How to distinguish between 304 stainless steel and 201 stainless steel?

1.304 and 201 stainless steel is used in stainless steel tanks and the surface is usually matte. So we identify it with the touch of the naked eye and the hand. 304 stainless steel has a good luster and is smooth to the touch of the hand; The color of 201 stainless steel is dark and dull, and the feel is rough but not smooth. Also, wet your hands with water and touch the two stainless steel plates separately. The water-stained fingerprint on the 304 stainless steel plate is easy to erase after touching, while the water-stained fingerprint on the 201 stainless steel plate is not easy to erase.
2. Install the grinding wheel on the grinding machine and gently grind the two kinds of plates. When grinding, the spark of the 201 stainless steel plate is longer, thicker and more, while the spark of the 304 stainless steel plate is shorter, thinner and less. When grinding, the force must be light, and the two grinding forces are consistent, which is easy to distinguish.

3. Apply stainless steel pickling paste on two stainless steel plates. After 2 min, observe the color change of the stainless steel on the smear. The color blackens to 201 stainless steel plate, and the whitening or non-color change is 304 stainless steel plate.