Microalloy HRB400E steel bar containing chrome and nitrogen and production method thereof

A technology of microalloying and production method, applied in the field of HRB400E steel bar and its production process, can solve the problems of poor welding performance, large fluctuation of steel bar performance, high vanadium or niobium content, etc., and achieve good welding performance and stable quality

Active Publication Date: 2012-03-21
长沙东鑫环保材料有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has the following problems: ①Silo-manganese and carbon content are high, and the cost of the alloy increases; ②Element segregation is easy to occur during solidification and cooling; ③High carbon equivalent has poor welding performance, and the content of vanadium or niobium is high. High cost; ④ prone to inconspicuous yield and mixed crystal phenomenon
This method is still in the stage of industrial experimentation and promotion. At the same time, this method has the following disadvantages: ①It is necessary to greatly increase the capacity of the rolling mill, greatly increase equipment investment and renovate the old rolling mill, which will bring a substantial increase in fixed asset investment; ②The steel bars produced cannot use conventional Welding, otherwise the strength of the steel bar will drop significantly due to the growth of the grain in the welding zone; ③The strength-to-yield ratio of the steel bar will decrease, and the shock resistance will decrea

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Add blast furnace molten iron, steel scrap or pig iron into the converter respectively, blow oxygen for smelting, and add slagging materials such as lime, and add reducing chromium oxide pellets and reducing manganese oxide pellets during 8 minutes of oxygen blowing smelting in the converter Mixture, top blowing oxygen for 5 minutes, and bottom blowing for 5 minutes at the same time, so that [C]=0.12-0.20% in molten steel at the end of smelting, [Mn] is between 0.15-0.25%, and [Gr] is between 0.15-0.25%;

[0035] Within 3 minutes before the converter is tapped, add reducing vanadium oxide pellets; blow oxygen for 3 minutes, and blow air for 3 minutes at the same time, so that the [V] in the molten steel is between 0.005-0.01%, and the content of other components such as molten steel sulfur is less than 0.040%. The phosphorus content is less than 0.040%, which meets the standard requirements, and the steel is tapped under the condition that the temperature meets the require...

Embodiment 2

[0041] Add blast furnace molten iron, steel scrap or pig iron into the converter respectively, blow oxygen for smelting, and add slagging materials such as lime, and add the mixture of reducing chromium oxide pellets and reducing manganese oxide pellets during 11 minutes of oxygen blowing smelting in the converter ;Make the molten steel [C] between 0.08-0.15%, [Mn] between 0.30-0.40%, and [Gr] between 0.30-0.40%;

[0042] Add reduced vanadium oxide pellets and reduced niobium oxide pellets within 8 minutes before tapping the converter; blow oxygen for 8 minutes and bottom blow for 8 minutes at the same time, so that [V]+[Nb] in molten steel is between 0.025-0.035% , other components meet the standard requirements for tapping;

[0043] The steel is tapped under the condition that the sulfur content of the converter molten steel is less than 0.040%, the phosphorus content is less than 0.040%, and the temperature meets the requirements of the continuous casting process. Within 6...

Embodiment 3

[0049] Add blast furnace molten iron, steel scrap or pig iron into the converter respectively, blow oxygen for smelting, and add slagging materials such as lime, and add reducing chromium oxide pellets and reduced manganese oxide pellets during 3 minutes of oxygen blowing smelting in the converter Mixture, top blowing oxygen for 6 minutes, and bottom blowing for 6 minutes at the same time, so that [C] = 0.10-0.15% in molten steel at the end of smelting, [Mn] is between 0.30-0.40%, and [Gr] is between 0.25-0.35%;

[0050] Add reducing niobium oxide pellets within 5 minutes before tapping the converter; blow oxygen for 5 minutes and bottom blow for 5 minutes at the same time, so that [Nb] in molten steel is between 0.020-0.030%, and other components such as molten steel sulfur are less than 0.040%. The phosphorus content is less than 0.040%, which meets the standard requirements, and the steel is tapped under the condition that the temperature meets the requirements of the contin...

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PUM

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Abstract

The invention discloses a microalloy HRB400E steel bar containing chrome and nitrogen and a production method thereof. By fully utilizing the strengthening effect and the corrosion-proof effect of chrome on the steel bar, solid solution strengthening elements, namely manganese and silicon, are partially substituted, and a microalloy element, namely vanadium or columbium is partially or fully substituted; a cheap nitrogen element is used for performing microalloy treatment on the steel bar, so that the micro nitrogen separating strengthening effect is achieved; by the production method, the HRB400E steel bar can be produced; Rel of the steel bar is 430 to 490MPa, Rm of the steel bar is 570 to 650 MPa, A is 24 to 35 percent, Rm/Rel is 1.30 to 1.40, the cold bending qualified rate is 100 percent, the welding carbon equivalent weight is less than or equal to 0.45, and the comprehensive cost of one ton of the steel bar is 20 to 80 yuan lower than that of one ton the steel bar produced by the conventional method; during aging of three months, the fluctuations of the Rm value and the Rel value are less than 10MPa; the welding performance is excellent; and the steel bar has good corrosion-proof property.

Description

technical field [0001] The invention relates to a micro-alloyed steel bar containing chromium and nitrogen and a production process thereof, in particular to a HRB400E steel bar with micro-alloying treatment containing chromium and nitrogen and a production process thereof. Background technique [0002] At present, there are three types of production processes for HRB400MPa steel bars. One is the carbon-manganese steel system composition design mainly based on 20MnSi, using manganese and silicon-based iron alloys for manganese and silicon alloying, using vanadium-iron or vanadium-nitrogen alloys for vanadium microalloying, or using niobium-iron alloys for niobium Microalloying, the main components of which are controlled between [Mn] 1.2-1.6%, [Si] between 0.40-0.60%, [C] between 0.17-0.25%, and [V] between 0.04-0.12% Between or [Nb] is controlled between 0.03-0.08%, yield strength (Rel) ≥ 400MPa, tensile strength ≥ 550MPa, reduction of area (A) ≥ 16%, mainly relying on car...

Claims

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Application Information

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IPC IPC(8): C22C38/26C22C38/24C21C7/00C21C7/072C22B1/16
Inventor 吴光亮
Owner 长沙东鑫环保材料有限责任公司
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