Grade 304 and 202 are austenitic stainless steel. The face-center cube is the lattice arrangement for both grades. Grade 304 contains a larger nickel concentration than grade 202. Grade 202 is characterized by the presence of manganese and nitrogen in its chemistry. On visual cue, both grades will appear identical.
- Grinder test can be employed to state the identification between the grade 304 and 202. Grade 304 will show thin reddish-orange sparks and sparks will fly for a long time due to the higher density of more nickel content. On the other hand, thick yellow sparks will appear for grade 202.
- Manganese and nickel spot tests can be administered on grades 304 and 202. Grade 304 has more nickel concentration and grade 202 has higher manganese.
- X-ray fluorescence spectroscopy is a reliable but expensive method.
Nickel is a traded commodity and has volatile prices. Grade 304 is more expensive than grade 202 as it contains 8-10% of nickel. Grade 304 is widely used in the food processing industry, heat exchangers, etc whereas grade 202 is an economical substitution of grade 304 in some of the applications.