Technique for smelting mother liquor of stainless steel from electric furnace

Abstract

This invention relates to an electric furnace smelting technique for crude stainless steel liquid with its process including: a) materials proportioning. Waste stainless steel shares 15~25% in total added metal. Chromium-iron alloy shares 15~25% in total added metal. Lime is added to an amount of 30~45 kg per ton of added metal. And dephosphorized molten iron shares 35~60% with its element content of 2.50~3.80% of C, less than 0.020% of phosphorus, less than 0.040% of sulfur. b) Smelting. Oxygen blowing amount is controlled at 5~10 cu m / t and blowing flux is controlled at 1500~2500N cu m / h. c) reduction. Ferrosilicon powders are spitted at 2.5~3.5kg / t and carbon powders at 1.5~2.5kg / t. Or ferrosilicon is added at 2.5~3.5kg / t and aluminium at 1.5~2.5kg / t. d) tapping, with ultimate temperature controlled at 1640~1660 deg.C. This invention employs dephosphorized molten iron, which reduces the raw materials proportioning cost and smelting time as well as the consumption of electricity power, electrodes and patching materials in electric furnaces.

Description

technical field [0001] The invention belongs to the stainless steel smelting process. Background technique [0002] The stainless steel smelting process path is usually: electric furnace → AOD → LF (or VOD). The existing process for smelting stainless steel in an electric furnace is that the ratio of raw materials is 100% scrap steel, solid chromium-nickel alloy, coke, etc. According to the different proportions of the scrap resource piles, the operation of batching into the furnace is usually 2 to 3 baskets. The main points of its technical control are, taking a 100-ton AC electric arc furnace and 80MW transformer power as an example, the characteristics of each stage of smelting: the first stage: use low voltage and low current to generate a stable arc, and melt about 1.5% of scrap steel; the second stage: electrify After a period of time, the electrodes in the furnace are all liquid under the well, and the electrodes are surrounded by scrap steel. At this time, the long...

AI Technical Summary

Problems solved by technology

However, its disadvantages are: 1) steel scrap resources are tight, the sources are miscellaneous, and there is no necessary means for the control of components, especially harmful elements; 2) the smelting time is long, and the time from tapping to tapping is 80-90 minutes; 3) the power consumption is high, and the power-on time 60~65min, power consumption 400~450Kwh / t; 4) The environmental noise is loud and lasts for a long time. In the stage of strong noise before the scrap steel is melted, the noise level is usually greater than 85 decibels