BS600MCJ4低合金高强钢焊接接头组织与力学性能研究

Research on Microstructures and Mechanical Properties of BS600MCJ4 Low Content and High Strength Alloy Welded Joints

通过拉伸、弯曲、冲击、硬度、金相分析等试验对BS600MCJ4低合金高强钢焊接接头的力学性能和组织形态进行了研究。结果表明,采用ER70-G焊丝焊接时,BS600MCJ4焊接接头具有良好的拉伸、弯曲和冲击性能;其焊缝组织为有少量先共析铁素体、少量无碳贝氏体从晶界伸向晶内,晶内为针状铁素体,个别部位有粒状贝氏体。熔合区及粗晶区组织为粒状贝氏体和少量针状铁素体。正火区组织为索氏体和粒状贝氏体。BS600MCJ4焊接接头的硬度值在243~330 HV之间,焊缝处硬度最高,但与热影响区和母材相差不大,热影响区软化不明显。

Microstructure and properties of BS600MCJ4 low content and high strength alloy welding joint were investigated by tensile,bending,impact,hardness test and metallographic analysis.The results showed that tensile,bending and impact properties of the BS600MCJ4 welding joint which is welded with ER70-G welding wire are excellent;The microstructure in the weld metal contains a little proeutectoid ferrite that locates at the grain boundary,a little carbon-free bainite which stretch from grain boundary into the grain,and acicular ferrite present within the grain,also some granular bainite distributes at exceptional locations.The microstructure in the fusion zone of welding joint contains some granular bainite and a little acicular ferrite.The microstructure in the normalized zone of welding joint contains sorbite and granular bainite.The magnitude of BS600MCJ4 welding joint is between 243-330 HV.The valve of the magnitude in the weld metal is higher than HAZ and parent metal,but the distinction of them is not obvious.There is softing phenomenon in HAZ,which is neither obvious.