Ferritic stainless steel refers to the stainless steel with 10.5% ~ 30% Chromium content and without Nickel. The main grades including 405, 409, 410, 430, 434,439, 441, 445, 446, 447, of which the most widely used are 409, 410, 430 series. Ferritic stainless steels contain more chromium than Austenitic stainless steels, are less costly and can be used as an alternative material to the 304 or 200 series stainless steels sometimes. According to the chromium content, it can be divided into three groups: Cr10% ~ 15%, Cr16% ~ 20% and Cr21% ~ 30%.
10% -14% Cr: 409、410L
409, 410 have the lowest chromium content and the cheapest in all of Ferritic stainless steels, suitable for environments where no corrosion or slight corrosion and local slight rust are allowed. Type 409 was originally designed specifically for automotive exhaust mufflers. 410L stainless steel low carbon content, welding parts of the bending performance, processing performance, good resistance to high temperature oxidation performance, often used in automotive exhaust steam treatment device, boiler combustion chamber, nozzle, container, bus and coach car, etc., in recent years also used as LCD display frame.
14%-18% Cr: 430、430Ti、439、434、436、444
The 430 is the most widely used ferritic stainless steel, and the higher chromium gives it better corrosion resistance. In some applications, can be replaced by 304. Typical uses include washing machine rollers, interior panels, kitchen equipment, food industry, etc.
430Ti and 439 contain stabilizing elements Ti and Nb, which have good weldability and formability. Typical applications include the food industry, kitchen tools, heat exchangers (sugar, energy, etc.), automotive exhaust systems (service time longer than 409), and welding parts of washing machines, even replacing 304 for more demanding applications. The 430Ti has better welding performance, better intergranular corrosion resistance, better deep drawing performance, better impact toughness and lower brittle transition temperature than the 430 stainless steel. Type 439 is often found in building decoration, automobile exhaust system and inner cylinder of washing machine. The 441 stainless steel has good high temperature resistance and is generally used in the manifold and front tube sections of the exhaust pipe. 434, 436 and 444 contain more molybdenum and have stronger corrosion resistance, among which 444 has almost the same corrosion resistance as 316. Typical applications are hot water tanks, solar water heaters, automotive exhaust systems, electric heating kettles and microwave oven components, automotive trim strips and outdoor panels.
Superferrite stainless steel 446, 445/447 contains more chromium and molybdenum, its corrosion resistance and oxidation resistance is better than 316, has good Cl ion pitting resistance. Typical uses include coastal and other highly corrosion resistant environments.