The difference between stainless steel 201, 202, 304 and 316

- Oct 08, 2019-

I used to separate 201 stainless steel, 202 stainless steel, 304 stainless steel and 316 stainless steel. Let's take a look at their differences.

1. Grade:

201:1Cr17Mn6Ni5N; 202: 1Cr18Mn8Ni5N;

304: 06Cr19Ni10, 304L: 00Cr19Ni10;

316:0Cr17Ni12Mo2, 316L: 00Cr17Ni14Mo2

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2. Chemical composition

201 stainless steel and 202 stainless steel composition table

304 stainless steel and 316 stainless steel composition table

3. Corrosion resistance

The corrosion resistance of 200 series stainless steel is obviously better than that of 304 and 316 stainless steel in 300 series, but in general, both 304 stainless steel and 316 stainless steel have little difference in chemical resistance, but there are some specific media. The difference. Among various types of water quality (distilled water, drinking water, river water, boiler water, etc.), 304 stainless steel and 316 stainless steel have almost the same corrosion resistance, but when the content of chloride ions in the medium is very high, 316 stainless steel is more suitable. Specific analysis of the specific situation.

4. Application range difference

Due to their different corrosion resistance, 201 and 202 are basically used in the field of decorative tubes where the material requirements are not strict. 304 and 316 can be used in coastal or humid environments, but the real stainless steel products by the sea are recommended to be 316 stainless steel or better.

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5. Food grade issues

The most recent ones have been about stainless steel food grades. I have shared two such questions before. In this simple sharing, 201 and 202 are not classified into food grade stainless steel according to the material. Currently, the food grade stainless steel commonly used in the market is three. Class: 304, 316 and 430 stainless steel. However, the food grade refers not only to the food grade, but also to all aspects of production.

6. Low carbon type

The corrosion resistance of austenitic stainless steel comes from the chromium oxide protective layer formed on the metal surface. When the temperature of the material is heated to 450-900 degrees, the structure changes, and chromium carbide is formed along the edge of the crystal to In particular, higher intergranular corrosion sensitivity does not mean that non of a reducing oxide resistance layer, such reducing corrosion resistance, which is also called "intergranular corrosion". This has 304L and 316L, both of which reduce intergranular corrosion due to less carbon. -low carbon content is more susceptible to corrosion, and in high chlorine environments, this sensitivity is also higher.

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