Ferritic stainless steel having excellent ridging property and excellent surface quality and method of manufacturing the same

Abstract

Disclosed herein are a ferritic stainless steel having excellent ridging properties and excellent surface quality of a final product by modifying a microstructure of a central area of a cross-section by further performing cold rolling before hot annealing.A ferritic stainless steel according to the present disclosure includes, by wt %, 0.005 to 0.1% of carbon (C), 0.01 to 2.0% of silicon (Si), 0.01 to 1.5% of manganese (Mn), 0.05% or less of phosphorus (P), 0.005% or less of sulfur (S), 10 to 30% of chromium (Cr), 0.005 to 0.1% of nitrogen (N), 0.005 to 0.2% of aluminum (Al), and the remainder of iron (Fe) and other impurities, wherein a γmax value is in the range of 20% to less than 50%, and a surface microgroove area ratio is 2.0% or less.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]This application claims the benefit of Korean Patent Application No. 2016-0169696, filed on Dec. 13, 2016 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.BACKGROUND1. Field[0002]Embodiments of the present disclosure relate to a ferritic stainless steel having excellent ridging properties and excellent surface quality and a method of manufacturing the same, and more particularly, to a ferritic stainless steel having excellent ridging properties and excellent surface quality by improving a structure of the thickness center by further performing cold rolling before conducting hot annealing after hot rolling, and a method of manufacturing the same.2. Description of the Related Art[0003]In general, stainless steels are classified according to components or metal structures. According to the metal structures, stainless steels are classified into austenitic, ferritic, martensitic, and dup...

AI Technical Summary

Benefits of technology

The present disclosure provides a method for manufacturing ferritic stainless steel that reduces ridging defects on the surface of the product by lowering the aspect ratio of the band structure of a thickness center of a cross-section of a steel sheet by performing cold rolling before hot annealing. Additionally, the method improves surface glossiness and reduces ridging height during a forming process with excellent ridging properties.

Problems solved by technology

However, ferritic stainless steel has a problem of ridging defects which are surface defects in the form of winkles parallel to a rolling direction caused during a forming process such as a deep drawing process.

The ridging defects not only deteriorate an appearance of a product but also requires an additional polishing process after the forming process in the case of serious ridging defects causing increases in time and costs for manufacturing.

However, there has been almost no attempt to improve texture by performing symmetric rolling or asymmetric rolling of a hot rolled steel sheet coiled at a high temperature before annealing, and then performing continuous annealing.

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