热输入量对890MPa臂架管焊接热影响区组织性能的影响

Effect of Heat input on Microstructure and Properties of Heat Affected Zone in 890 MPa Welded Tube for Crane Boom Service

依据等强匹配原则,选用BHG-5焊丝对起重机臂架用890 MPa无缝钢管进行了斜Y型坡口焊接裂纹试验和不同热输入量的多层多道手动焊接试验,探究了材料的冷裂纹敏感性,以及不同热输入量对焊接接头组织和力学性能的影响。结果表明,预热温度为150℃时,可完全避免焊接冷裂纹的产生;随着热输入量的增加,焊缝金属接头强度变化不大,但焊接接头热影响区冲击韧性明显下降,选择小于20 kJ/cm热输入量焊接时可保证焊接接头具有较好的强韧性。

According to the principle of equal strength matching,the BHG-5 welding wire is selected for the conducting the Y bevel cracking test and the multi-layer and multi-pass manual welding test with different heat inputs to the 890 MPa seamless steel tube for crane boom service.The cold cracking sensitivity of the material,and the effects by different heat inputs on the microstructure and the mechanical properties of the weld joint are investigated.As a result it is revealed that when the pre-heating temperature is 150℃,the occurrence of the cold cracking can be completely avoided;and along with the increase of the heat input,the strength of the weld metal joint just changes slightly,whereas the impact toughness of the HAZ of the weld joint drops obviously.Using the heat input under 20 kJ/cm will surely get the weld joint have better strength and toughness.