大热输入对焊条电弧焊低合金钢力学性能的影响

Effect of High Heat Input on Mechanical Properties of Low Alloy Steel by Electrode Arc Welding

本工作研究了用E9015-B3焊材焊接ZG15Cr1Mo1V低合金钢的接头在大热输入条件下的组织与综合性能。结果表明:热输入的变化对焊接接头有一定的影响,随着热输入的增加,高温停留时间更长而冷却速度也降低,焊缝主要强化元素Cr、Mo等呈下降特征,焊缝出现明显的块状铁素体和粗大的贝氏体组织,降低了接头的常温和高温抗拉强度,其中当立向上焊接摆幅在30~50 mm时,焊接点热源对固定位置的高温停留时间影响最大,此时焊缝的综合力学性能最差。为了保证产品焊接接头的质量,需要在一定程度上控制焊接热输入,尤其需要在焊接摆幅为30~50 mm时选择较小的焊接电流。

In this paper,the structure and comprehensive properties of ZG15Cr1Mo1V low alloy steel joints welded by E9015-B3 under high heat input were studied.The results show that the changes of heat input has a certain effect on the welded joint.The high temperature duration increased and the cooling rate decreased when the heat input were elevated,the main strengthening elements,such as Cr and Mo,were decreased,ob-vious massive ferrite and coarse bainite structure appeared in the welded seam,which reduced the normal and high temperature strength of the joint.When the vertical upward welding swing is 30—50 mm,the point heat source has the greatest influence on the high temperature duration of the specified position,and the comprehensive mechanical properties of the weld seam are the worst at this time.In order to ensure the quality of welded joints,it is necessary to control the heat input to a certain extent,especially to choose a smaller welding current in the 30—50 mm welding swing stage.