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A production method of φ36~40mm HRB500E threaded steel bar

A technology of threaded steel bar and production method, applied in the field of iron and steel metallurgy, can solve the problems of large difference in microstructure of steel bar, small rolling compression ratio, low performance qualification rate and the like

Active Publication Date: 2020-10-27
SHOUGANG SHUICHENG IRON & STEEL GRP
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for large-scale threaded steel bars of φ28-40mm, due to the large cross-section of the steel bar, the rolling compression ratio from the billet to the steel bar is small, and the composition difference from the surface to the center of the steel bar is large. Finally, the cooling rate difference from the surface of the rolled piece to the center of the rolled piece is large, which also leads to a large difference in the microstructure and performance of the steel bar from the surface to the center, which often results in unqualified performance of the steel bar and a low pass rate of performance
At the same time, for high-strength steel bars with unqualified strength, even if they are changed to low-strength steel bars, there are few occasions where they can be used, and there are often no sales channels

Method used

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  • A production method of φ36~40mm HRB500E threaded steel bar
  • A production method of φ36~40mm HRB500E threaded steel bar
  • A production method of φ36~40mm HRB500E threaded steel bar

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] 1. Steelmaking

[0062] Taking 100t converter smelting 11 furnaces of Φ36~40mm HRB500E rebar as an example, the following steps of smelting test were carried out:

[0063] 1) Raw material requirements

[0064] The composition and temperature of molten iron are shown in Table 1 below.

[0065] Table 1 Composition and temperature of molten iron used in 11 heats of HRB500E steel

[0066]

[0067] (2) Lime composition (%): CaO>90, SiO 2 ≤1.5, S310ml.

[0068] 2) Loading system:

[0069] The loading amount of each raw material in the converter and the amount of slag in the smelting process are shown in Table 2 below.

[0070] Table 2 The amount of metal material charged in 11 heats of HRB500E steel and the amount of slag added in the smelting process

[0071]

[0072] Among them, the composition of the slagging agent is MnO≥13%, Fe 2 o 3 ≥20%, SiO 2 ≤20%, P≤0.20%, S≤0.20%, moisture≤3%.

[0073] 3) Smelting conditions

[0074] (1) The working oxygen pressure ...

experiment example 1

[0126] The multiple batches of φ36~40mm HRB500E threaded steel bars prepared in Example 1 are detected, specifically as follows:

[0127] 1 produces the effect

[0128] The microstructure and mechanical properties of the prepared batches of Φ36-40mm HRB500E threaded steel bars meet the GB / T1499.2-2018 standard and user requirements, and the performance qualification rate reaches 100%.

[0129] 2 microstructure

[0130] The microscopic inclusion ratings of Φ40mm HRB500E steel bars are shown in Table 9 below.

[0131] Table 9 Inclusion rating / level of Φ40mm HRB500E steel bars

[0132]

[0133] It can be seen from Table 9 that there are a small amount of silicate and spherical oxide inclusions in the steel bar, but no other inclusions, indicating that the steel is relatively clean.

[0134] At the same time, the metallographic microstructure of Φ40mm HRB500E steel bar is ferrite + pearlite, pearlite accounts for about 53%, and the grain size is 9.5-10. Its microstructure is...

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Abstract

The invention provides a production method of phi 36-40 mm HRB500E twisted steel. The production method comprises the following steps: after molten iron, waste steel and slag are added in a converterfor smelting, steel is discharged through pushing off the slag; molten steel is deoxidized and alloyed for continuous casting in a LF refining furnace after refining; and an obtained steel blank is rolled to obtain the phi 36-40 mm HRB500E twisted steel, wherein finished molten steel comprises the following components in percentage weight: 0.22-0.25% of C, 0.60-0.70% of Si, 1.50-1.60% of Mn+Cr, Pnot more than 0.045%, S not more than 0.045%, 0.11-0.13% of V, and the balance of iron and inevitable impurities. In the method, through adjustment and control of such condition parameters as production flow steps and temperature and such factors as N and V element contents in the steel, the finished steel with high mechanical property and high stability can be obtained.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a method for producing a φ36-40mm HRB500E threaded steel bar. Background technique [0002] Rebar is a must-use steel for medium-sized and above-sized building components. In the construction industry, the largest amount is φ6-25mm medium and small-scale rebar, and a small amount is φ28-40mm large-scale rebar. For medium and small-sized threaded steel bars of φ6-25mm, the production technology is relatively simple, and general iron and steel enterprises can carry out large-scale production, and even medium and small-sized high-strength steel bars with unqualified strength can also be modified. It is used for low-strength steel bars, and its application scope and sales channels are many. However, for large-scale threaded steel bars of φ28-40mm, due to the large cross-section of the steel bar, the rolling compression ratio from the billet to the steel bar is smal...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/12C22C38/24C22C38/38C21C7/00C21C7/06C21C7/072C22C33/04
CPCC21C7/0006C21C7/06C21C7/072C22C33/04C22C38/02C22C38/04C22C38/12C22C38/24C22C38/38Y02P10/20
Inventor 王琳松张新建常进陈黔湘周奇荣高长益刘欣练昌李正嵩张东升陈海英叶雅妮丁云江
Owner SHOUGANG SHUICHENG IRON & STEEL GRP
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