There are many types of stainless steel, of which the conventional ones are 201 stainless steel, 304 stainless steel and 316 stainless steel. Each country's code is different, of course, there will be differences in the use of standards, in China drinking water pipes, water pipes, gas pipes will also be used to 304 stainless steel. 201 stainless steel has acid resistance, alkali resistance, high density, polishing without bubbles, no pinholes and other characteristics, is the production of a variety of cases, strap bottom cover quality materials, etc.. It is mainly used for making decorative tubes, industrial tubes, some shallow drawn products. Stainless steel basically contains a very important element nickel. This is one of the big differences between 201 and 304, 201 has a very low nickel content, almost none. Whereas 304 has more nickel than 201, about 8 or so. As a result, 201 stainless steel is generally much easier to rust than 304. If there is greater cost control, 201 is usually used instead of 304, after all, the cost is lower. On the other hand, due to the low nickel content of 201, it is usually alloyed as 201, for example by adding manganese or nitrogen to give 201 more oxidation resistance, as well as increased corrosion resistance.