磁场下镁合金A-TIG接头成形性及显微组织分析

Formability and microstructure of magnesium alloy welded by A-TIG under magnetic field

在对5 mm厚的AZ31B镁合金板材进行A-TIG焊焊接过程中引入外加纵向磁场,试验所用的活性剂是以氧化物为基的活性剂,试验中改变磁场参数,对焊接接头的成形性、组织及性能进行试验和检测,研究磁场参数对镁合金A-TIG焊过程的影响规律.结果表明,活性剂及磁场共同作用可以改善焊接接头的成形性和组织形态,在磁场频率为10 Hz,磁场电流为2 A时,焊接接头的成形系数和性能得到了最佳值,此时成形系数为2.304,硬度为980.98 MPa;外加磁场通过电磁搅拌作用与活性剂相结合,改变了熔池的流行形态,使金属液由四周向中心流动并伴有搅拌,进而使焊缝熔深增大的同时细化组织,改善接头力学性能.

The AZ31B magnesium alloy plates of 5 mm in thickness were welded by A-TIG welding under longitudinal magnetic field. The mixed oxides were used as activating fluxes. The form factor,microstructure and mechanical properties of welded joint at different magnetic field parameters were tested. The effects of magnetic field parameters on A-TIG welding process of magnesium alloy were also investigated. The results show that the formability and microstructure of magnesium alloy welded joint can be improved due to the magnetic field. When the magnetic frequency is 10Hz and the magnetic current is 2 A,the form factor and properties of welded joint are tested,the form factor is 2. 304 and the hardness is 980. 98 MPa. The flow of molten pool will be changed by the activating fluxes and electromagnetic( which forming by magnetic field). The liquid metal in molten pool will move from all around to center,which makes the weld be deeper,refines the microstructure and improves the properties of welded joint.