steel non-containing Zr,and microhardness HV10 value of Zr steels was 177~251.The Zr steels had excellent weldablity and at same heat input the grain in CGHAZ of non-containing steel was coarser than that of Zr steel and with heat input of 30 kJ/cm the bainite was dominant in structure of CGHAZ while with increasing the heat input the acicular ferrite and few pearlite occured in CGHAZ.

Key words: HSLA Steel, High Heat Input Welding, Structure, Mechanical Properties

摘要： 用焊接热模拟法研究了Zr处理对 (%):≤ 0.18C-1.2～1.6Mn低合金高强度(HSLA)钢焊接粗晶热影响区(CGHAZ)组织和性能的影响。试验结果表明,Zr含量在0.01%～0.03%时,经过30～100kJ/cm线能量焊接热模拟后,CGHAZ的强度、塑性和-50℃冲击韧性都高于没有经过Zr处理的试验钢;Zr钢显微硬度(HV10)177～251,具有优良的焊接性。焊接线能量相同时,没有经过Zr处理试验钢CGHAZ的晶粒比Zr处理钢粗大;焊接线能量为 30kJ/cm时 ,各试验钢CGHAZ的组织以贝氏体为主 ,随着焊接线能量提高 ,CGHAZ中出现针状铁素体和少量珠光体。

关键词: 低合金高强度钢, 大线能量焊接, 组织, 力学性能