Stainless steel heat treatment technology in precision casting plants

(1) Ma Tian loose iron stainless steel: This type of stainless steel has a body centered cubic structure (BCC) that can attract magnets and be rapidly cooled from Ostian temperature. It has good corrosion resistance, but the material is hard and brittle. Tempering can increase ductility, but the corrosion resistance will decrease, especially when tempered between 450 ° C and 650 ° C. This will cause carbon atoms to diffuse and precipitate in the crystal lattice gaps, forming a network of chromium carbide with chromium, resulting in the consumption of chromium elements in the adjacent area and the inability to form a protective film, thus losing corrosion resistance. Therefore, special attention should be paid. The following are the heat treatment temperatures for precision casting of various Ma Tian loose iron stainless steel materials.

(a) The temperature of 403410416se is between 650-750 ℃.

(b) The temperature of 414 is between 650-730 ℃.

(c) The temperature of 431 is between 6. (d) The temperature of 440-A, 440-B, 440-C, and 420 is between 680-750 ℃.

(2) Fatty iron stainless steel: This type of stainless steel has a body centered cubic structure (BCC) that can attract magnets. It is commonly used in the automotive or chemical industries, and its strength does not change due to heat treatment, but can be increased by cold processing.

(3) Ostian iron-based stainless steel: This type of stainless steel has a face centered cubic structure (FCC) that does not work with magnets. As mentioned earlier, this type of material is easy to process, so after processing, it eliminates residual stress and can be subjected to different heat treatments.

(4) Precipitation hardening stainless steel: This type of stainless steel is quenched at high temperatures and then subjected to low-temperature heat treatment. Due to the precipitation of aluminum or copper elements in the material, inter metallic compounds are formed along the slip surfaces or grain boundaries, which can enhance its strength or hardness. Commonly used precipitation hardening stainless steel 17-4PH, other types include 17-7PH, PH15-7MO, AM-350, AM-355, etc.

Heat treatment of various types of stainless steel after welding: The chromium element contained in stainless steel often diffuses and precipitates with carbon to form chromium carbide in the high-temperature zone (heat affected zone) after welding, resulting in a decrease in local chromium content and the inability to form a protective film. Corrosion such as perforation often occurs in these heat affected zones, which can remedy this situation. After welding, the object is often subjected to heat treatment, which can cause chromium elements from other areas to diffuse to the chromium deficient area, achieving a protective effect.