Structural stainless steel sheet having excellent corrosion resistance at weld and method for manufacturing same

Abstract

A structural stainless steel sheet which can be manufactured at a low cost and with high efficiency, and possesses excellent welded-part corrosion resistance and a manufacturing method thereof are provided. The structural stainless steel sheet has a composition which contains by mass % 0.01 to 0.03% C, 0.01 to 0.03% N, 0.10 to 0.40% Si, 1.5 to 2.5% Mn, 0.04% or less P, 0.02% or less S, 0.05 to 0.15% Al, 10 to 13% Cr, 0.5 to 1.0% Ni, 4×(C+N) or more and 0.3% or less Ti, and Fe and unavoidable impurities as a balance, V, Ca and O in the unavoidable impurities being regulated to 0.05% or less V, 0.0030% or less Ca and 0.0080% or less O, wherein an F value expressed by Cr+2×Si+4×Ti−2×Ni−Mn−30×(C+N) satisfies a condition that F value≦11 and an FFV value expressed by Cr+3×Si+16×Ti+Mo+2×Al−2×Mn−4×(Ni+Cu)−40×(C+N)+20×V satisfies a condition that FFV value≦9.0.

Description

TECHNICAL FIELD [0001]The present invention relates to a structural stainless steel sheet having excellent welded part corrosion resistance which is suitably used as a material for a body of a railway wagon which carries coal or iron ore, for example, and a method of manufacturing the structural stainless steel sheet.BACKGROUND ART [0002]As a material for a body of a railway wagon which carries coal or iron ore, stainless steel has been popularly used. Since mined coal contains large sulfur content, the material for the body of the railway wagon is required to possess sulfuric acid corrosion resistance, and particularly intergranular corrosion resistance of the welded part.[0003]As the stainless steel which possesses both corrosion resistance and weldability, for example, patent document 1 discloses a Ti-containing ferritic stainless steel which exhibits excellent weld toughness thereof. However, in the technique disclosed in patent document 1, components are designed such that the ...

AI Technical Summary

Benefits of technology

The present invention provides a cost-effective and efficient way to produce a stainless steel sheet that has excellent resistance to corrosion when welded. This sheet is ideal for use as a material for the body of a railway wagon carrying coal or iron ore.

Problems solved by technology

However, in the techniques disclosed in these patent documents 2 to 5, studies on an optimum component range have not been entirely sufficient.

Particularly, manufacturability has been hardly taken into consideration in these techniques.

Accordingly, the occurrence of cracks in a slab stage and the occurrence of a surface defect called as scabs are conspicuous and hence, it is difficult to obviate a cost rise caused by lowering of a yield ratio.

Images