The material of stainless steel BL flanges is made of different types and chemical compositions of different uses. Stainless steel can be roughly classified according to use, chemical composition and metallographic arrangement.

　　Stainless steel BL flanges are classified by chemical composition: 1CR series: ferrite series, martensite series 2CR-NI series: austenite series, abnormal series, precipitation hardening series.

　　Stainless steel BL flanges are classified by metallographic arrangement: 1 austenitic stainless steel 2, ferritic stainless steel 3, martensitic stainless steel 4 duplex stainless steel 5, precipitation hardening stainless steel.

　　Stainless steel BL flanges are available in the following materials

　　1. Stainless steel BL flange material 301- has good ductility and is used for flange forming products. It can also be rapidly hardened by machining. It has good weldability, wear resistance and fatigue strength better than 304 stainless steel.

　　2. Material 302-corrosion resistance is the same as 304, because the carbon content is relatively high, so the strength is better.

　　3. Stainless steel BL flange material 303 - after adding a small amount of sulfur and phosphorus, it is easier to cut than 304.

　　4. The general type of material 304-that is, 18/8 stainless steel, the GB number is 0Cr18Ni9.

　　5. Material 309- has better temperature resistance than 304.

　　6. Stainless steel BL flange material 316 - the second widely used steel after 304, mainly used in dry food industry and surgical equipment, adding molybdenum element to obtain a special structure of anti-corrosion clock.

　　7. Material 321 - similar to 304, 400 series - ferritic and martensitic stainless steel except that the risk of material weld corrosion is reduced due to the addition of titanium.

　　8. Stainless steel BL flange material 408 - good heat resistance, weak corrosion resistance, 11% Cr8% Ni type 409 - cheap type.