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Preparation method for controlling non-quenched and tempered steel large particle inclusions

A large particle inclusion, non-quenched and tempered steel technology, applied in the manufacture of converters, etc., can solve the problems of insufficient control, poor mechanical properties of non-quenched and tempered steel, etc., to improve product quality, reduce H and O content, and excellent fatigue resistance performance-destroying effects

Inactive Publication Date: 2020-07-14
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Purpose of the invention: the purpose of the present invention is to provide a preparation method for controlling large particle inclusions in non-quenched and tempered steel, which solves the lack of control of gas elements and inclusions such as O and H in the existing non-quenched and tempered steel, which leads to non-tempered steel The problem of poor mechanical properties of high-quality steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The present invention is a preparation method for controlling large-grained inclusions in non-quenched and tempered steel, comprising the following steps:

[0023] (1) Converter smelting: During the converter smelting process, control the end point C of the converter: 0.105% (tapping TSO: 281ppm), tapping temperature 1631°C, strictly control the oxygen level, and create good conditions for the subsequent process;

[0024] (2) Converter tapping: Turn on the bottom stirring of the converter before tapping the molten steel to reduce the oxidation of molten steel and the P content of the molten steel, and reduce the P content to below 0.025% by stirring at the bottom of the tapping; Carbon powder is pre-deoxidized, and then aluminum block (0.6~0.7kg / ton steel), ferrosilicon (4kg / ton steel), ferromanganese (18kg / ton steel) and lime (4~5kg / ton steel) are sequentially added for deoxidation Alloying, nitrogen blowing is maintained throughout the process of deoxidation alloying,...

Embodiment 2

[0029] The present invention is a preparation method for controlling large-grained inclusions in non-quenched and tempered steel, comprising the following steps:

[0030] (1) Converter smelting: during the converter smelting process, control the converter end point C: 0.137% (tapping TSO: 256ppm), tapping temperature 1642°C, strictly control the oxygen level, and create good conditions for the subsequent process;

[0031] (2) Converter tapping: Turn on the bottom stirring of the converter before tapping the molten steel to reduce the oxidation of molten steel and the P content of the molten steel, and reduce the P content to below 0.025% by stirring at the bottom of the tapping; Carbon powder is pre-deoxidized, and then aluminum block (0.6~0.7kg / ton steel), ferrosilicon (4kg / ton steel), ferromanganese (18kg / ton steel) and lime (4~5kg / ton steel) are sequentially added for deoxidation Alloying, nitrogen blowing is maintained throughout the process of deoxidation alloying, and th...

Embodiment 3

[0036] The present invention is a preparation method for controlling large-grained inclusions in non-quenched and tempered steel, comprising the following steps:

[0037] (1) Converter smelting: During the converter smelting process, control the end point C of the converter: 0.163% (tapping TSO: 217ppm), tapping temperature 1638°C, strictly control the oxygen level, and create good conditions for the subsequent process;

[0038](2) Converter tapping: Turn on the bottom stirring of the converter before tapping the molten steel to reduce the oxidation of molten steel and the P content of the molten steel, and reduce the P content to below 0.025% by stirring at the bottom of the tapping; Carbon powder is pre-deoxidized, and then aluminum block (0.6~0.7kg / ton steel), ferrosilicon (4kg / ton steel), ferromanganese (18kg / ton steel) and lime (4~5kg / ton steel) are sequentially added for deoxidation Alloying, nitrogen blowing is maintained throughout the process of deoxidation alloying, ...

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PUM

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Abstract

The invention discloses a preparation method for controlling non-quenched and tempered steel large particle inclusions. The preparation method for controlling the non-quenched and tempered steel largeparticle inclusions comprises the following steps that (1) converter smelting is carried out, specifically, in the process of converter smelting, the converter end point C mass percent content is controlled to be greater than or equal to 0.10% or the tapping TSO oxygen level is less than or equal to 300 ppm, and the tapping temperature is greater than or equal to 1600 DEG C; and (2) converter tapping is carried out, specifically, converter bottom stirring is started before molten steel tapping, the oxidation of molten steel and the P content of the molten steel are reduced; and carbon powderis added for pre-deoxygenation in the tapping early stage, then a deoxidizer, an alloy and slag are added for deoxidize alloying in sequence, the whole process of nitrogen blowing is kept in deoxidizing alloying process, and a double stop way is adopted for tapping in the tapping later stage to strictly control roughing slag. Non-quenched and tempered steel can stably control the total oxygen below 15 ppm and the H content below 1.5 ppm, the H and O content in the steel are effectively reduced, the product quality is improved, the steel produced for automobiles has low full O, H and high purity level, and the non-quenched and tempered automobile steel with excellent anti-fatigue damage performance is ensured.

Description

technical field [0001] The invention belongs to the technical field of non-quenched and tempered steel production, and in particular relates to a preparation method for controlling large particle inclusions in non-quenched and tempered steel. Background technique [0002] With the advancement of automobile manufacturing, the requirements for non-quenched and tempered steel materials for automobile crankshafts, connecting rods and other parts are also increasing, and materials are required to have good processing performance, high strength and high toughness. The non-quenched and tempered steel mainly relies on the addition of Nb, Ti, V and other trace elements combined with the subsequent forging and controlled cooling process to control the strength of the parts in an appropriate range. [0003] The inclusions of non-quenched and tempered steel are mainly composite inclusions containing Al, Ca, O, and S. The outer dimensions are clustered inclusions with a width or diameter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/28C21C7/00C21C7/06C21C7/10C22C33/06C22C38/02C22C38/04C22C38/06C22C38/12C22C38/16C22C38/20C22C38/24C22C38/42C22C38/46
CPCC21C5/28C21C7/0006C21C7/06C21C7/10C22C33/06C22C38/001C22C38/002C22C38/02C22C38/04C22C38/06C22C38/12C22C38/16C22C38/20C22C38/24C22C38/42C22C38/46
Inventor 殷天颖胡志勇周杨鲁川陈鹏涛刘义
Owner NANJING IRON & STEEL CO LTD
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