Production technology of steel containing sulphur easy cuwtting

A production process and free-cutting steel technology, which are applied in the production process of free-cutting steel and the electric furnace continuous casting production process of free-cutting steel, to achieve the effects of low production cost, reduction of steel breakout accidents, and reduction of internal cracks in casting billets.

Inactive Publication Date: 2005-01-05
NANJING NANGANG IND DEV CO LTD
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Problems solved by technology

[0004] Purpose of the invention: In order to overcome the shortcomings of the above-mentioned production process, the present invention provides a process technology for producing sulfur-containi

Method used

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Embodiment Construction

[0022] The free-cutting steel grade SUM43 is produced by an electric furnace, and its chemical composition is:

[0023] C: 0.40~0.48% Mn: 1.35~1.65% P: ≤0.040%

[0024] S: 0.24~0.33% Si: ≤0.35%

[0025] Continuous casting slab requirements: 150mm×150mm

[0026] A 70-ton high-impedance electric furnace and a five-machine five-strand alloy steel billet continuous casting machine are used. Full protection pouring from the ladle to the crystallizer, continuous temperature measurement of the tundish; electromagnetic stirring and liquid level detection are adopted during the continuous casting pouring process, the liquid level detection adopts Cs radiation detection, and the crystallizer liquid level control adopts servo motor automatic control type stopper; The continuous casting casting speed is automatically controlled according to the superheat of the tundish, and the crystallizer and the secondary cooling are automatically distributed with water.

[0027] The higher the sulf...

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Abstract

The invention provides a process technique of using continuous casting process to produce sulfur-containing easy-to-cut steel SUM43, during melting, contolling sulfur content in the steel according to the medium-top limit required by steel composition, and contolling the Mn content to the top limit; necessarily firing molten steel in tunish to above 1000 deg.C; as electric melting, adding high-sulfur iron in 30%-50%; adding sulfur in refining furnace by sulfur iron block and sulfur-feeding iron wire process; the continous casting stage adopts a course-control mthod and the controlling cooling strength of secondary-cooling system: adopting a secondary-cooling system, the front stage adopts all-water spray cooling and the back stage adopts steam-water spray cooling, and automatically regulating the spray water rate of the secondary cooling. The surface finish of cast blanks reaches grade 6 above; over 90% of cast blanks have no crackes on the surfaces. The sulfur iron and sulfur-feeding iron wire process can accurately control sulfur content.

Description

technical field [0001] The invention relates to a production process of free-cutting steel, in particular to an electric furnace continuous casting production process of free-cutting steel, and relates to the technical field of iron and steel smelting in the metallurgical industry. technical background [0002] Free-cutting steel is widely used in many fields such as household appliances and instrumentation industries due to its good machinability, high surface finish and high dimensional accuracy. At present, the mass-produced free-cutting steel is mainly sulfur-containing free-cutting steel. The higher the value, the better the machinability, but the stronger the crack sensitivity, the easier it is to produce slab cracks and slab leaks in the continuous casting process. Due to the difficulty in casting free-cutting steel, most manufacturers use die-casting technology to produce, and the cost High, restricting the production and application of this type of steel. [0003] ...

Claims

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Application Information

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IPC IPC(8): B22D11/18C22C33/00C22C38/60
Inventor 林国强孔凡杰王金干吴建勇孙华
Owner NANJING NANGANG IND DEV CO LTD
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