Method for smelting ferritic stainless steel from total molten iron

Abstract

This invention relates to a molten iron smelting method of ferritic stainless steel which includes: a) temperature-controlled smelting. The temperature is raised to 1580~1600 deg.C before converting. Ferrosilicon containing 4~15kg of steels per ton is added followed by temperature-raising. b) When temperature in molten pool is raised to 1670~1720 deg.C, chromium-iron alloy is added at a rate of 2~3 ton per minute with a total amount of up to 250~280 kg per ton of steel. Then hold the temperature. c) Decarbonization, when it is finished, the carbon concentration is 0.03~0.05% and the temperature is held at 1700~1730 deg.C. d) Reduction and desulfurization. This invention adopts hot metal smelting all through the process and avoids the influences of impure waste iron. Besides the AOD direct smelting technique doesní»t need any crude stainless steel liquid in electric furnace.

Description

technical field [0001] The invention belongs to the field of stainless steel smelting technology. Background technique [0002] At present, the traditional process used in the field of stainless steel smelting is: EAF+AOD+(VOD), which uses scrap steel + alloy to melt into a stainless steel mother liquor (rough smelting molten steel) with a certain temperature and composition in EAF, and then puts the stainless steel mother liquor (rough smelting molten steel) into Refining in AOD furnace. [0003] The existing ferritic stainless steel smelting process is as follows: [0004] Scrap steel (adding molten iron)→electric furnace smelting→AOD refining→(VOD refining)→continuous casting [0005] Among them, AOD refining process: [0006] Mother liquor composition: C 1.0%~3.0%, Mn 0~0.2%, Si 0~0.2%, S 0~0.020%, P0~0.030%, Cr 13.0%~14.0%, Ni 0~0.5%; mother liquor temperature: 1500 ~1580℃, mother liquor weight 110~115 tons. [0007] AOD smelting process: [0008] Put the electric...

AI Technical Summary

Problems solved by technology

[0017] The original smelting process must use an electric furnace to melt scrap steel, alloys and part of the molten iron, which is also feasible in terms of technology, but the use of an electric furnace to smelt stainless steel mother liquor has the disadvantage of relatively high power consumption. The power consumption per ton of steel is 320-360kwh, which increases the production cost accordingly. , In addition, after 7-10 days of production, the electric furnace must be shut down for refractory maintenance, and production needs to be shut down for 10-24 hours, so that the entire stainless steel production line has to be shut down for 10-24 hours, and the production capacity is greatly affected