Method for smelting primary steel making liquid for high-alloy steel casting

Abstract

A method for smelting primary steel making liquid for a high-alloy steel casting includes the following steps that a preset amount of low-phosphorous slag-free molten steel of the last time is reserved in an electric arc furnace, and high-alloy returns are added into the electric arc furnace; high-alloy returns in an electric melting furnace are conveyed to the electric arc furnace, a power supply is cut off after 70%-80% of the high-alloy returns are melted, then high-alloy returns are added again, power is supplied, an oxygen blowing pipe extends into the furnace after the high-alloy returns become red and molten steel appears when the furnace is inclined, and oxygen is blown towards the high-alloy returns exposed out of the molten steel to complete cutting; large high-alloy return blocks are prevented from being attached to the wall of the electric arc furnace, and the large high-alloy return blocks exposed outside the molten steel are cut and smashed, fall into the molten steel and are quickly molten. After the content of phosphorus in the molten steel meets the preset technical requirements, an aluminum block, CaSi grains and aluminum grains are inserted into the molten steel, and sample analysis is carried out after 15 min; when the mass fraction of Al accounts for 0.03%-0.06% of the total mass of the molten steel and added reduction agents, steel is output.

Description

technical field [0001] The invention relates to the technical field of molten steel smelting, in particular to a method for primary molten steel for smelting high-alloy steel castings. Background technique [0002] The raw materials for steelmaking are various alloys, return materials, steel scrap, steelmaking pig iron, coke, etc. Generally, the process yield rate of castings is about 50%, and about 10% of the loss is removed, and the return materials accounting for at least 40% of the pouring weight are required Processing, of which high alloy return material accounts for about 10%. In order to maximize the recycling of precious alloy elements in the returned material and reduce production costs, the returned material needs to be returned to the smelting workshop and re-used in the furnace. It is an important raw material for molten steel smelting. [0003] In the existing method of smelting high-alloy primary molten steel using an electric arc furnace, there is generally ...

AI Technical Summary

Problems solved by technology

However, the above prior art has the following problems: the excessive oxygen blown in will seriously oxidize the precious alloying elements (such as Cr, Mn, Si, etc.) contained in the molten steel, resulting in waste of precious alloying elements and greatly reducing the recovery rate of alloying elements; In addition, if the oxygen blowing process takes a long time, the oxygen blowing is too strong, or the oxygen lance is not stirred back and forth in the furnace, it is easy to cause the electric arc furnace to boil, and the steel sparks thrown out will cause great safety hazards to the on-site operators and equipment. The working environment is poor; furthermore, the phosphorus content in the high-alloy return material is about 0.020%. According to the traditional electric arc furnace smelting process, when the smelting raw materials are all made of high-alloy return materials, the obtained primary molten steel can easily meet the customer's requirements (the phosphorus content is about 0.030%) upper limit or even exceeded, unable to meet customer's technical requirements

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