High young's modulus steel plate, zinc hot dip galvanized steel sheet using the same, alloyed zinc hot dip galvanized steel sheet, high young's modulus steel pipe, and method for production thereof

Abstract

One aspect of the high Young's modulus steel sheet of the present invention contains C: 0.0005% to 0.30%, Si: 2.5% or less, Mn: 2.7 to 5.0%, P: 0.15% or less, and S: 0.015% or less in mass % , Mo: 0.15~1.5%, B: 0.0006~0.01%, Al: 0.15% or less, and the balance is composed of Fe and unavoidable impurities. {110}<223> and { Either one or both of 110}<111> has a pole density of 10 or more, and the Young's modulus in the rolling direction exceeds 230GPa. Another aspect of the high Young's modulus steel sheet contains, by mass %, C: 0.0005 to 0.30%, Si: 2.5% or less, Mn: 0.1 to 5.0%, P: 0.15% or less, S: 0.015% or less, Al: 0.15% or less, N: 0.01% or less; also contains Mo: 0.005-1.5%, Nb: 0.005-0.20%, Ti: (48 / 14×N)%-0.2%, B: 0.0001-0.01% 1 or 2 or more of them, the total is 0.015-1.91% by mass; and the balance is composed of Fe and unavoidable impurities, in {110}<223> and / or {110}< The pole density of 111> is 10 or more, and the Young's modulus in the rolling direction exceeds 230GPa.

Description

technical field [0001] The present invention relates to a high Young's modulus steel sheet, a hot-dip galvanized steel sheet using the same, an alloyed hot-dip galvanized steel sheet, a high Young's modulus steel pipe, and methods for producing them. [0002] This application is to Japanese patent application 2004-218132 filed on July 27, 2004, Japanese patent application 2004-330578 filed on November 15, 2004, Japanese patent application 2005-019942 filed on January 27, 2005, 2005 Priority is claimed to Japanese Patent Application No. 2005-207043 filed on July 15, the contents of which are incorporated herein by reference. Background technique [0003] There have been many reports on techniques for increasing Young's modulus. Most of these relate to techniques for increasing Young's modulus in the rolling direction (RD) and in the width direction (TD) perpendicular to the rolling direction (RD). [0004] Patent documents 1 to 9 etc. all disclose that by α+γ 2 A technolog...

AI Technical Summary

Problems solved by technology

For example, when the load is removed after bending, there is a problem that the steel plate returns to its original shape due to springback, so that the desired shape cannot be obtained.

This phenomenon becomes more pronounced with higher strength, and becomes an obstacle to the application of high-strength steel plates to structural members

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