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Microalloy HRB500E steel bar containing chrome and nitrogen and production method thereof

A technology of microalloying and production method, applied in the field of HRB500E steel bar and its production process, can solve the problems of high welding performance, aging phenomenon, large fluctuation of steel bar performance, etc., and achieve good welding performance, stable quality and good anti-corrosion characteristics Effect

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: ① high silicon-manganese and carbon content, high carbon equivalent, poor welding performance, and high alloy cost; ② element segregation is easy to occur during solidification and cooling; ③ high vanadium or niobium content, On the one hand, a large amount of precious resources are consumed, and on the other hand, the cost of the alloy is high; ④ Yield is not obvious and mixed crystals are prone to occur
The disadvantages of this method are: ①It is necessary to greatly increase the capacity of the rolling mill or to build a new rolling production line, which requires a huge investment, and the existing equipment cannot be used; The strength is greatly reduced; ③The production of HRB500 by this method is still in the stage of industrial exploration and experimentation, the technology is immature, there are many uncontrollable factors, and the product quality is unstable
The third category is to control the composition to the lower limit, and rarely use vanadium or niobium, and the composition of the alloy can be greatly reduced by forced cooling through water after rolling. This method is only in the stage of industrial testing, and has the following obvious defects: ① Need Increase water-piercing equipment and increase investment; ②The performance of steel bars fluctuates greatly, the aging phenomenon is serious, and the stability of product quality is extremely poor; The HRB500 steel bar produced by this method is not accepted; ④The surface and core structure of the steel bar are inconsistent, and the surface is prone to tempered martensite and tempered sorbite, which exceeds the basic requirements of the national standard that the steel bar structure is ferrite + pearlite

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Add blast furnace hot metal and scrap or pig iron into the converter separately, blow oxygen to smelt, and add slagging materials such as lime, and add reducing chromium oxide pellets and reducing manganese oxide pellets to the converter for 7 minutes For the mixture, blow oxygen at the top for 3 minutes and at the same time blow at the bottom for 3 minutes, so that [C]=0.08-0.120%, [Mn] between 0.12-0.20%, and [Gr] between 0.65-0.750% in molten steel at the smelting end;

[0039] Add reducing vanadium oxide pellets within 4 minutes before the converter tapping; blow oxygen for 4 minutes, while blowing at the bottom for 4 minutes, so that the [V] of the molten steel is between 0.02-0.04%, and the sulfur content of other components such as molten steel is less than 0.035%. The phosphorus content is less than 0.035%, etc. to meet the standard requirements, and the temperature meets the requirements of the continuous casting process for tapping;

[0040] Within 30 seconds after...

Embodiment 2

[0045] Add blast furnace hot metal and scrap steel or pig iron into the converter separately, blow oxygen to smelt, and add slagging materials such as lime, add a mixture of reducing chromium oxide pellets and reducing manganese oxide pellets when oxygen is blown to the converter for 3 minutes ; Top blowing oxygen for 7 minutes, while blowing at the bottom for 7 minutes, so that [C] in the smelting end molten steel is between 0.06-0.10%, [Mn] between 0.30-0.40%, and [Gr] between 0.30-0.40%

[0046] Add reducing vanadium oxide pellets and reducing niobium oxide pellets within 8 minutes before tapping from the converter; blow oxygen for 8 minutes, while blowing at the bottom for 8 minutes, so that [V] + [Nb] in molten steel is between 0.035-0.050% , Other components meet the standard requirements for steel tapping;

[0047] When the converter molten steel has a sulfur content of less than 0.035%, a phosphorus content of less than 0.035%, and the temperature meets the requirements of ...

Embodiment 3

[0053] Add blast furnace hot metal and scrap steel or pig iron into the converter separately, blow oxygen to smelt, and add slagging materials such as lime, and add reducing chromium oxide pellets and reducing manganese oxide pellets when oxygen is blown to the converter for 10 minutes. For the mixture, blow oxygen at the top for 5 minutes and at the same time blow at the bottom for 5 minutes to make [C]=0.10-0.15%, [Mn] between 0.20-0.30%, and [Gr] between 0.45-0.65%;

[0054] Add reducing niobium oxide pellets within 6 minutes before tapping from the converter; blow oxygen for 6 minutes while blowing at the bottom for 6 minutes to make the [Nb] in the molten steel between 0.05-0.07%, and other components such as the sulfur content of molten steel less than 0.035%. The phosphorus content is less than 0.035%, etc. to meet the standard requirements, and the temperature meets the requirements of the continuous casting process for tapping;

[0055] Within 90 seconds after tapping, add...

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PUM

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Abstract

The invention discloses a microalloy HRB500E 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 HRB500E steel bar can be produced; Rel of the steel bar is 520 to 580MPa, Rm of the steel bar is 640 to 730 MPa, A is 22 to 32 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 0.50, and the comprehensive cost of one ton of steel bar is 40-100 yuan lower than that of one ton of the steel bar produced by the conventional method; during aging of three months, the fluctuation values of the Rm value and the Rel value are less than 10MPa; and the steel bar has excellent welding performance and good corrosion-proof property.

Description

Technical field [0001] The invention relates to a chromium-nitrogen-containing microalloyed steel bar and its production process, in particular to a chromium- and nitrogen-containing microalloyed steel bar and its production process. Background technique [0002] At present, there are three types of production processes for HRB500MPa grade steel bars. The first type is the carbon-manganese steel composition design mainly based on 20MnSi. Manganese and silicon-based iron alloys are used for manganese and silicon alloying, vanadium iron or vanadium-nitrogen alloys are used for vanadium microalloying, and ferro-niobium alloys are used for niobium microalloying. For alloying, the main components of [Mn] are controlled between 1.3-1.6%, [Si] between 0.45-0.80%, [C] between 0.17-0.25%, and [V] between 0.08-0.12% Sometimes [Nb] is controlled between 0.05-0.12%, or composite alloying with vanadium + niobium is used. Yield strength (Rel) ≥ 500MPa, tensile strength (Rm) ≥ 630 MPa, reduct...

Claims

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Application Information

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IPC IPC(8): C22C38/18C22C38/26C22C38/24C22C33/06C21D8/08
Inventor 吴光亮
Owner 长沙东鑫环保材料有限责任公司
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