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Production process of S-Al-N-controlled non-quenched and tempered steel

A non-quenched and tempered steel, production process technology, applied in the field of metallurgy, can solve the problems of polluted molten steel, inability to produce high-quality non-quenched and tempered steel, and increased contact area of ​​steel slag, to achieve good cutting performance, excellent fatigue performance, and realize The effect of localization

Active Publication Date: 2016-11-23
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reducing atmosphere and low oxygen content formed by the above process also promote the desulfurization of molten steel. In addition, the contact area of ​​steel slag in VD increases. Molten steel, which makes the high cleanliness required by high-grade non-quenched and tempered steel and the control of sulfur and nitrogen have great contradictions in steelmaking production, and it is impossible to produce high-quality non-quenched and tempered steel for a long time

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] This example is a production process for non-quenched and tempered steel with sulfur control, aluminum control, nitrogen control, and a process for producing high-grade non-quenched and tempered steel with sulfur control, aluminum control, and nitrogen control by using the EAF-LF-VD-CCM process flow. The mass percentage contents of S, Alt and N in steel are respectively: S: 0.020-0.055, Alt: 0.015-0.055%, N: 0.070-0.150%. The production process of this embodiment is carried out in the following process flow: scrap steel + hot charging Hot metal → 100t EBT electric arc furnace smelting → 100t LF refining → 100t VD vacuum degassing → continuous casting of blooms.

[0018] The content of the present invention is realized through the following technical measures in the above-mentioned technological process:

[0019] ⑴The oxygen content of the molten steel is controlled below 300ppm by adding 1 to 3 tons of molten iron twice for deoxidation before tapping the electric furnac...

Embodiment 2

[0026] This embodiment is a production process of non-quenched and tempered steel with sulfur control, aluminum control and nitrogen control, specifically:

[0027] ⑴The oxygen content of the molten steel is controlled below 300ppm by adding molten iron twice for deoxidation before tapping the electric furnace;

[0028] ⑵In the process of smelting and tapping in the electric arc furnace, argon is normally blown at the bottom of the ladle. Except for S, Alt, and N, the main elements are adjusted to 85% of the lower limit of the judgment range by using corresponding alloys and carburizers. Alt reaches the first place in the refining furnace. A sample reaches the upper limit of the determined composition range;

[0029] (3) During the refining process, if the nitrogen content of the finished product is above 100ppm, blow nitrogen for 35 minutes throughout the process; if the nitrogen content is 70ppm, shorten the nitrogen blowing time, control the nitrogen blowing time at 25 minu...

Embodiment 3

[0033] This embodiment is a production process of non-quenched and tempered steel with sulfur control, aluminum control and nitrogen control, specifically:

[0034] ⑴The oxygen content of the molten steel is controlled below 300ppm by adding molten iron twice for deoxidation before tapping the electric furnace;

[0035] ⑵In the process of smelting and tapping in the electric arc furnace, argon is normally blown at the bottom of the ladle. Except for S, Alt, and N, the main elements are adjusted to 85% of the lower limit of the judgment range by using corresponding alloys and carburizers. Alt reaches the first place in the refining furnace. A sample reaches the upper limit of the determined composition range;

[0036] (3) During the refining process, if the nitrogen content of the finished product is above 100ppm, blow nitrogen for 40 minutes throughout the process. If the nitrogen content is 80ppm, shorten the nitrogen blowing time, control the nitrogen blowing time at 30 minu...

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PUM

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Abstract

The invention discloses a production process of S-Al-N-controlled non-quenched and tempered steel. The production process comprises the process flows of scrap steel and hot metal charging, electric arc furnace smelting, LF refining, VD vacuum degassing and bloom continuous casting (EAF-LF-VD-CCM process flows); the non-quenched and tempered steel respectively comprises the following components in percentage by mass: 0.020-0.055% of S, 0.015-0.055% of Alt and 0.070-0.150% of N. The S-Al-N-controlled high-grade non-quenched and tempered steel disclosed by the invention is high in purity, uniform in component and macrostructure and low in anisotropy, the bandwidth can be controlled within 4HRC for the steel with a hardenability requirement, and the produced automobile steel is not required to be subjected to quenching and tempering treatment, can be directly used for turning by a user, is good in cutting performance and also has excellent anti-fatigue performance.

Description

technical field [0001] The invention relates to a production process of non-quenched and tempered steel in the field of metallurgy, specifically a production process for manufacturing high-grade non-quenched and tempered steel with sulfur control, aluminum control and nitrogen control in an EAF-LF-VD-CCM short-flow production line. Background technique [0002] Steel materials have good strength and low temperature toughness, so they play an important role in machinery, automobile, and engineering manufacturing. The quality, service life and processing performance of steel directly restrict economic development and energy conservation and environmental protection. The oil crisis that began in the 1970s had a strong impact on the materials and processes used in the automotive industry, and there was great interest in whether the quenching and tempering process that consumes a lot of energy could be saved, thus promoting the research and development of non-quenched and tempere...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/52C21C7/00C21C7/072C21C7/10C22C38/00C22C38/06C22C38/60
CPCC21C5/5229C21C7/0056C21C7/072C21C7/10C22C38/001C22C38/06C22C38/60Y02P10/20
Inventor 朱守欣杨利委
Owner NANJING IRON & STEEL CO LTD
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