Surface modification method of the stainless steel plate

摘要

PROBLEM TO BE SOLVED: To provide a surface modification method for a stainless steel sheet, by which high corrosion resistance is imparted to the stainless steel sheet by solid-solving high concentration nitrogen in a short period of time without forming nitride.;SOLUTION: The surface modification method for a stainless steel sheet according to one embodiment comprises: holding a steel sheet having a plate thickness of 0.5-2.0 mm and containing Cr of 18.0-20.0 mass%, Ni of 9.0-13.0 mass% and the remainder comprising Fe and inevitable impurities at a temperature equilibrated with an austenite single phase for 30-90 seconds in the temperature range of 1,140-1,210°C in a furnace having an atmosphere composed of a nitrogen partial pressure of 0.7 atm. and the remainder of a reducing gas; solid-solving a nitrogen of 0.3 mass% or more while forming the austenite single phase on the steel sheet surface; cooling the steel sheet in the furnace while maintaining the gas atmosphere; and maintaining the steel sheet surface in the austenite single phase having the solid-solved nitrogen. In the surface modification method for a stainless steel sheet according to another embodiment, the nitrogen partial pressure is 0.5 atm., the temperature range is 1,139-1,210°C, and the alloy contents are Cr of 16.0-18.0 mass%, Ni of 12.0-15.0 mass%, Mo of 2.0-3.0 mass% and the remainder comprising Fe and inevitable impurities.;COPYRIGHT: (C)2015,JPO&INPIT