JP2007231371A5

JP2007231371A5 -

Info

Publication number: JP2007231371A5
Application number: JP2006054896A
Authority: JP
Filing date: 2006-03-01
Publication date: 2009-07-16
Anticipated expiration: 2026-03-01

Claims

質量％で、Ｃ：０．０００５％以上０．００４％未満、Ｓｉ：０．５％以下、Ｍｎ：０．１〜２．５％、Ｐ：０．０６％以下、Ｓ：０．０５％以下、ｓｏｌ．Ａｌ：０．００５％以上０．１％以下、Ｎ：０．００６％以下、Ｔｉ：（Ｎ／１４×４８×０．５）％以上、（０．０２＋Ｎ／１４×４８）％以下およびＮｂ：０．０４〜０．２０％を含有し、残部がＦｅおよび不純物からなるとともに、ＴｉおよびＮｂの含有量が２≦Ｎｂ／Ｔｉ≦２０の関係式を満足する化学組成を備え、ｒ値の最小値が１．０以上であり、さらに圧延方向に対する角度が４５°方向におけるｒ値が１．５以上であることを特徴とする引張強度が３４０ＭＰａ以上の高強度冷延鋼板。 In mass%, C: 0.0005% or more and less than 0.004%, Si: 0.5% or less, Mn: 0.1 to 2.5%, P: 0.06% or less, S: 0.05% Hereinafter, sol. Al: 0.005% or more and 0.1% or less, N: 0.006% or less, Ti: (N / 14 × 48 × 0.5)% or more, (0.02 + N / 14 × 48)% or less, and Nb : Containing 0.04 to 0.20%, the balance being Fe and impurities, and the content of Ti and Nb satisfying the relational expression of 2 ≦ Nb / Ti ≦ 20, A high-strength cold-rolled steel sheet having a tensile strength of 340 MPa or more, wherein the minimum value is 1.0 or more, and the r value in a 45 ° direction with respect to the rolling direction is 1.5 or more.

前記Ｆｅの一部に代えて、質量％で、Ｂ：０．００２０％以下を含有することを特徴とする請求項１に記載の高強度冷延鋼板。 The high-strength cold-rolled steel sheet according to claim 1, wherein the high-strength cold-rolled steel sheet according to claim 1 contains B: 0.0020% or less in mass% instead of part of the Fe.

前記Ｆｅの一部に代えて、質量％で、Ｃｒ：１％以下、Ｍｏ：１％以下、Ｖ：１％以下およびＮｉ：１％以下の群から選ばれる１種または２種以上を含有することを特徴とする請求項１または２に記載の高強度冷延鋼板。 Instead of a part of the Fe, it contains one or more selected from the group consisting of Cr: 1% or less, Mo: 1% or less, V: 1% or less and Ni: 1% or less in mass%. The high-strength cold-rolled steel sheet according to claim 1 or 2.

請求項１〜３のいずれかに記載の高強度冷延鋼板の表面に溶融亜鉛めっき層を備えることを特徴とする高強度溶融亜鉛めっき鋼板。 A high-strength hot-dip galvanized steel sheet comprising a hot-dip galvanized layer on the surface of the high-strength cold-rolled steel sheet according to claim 1.

請求項１〜３のいずれかに記載の化学組成を備える鋼塊または鋼片を１１００〜１２８０℃として熱間圧延を施し、Ａｒ_３〜１０００℃で熱間圧延を完了して４００〜６５０℃で鋼帯に巻き取り、酸洗を行った後に圧下率５０％以上で冷間圧延を施し、次いで７８０〜９００℃で焼鈍することを特徴とする高強度冷延鋼板の製造方法。 The steel ingot or steel slab having the chemical composition according to any one of claims 1 to 3 is subjected to hot rolling at 1100 to 1280 ° C, and hot rolling is completed at Ar _{3 to} 1000 ° C, at 400 to 650 ° C. A method for producing a high-strength cold-rolled steel sheet, which is wound around a steel strip, pickled, cold-rolled at a reduction rate of 50% or more, and then annealed at 780 to 900 ° C.

請求項５に記載の製造方法により得られる高強度冷延鋼板に溶融亜鉛めっきを施すことを特徴とする高強度溶融亜鉛めっき鋼板の製造方法。 A method for producing a high-strength hot-dip galvanized steel sheet, comprising subjecting a high-strength cold-rolled steel sheet obtained by the production method according to claim 5 to hot dip galvanizing.