IS202 and IS304 stainless steel can be distinguished primarily by their chemical composition and mechanical properties. IS202 is a nickel-free stainless steel with a higher manganese content, making it less corrosion-resistant compared to IS304, which contains a significant amount of nickel and chromium, providing excellent corrosion resistance. Additionally, IS304 typically has better formability and weldability than IS202. Identifying them can also involve examining their physical characteristics, such as magnetic properties, where IS202 may exhibit slight magnetism due to its alloying elements.