Ferritic stainless steel sheet and method for manufacturing the same

Abstract

The present invention provides a ferritic stainless steel sheet and a method for manufacturing the same. A ferritic stainless steel sheet has a composition containing C: 0.001 to 0.020%, Si: 0.05 to 0.35%, Mn: 0.05 to 1.00%, P: 0.04% or less, S: 0.01% or less, Al: 0.001 to 0.300%, Cr: 10.0 to 13.0%, Ni: 0.75 to 1.50%, Ti: 0.05 to 0.35%, and N: 0.001 to 0.020%, with the balance being Fe and inevitable impurities, in which γI [AD] represented by formula (1) below is 65% or more, and a metal structure has an average crystal grain size of 45 μm or less: γI [%]=24Ni+12Mn+6Cu−18Si−12Cr−12Mo+188 (1), where Ni, Mn, Cu, Si, Cr, and Mo represent contents of the respective elements (percent by mass), and an element not contained represents 0.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is the U.S. National Phase application of PCT / JP2018 / 038400, filed Oct. 16, 2018, which claims priority to Japanese Patent Application No. 2017-209061, filed Oct. 30, 2017, the disclosures of these applications being incorporated herein by reference in their entireties for all purposes.FIELD OF THE INVENTION[0002]The present invention relates to a ferritic stainless steel sheet and a method for manufacturing the same, and more particularly relates to a ferritic stainless steel sheet having excellent toughness and excellent corrosion resistance, which is suitable for use as a material for flanges, and a method for manufacturing the same.BACKGROUND OF THE INVENTION[0003]An automobile exhaust gas passage is composed of various components, such as an exhaust manifold, a muffler, a catalyst, a flexible tube, a center pipe, and a front pipe. When these components are connected, fastening components called flanges are frequently used. Flang...

AI Technical Summary

Benefits of technology

The present invention provides a ferritic stainless steel sheet with better toughness and corrosion resistance. The steel sheet can be used for thick flanges with burring portions without cracking. The method involves heating a slab containing appropriate steel elements, hot rolling, and hot-rolled sheet annealing to refine the metal structure and obtain the desired impact value. Overall, the invention offers a high-quality ferritic stainless steel sheet suitable for various applications.

Problems solved by technology

However, when the present inventors tried to form the stainless steel sheet described in Patent Literature 1 into the shape of a thick flange having a burring portion, in some cases, cracks occurred in the burring portion, and it was not possible to obtain a predetermined flange shape, revealing that the stainless steel sheet was not sufficient to be used for thick flanges.