Nickel-saving RE-containing austenitic stainless steel and its prepn

Abstract

The present invention belongs to the field of alloy steel, and is nickel-saving RE-containing austenitic stainless steel comprising C not more than 0.08 wt%, Si 0.3-0.8 wt%, Mn 5.0-8.5 wt%, S not more than 0.05 wt%, P not more than 0.04 wt%, Ni 3.0-5.5 wt%, Cr 14-19 wt%, Cu 1.0-4.0 wt%, N not more than 0.20 wt%, total O not more than 0.005 wt%, RE 0.05-0.3 wt% and Fe the rest. The preparation process of the stainless steel includes the technological steps of: smelting, casting at 1500-1650 deg.c, cogging at initial temperature of 1080-1240 deg.c and final forging temperature over 900 deg.c, rolling at initial temperature of 1100-1240 deg.c and final temperature over 900 deg.c, and solution treatment at 1050-1150 deg.c for 20-30 min. During the smelting, the molten steel has oxygen content not more than 50 ppm before RE is added, and RE is added in 30 sec before casting.

Description

technical field [0001] The invention belongs to the field of alloy steel, and mainly relates to austenitic stainless steel and a preparation method thereof. Background technique [0002] In austenitic stainless steel, the more typical steel grade is SUS304 austenitic stainless steel, which has been widely used in the production of kitchen utensils, utensils, washing machine drums, automobile components and train carriages, etc. ([Stainless Steel Anthology] 1985, the first Issue, pp. 1-9; [Stainless Development] 2001, Issue 1, pp. 7-22; [Stainless] 2002, Issue 3, pp. 1-12). The prominent features of this steel are moderate strength, good plasticity and toughness, and good corrosion resistance. However, due to the high nickel content of more than 8%, the cost is relatively high and the price is expensive. In China, and even in the world, there are few mineable mineral reserves for nickel, so nickel is a scarce strategic material, and its application, especially in the future,...

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Problems solved by technology

In order to save nickel, the relevant domestic departments have researched and developed 200 or 201 chromium manganese nitrogen austenitic stainless steel ([Stainless Development] 2004, the first issue, pages 4-22; [World Metal Bulletin] 2004.9.7, total No. 1702 Period), currently in circulation in the market, but there are many problems with this type of steel, mainly because the composition design is not scientific and reasonable. In this type of steel, some do not contain nickel, but their strength is relatively high and their elongation is relatively low. Low, high cold work hardening index, low cold-rolled yield, poor corrosion resistance and other shortcomings, so its application is also limited

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