Method for smelting low-phosphorus steel with semi-steel

Abstract

The invention discloses a method for smelting low-phosphorus steel with semi-steel. The method includes a converter oxygen-blowing smelting process. Silicon-manganese alloy is added at a ratio of 1-3 kg of the silicon-manganese alloy per ton of steel after the semi-steel is added into a converter. Active lime is added at a ratio of 8-15 kg of the active lime per ton of the steel and high-magnesium lime is added at a ratio of 10-15 kg of the high-magnesium lime per ton of the steel at the starting of the oxygen-blowing process. A composite slag-making agent is added at a ratio of 2-6 kg of the composite slag-making agent per ton of the steel after the oxygen-blowing process lasting for 3-5 min. The active lime, the high-magnesium lime and the composite slag-making agent are added when an oxygen-blowing progress rate is 80-100%. During the whole converter oxygen-blowing smelting process, total consumption amount of the auxiliary materials is controlled by following conditions: 15-20 kg of the active lime per ton of the steel, 15-20 kg of the high-magnesium lime per ton of the steel and 6-10 kg of the composite slag-making agent per ton of the steel. On the premise of ensuring a low consumption amount of the auxiliary materials, through the method for smelting the low-phosphorus steel with the semi-steel, phosphorus content in terminal molten steel is not more than 0.006% by weight and total iron content in slag is not more than 20% by weight. Metal loss is little and a hidden danger is small.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for smelting low-phosphorus steel from semi-steel. Background technique [0002] Because the carbon mass percentage (3.4%-4.0%) of semi-steel steelmaking is lower than that of ordinary molten iron, silicon and manganese in semi-steel generate heat and form slag, and the element content is traces. Therefore, semi-steel smelting has less acidic slag-forming substances in the blowing process , single slag system components, late initial slag formation time, and insufficient heat, which make semi-steel steelmaking more difficult than molten iron steelmaking, and the dephosphorization rate is lower. [0003] In the existing patent literature, there have been reports on semi-steel steelmaking and dephosphorization, such as patent application CN101696462A "A Production Method for Semi-steel Smelting Low Phosphorus Steel" mainly by adjusting the slagging parameter...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the above-mentioned defects in the prior art, and provide a method for smelting low-phosphorus steel from semi-steel, which realizes that the phosphorus content of the end point molten steel is not higher than 0.006% by weight under the condition of low consumption of converter auxiliary materials And the target that the total iron content of the terminal slag is not higher than 20% by weight, with less metal loss and low safety hazard