Representation method of steel grade in China (IX): Stainless steel and heat resistant steel

The grades of stainless steel and heat-resistant steel are indicated by alloy element symbols and Arabic numerals specified in the standard. For cutting stainless steel and free cutting heat-resistant steel, add “Y” at the head of the grade.

Generally, one Arabic numeral is used to represent the average carbon content (in thousands); When the average carbon content is ≥ 1.00%, it is represented by two Arabic numerals; When the upper limit of carbon content is less than 0.10%, the carbon content is represented by “0”; When the upper limit of carbon content is ≤ 0.03% and > 0.01% (ultra-low carbon), the carbon content is represented by “03”; When the upper limit of carbon content (≤ 0.01%, very low carbon), the carbon content is represented by “01”. When there is no lower limit for carbon content, Arabic numerals shall be used to represent the upper limit of carbon content.

The expression method of alloy element content is the same as that of alloy structural steel. For example: stainless steel with an average carbon content of 0.20% and chromium content of 13% is indicated as “2Cr13”; Chromium nickel stainless steel with the upper limit of carbon content of 0.08%, average chromium content of 18% and nickel content of 9% is indicated as “0Cr18Ni9”; Sulfur free cutting chromium stainless steel with upper limit of carbon content of 0.12% and average chromium content of 17% is indicated as “y1cr17”; The grade of high carbon chromium stainless steel with average carbon content of 1.10% and chromium content of 17% is “11cr7”; The upper limit of carbon content is 0.03%, the average chromium content is 19% and the nickel content is 10%. The brand of ultra-low carbon stainless steel is “03cr19ni10”; The upper limit of carbon content is 0.01%, the average chromium content is 19% and the nickel content is 11%. The brand of very low carbon stainless steel is “01cr19ni11”.

The current domestic standard of stainless heat-resistant steel is revised with reference to JIS standard, but the brand representation method of stainless heat-resistant steel is different from that of Japan and other countries. We use alloying elements and average C content, and Japan uses letters and Arabic numerals to indicate purpose. For example, stainless steel grades SUS202, SUS316, SUS430, S-STEEL, u-use and s-stainless. For example, heat-resistant steel grades suh309, suh330, suh660 and h-heatresistins. Different numbers in the brand represent different types of stainless and heat-resistant steel. Japan said that for different products of stainless and heat-resistant steel, the corresponding letters should be added after the brand, such as stainless steel rod sus-b and hot-rolled stainless steel plate sus-hp; Heat resistant steel bar suhb, heat resistant steel plate suhp. In Britain, the United States and other western countries, the brand representation method of stainless heat-resistant steel is basically the same as that in Japan, which is mainly expressed in Arabic numerals, and the numbers are the same, that is, the brand is the same.