A kind of low-carbon ferrophosphorus for non-oriented silicon steel and its smelting method

Abstract

The invention provides low-carbon ferrophosphorus for non-oriented silicon steel and a smelting method thereof. The low-carbon ferrophosphorus comprises, by weight, less than or equal to 0.10% of C, less than or equal to 1.5% of Si, less than or equal to 1.5% of Mn, 25-27% of P, less than or equal to 0.005% of S, less than or equal to 0.0010% of Nb, less than or equal to 0.0010% of V, and less than or equal to 0.0010% of Ti. Apatite, coke, silica and scrap iron are mixed to form furnace burden according to the ratio of 100 to 16 to 26 to 42, then the furnace burden is continuously loaded into an electric furnace from a high-level material bin, molten iron is discharged into a separation tank of a phosphorus cooling system after smelting of two hours, and the ferrophosphorus and slag are separated; and the alloy material proportion is adjusted according to the test result of the molten iron, 400-500 kg of the adjusted burden is put into the furnace, and the steps are repeated. According to the low-carbon ferrophosphorus for the non-oriented silicon steel and the smelting method thereof, the purity of the low-carbon ferrophosphorus can be greatly improved, the low-carbon ferrophosphorus does not contain harmful elements such as Nb, V and Ti, carbon nitride which prevents grain growth in the continuous annealing process of cold rolled plates in the steel is reduced, the chemical components of the produced low-carbon ferrophosphorus are stable, and the tromagnetic performance of the non-oriented silicon steel produced by utilizing the low-carbon ferrophosphorus is obviously improved.

Description

technical field [0001] The invention belongs to the technical field of smelting technology, and in particular relates to a high-purity low-carbon ferrophosphorus for non-oriented silicon steel and a smelting method thereof. Background technique [0002] Phosphorus is a key element in non-oriented silicon steel, which can improve the mechanical properties of steel and the machinability of silicon steel. Generally, the phosphorus content in non-oriented silicon steel is 0.02-0.20%, and the phosphorus content in low-carbon phosphorus iron is 25-30%. At present, low-carbon ferrophosphorus for silicon steel contains harmful inclusions such as Nb, V, Ti, etc., generally between 0.05 and 0.8%. The V content is greater than 0.4%, so after the non-oriented silicon steel is smelted, the Ti element content is 10-80ppm, and the Nb and V contents of the non-oriented silicon steel in individual furnaces are respectively greater than 40ppm, which has a great influence on the electromagnet...

AI Technical Summary

Problems solved by technology

Therefore, the presence of (N, C) compounds of Nb, V, and Ti in steel seriously deteriorates the electromagnetic properties of non-oriented silicon steel, and is a harmful residual element.

[0004] At present, the smelting method of low-carbon ferrophosphorus for non-oriented silicon steel on the market is smelting in an electric furnace, and the smelting raw material is apatite Ca5[(FCI)(PO4)3] containing phosphorus elements, among which P 2 o 5 The content is between 20% and 30%. These apatites are mixed with raw materials such as coke, silica, and iron filings in a certain proportion. After high-temperature smelting, the P element in the compound in the phosphate rock is reduced and added during the smelting process. The scrap steel contains a large amount of harmful elements such as niobium, vanadium, titanium, etc., and the whole smelting process is a reducing atmosphere. The niobium, vanadium and titanium cannot be oxidized, and the residual amount is limited by the purity of the scrap steel, and the residual harmful components are uncontrollable.

These harmful elements will form fine nitrogen carbides in the process of smelting non-oriented silicon steel and continuous annealing of hot-rolled and cold-rolled sheets, which greatly hinders recrystallization and grain growth in the process of continuous annealing of non-oriented silicon steel cold-rolled sheets, seriously Affect the electromagnetic properties of non-oriented silicon steel

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