First, when the welding speed and arc voltage and other parameters to determine the welding current as an important factor to TZM weld joint quality. After study the different welding current found when the welding current is 190A, the weld joint partial fusion is not complete and there are a few small holes. Besides the appearance of weld joint is uneven. Welding current at 230A, weld joint width is large and there are large holes and cracks appearing in the weld. When the current is 210A, the welding is flat and there are no voids and cracks in the weld joint. Besides, the appearance is smooth.
In addition, before welding the tensile fracture of TZM alloy showed significant lamellar morphology and intergranular brittle fracture morphology. And after welding, the tensile fracture of alloys although showing intergranular brittle fracture morphology, but coarse equiaxed grains replace the lamellar crystals. Although the strength of the alloy decreased, but the plasticity has been improved.
TZM alloy after TIG welding the weld joint organization although is large, but due to the thermal effect of welding process, part of the lamellar fibrous structure of TZM alloy can eliminate when formed by rolling, weakening the strength of the material, but an appropriate increase the alloy‘s plastic toughness, maintaining a sufficient strength to meet the basic requirements of the alloy.
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