METHOD FOR ROLLING/DRAWING NICKEL-FREE HIGH-NITROGEN STAINLESS STEEL MATERIAL, NICKEL-FREE HIGH-NITROGEN STAINLESS STEEL SEAMLESS THIN PIPE, AND METHOD FOR PRODUCING SAME

摘要

This method for rolling/drawing a nickel-free high-nitrogen stainless steel material comprises: an intermediate annealing step (S11) wherein a nickel-free high-nitrogen stainless steel material composed of a fine grain structure having a maximum crystal grain size of 30 mum or less is annealed at a temperature from 900°C to 1,000°C (inclusive) and then air cooled to room temperature; a rolling/drawing step (S12) wherein the nickel-free high-nitrogen stainless steel material is drawn, while reducing the thickness or the diameter of the nickel-free high-nitrogen stainless steel material; and a final solution treatment step (S13) wherein the nickel-free high-nitrogen stainless steel material is heated to a temperature from 1,200°C to 1,400°C (inclusive) and then air cooled to room temperature. A seamless thin pipe (10) for nickel-free high-nitrogen stainless steel stents is obtained by subjecting a nickel-free high-nitrogen stainless steel pipe stock, which is composed of a fine grain structure (11) having a maximum crystal grain size of 30 mum or less, to plastic working according to this method for rolling/drawing a nickel-free high-nitrogen stainless steel material. This seamless thin pipe for nickel-free high-nitrogen stainless steel stents is composed of a fine grain structure that has a maximum crystal grain size of 30 mum or less.