Smelting process for producing nodular iron castings by using scrap steel

Abstract

The invention discloses a smelting method for producing nodular iron castings by using scrap steel, which comprises: step 1, adding steel into a furnace, adding a carburant on the steel, and then heating the steel so that the steel is melted down and carburized sufficiently; step 2, adding steel again, and adding foundry returns into the furnace; step 3, adding a nodulizer and an inoculant for nodularization and inoculation; and step 4, casting. The method adopts the prior method for smelting the nodular iron castings in an electric furnace and uses the scrap steel to produce the nodular iron castings. The principle of the method is that the main difference between steel and iron is carbon content, and the steel becomes the iron by carburizing to certain degree. The method has the advantages of low cost because the scrap steel is cheaper than nodular pig iron, good quality because the transmissibility of the scrap steel is better than that of the nodular pig iron, two times of specific elongation under the condition of stable tensile strength, and less waste products because the waste products caused by unqualified mechanical property are almost not generated.

Description

technical field [0001] The invention relates to a smelting method for producing ductile iron castings by using scrap steel. Background technique [0002] Existing ductile iron castings all adopt the method of ductile iron smelting. The normal structure of existing nodular cast iron is fine and round graphite spheres plus metal substrates. Since the spheroidization rate of graphite can reach 70%-95%, the mechanical properties of nodular cast iron are much higher than gray cast iron, and the tensile strength is much higher than that of gray cast iron. It can even be compared with steel, and its plasticity and toughness are greatly improved compared with gray cast iron. [0003] The existing nodular cast iron requires strict requirements on its chemical composition during the smelting process. The raw material for the production of nodular cast iron is generally nodular pig iron, so the cost is relatively high. In the existing society, along with the economic development, a l...

AI Technical Summary

Problems solved by technology

[0003] Existing nodular cast iron has strict requirements on its chemical composition during the smelting process. The raw material for the production of nodular cast iron is generally nodular pig iron, so the cost is relatively high