Magnetic Causes and Solutions of Stainless Steel Castings

After the production of stainless steel castings is completed, magnetic products will be unqualified. Therefore, many details should be paid attention to in the process of processing and producing stainless steel castings to avoid magnetic properties of stainless steel castings formed by cooling. The following is an explanation of the causes and solutions of magnetic properties of stainless steel castings.

As we all know, austenitic stainless steel for the production of stainless steel castings should not be magnetic, but some products produced are magnetic. Some manufacturers think it is the reason for the material, but after spectral testing, the material is qualified and there is no abnormality. Many people cannot find the problem and cannot solve this problem. We have made new discoveries after consulting a large amount of data and communicating with relevant technicians, the reason why the stainless steel castings formed by cooling are magnetic is that the internal structure of austenitic stainless steel changes during the cooling process, and part of austenite transforms into martensite, while the martensitic stainless steel with body core structure is magnetic. So why does the austenite structure transform into a martensite structure?

Stainless steel according to the structure can be divided into austenitic stainless steel, martensitic stainless steel, ferritic stainless steel. Among them, austenitic stainless steel is a kind of stainless steel with a usage of * * * * *. Stainless steel with austenitic structure is theoretically non-magnetic, but austenitic stainless steel will produce magnetism after cold working. According to some studies at home and abroad, the reason for the magnetism of austenitic stainless steel castings is that when the stainless steel is heated above the austenitic transformation temperature and kept for a period of time during the processing, the stainless steel will transform into austenite, however, stainless steel castings need to be cooled and formed. During the rapid cooling process, when the austenite is cooled to the martensite transformation temperature, its organization begins to transform into martensite, and the transformation will not be stopped until the temperature drops below the transformation temperature of the martensite structure. In the production of stainless steel castings, the stability of austenitic stainless steel, processing deformation, processing methods, etc. may affect its transformation into martensitic stainless steel.

Therefore, according to the causes and influencing factors of martensite, in order to avoid magnetic properties of stainless steel castings, austenitic stainless steel with high content of austenitizing elements must be purchased when purchasing raw materials. It is also possible to eliminate magnetism and work hardening by means of a hot-melt treatment. * There is a "alloy degaussing agent" that can eliminate the magnetism of stainless steel castings on the market recently. The iron element in stainless steel castings can be transformed into austenite, so as to achieve the purpose of degaussing. At the same time, after adding the alloy degaussing agent, the corrosion resistance and salt spray test of stainless steel castings are good.