How to distinguish between 304 and 201 stainless steel?

304 stainless steel is one of the most widely used mainstream steels at present, because of its obvious corrosion resistance, while 201 stainless steel has relatively poor corrosion resistance, resulting in different widely used areas and different prices. The price of 201 is lower than that of 304. In reality, some opportunistic and unscrupulous manufacturers often pretend to be 304 to promote and sell externally in order to obtain high profits.

The chemical content of chromium in stainless steel is 19-5%, and the content of chromium in stainless steel is 1-8% to 18.5%. High nickel content means strong anti-rust ability, and it also means that 304 is more expensive than 201, so uninformed people will be deceived by unscrupulous merchants. So how to distinguish 201 and 304?

First, the conventional method, we identify by the naked eye and hand touch. To the naked eye, 304 stainless steel has a good luster and shine, and the hand touch is very silky; 201 stainless steel is dull and dull in color, and feels rough and not smooth to the touch. In addition, wet your hands with water and touch two stainless steel plates respectively. After touching, the water-stained fingerprints on the 304 stainless steel plate are easier to erase, and the 201 stainless steel plate is not easy to erase.

Second, use the detection tool to apply the stainless steel pickling paste on the stainless steel plate one by one. Wait two minutes to see the change in the color of the stainless steel where you apply it. 201 when the color becomes black, 304 when it becomes white or unchanged. It is recommended to try this method

Third, use mechanical operation, install the grinding wheel with a grinder and lightly grind the two types of plates. When grinding, the sparks of the 201 plate are longer, thicker and more, while the sparks of the 304 plate are shorter, thinner and less. Note: When grinding, it needs to be light and consistent, so it is easy to distinguish, and it requires a certain amount of experience to control.

Fourth, in terms of chemical composition, because the carbon content of 201 is higher than that of 304, 201 is harder and more brittle than 304, and 304 has better toughness. If you use a hard scratching knife to scratch the surface of 201, there will generally be obvious scratches. The scratches on the 304 are not very obvious.