HOT-DIP GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING THE SAME

PROBLEM TO BE SOLVED: To provide a hot-dip galvanized steel sheet having improved warm formability.SOLUTION: A hot-dip galvanized steel sheet has a composition comprising, in mass%, C: 0.08-0.20%, Si: 0.5% or less, Mn: 0.8-1.8%, P: 0.10% or less, S: 0.030% or less, Al: 0.10% or less, and N: 0.010% or less and also comprising one or more of Ti: 0.01-0.3%, Nb: 0.01-0.1%, and V: 0.01-1.0% so as to satisfy the condition of (Ti/48+Nb/93+V/51)×12 of 0.07 or more, with the balance being Fe and inevitable impurities, and has a structure in which the total area ratio of a ferrite phase and a tempered bainite phase is 95% or more, an average particle size of the surface structure is 5.0 μm or less, an amount of Ti, Nb, V precipitated as precipitates with a particle size of less than 20 nm is 0.025 mass% or more in terms of a precipitated C corresponding amount, and an amount of solidified C on the surface layer is 0.005 mass% or more.SELECTED DRAWING: None 【課題】温間成形性により優れた溶融亜鉛めっき鋼板を提供すること。【解決手段】質量％で、Ｃ：０．０８〜０．２０％、Ｓｉ：０．５％以下、Ｍｎ：０．８〜１．８％、Ｐ：０．１０％以下、Ｓ：０．０３０％以下、Ａｌ：０．１０％以下、Ｎ：０．０１０％以下を含み、さらにＴｉ：０．０１〜０．３％、Ｎｂ：０．０１〜０．１％、Ｖ：０．０１〜１．０％の１種あるいは２種以上を（Ｔｉ／４８＋Ｎｂ／９３＋Ｖ／５１）×１２が０．０７以上となるように含有し、残部Ｆｅおよび不可避的不純物からなる組成と、フェライト相と焼き戻しベイナイト相の合計が面積率で９５％以上であり、かつ、表層の組織の平均粒径が５．０μｍ以下であり、さらに、粒径２０ｎｍ未満の析出物として析出したＴｉ、Ｎｂ、Ｖの析出量が析出Ｃ相当量として０．０２５質量％以上、かつ、表層の固溶Ｃ量が０．００５質量％以上である組織と、を有することを特徴とする溶融亜鉛めっき鋼板。【選択図】なし