焊接电流对Q4Sn-6Zn青铜焊缝力学性能和颜色的影响

Effects of Welding Currents on the Mechanical Properties and Colors of Q4Sn-6Zn Bronze Welding Joint

采用偏光显微镜、紫外可见光光度计、3NH色差仪、显微硬度计等仪器,研究了不同焊接电流对Q4Sn-6Zn青铜焊缝力学性能和颜色的影响。结果表明:当焊接电流为110和130 A时,由于焊接热输入量的不足,焊缝出现未焊透现象,焊接质量差,无法满足使用要求;当焊接电流达到170和190 A时,由于电流太大,焊接热输入量过大,晶粒长大倾向变强,呈现明显粗大的柱状,分布具有较强的方向性,导致焊接接头力学性能下降;当焊接电流为150 A时,焊缝的力学性能最优。通过研究分析不同焊接电流焊接的着色及未着色焊缝与母材反射率和CIE1976L*a*b*数值发现,焊接电流为150 A时焊缝与母材色差值最小,颜色与母材最接近。

The effects of different welding currents on the mechanical properties and colors of welding joints in Q4 Sn-6 Zn bronze were investigated by polarizing microscope, UV-vis spectrophotometer, 3 NH colorimeter, microhardness tester and so on. The results show that when the welding current is only 110 and 130 A, the lack of penetration appears due to the insufficiency of welding heat input, and the poor welding quality cannot meet the requirements for the usages. When the welding current reaches 170 and190 A, the large current leads to the great welding heat input, which makes the grain show strong growth trends and obviously large columnar shape with strong distribution directionality, and then causes the decrease in the mechanical properties of welded joints. When the welding current is 150 A, the weld joint shows the best mechanical properties. By analyzing the reflectivity and CIE1976 L*a*b* values of colored and unpainted joints as well as the base metal under different welding currents, it is found that the weld joint under the welding current of 150 A shows the smallest color difference and the closest color with the base metal.