| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a member with a weld joint part which is constituted by arc-welding a hot-dip Zn-Al-Mg based alloy plated steel sheet as a material and subjected to electrodeposition coating, the member capable of inhibiting blister corrosion under coating occurring at the weld joint part. <P>SOLUTION: The problem of blister corrosion under coating is solved by further improving the adhesion between a phosphate treatment coating and an electrodeposition coating by a step of forming the phosphate treatment coating on a surface of the member prepared by arc-welding the hot-dip Zn-Al-Mg based alloy plated steel sheet by using a treatment liquid containing 0.01-0.5 mol/L of at least one kind of cations selected from Zn, Ni, Co, Fe, Mn and Mg and 0.01-1.0 mol/L of nitrate ions, and a step of subsequently forming on the surface of a chemical conversion coating by using a treatment liquid containing a salt of a valve metal and a fluoride of a valve metal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
