Stainless steel casting generally to carry out two deoxidation, the first deoxidation and after a deoxidation. Deoxidizer and deoxidizer process should be reasonable to ensure the quality of stainless steel casting.
1, stainless steel casting stage deoxidation, first with manganese (99.7% electrolytic manganese sheet, a national standard) and ferrosilicon for a deoxidation. A single deoxidation can remove most of the oxygen in the molten steel, for example, up to 70-90%. However, you should never assume that everything is safe and secure, those who are "silent" and "stubborn" tend to lead to the casting defect rate.
2, for those stubborn oxygen, the primary deoxygenation process has been powerless. Temperature and deoxidation capacity determine that the primary deoxidizer has done its job, so who will complete the fatal blow to the residual oxygen? The answer: deoxygenation! Deoxidizers are usually so-called compound deoxidizers that contain two or more ingredients. A large number of practices have shown that when the composite deoxidizer containing multiple elements enters the liquid steel, it not only plays its own role in the collaborative operation, but also coagulates with each other. Compared with the single combat, it can significantly improve the self-deoxidizing efficiency. Therefore, in the design of compound deoxidizer products, the idea of 1+1=3 is a very important design element. Of course, compound deoxidizer has other important indicators. Aluminum, for example, works exceptionally well in theory, but here's the problem. Aluminum proportion is small, burning serious. What should I do? It is now known that greater deoxidation efficiency can be achieved by adding bulk aluminum blocks to large tanks, adding aluminum by caisson method, and feeding aluminum wires. If the deoxidation ability of aluminum alone is not in doubt, then insertion into the bottom of the molten steel becomes a critical issue. Of course, aluminum deoxidation may also bring alumina insoluble particles to stainless steel, and aluminum deoxidation aging time is very short, so the use of aluminum stainless steel precision casting deoxidation is very careful. Some deoxidizers combine rare earth elements for specific purposes, but in my experience, this is something to be careful of. If it's bad, it's counterproductive. I'm not talking about that here. I am particularly offended by sellers who always use rare earth deoxidizer. First, there is the question of rare earths. Two, are you sure it's appropriate to add rare earths? It's just a gimmick!
3. The price of deactivating agent. The initial deoxidation with electrolytic manganese price fluctuations, this year the ferrosilicon increase. At present, the growth of ferroalloy is rapid, and many brothers in the surrounding industrial areas have stopped work. Of course, other raw materials are also rising in price, and environmental protection is tight. The price mainly depends on your purchase quantity, general stainless steel casting enterprises do not use. Our casting output is about 100 tons per month, but we can only buy one ton at a time. Compound deoxidizer, such as rare earth deoxidizer of Baotou rare Earth Research Institute, is very good, especially for the mechanical properties of the casting. Other stainless steel compound deoxidizer effect is good, the price is different. Henan has a lot of deoxidizer enterprises, have not tried, do not need to test. The price is surprisingly low, only a few thousand to ten thousand yuan. Think about the price of ferrosilicon, it is estimated that the large furnace of the crude steel mill is used, and it has nothing to do with casting. Some enterprises sell deoxidizer is imported, pure nonsense! Number one exporter of iron alloys including deoxidants and rare earths, okay? Our current stainless steel casting process is electrolytic manganese 99.7 and 75 silicon initial deoxidation, add 0.15%, final deoxidation deoxidizer add 0.3%, 150 kg furnace does not lift ladle. The temperature should be measured and it is important to keep records.
