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Method for refining grain size of sulfur-containing non-quenched and tempered steel

A non-quenched and tempered steel, grain size technology, which is applied in the field of refining the grain size of sulfur-containing non-quenched and tempered steel, can solve the problems that cannot meet the requirements of high-quality non-quenched and tempered grain size and performance, and achieve high economic value and practical value, improve the control level, and refine the effect of grain size

Inactive Publication Date: 2021-01-08
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above-mentioned technical means are conventional technologies, which cannot meet the requirements of high-quality non-tempered grain size and performance at present.

Method used

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  • Method for refining grain size of sulfur-containing non-quenched and tempered steel
  • Method for refining grain size of sulfur-containing non-quenched and tempered steel
  • Method for refining grain size of sulfur-containing non-quenched and tempered steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Smelting in a 100-ton electric furnace, controlling the end point of the electric furnace: C: 0.10%, P: 0.0053%, and the tapping temperature is 1639°C.

[0021] 1 minute and 30 seconds after tapping, add 692kg of silicon-manganese alloy, 103kg of ferrosilicon, 550kg of lime, and 252kg of refining slag into the ladle.

[0022] Nitrogen is blown throughout the LF furnace, with a flow rate of 75.0L / min; during the LF refining process, 130kg of silicon carbide is used to deoxidize the slag surface, and the element content and composition are adjusted. Sampling and testing when leaving the LF furnace shows that the carbon element content in molten steel is 0.705%, and the silicon element content is . 0.156%, the manganese content is 0.565%, the aluminum content is 0.004%, and the sulfur content is 0.0586%.

[0023] In the VD refining process, the vacuum degree is 1.1mbar, the high vacuum treatment time is 12min, nitrogen is used as the lifting gas throughout the process, and...

Embodiment 2

[0029] Smelting in a 100-ton electric furnace, controlling the end point of the electric furnace: C: 0.083%, P: 0.0049%, and the tapping temperature is 1642°C.

[0030] 1 minute and 30 seconds after tapping, add 694kg of silicon-manganese alloy, 87kg of ferrosilicon, 550kg of lime, and 254kg of refining slag into the ladle.

[0031] Nitrogen is blown throughout the LF furnace, with a flow rate of 75.0L / min; during the LF refining process, 70kg of silicon carbide is used to deoxidize the slag surface, adjust the element content and composition, and take samples for testing when the LF is out. The molten steel C: 0.689%, Si: 0.178%, Mn: 0.567%, Al: 0.005%, S: 0.0494%.

[0032] In the VD refining process, the vacuum degree is 1.1mbar, and the high vacuum treatment time is 12min. Nitrogen is used as the lifting gas throughout the VD refining process, and the gas flow rate is 71.2L / min when the vacuum is maintained.

[0033] After the soft blowing of the VD refining process, 100 m...

Embodiment 3

[0037] Smelting in a 100-ton electric furnace, controlling the end point of the electric furnace: C: 0.071%, P: 0.0056%, and the tapping temperature is 1635°C.

[0038] 1 minute and 30 seconds after tapping, add 693kg of silicon-manganese alloy, 91kg of ferrosilicon, 550kg of lime, and 252kg of refining slag into the ladle.

[0039] Nitrogen is blown throughout the LF furnace, with a flow rate of 75.0L / min; during the LF refining process, 120kg of silicon carbide is used to deoxidize the slag surface, adjust the element content and composition, and take samples for testing when the LF is out. The molten steel C: 0.685%, Si: 0.182%, Mn: 0.546%, Alt: 0.0092%, S: 0.0611%.

[0040] In the VD refining process, the vacuum degree is 1.3mbar, and the high vacuum treatment time is 12min. Nitrogen is used as the lifting gas in the whole process of RH or VD refining, and the gas flow rate is 71.2L / min when the vacuum is maintained.

[0041] Feed 120 meters of sulfur-iron wire after soft...

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Abstract

The invention discloses a method for refining the grain size of sulfur-containing non-quenched and tempered steel. The method comprises the following steps of: adding a certain amount of Mg element after other components are adjusted in a VD or RH refining process, and modifying MnS inclusions by using the Mg element to form fine manganese sulfide and magnesium-aluminum oxide compound inclusions which are distributed dispersedly to serve as ferrite nucleation cores; and forming isometric ferrite through induction, and refining grains. Test data show that according to the method, the grains ofthe sulfur-containing non-quenched and tempered steel can be effectively refined to obtain the fine-grain non-quenched and tempered steel, the performance is excellent, the cost is low, industrial production is easy to implement, and the grain size control level of the sulfur-containing non-quenched and tempered steel is improved.

Description

technical field [0001] The invention relates to a method for refining the grain size of sulfur-containing non-quenched and tempered steel. Background technique [0002] Non-quenched and tempered steel is a kind of high-quality structural steel that achieves the mechanical properties of quenched and tempered steel by means of strengthening and toughening methods such as microalloying, controlled rolling, and controlled cooling, without quenching and tempering heat treatment. Non-quenched and tempered steel does not require heat treatment and straightening of the product during the production process, which simplifies the process operation, improves the product yield, reduces energy consumption and reduces environmental pollution, so it is called "green steel". Non-quenched and tempered steel is mainly used in automotive engine connecting rods, crankshafts and other parts, and has also been successfully applied to N80 oil casings, seamless steel pipes and other products, and i...

Claims

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Application Information

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IPC IPC(8): C21C7/00
CPCC21C7/0006C21C7/0056
Inventor 张东王国柱李凯李磊袁金甲赵张发于湛刘晓彬
Owner NANJING IRON & STEEL CO LTD
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