What is the nitrogen content of cast iron melted by induction melting furnace?

When smelted in a cupola, the nitrogen content in gray cast iron is generally 0.004~0.007%.

Cast iron contains a small amount of nitrogen, which can promote pearlite and help improve the mechanical properties of cast iron. If the nitrogen content is above 0.01%, the casting is prone to nitrogen-induced pores.

Generally, the nitrogen content in scrap steel is much higher than that in cast iron. When smelting cast iron in an induction melting furnace, since there are few cast iron ingots and more scrap steel used in the charge, the nitrogen content in the cast iron produced by smelting will be correspondingly higher. high. In addition, due to the large amount of scrap steel used in the charge, recarburizers must be used, and most of the recarburizers have relatively high nitrogen content, which is another factor that causes the nitrogen content in cast iron to increase.

Therefore, when smelted in an induction melting furnace, the nitrogen content in cast iron is higher than that in a cupola. Generally speaking, when the amount of scrap steel in the furnace charge is 15%, the nitrogen content in cast iron is about 0.003~0.005%; when the amount of scrap steel is 50%, the nitrogen content can reach 0.008~0.012%; when the charge is all scrap steel, the nitrogen content can be As high as 0.014% or more.