电焊机2025，Vol.55Issue(4)：56-63,8.DOI:10.7512/j.issn.1001-2303.2025.04.08
焊修次数对Q450NQR1耐候钢MAG焊对接接头组织和性能的影响
Influence of Welding Repair Times on the Microstructure and Properties of Q450NQR1 Atmospheric Corrosion Resistant Steel MAG Welded Joints
戴忠晨 1付宁宁 1王鹏飞 1丁亚萍 1李林瞳 2孟炜丰 2刘范杰 2丁成钢2
作者信息
- 1. 中车南京浦镇车辆有限公司,江苏 南京 210031
- 2. 大连交通大学 材料科学与工程学院,辽宁 大连 116028
- 折叠
摘要
Abstract
In response to the welding repair needs of Q450NQR1 atmospheric corrosion resistant steel welded joints in rail transit equipment manufacturing and maintenance,this study investigates the effects of MAG welding repair processes(1～4 times)on the evolution of microstructure and mechanical properties of the joints.The results show that after 1～4 times of welding repair,the types of joint microstructure remain consistent,with the weld zone and fusion zone mainly consisting of pro-eutectoid ferrite and acicular ferrite,and a small amount of pearlite and granular bainite.However,the grain size in the overheated zone increases significantly with the increase in the number of welding repairs.After 4 times of welding repair,the average equivalent diameter of grains in the cover coarse grain zone increased by about 20%,while that in the underbead zone increased by about 8%.Tensile and bend tests of the welded joints indicate that the welds have good plasticity and toughness.With the increase in the number of welding repairs,both the impact toughness and fatigue strength of the joints decrease.After 4 times of welding repair,the impact energy value in the weld zone decreased by about 4.2%,while in the heat affected zone it decreased by about 40.1%;the median fatigue strength decreased by about 29.0%.The accumulated thermal input during the welding repair process leads to grain growth in the overheated zone,reducing the toughness of the joints.At the same time,the repeated action of welding thermal cycles on the heat-affected zone causes grain refinement,fur-ther reducing the impact toughness and fatigue strength of the joints.This study reveals the influence pattern of the number of welding repairs on the microstructure and properties of Q450NQR1 atmospheric corrosion resistant steel welded joints,pro-viding an important theoretical basis for optimizing welding repair processes and enhancing the reliability of welded joints.关键词
Q450NQR1耐候钢/MAG焊/对接接头/焊修/接头组织及力学性能Key words
Q450NQR1 weathering steel/MAG welding/butt joint/weld repair/joint microstructure and mechanical properties分类
金属材料引用本文复制引用
戴忠晨,付宁宁,王鹏飞,丁亚萍,李林瞳,孟炜丰,刘范杰,丁成钢..焊修次数对Q450NQR1耐候钢MAG焊对接接头组织和性能的影响[J].电焊机,2025,55(4):56-63,8.
