First, put the clustered scraps into the smelting furnace (medium frequency electric furnace),add alloying elements if it is alloy steel,and add iron scraps until the steel liquid take up the 75% of the furnace.When the steel liquid turns white .AI wire is used for deoxidation and the steel liquid is ready for the first chemical analysis where spectrograph are employed. If the result of the first chemical analysis shows that composition conforms with what is required,than the steel liquid is ready for pouring.Or Otherwise,the composition should be adjusted by adding appropriate materials and be sent for more chemical analysis until the result shows that the composition accords with the specific steel designation.
After the adjustment of the chemical composition. The temperature is then raised up to 1630--1650℃(temperature controller is used).When the steel liquid id white with heavy smoke,press the red button to put the electric speed reducer into motion ,which can tilt the furnace, and thus the steel liquid is poured into the casting ladle.Then two men carry the ladle and pour the steel liquid into sand shells which have already been buried in the sand,at a high or low speed (as required by specific techniques). The shells are cooled in sand for20-30 minutes (determined by the physical dimension and production conditions. Generally 30 minutes for large ones and 20 minuter for smaller ones).If they are pulled out too early , deformation of hot cracking may occur;if pulled out too late, decarburized layer may occur in some castings with high carbon content.