Abstract
Aluminum alloys and stainless steels are used in the construction of many types of industrial equipment, but the welds in these materials are subject to micro-cracking and blowholes.
In order to reduce such welding defects, the authors used magnetic stirring in TIG welding of an Al-Mg-Mn alloy (5083) and SUS316, and studied the effects of magnetic field intensity and frequency and welding conditions on the solidification structures, hot cracking and blowholes in the welds.
The test results are summarized as follows:
1) When aluminum alloys had a field intensity between 100 and 300 gausses and field frequency between 5 and 10 Hz and stainless steels had field intensity between 200 and 300 gausses and field frequency between 1 and 5 Hz, the magnetic stirring reduces the grain size. The combined effects using the pulse arc were also observed.
2) Under the conditions in 1), the columnar structure disappeared. This contributed to the reduction of hot cracking.
3) The magnetic stirring released gas from the molten metal, and as a result, reduced the occurrence of blowholes.
