304 stainless steel plate is often used as the inner layer (that is, in direct contact with water) due to its excellent corrosion resistance. 201 stainless steel plate cannot be used as the inner layer due to its poor corrosion resistance and is often used as the outer layer of the insulated water tank. However, 201 is cheaper than 304 and is often used by some unscrupulous merchants as 304. Stainless steel water tanks made of 201 stainless steel plates have a very short service life and are often corroded by water in 1-2 years, leaving potential safety hazards for users.

Let’s teach you how to identify these two materials in a simple way:

1. The surface of 304 stainless steel plates and 201 stainless steel plates used in stainless steel water tanks is usually matte. So we identify it by looking with the naked eye and touching it with our hands. To the naked eye, the 304 stainless steel plate has a very good luster and is very smooth to the touch; the 201 stainless steel plate is dark in color and has no luster, and feels rough and not smooth to the touch. In addition, wet your hands with water and touch the two stainless steel plates respectively. After touching, the water-stained fingerprints on the 304 stainless steel plate are easier to erase, while the 201 stainless steel plate is not easy to erase.

2. Use a grinder to install a grinding wheel and gently polish the two stainless steel plates. When polishing, the sparks of the 201 stainless steel plate are longer, thicker, and more, while the sparks of the 304 stainless steel plate are shorter, thinner, and less. The force must be light when polishing, and the two types of stainless steel plates must be polished with the same force to facilitate differentiation.

3. Apply stainless steel pickling paste to the two stainless steel plates respectively. After 2 minutes, observe the color change of the stainless steel plate at the applied location. If the color turns black, it is 201 stainless steel plate, if it turns white or does not change color, it is 304 stainless steel plate.