It was announced recently that domestic steel mills have issued new stainless steel grade standards. After comparative analysis, there is basically no major change in the identification of the new grade and the old grade. The main chemical element identification has not changed, only the carbon content identification and the chemical elements in individual steel grades. Changes:
1. Carbon (C) content identification
1) Old grade: The number before Cr indicates the content of parts per thousand of carbon. For example, 201 (1Cr17Mn6Ni5N): carbon (C) content of 1/1000; 2Cr13 (420), 7Cr17 (440A), respectively represent the carbon (C) content of two thousandths and seven thousandths; if C≤0.08% is low Carbon, marked as “0”, such as (304)0Cr18Ni9; C≤0.03% is ultra-low carbon, marked as “00”, such as 00Cr17Ni14Mo2(316L).
2) New grade: The number before Cr indicates the content of a few ten thousandths of carbon (C). For example, 201 grade is 12Cr17Mn6Ni5N, which means carbon (C) content is twelve ten thousandths (0.12%); 304 grade is 06Cr19Ni10, which means carbon (C) content is six ten thousandths (0.06%); 316L grade is 022Cr17Ni12Mo2, which means carbon ( C) The content is 2.2% (0.022%). Other signs remain basically unchanged.
The carbon (C) content in the new brand is more clear than before, and it also has higher requirements for product production technology.
2. The raw material content of individual materials is adjusted
Comparison of some steel grades with changes in raw material content:
NO Chinese Standard Japan (JIS) U.S.
New standard old standard
The content of Cr and Ni in 304 increased by 1 point each; the content of Ni in 316L increased by 2 points; the content of Cr in 444 increased by 1 point and added Nb and Ti trace elements; the content of Ni in 321 decreased 1 point; Ni content in 304N1 is reduced by 1 point.
Different steel grades have been adjusted to different degrees, and the adjustment range is relatively large in Ni-Aust.