How to deoxidize stainless steel casting

Stainless steel casting generally needs two deoxidation, primary deoxidation and final deoxidation.

Deoxidizer and deoxidation process should be reasonable to ensure the quality of stainless steel castings.

1. For deoxidation in stainless steel smelting stage, manganese (electrolytic manganese sheet 99.7%, which has national standards) and ferrosilicon are used for initial deoxidation. The initial deoxidation can remove most of the oxygen in the molten steel, for example, up to 70-90%. However, you must not think that everything is safe and sound. The main culprit for the failure of provocation is often the “silent” and “stubborn” 10% of the oxygen free from the legal net.

2. For those stubborn oxygen, the primary deoxidation process is powerless. The temperature and deoxidation ability determine that the primary deoxidizer has completed the task. Who will complete the fatal blow to the residual oxygen? The answer is: final deoxidation process! The final deoxidizer is generally a so-called composite Deoxidizer with two or more components. A large number of practices have shown that when the composite Deoxidizer containing multiple elements enters the molten steel, it not only cooperates with each other to perform its duties, but also congests each other. Compared with fighting alone, it can significantly increase its deoxidation efficiency. Therefore, this idea of 1+1=3 is a very important design element in the design of composite Deoxidizer products, Of course, there are other important indicators of Compound Deoxidizer, which seem not worth mentioning, but are actually indispensable.

For example, the theoretical deoxidation effect of aluminum is particularly good, but the problem is that the proportion of aluminum is small and the burning loss is serious. What should we do? Now we know that the maximum deoxidation efficiency can be achieved by adding large cans of bulk aluminum blocks, adding aluminum by caisson method and aluminum wire feeding process. If only the deoxidation ability of aluminum itself is beyond doubt, the insertion into the bottom of molten steel becomes a key problem. Of course, aluminum deoxidation for stainless steel may also bring insoluble fine particles of aluminum oxide. In addition, aluminum deoxidation aging time is very short, so the use of aluminum for stainless steel deoxidation should be very cautious. Some deoxidizers can also be mixed with rare earth elements to achieve special purposes.

Casting Manifold

3. As for the price of deoxidizer, the price of electrolytic manganese used for initial deoxidation fluctuates. Ferrosilicon has risen by a large margin this year. At present, the price of ferroalloy has risen rapidly. Many brothers in the surrounding industrial areas have stopped work. Of course, the price of other raw materials has also increased, and environmental protection is also important. The price mainly depends on your purchase volume. Generally, stainless steel casting enterprises will not use much. The casting output is about 100 tons per month, and a single purchase is only one ton. Composite deoxidizers, such as the rare earth deoxidizers of Baotou Rare Earth Institute, have good effects, especially for castings requiring mechanical properties. Other stainless steel composite deoxidizers have good effects and different prices. There are many deoxidizer enterprises in Henan, which have not tried and do not need to be tested. The prices are surprisingly low, only a few thousand yuan to 10000 yuan. It is estimated that they are used for large furnaces in crude steel mills and have nothing to do with casting.

China is the first country to export ferroalloys, including deoxidizers, including rare earths. The current smelting process in China is electrolytic manganese 99.7 and 75 silicon primary deoxidization, with the addition amount of 0.15% and final deoxidizer, with the addition amount of 0.3%. The 150kg furnace does not lift the ladle. The temperature should be measured and it is important to keep records.

4. It is worth noting that the deoxidizing process and deoxidizer used in stainless steel casting are totally different from those used in steel mills. Please don’t put on airs and airs. Especially, some furnace masters with working background in steel mills have this inertial thinking. Steel mills generally deoxidize through slagging diffusion, while foundries directly deoxidize by precipitation without slagging. In addition, the quality standard solution can’t be compared.


Post time: May-27-2022