Composition are different:
201 chemical composition: 17Cr-4.5Ni-6Mn-N(C:≤0.15；Si:≤1.0；Mn:5.5～7.50；Cr:16.0～18.0； N:≤0.25；P:≤0.060；S:≤0.030；Ni: 3.50-5.50%；Cu:0.8%)
304 chemical composition: 18Cr-9Ni(C:≤0.08；Si:≤0.75；Mn:≤2.0；Cr:18.0～20.0；P:≤0.045；S:≤0.030；Ni: 8.0-11.0%。
2. 201's acid resistance is poor，generally use it indoors or a place of dry and ventilation;304's acid resistance is better than 201，outdoors or a place of damp are not affect it.
3.201 is high manganese content, the surface is very bright with dark light, high manganese content is easy to rust.; 304 contains more chromium, the surface is matte and doesn't easy to rust..The two kinds are obviously different together,the important thing is corrosion resistance is different,201's corrosion resistance is poor than 304,and because 201 contains low nickel content,the price is cheaper.
How to distinguish the 304 and 201?
1、304 stainless steel plate and 201 stainless steel plate distance observation, the surface is the same luster, sublight color. But we can identify it in other ways.If you look at it directly with the naked eye, the color of 304 is saturated and shiny, and the feel is very smooth;And 201, will show a little dark, low color saturation, hands will feel a little rough.In the case of water contamination experiment, the watermark on 304 surface is very easy to remove, and 201 treatment is very troublesome.
2、It is distinguished by a grinder: when grinding 304 stainless steel plate, the sparks are short and less, while 201, on the contrary, the sparks are splashed and more. When we distinguish in this way, we should keep the intensity of grinding consistent.
3、Distinguish by stainless steel pickling paste: smear the lotion on 304 and 201 to observe its color change,if the color is white or not discolored, it is 304; on the contrary, blackening is 201.