Page 76 - 机械工程材料2024年第十一期

蔡 军，等：工艺参数对热丝脉冲TIG堆焊Inconel 625合金成形性能及组织的影响

Effects of Process Parameters on Formability and Microstructure of Inconel
625 Alloy by Hot Wire Pulsed TIG Welding

CAI Jun , CHEN Cheng 2
1
(1. School of Mechanical and Electrical Engineering, Nantong Open University, Nantong 226006, China; 2. School of Mechanical
and Power Engineering, Nanjing Tech University, Nanjing 211816, China)

Abstract: Inconel 625 alloy cladding layer was prepared on AISI 4130 steel surface by hot-wire tungsten
inert gas (TIG) welding under a low current (peak/base currents of 160 A/95 A) and different welding speeds (220‒
−1
300 mm · min ). The effects of welding current and welding speed on the formability and microstructure of the cladding
layer were investigated, and compared with those at a high current (peak/base currents of 190 A/110 A). The results
show that at the low current, with the increase of welding speed, the width, depth of fusion of the cladding layer
decreased, and the height and the ratio of depth of fusion to height of the cladding layer first decreased and then increased.
The width, depth of fusion and the ratio of depth of fusion to height of the cladding layer at the low current were lower
than those at the high current, and the height was higher than that at a high current. Low current and low welding speed
could obtain the narrow and high cladding layer with low dilution rate. At the low current, cellular crystals and dendritic
crystals were mainly formed near the surface and away from the bottom of the molten pool on the cross-section of the
cladding layer, and planar crystals were dominant at the bottom of the molten pool. With the decrease of welding speed,
the planar crystal region expanded, the grains near the surface developed into columnar or dendritic crystals, and the
grains away from the bottom of the molten pool developed into cellular crystals. Under 160 A/95 A peak/base current,
240 mm · min −1 welding speed and 30% bonding rate, the three-layer ten-pass cladding layer was continuously dense and
the microhardness was (280±20) HV. After cladding welding, annealing treatment was required to reduce the hardness.
Key words: Inconel 625 alloy; TIG cladding; microstructure; microhardness; process optimization

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