However, casting is generally divided into two types: gray casting and ductile iron. Due to different castings and processes, the required recarburizers are different, and the final effects achieved by different recarburizers are also different. When the initial carbon content in the molten iron is high, the absorption speed of the recarburizer is slow, the absorption amount is small, and the burning loss is relatively large under a certain solubility limit, and the absorption rate of the recarburizer is low. When it is low, the situation is the opposite. In addition, the silicon and sulfur in the molten iron hinder the absorption of carbon and reduce the absorption rate of the recarburizer; while the manganese element contributes to the absorption of carbon, updating the iterative recarburizer absorption rate, in terms of the degree of influence , Silicon is the largest, followed by manganese, and carbon and sulfur have less impact. Therefore, in the actual production process, manganese should be added first, then carbon, and then silicon.
Generally, the recarburizer for gray casting requires a lower sulfur content. Normal sulfur below 0.5 can be used. The requirements are not so strict. Generally fixed carbon 98.5/98/90/95/92 can be used, and even some manufacturers In order to save costs, fixed carbon 85 can also be used, as long as the final absorption rate can be reached. But for nodular cast iron, the requirements are more stringent. It not only requires a fixed carbon content, but also requires low sulfur and low nitrogen, especially the sulfur content must be low, and only the ones below double zero can be used, otherwise the produced castings It is easy to be brittle and has cracks, which greatly affects the final effect, and there are certain requirements for nitrogen. It must be low nitrogen, preferably 600ppm or less than 300ppm. Some manufacturers even require less than 100ppm. Of course, the lower the nitrogen, the better, because the more nitrogen Castings produced at low levels are smoother and flat, without pores. Higher nitrogen will cause uneven castings, and some even have pores and cracks, so you must be cautious when choosing a recarburizer, and must be based on your own reality. The most important thing is to choose the right product for the situation.
Therefore, in ductile castings, the requirement for recarburizers is that the lower the sulfur and nitrogen, the better. If you need to buy recarburizer, please email us. Or follow Shengchi Ferroalloy's official website http://www.scferroalloy.com/