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Heat Treatment Technology Of Stainless Steel
Oct 20, 2017

Chromium element for such materials with stainless factors, in the past found that the chromium content must have more than 12% in order to form a dense surface oxide film to achieve the role of corrosion protection, so any heat treatment of stainless steel must take into account the composition of chromium Whether or not there is any change.


(BCC) can be attracted to the magnet, which is made from the Austrian field temperature quenching, the corrosion resistance of the best, but the material hard (1) Ma Tian scattered iron: stainless steel for the body of the heart of the structure (BCC) Then the brittle, followed by tempering can increase the ductility, but the corrosion resistance will be reduced, especially in the 450 degrees Celsius to 650 degrees between the tempering, will make the crystal lattice gap in the diffusion of carbon atoms and chromium to form a network Of chromium carbide caused by the consumption of chromium near the region to reduce the chromium content, can not form a protective film, and the loss of corrosion resistance, it is necessary to pay special attention. The following are the heat treatment temperatures for various Amantha iron-based stainless steels.

(A) 403, 410, 416se the temperature is 650-750 ℃.

(B) 414 has a temperature of 650-730 ° C.

(C) the temperature of 431 is 6. 

(D) 440-A, 440-B, 440-C, 420 at a temperature of 680-750C.


(2) fat iron type stainless steel: This kind of stainless steel body-centered cubic structure (BCC) can be used for magnet attracting is usually used in the automotive industry or chemical industry, the intensity will not change due to heat treatment, but can increase the intensity of cold processing.


(3) Osti iron stainless steel: This stainless steel for the face-centered cubic structure (FCC) on the magnet does not work, as mentioned above, such materials are easy to process, so after processing to eliminate the residual stress of the material Apply a different heat treatment.


(4) precipitation hardening stainless steel: This kind of stainless steel after high temperature quenching at low temperature heat treatment, due to the material containing aluminum, or copper element precipitation along the poor row of flat or grain boundaries to form compounds (inter-metallic compounds) Improve its strength or hardness. Commonly used precipitation hardening stainless steel 17-4 PH, there are other 17-7 PH, PH15-7MO, AM-350, AM-355 and so on.


(5) all kinds of stainless steel after welding heat treatment: stainless steel contained in the chromium element, after welding, in the high temperature region (heat affected zone) tends to diffuse and lead to carbon carbide into chromium, resulting in local reduction of chromium content, can not The formation of protective film, and perforation and other corrosion conditions often occur in these heat affected areas, in order to remedy this situation often after welding, the object heat treatment, its role in the other areas of the chromium element diffusion to this chromium lack of regional , To achieve the protective effect. 





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