The main difference of grade 201 and 304 is the chemical composition. Grade 304 has 8% Ni while grade 201 has 1~1.2% Ni, which make 304 have a better quality than 201 and more expensive. So how can we identify 201 and 304?
It is difficult to see the difference by our eyes, but we could use professional test liquid to identify. The color of the liquid is green, the different materials will cause difference chemical reaction and turns to different color.
The test is very simple. Clean the stainless steel surface and apply one drop of liquid on it.
The color of the liquid will turns to red within 3 minutes if it is 201 and the color will remains same as green if it is 304.