Precision cast stainless steel heat treatment technology
Precision cast stainless steel heat treatment technology
(1) Ma Tian loose iron stainless steel: This type of stainless steel body-centered cubic structure (BCC) can attract magnets and cool them from Aostian temperature, which has the best corrosion resistance, but the material is hard and brittle. The tempering can then increase the ductility, but the corrosion resistance will decrease, especially when tempering between 450 and 650 degrees Celsius will cause the carbon atoms in the crystal lattice gap to diffuse and form a chromium-like carbonized chromium. The consumption of chromium in the adjacent area causes the chromium component to decrease, the protective film cannot be formed, and the corrosion resistance is lost, so special care is required. The following are the heat treatment temperatures for various granulated iron-based stainless steels.
(a) The temperature of 403, 410, 416se is between 650 and 750 °C.
The temperature of (b) 414 is between 650 and 730 °C.
(c) 431 has a temperature of 6. (d) 440-A, 440-B, 440-C, 420 at a temperature of 680-750 °C.
(2) Fertilizer iron stainless steel: This stainless steel body-centered cubic structure (BCC) can attract magnets and is usually used in the automotive industry or chemical industry. The strength is not changed by heat treatment, but the strength can be increased by cold working.
(3) Austin ferrous stainless steel: This kind of stainless steel face-centered cubic structure (FCC) does not work on magnets. As mentioned above, such materials are easy to process, so the residual stress of the material can be eliminated after processing. Heat treatment.
(4) Precipitation-hardening type stainless steel: This type of stainless steel is heat-treated at a low temperature after high-temperature quenching, and can be improved by the aluminum or copper element precipitated in the material along the slip surface or inter-metallic compound of the difference row. Its strength or hardness. Commonly used precipitation hardened stainless steel 17-4PH, others have 17-7PH, PH15-7MO, AM-350, AM-355 and so on.
(5) Post-weld heat treatment of all kinds of stainless steel: The chromium element contained in the stainless steel, after welding, tends to diffuse and precipitate carbon and form chromium carbide in the high temperature region (heat-affected zone), resulting in a decrease in local chromium content. A protective film is formed, and corrosion such as perforation often occurs in these heat-affected zones. This situation can be remedied. The manufacturer often heats the object after welding, and the effect is to diffuse the chromium element in other regions to the chromium-deficient region. To achieve protection.