| 摘要 |
PROBLEM TO BE SOLVED: To obtain a welding strength higher than that of galvanized steel plates even if blowholes are generated when the galvanized steel plates where blowholes are easily created are welded by the arc welding using a lap fillet joint. SOLUTION: When performing the arc welding of plated steel plates, a preliminary welding test is carried out by variously changing the thickness t<SB>d</SB>(mm) of a plated layer and the gap G (mm) between the plates in advance in accordance with the kind of a welding wire and shield gas, the blowhole occupation ratio B<SB>r</SB>is measured, and the coefficient A is obtained from the formula (2) below. Welding is performed to realize the throat thickness t<SB>n</SB>(mm) satisfying the formula (1) below so that the welding strength T of the weld part of the actual galvanized steel plate lap fillet joint is not less than the strength T<SB>s</SB>×t×L<SB>w</SB>of a member to be welded. Here, the inequality (1) is expressed by T=W<SB>s</SB>×t<SB>n</SB>×(1-B<SB>r</SB>)×L<SB>w</SB>≥T<SB>s</SB>×t×L<SB>w</SB>, and the formula (2) is expressed by B<SB>r</SB>=A×t<SB>d</SB>/(1+G), where W<SB>s</SB>is the tensile strength (N/mm<SP>2</SP>) of the weld metal having no blowholes, T<SB>s</SB>is the tensile strength (N/mm<SP>2</SP>) of the work, t is the thickness (mm) of the member to be welded, and L<SB>w</SB>is the length of a weld beam. COPYRIGHT: (C)2004,JPO
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