| 摘要 |
[Problem] To provide an arc-welded structural member which includes a Zn-Al-Mg-coated steel plate member and has excellent molten-metal brittle crack resistance, without involving a restriction on the kind of the steel of the plated base or a considerable increase in cost. [Solution] When a welded structural member is produced by bonding steel materials to each other by gas-shielded arc welding, a hot-dip Zn-Al-Mg-coated steel plate member is used as at least one of the members to be bonded and use is made of a shielding gas which comprises, as the base, Ar gas, He gas, or a gas mixture of Ar and He and which has been regulated so as to have a CO2 concentration CCO2 (vol%) that satisfies relationship (2) in accordance with the welding heat input Q (J/cm). 0≤CCO2≤2900Q-0.68 (2). |
