The composition of the recarburizer should be distinguished by the amount of nitrogen.
What level of nitrogen content to choose is very important! ! !
Now take the example of adding more than 50-60% of the scrap steel to the induction furnace to smelt synthetic cast iron. The greater the amount of scrap added, the greater the nitrogen content of the molten iron. Since the titanium, lead, antimony, and other harmful elements in the synthetic cast iron are very low, it should be Use low-nitrogen recarburizers. If the recarburizer has a high nitrogen content, the synthetic nitrogen content will cause nitrogen holes in the casting.
In my casting work in 2004-09, I found that high-end customers in the United States and Japan had to test the content of nitrogen, titanium, lead, arsenic and other harmful elements in the cast iron for the acceptance of ordinary gray iron. Among them, the content of nitrogen is generally hoped. The best in 80-120PPM. If you use a high-nitrogen recarburizer (generally a low-end recarburizer product), since the content of titanium in the molten iron is very low, it is impossible to use Ti to consume a large amount of nitrogen, making the castings prone to nitrogen holes due to too high nitrogen content , Crack-like nitrogen holes or related defects. This phenomenon has occurred in the unit where I have worked before. Many experts have also talked about the heavy losses caused by poor quality recarburizers. Special emphasis is placed on the smelting of synthetic cast iron. The key is to use good quality. , Calcined petroleum coke with low nitrogen content.
Many people in the foundry industry believe that the high sulfur content of the recarburizer will not affect the quality of ordinary gray iron (inoculated cast iron), but the high sulfur content of the recarburizer will cause high nitrogen content, which will cause quality problems.