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A low-cost deoxidation method for low-aluminum medium-carbon steel

A low-cost, carbon steel technology, applied in the field of metallurgy, can solve the problems of easy overoxidation of molten steel, high oxygen potential of tapping molten steel, and increased blowing loss rate, etc. volume reduction effect

Active Publication Date: 2016-04-27
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: (1) Low-carbon tapping of converter, molten steel is easy to peroxidize, increase blowing loss rate, resulting in high consumption of steel material; (2) Add sufficient amount of Al for deep deoxidation when tapping, because Al density is less than The density of molten steel is easy to float on the surface of molten steel, and part of Al reacts with oxygen in the air. The greater the amount of Al used, the higher the burning loss rate, resulting in a greater consumption of Al for deoxidation
The disadvantages of these processes are: (1) low-carbon tapping of converter or electric furnace, high blowing loss rate, increasing consumption of steel materials; high oxygen potential of tapping molten steel, increasing consumption of deoxidizer; (2) using carbon The pre-deoxidation of materials will generate a large amount of CO gas, which will cause the molten steel to boil, and it is prone to safety accidents such as "turning over the bag"
In addition, the generated CO gas is not easy to collect, and there are certain safety hazards

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Target steel type: Q235

[0014] Process flow: pre-desulfurization of molten iron—converter smelting—LF refining—continuous casting

[0015] After the molten iron is pre-desulfurized, it is blended into the converter for smelting. The carbon content at the end of smelting is 0.091%, the oxygen content is 0.026%, and the temperature is 1607°C. The steel tapping capacity of the converter is 180t. When the steel tapping capacity reaches 30t, 440kg of lime, 137kg of fluorite pre-slag are added, 215kg of ferrosilicon alloy, 526kg of silicon manganese alloy, and 87kg of aluminum ingot are added for deoxidation and alloying. After tapping, transfer to LF ladle refining station, add 50m of aluminum wire, add 302kg of lime to make slag, add 100kg of silicon-manganese alloy, add 105kg of carburant, and tap after 26 minutes of refining. The aluminum content is 0.0132%, and the total oxygen content is 0.0024%. After tapping, it is transported to the continuous casting platform fo...

Embodiment 2

[0017] Target steel type: Q235

[0018] Process flow: pre-desulfurization of molten iron—converter smelting—LF refining—continuous casting

[0019] After pre-desulfurization treatment, the molten iron is blended into the converter for smelting. The carbon content at the end of smelting is 0.113%, the oxygen content is 0.023%, and the temperature is 1617°C. The steel output of the converter is 180t. When the steel output reaches 30t, 430kg of lime, 136kg of fluorite pre-cast slag, 264kg of ferrosilicon alloy, 566kg of silicon manganese alloy and 82kg of aluminum ingot are added for deoxidation and alloying. After tapping, transfer to the LF ladle refining station, add 0m of aluminum wire, add 262kg of lime to make slag, add 75kg of carburant, tap after 28 minutes of refining, the aluminum content of the molten steel is 0.0131%, full The oxygen content is 0.003%. After tapping, it is transported to the continuous casting platform for pouring. Compared with the original proces...

Embodiment 3

[0021] Target steel type: Q235

[0022] Process flow: pre-desulfurization of molten iron—converter smelting—LF refining—continuous casting

[0023] After pre-desulfurization treatment, the molten iron is blended into the converter for smelting. The carbon content at the end of smelting is 0.093%, the oxygen content is 0.031%, and the temperature is 1616°C. The steel output of the converter is 180t. When the steel output reaches 30t, 339kg of lime, 96kg of fluorite preformed slag, 256kg of ferrosilicon alloy, 551kg of silicon manganese alloy, 72kg of aluminum ingot, and 61kg of recarburizer are added for deoxidation and alloying. After tapping, transfer to LF ladle refining station, feed aluminum wire 50m, add lime 223kg for slagging, add carburant 30kg, refine 26 minutes after tapping, aluminum content in molten steel is 0.0081%, The total oxygen content is 0.0035%. After tapping, it is transported to the continuous casting platform for pouring. Compared with the original p...

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Abstract

The invention relates to a low-cost deoxygenation method for low-aluminum medium-carbon steel, belonging to the technical field of metallurgy. The method specifically comprises the following steps: 1) in a converter blowing process, controlling the carbon content at the blowing endpoint over 0.08%, and controlling the oxygen content of the molten steel at the endpoint below 0.04%; 2) in converter tapping, adding the ferroalloys of silicon and manganese as well as aluminum to perform deoxygenation alloying, wherein the addition amount of aluminum is 0.3-1kg per ton of steel, and the addition amount of the alloys of silicon and manganese meets the requirements of the steel type; 3) after tapping, transferring to an LF refining station, and supplementing 0-1.5m of aluminum wire per ton of steel once according to the deoxygenation condition of molten steel; in the refining process, finely adjusting the composition and removing inclusions, and controlling the aluminum content at the LF endpoint within 0.015%. The method provided by the invention has the advantages that the endpoint carbon content of the converter is increased, and the aluminum dosage for deoxygenation is reduced; a small amount of aluminum is added for soft deoxygenation in tapping, the aluminum content of molten steel at the refining endpoint is relatively low, and the aluminum consumption for deoxygenation is reduced.

Description

technical field [0001] The invention relates to a low-cost deoxidation method for low-aluminum medium-carbon steel, which belongs to the technical field of metallurgy. Background technique [0002] The situation of the iron and steel industry is becoming increasingly severe, and my country's iron and steel industry is gradually entering a stage of competitive development with high costs and low profits. The improvement and innovation of process technology is an important means to improve the competitiveness of iron and steel enterprises, and its ultimate goal is to reduce production costs and increase product profitability. [0003] Q235 series steel is a common ordinary carbon structural steel. The commonly used production process of this type of steel is "hot metal pre-desulfurization-converter smelting-LF refining-continuous casting". Converter smelting low-carbon steel, the molten steel has a high oxygen potential, during the tapping process, a sufficient amount of Al i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/06
Inventor 邹长东耿涛赵家七丁振涛马建超
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE