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Smelting method of high-sulfur free-cutting steel

A technology of free-cutting steel and smelting methods, applied in the manufacture of converters, etc., can solve the problems of discontinuous continuous casting production process, high production cost, and low production efficiency, so as to prevent production accidents such as steel breakout and save converter flux Cost, continuous effect of continuous casting production process

Inactive Publication Date: 2019-11-19
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, in the smelting process of high-sulfur free-cutting steel, a large amount of sulfur iron and deoxidizer are required, and the production cost is high; porosity and crack defects often occur inside and on the surface of the slab, and the continuous casting production process is discontinuous, unstable, and leakage cannot be contained. The occurrence of production accidents such as steel cannot guarantee the continuous and stable production of high-sulfur free-cutting steel, the production efficiency is low, and the production cost is high

Method used

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  • Smelting method of high-sulfur free-cutting steel

Examples

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Embodiment 1

[0035] In this embodiment, a sulfur-containing free-cutting steel, its constituent elements and their element mass percentages are shown in Table 1 below. The sulfur-containing free-cutting steel in this embodiment contains C, Si, Mn, P, S, and the balance For iron and unavoidable impurities.

[0036] Table 1. Control of main chemical components of sulfur-containing free-cutting steel in Example 1

[0037]

[0038] A method for smelting sulfur-containing free-cutting steel in this embodiment comprises the following steps:

[0039] (1) The molten iron in the converter is not desulfurized, smelted with less slag, no lime is added, and the amount of light burning dolomite is 27kg / t to reduce the basicity of the final slag to increase the phosphorus content at the end of the converter, and control the phosphorus content of tapping to no more than 0.06% ; The carbon content at the end of the converter is 0.05%, and the tapping temperature is 1665°C.

[0040] (2) Control the he...

Embodiment 2

[0053] This embodiment is basically the same as Embodiment 1, and the special features are:

[0054] In this embodiment, a sulfur-containing free-cutting steel, its constituent elements and their element mass percentages are shown in Table 2 below. The sulfur-containing free-cutting steel in this embodiment contains C, Si, Mn, P, S, and the balance For iron and unavoidable impurities.

[0055] Table 2. Control of main chemical components of sulfur-containing free-cutting steel in Example 2

[0056]

[0057] A method for smelting sulfur-containing free-cutting steel in this embodiment comprises the following steps:

[0058] (1) The molten iron in the converter is not desulfurized, it is smelted with less slag, no lime is added, the amount of light burning dolomite is 25kg / t, and the amount of magnesite is 6kg / t to reduce the basicity of the final slag, so as to increase the phosphorus content at the end of the converter and control tapping The phosphorus content is not hig...

Embodiment 3

[0072] This embodiment is basically the same as the previous embodiment, and the special features are:

[0073] In this embodiment, a sulfur-containing free-cutting steel, its constituent elements and their element mass percentages are shown in Table 3 below. The sulfur-containing free-cutting steel in this embodiment contains C, Si, Mn, P, S, and the balance For iron and unavoidable impurities.

[0074] Table 3. Control of main chemical components of sulfur-containing free-cutting steel in Example 3

[0075]

[0076] A method for smelting sulfur-containing free-cutting steel in this embodiment comprises the following steps:

[0077] (1) The molten iron in the converter is not desulfurized, smelted with less slag, no lime is added, the amount of light burning dolomite is 20kg / t, and magnesite is 10kg / t to reduce the basicity of the final slag, so as to increase the phosphorus content at the end of the converter and control tapping The phosphorus content is not higher than...

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Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to a smelting method of high-sulfur free-cutting steel. The S content of the high-sulfur easy-cutting steel is largerthan or equal to 0.1wt%; the method comprises the steps that 1), during converter smelting, less slag smelting is adopted, no pale gray is added, and slag is not reserved; 2), the clearance is controlled to be 400 mm - 600 mm in the steel tapping process; 3) silicon-calcium-barium-iron is added, wherein the addition amount of the silicon-calcium-barium-iron is controlled to be 0.5 - 2.0 kg / t, theoxygen content in steel is controlled, and then the S yield is improved; and the sulfur-containing molten iron pretreatment slag is added, wherein the addition amount of the sulfur-containing molten iron pretreatment slag is controlled to be 15 - 20 kg / t; 4), 100 - 400 kg / t pre-melting wollastonite and 100 - 300 kg / g pale gray granule are added into a LF refining furnace, and the basicity of top slag is controlled to be 1.0 - 2.0; 5), the refining alloying adopts high-carbon ferromanganese, ferrophosphorus and sulfur-iron to adjust components so as to ensure that the manganese-sulfur ratio isgreater than 3.0; and 6), the oxygen content is determined before moving out the steel. According to the smelting method of the high-sulfur free-cutting steel, the slag which is removed by pretreatment of the molten iron is used for replacing part of sulfur iron and deoxidizing agent, so that the cost of a converter flux is saved; and the parameters of the continuous casting process are set, so that the continuous and stable production of the high-sulfur free-cutting steel is ensured, and the production cost is effectively reduced.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a method for smelting high-sulfur free-cutting steel. Background technique [0002] High-sulfur free-cutting steel is a kind of steel that uses the effects of sulfur, phosphorus and other elements in steel to improve the cutting performance of steel, so as to be suitable for high-speed cutting on ordinary machine tools or automatic machine tools. In the cutting process, compared with non-free cutting steel, it can prolong tool life, reduce cutting resistance, improve the surface finish of processing, and easily remove chips. Sulfur-based free-cutting steel is a type of free-cutting steel with the earliest production and application at home and abroad, the largest consumption and the widest application. At present, sulfur-based free-cutting steel accounts for more than 90% of the total free-cutting steel. [0003] At present, in the smelting process of high-sulf...

Claims

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Application Information

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IPC IPC(8): C21C7/06B22D11/117B22D11/16C21C5/28C21C7/00
CPCB22D11/117B22D11/16C21C5/28C21C7/0006C21C7/0056C21C7/06
Inventor 李泽林李旭潘瑞宝李泊秦海山梁凤友赵帅
Owner ANGANG STEEL CO LTD