旋挖钻机桅杆用16Mn碳素结构钢的双丝埋弧焊接工艺研究

Study on Twin-wire Submerged Arc Welding Technology of 16Mn Carbon Structural Steel for Rotary Drilling Rig Mast

采用双丝埋弧焊接工艺对旋转钻机桅杆用16Mn碳素结构钢进行了不同焊接电流、焊丝间距和焊接速度的焊接试验。研究了焊接参数对焊接接头硬度、力学性能和显微组织的影响,得到了适宜的焊接工艺参数,并提出了焊接过程的质量控制措施。结果表明,随着焊接电流的减小,焊接接头热影响区的显微硬度降低,而焊缝区的显微硬度却逐渐升高;不同焊丝间距下显微硬度峰值都在焊接热影响区,焊丝间距对焊接接头显微硬度影响不大;不同焊接速度下焊接接头焊缝区的显微硬度都要高于母材或与母材相当,热影响区的显微硬度要高于母材和焊缝区。焊缝热影响区组织为针状铁素体、片状先共析铁素体、珠光体。焊接电流为700 A、焊接速度为0.0083 m/s、焊丝间距为0.07 m时焊接接头可以获得最佳的强度和塑性,断裂位置位于母材。

The welding tests of 16Mn carbon structural steel for rotary drilling rig mast were carried out by using the twin-wire submerged arc welding under different welding currents, welding wire spacings and welding speeds. The influence of welding parameters on the hardness, microstructure and mechanical properties of the welded joint was studied, and appropriate welding parameters were obtained. The quality control measures in the welding process were put forward. The results show that with the decrease of welding current, the microhardness of heat affected zone of the welded joint decreases and the microhardness of weld zone increases. The peak value of microhardness is in the weld heat affected zone under different wire spacings, and the welding wire spacing has little effect on the microhardness of the welded joints. The microhardness of weld zone of welded joint is higher than or equal to that of base metal under different welding speeds and the microhardness of heat affected zone is higher than that of base metal and weld zone. The microstructure of heat affected zone of the welded joint is composed of acicular ferrite, flake proeutectoid ferrite and pearlite. When the welding current is 700 A, the welding speed is 0.0083 m/s, and the wire spacing is 0.07 m, the welded joint has the best strength and plasticity, and the fracture position is in the base metal.