Steel sheet and enameled product

Abstract

This steel sheet contains, in terms of mass%, up to 0.0060% C, 0.0010-0.050% Si, 0.05-0.50% Mn, 0.005-0.100% P, up to 0.0500% S, 0.0010-0.010% Al, 0.010-0.045% Cu, 0.0250-0.0700% O, and 0.0010-0.0045%N, with the remainder comprising Fe and unavoidable impurities. The steel sheet has a structure which comprises ferrite, and the ferrite located at a sheet-thickness-direction depth corresponding to1/4 the sheet thickness from a surface of the steel sheet has an average crystal-grain diameter of 20.0 [mu]m or smaller. The structure contains oxides containing Fe and Mn. Among the oxides, the number density of the oxides having diameters larger than 1.0 [mu]m but not larger than 10 [mu]m is 1.0*103-5.0*104 grains/mm<2>, and the number density of the oxides having diameters of 0.1-1.0 [mu]m is5.0*103 grains/mm<2> or greater.

Description

technical field [0001] The invention relates to steel plates and enamel products. [0002] This application claims priority based on Japanese Patent Application No. 2015-179722 for which it applied in Japan on September 11, 2015, and uses the content here. Background technique [0003] Enamel products are made by firing glass on the surface of steel plates for enameling. Enamel products have been widely used as materials for kitchen utensils such as pots and sinks, and building materials because of their heat resistance, weather resistance, chemical resistance, and water resistance. Such enameled products can generally be produced by processing steel plates into a predetermined shape, assembling them into a product shape by welding or the like, and then performing enameling treatment (firing treatment). [0004] Steel sheets for enameling, which are used as raw materials for enameled products, require firing deformation resistance, scale resistance, adhesion, foam resistan...

AI Technical Summary

Problems solved by technology

However, in this method that does not utilize the pinning of precipitates and inclusions to suppress grain growth, it is considered that the desired effect may not be obtained due to uneven particle size due to temperature fluctuations in the member during enamelling. possibility

In this case, the strength after enamel treatment cannot be obtained stably

In addition, in Patent Document 2, the object of suppressing the deflection of the enamelled member is to study only the yield stress before and after the enameling treatment, so the change in the tensile strength that affects the fatigue properties is unknown.

[0009] In this way, the fact is that it has not been possible to provide a high-strength steel sheet that fully satisfies the scale resistance, which is an important characteristic of steel sheets for enamelling, and the strength characteristics that are indicators of steel sheet reliability in consideration of the manufacturing process, and there are still problems for further improvement of the characteristics.

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