Production method for VN reinforcement bar with yield strength not less than 400MPa

A technology of yield strength and production method is applied in the production field of VN steel bars with a yield strength of 400MPa, which can solve the problems of the surface quality of steel bars cannot meet the requirements and the yield of VN is low, so as to improve the surface quality of products, reduce production costs, Good mechanical properties and stability

Active Publication Date: 2013-01-02
WUHAN IRON & STEEL GRP ECHENG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problems such as low VN recovery rate and unsatisfactory surface quality of steel bar in the current production of VN steel bars with yield strength greater than 400MPa, and provide a method to reduce volatilization of alloys and improve the recovery rate and performance of VN alloys. A production method of VN steel bars with a yield strength ≧400MPa grade that stabilizes and improves the surface quality of finished products

Method used

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  • Production method for VN reinforcement bar with yield strength not less than 400MPa
  • Production method for VN reinforcement bar with yield strength not less than 400MPa

Examples

Experimental program
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Effect test

Embodiment 1

[0023] The production yield strength is HRB400 grade, the steel bar diameter is 14 mm, and its melting chemical composition and weight percentage are: C: 0.23%, Mn: 1.45%, Si: 0.63%, P: 0.023%, S: 0.036%, V: 0.039 %, Ceq: 0.48; the test conditions are in a 70t converter, and the steps are:

[0024] 1) Fill 89% of the total volume of molten iron in a 70-ton converter, that is, the amount of molten iron loaded is 62.3 tons, and the weight percentage P of phosphorus in the molten iron is controlled at 0.110%, and the weight percentage S of sulfur is 0.047%;

[0025] 2) Add 11% of the total volume of steel scrap to the 70-ton converter, that is, 7.7 tons;

[0026] 3) Conventional oxygen blowing;

[0027] 4) Conventional baking of the ladle;

[0028] 5) Put the added VN16 alloy into a container made of ordinary quality carbon structural steel and seal it and put it into a 70-ton steel ladle. The amount of addition: the diameter of the steel bar is 14 mm, and the amount of additi...

Embodiment 2

[0038] The production yield strength is HRB400 grade, the steel bar diameter is 25 mm, and its melting chemical composition and weight percentage are:

[0039] C: 0.22%, Mn: 1.40%, Si: 0.57%, P: 0.034%, S: 0.033%, V: 0.046%, Ceq: 0.47; the test conditions are in a 35t converter, and the steps are:

[0040] 1) Fill 87% of the total volume of molten iron in a 35-ton converter, that is, the amount of molten iron loaded is 30.45 tons, and the weight percentage P of phosphorus in the molten iron is controlled at 0.120%, and the weight percentage S of sulfur is 0.049%;

[0041] 2) Add 13% of the total volume of steel scrap to the 35-ton converter, that is, 4.55 tons;

[0042] 3) Conventional oxygen blowing;

[0043] 4) Conventional baking of the ladle;

[0044] 5) Put the added VN16 alloy into a container made of ordinary quality carbon structural steel and seal it and put it into a 35-ton steel ladle. The amount of addition: the diameter of the steel bar is 25 mm, and the amount...

Embodiment 3

[0054] The production yield strength is HRB400 grade, the steel bar diameter is 18 mm, and its melting chemical composition and weight percentage are:

[0055] C: 0.23%, Mn: 1.35%, Si: 0.57%, P: 0.031%, S: 0.030%, V: 0.038%, Ceq: 0.46; the test conditions are in a 35t converter, and the steps are:

[0056] 1) Fill the 35-ton converter with 85.2% of the total volume of molten iron, that is, the amount of molten iron loaded is 29.82 tons, and the weight percentage P of phosphorus in the molten iron is controlled at 0.115%, and the weight percentage S of sulfur is 0.048%;

[0057] 2) Add 14.8% of the total volume of steel scrap to the 35-ton converter, that is, 5.18 tons;

[0058] 3) Conventional oxygen blowing;

[0059] 4) Conventional baking of the ladle;

[0060] 5) Put the added VN16 alloy into a container made of ordinary quality carbon structural steel and seal it and put it into a 35-ton steel ladle. The amount of addition: the diameter of the steel bar is 18 mm, and th...

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Abstract

The invention relates to a production method for VN reinforcement bar with yield strength not less than 400MPa. The method comprises the following steps of: adding molten iron to a converter, wherein the amount of the molten iron is 85-90% of the total volume of the converter; adding scrap steel to the converter, wherein the amount of the scrap steel is 10-15% of the total volume of the converter; carrying out conventional oxygen blowing; baking a ladle; adding VN16 alloy into a general-quality carbon structural steel container, sealing and placing the container in the ladle for rolling and water cooling; and cutting, packaging and testing for later use. According to the invention, the recovery rate of the VN16 alloy is improved, the VN reinforcement bar has better mechanical properties and stability, and the surface quality of the product is improved, thus meeting user requirement and lowering production cost.

Description

technical field [0001] The invention relates to a production method of steel bars, in particular to a production method of VN steel bars with a yield strength of 400MPa to 500MPa. Background technique [0002] At present, the United States, Germany and other countries use VN alloys to produce rebars. The alloy addition method is: during the tapping process, it is added together with the deoxidized alloying alloy material. Scope, there is no subdivision of the alloy addition amount according to the specification group interval. [0003] Domestic manufacturers such as Panzhihua Iron and Steel, Maanshan Iron and Steel, and Shougang use VN alloys to produce rebars. The alloy addition method is to add 0.5~0.6kg / t (HRB400) or 1.0~1.2kg / t (HRB500) on the basis of HRB335. The adding method is: add together with the deoxidized alloying alloy material during the tapping process; the specification group distance is: φ10~φ25, φ28~φ32, the heating temperature and final rolling temperatu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C5/28B21B37/74
CPCY02P10/20
Inventor 朱兆顺张青山王志衡盛细刚方建红尹志香吕婷婷黄海玲蔡利群夏金魁吴卫明黄斌
Owner WUHAN IRON & STEEL GRP ECHENG IRON & STEEL CO LTD
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