Material Classification: Industry professionals generally distinguish stainless steel into the 200 series, 300 series, and 400 series, which is a method based on the American standard for grade classification. Specific grades are used to differentiate between these series:

The 200 series includes 201 and 202,
The 300 series includes 304 and 316,
The 400 series includes 410 and 430.

It is important to note that, according to the national standard, only the 300 and 400 series grades are recognized. These can be further categorized into five types: ferritic, martensitic, austenitic, duplex, and precipitation hardening. Based on composition, stainless steel can be divided into the chromium series, chromium-nickel series, and chromium-nickel-manganese series.

304 and 316 are the two most widely used materials in the 300 series. 304 is the most commonly used stainless steel due to its good overall performance, including high elongation, good weldability, and excellent corrosion resistance. It can replace nearly all applications where steel is used (except in high-strength requirements). 316 was developed based on 304, primarily by adding molybdenum (Mo) to enhance corrosion resistance, making it suitable for coastal environments.

430 is the most commonly used material in the 400 series. In home appliances, kitchens, and bathrooms, 430 is a good substitute for 304 stainless steel. However, due to its lower elongation and poor weldability, its usage is less than that of 304. 410S is the most widely used low-chromium (Cr Less than or equal to 13.5%) stainless steel, commonly found in lower-end products like knives, forks, spoons, and basins.

The 200 series combines the good processability of the 300 series with the cost-effectiveness of the 400 series, making it a popular replacement material. Its usage is second only to the 300 series (with market sales ratios of 300:200:400 being approximately 5:3:2). In addition to the previously mentioned stainless steels, the usage of other types is relatively low. For example, martensitic stainless steel (410/420) is used for table knives and forks, ultra-pure ferritic stainless steel (409, 441) is used in automotive exhaust systems, duplex stainless steel (2507) is applied in the petrochemical industry, and precipitation hardening stainless steel (630) is utilized in the electronics industry.