Arc welding method for hot-dip galvanized steel plate having excellent appearance of welded part and high welding strength, method for manufacturing welding member, and welding member
Hot dip Zn-based alloy coated steel sheets ( 1, 1 ′) are arc-weld in such a way that (a) a current waveform is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V. Each of the hot dip Zn-based alloy coated steel sheets ( 1, 1 ′) includes a coating layer that contains Zn as a main component and that contains Al at a concentration of 1.0% by mass to 22.0% by mass, and has a coating weight W of 15 g/m 2 to 250 g/m 2 .
1. A method of arc-welding hot dip Zn-based alloy coated steel sheets each of which includes a coating layer that contains Zn as a main component and that contains Al at a concentration of 1.0% by mass to 22.0% by mass,
each of the hot dip Zn-based alloy coated steel sheets having a coating weight W of 15 g/m 2 to 250 g/m 2 per surface,
the hot dip Zn-based alloy coated steel sheets being arc-welded in such a way that (a) a current waveform formed by a welding current is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V,
the hot dip Zn-based alloy coated steel sheets being arc-welded with use of an Ar—CO 2 mixed gas to which no O 2 is added as a shielding gas.
2. The method as set forth in claim 1 , wherein the coating weight W (g/m 2 ) of the each of the hot dip Zn-based alloy coated steel sheets and an Al concentration C Al (% by mass) of the coating layer included in the each of the hot dip Zn-based alloy coated steel sheets satisfy the following expression (1):
0.0085 W+ 0.87≤ C Al ≤22 (1)
3. The method as set forth in claim 1 , wherein the coating layer included in the each of the hot dip Zn-based alloy coated steel sheets further contains at least one selected from the group consisting of Mg, Ti, B, Si, and Fe, the coating layer containing the Mg at a concentration of 0.05% by mass to 10.0% by mass, the Ti at a concentration of 0.002% by mass to 0.10% by mass, the B at a concentration of 0.001% by mass to 0.05% by mass, the Si at a concentration of 0% by mass to 2.0% by mass, and/or the Fe at a concentration of 0% by mass to 2.5% by mass.
4. The method as set forth in claim 1 , wherein the hot dip Zn-based alloy coated steel sheets are arc-welded so that:
a number of spatters adhering to a region, which has a length of 100 mm and a width of 100 mm and in which a weld bead is middled, is not more than 20; and
a blowhole occupancy Br, which is calculated from the following expression (2), is not more than 30%:
Br =(Σ di/L )×100 (2)
where:
di represents a length of the ith blowhole observed; and
L represents a length of the weld bead.