Method for controlling morphology of sulfide in low-carbon high-sulfur easy-cutting steel

A free-cutting steel and sulfide technology, applied in the direction of process efficiency improvement, furnace type, furnace, etc., can solve problems such as toxicity, difficult addition control, and unenvironmental protection.

Inactive Publication Date: 2019-08-16
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because Pb is toxic and not environmentally friendly, it is difficult to control the addition of easily oxidized elements such as Bi in the smelting process, and most of the production is still sulfur-containing

Method used

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  • Method for controlling morphology of sulfide in low-carbon high-sulfur easy-cutting steel
  • Method for controlling morphology of sulfide in low-carbon high-sulfur easy-cutting steel
  • Method for controlling morphology of sulfide in low-carbon high-sulfur easy-cutting steel

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) 65 tons of molten iron was used for electric furnace smelting, the mass percentage of tapping C was 0.04%, and the tapping temperature was controlled to reach 1640°C.

[0022] (2) Add silicon manganese 6kg / t and low-carbon ferromanganese 7kg / t for alloying in the tapping process of electric furnace for deoxidation, do not use aluminum for deoxidation, add iron sulfide 16kg / t to adjust sulfur composition, add lime 6kg / t to control electric furnace alloying After reaching the initial oxygen content of the refining furnace is 120ppm.

[0023] (3) Refining uses ferrosilicon powder and deoxidation slagging agent diffusion deoxidation to control the mass percentage of Si to 0.03%, adjust silicomanganese and low-carbon ferromanganese to control the mass percentage of Mn to 1.22%, and feed 150 meters of sulfur line to adjust the mass percentage of S to 0.35%, Control the oxygen content to 80ppm and prepare for pouring.

[0024] (4) The pouring section is 320mm*480mm, the d...

Embodiment 2

[0027] (1) Use 40 tons of molten iron for electric furnace smelting, tap C to 0.03%, and control tap temperature to 1680°C.

[0028] (2) Add silicon manganese 7kg / t and low carbon ferromanganese 8kg / t for deoxidation in the tapping process of electric furnace, do not use aluminum for deoxidation, add iron sulfide 18kg / t to adjust the sulfur composition, add lime 7kg / t to control the alloying of electric furnace After reaching the initial oxygen content of the refining furnace is 100ppm.

[0029] (3) Refining uses ferrosilicon powder and deoxidizing slagging agent to control Si mass percentage by diffusion deoxidation to 0.02%, adjust silicomanganese and low-carbon ferromanganese to control Mn mass percentage to 1.33%, and feed 100 meters of sulfur line to adjust S mass percentage to 0.38%, Control the oxygen content to 70ppm and prepare for pouring.

[0030] (4) The pouring section is 320mm*480mm, the degree of superheat is controlled at 25°C, the water volume of the crystall...

Embodiment 3

[0034] (1) 70 tons of molten iron is used for electric furnace smelting, the mass percentage of tapping C is 0.05%, and the tapping temperature is controlled to reach 1630°C.

[0035] (2) Add silicon manganese 5kg / t and low carbon ferromanganese 6kg / t for deoxidation in the alloying process of electric furnace tapping, do not use aluminum for deoxidation, add iron sulfide 14kg / t to adjust the sulfur content, add lime 6kg / t to control the alloying of electric furnace After reaching the initial oxygen content of the refining furnace is 200ppm.

[0036] (3) Refining uses ferrosilicon powder, deoxidation slagging agent diffusion deoxidation to control Si mass percentage 0.03%, adjust silicomanganese and low-carbon ferromanganese to control Mn mass percentage 1.05%, feed 200 meters of sulfur line to adjust S mass percentage 0.3%, Control the oxygen content to 120ppm and prepare for pouring.

[0037] (4) The pouring section is 320mm*480mm, the degree of superheat is controlled at 4...

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Abstract

The invention discloses a method for controlling the morphology of a sulfide in low-carbon high-sulfur easy-cutting steel. The method comprises the following steps that (1) an electric furnace is usedfor smelting, and the steel tapping C mass percentage and the tapping temperature are controlled; (2) silicon manganese and low-carbon ferromanganese are added for deoxidizing, ferric sulfide is added to adjust a sulfur component, lime is added, and the electric furnace is controlled to reach the initial oxygen content 100-200ppm of a refining furnace after alloying; (3) ferrosilicon powder and adeoxidation slag former are used for diffusion deoxidation in refining, the mass percent of Si is controlled to be less than or equal to 0.03%, the mass percentage of Mn is adjusted to be 1.05%-1.33%, the mass percent of S is adjusted to be 0.30%-0.38%, and the oxygen content is controlled to reach 70-120 pm; and (4) after casting, rolling and forming are carried out. According to the method, theinitial oxygen content and the molten steel component after tapping steel alloying are more easily controlled, so that the length-width ratio of the morphology of the sulfide is controlled, and the condition that the ratio is larger than 1 and is less than or equal to 3 is up to 90%.

Description

technical field [0001] The invention relates to a method for controlling morphology, in particular to a method for controlling the morphology of sulfide in low-carbon high-sulfur free-cutting steel. Background technique [0002] Free-cutting steels usually add S, Pb, Bi and other elements to improve the cutting performance of steel by using the characteristics of forming sulfide-forming compounds, or the insoluble characteristics of elements such as Pb and Bi in steel. Because Pb is toxic and not environmentally friendly, it is difficult to control the addition of easily oxidized elements such as Bi during the smelting process, and most of the production is still sulfur-containing. The formation of MnS in the steel destroys the continuity of the steel matrix and plays the role of brittle chips. The control of its shape determines the quality of the cutting performance of the steel, that is, the formation of slender strips of sulfide in the steel should be reduced or avoided....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/06C21C7/00C21C5/52
CPCC21C5/5264C21C7/00C21C7/06Y02P10/20
Inventor 李林孙华周蕾袁金甲杨利委
Owner NANJING IRON & STEEL CO LTD
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