线能量相同情况下焊接参数变化对堆焊焊缝成形和粗晶区组织的影响

Effect of welding parameters under a constant heat input on formation of overlay and coarse-grained heat-affected zone

利用MZ-1000型埋弧焊机进行堆焊试验,研究在线能量相同的情况下,焊接参数变化对堆焊焊缝成形和粗晶区组织的影响。试验线能量35 k J/cm、电弧电压37 V,在厚度为20 mm的钢板上通过改变电流和焊速进行堆焊。研究结果表明:在线能量不变的条件下,随着焊接电流的减小和焊接速度的同时减慢,熔深减小、熔宽增大;粗晶区的晶粒大小、焊缝余高和热影响区宽度先变小,后变大。因此在一定线能量下,可以通过调整电流和焊速来控制焊缝成形,达到提高效率、保证质量的目的。

The effect of welding parameters for a constant heat input on formation of weld overlay and its coarse-grained heat-affected zone was investigated for submerged-arc overlay welding. The heat-input was fixed at 35 kJ/cm and the welding voltage was fixed at 37 V,while the welding current and velocity were varied for overlay on a 20 mm thick low-carbon steel plate. The results show for the constant heat-input, a decreasing both welding current and velocity produce a smaller weld penetration and a greater weld width. The grain size in the coarse-grained heat-affected zone,weld reinforcement,and the width of the heat-affected zone also have a decreasing trend as the welding current and velocity decrease firstly ,and then increasing. It is therefore possible to adjust the current and velocity, under a constant heat-input, to achieve optimum overlay formation for both weld quality and efficiency.