Production process for controlling surface cracks of micro-alloyed hot-rolled round steel

A technology of micro-alloying and surface cracking, which is applied in the field of iron and steel metallurgy and steel rolling, can solve the problems of billet quality decline, steel bar surface warping, and billet surface transverse cracks, etc., so as to improve the quality of billet products, reduce cracking tendency, Reduce the effect of surface cracks

Inactive Publication Date: 2021-04-02
JIANGSU LIANFENG ENERGY EQUIP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, while improving the strength and comprehensive performance, the problem of cracks is still inevitable.
In the traditional formula, when the Nb content is too high, not only will the cost of the alloy increase, but also the quality of the slab will decrease due to the increase of niobium, and the stress in the continuous casting production will easily cause defects such as transverse cracks on the surface of the slab, resulting in warping of the surface of the steel bar. , folding and other defects

Method used

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  • Production process for controlling surface cracks of micro-alloyed hot-rolled round steel
  • Production process for controlling surface cracks of micro-alloyed hot-rolled round steel

Examples

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Comparison scheme
Effect test

Embodiment 1

[0028] A production process for controlling surface cracks of micro-alloyed hot-rolled round steel, comprising the following steps: continuously casting molten steel to obtain a billet, and sequentially reheating, rough rolling, finish rolling, normalizing, and cooling the billet; specifically :

[0029] In the steel slab, based on the total weight of the steel slab, the content of each component is: C 0.11-0.13wt%, Si0.10-0.20wt%, Mn 1.75-1.85wt%, V 0.03-0.06wt%, Mo 0.01-0.02wt%, N 0.01-0.013wt%, Ni 0.03-0.06wt%, and the rest are Fe and unavoidable impurities.

[0030] When reheating the steel slab, the steel slab was heated to 950°C.

[0031] The start rolling temperature of the rough rolling is 900°C, and the finish rolling temperature of the rough rolling is 870°C.

[0032] The start rolling temperature of the finish rolling is 800°C, and the finish rolling temperature is 750°C.

[0033] Normalizing heat treatment: Due to the use of microalloying, in order to ensure tha...

Embodiment 2

[0036] A production process for controlling surface cracks of micro-alloyed hot-rolled round steel, comprising the following steps: continuously casting molten steel to obtain a billet, and sequentially reheating, rough rolling, finish rolling, normalizing, and cooling the billet; specifically :

[0037] In the steel slab, based on the total weight of the steel slab, the content of each component is: C 0.11-0.13wt%, Si0.10-0.20wt%, Mn 1.75-1.85wt%, V 0.03-0.06wt%, Mo 0.01-0.02wt%, N 0.01-0.013wt%, Ni 0.03-0.06wt%, and the rest are Fe and unavoidable impurities.

[0038] When reheating the steel slab, the steel slab is heated to 1000°C.

[0039] The start rolling temperature of the rough rolling is 920°C, and the finish rolling temperature of the rough rolling is 880°C.

[0040] The start rolling temperature of the finish rolling is 820°C, and the finishing rolling temperature is 760°C.

[0041] Normalizing heat treatment: Due to the use of microalloying, in order to ensure ...

Embodiment 3

[0044] A production process for controlling surface cracks of micro-alloyed hot-rolled round steel, comprising the following steps: continuously casting molten steel to obtain a billet, and sequentially reheating, rough rolling, finish rolling, normalizing, and cooling the billet; specifically :

[0045] In the steel slab, based on the total weight of the steel slab, the content of each component is: C 0.11-0.13wt%, Si0.10-0.20wt%, Mn 1.75-1.85wt%, V 0.03-0.06wt%, Mo 0.01-0.02wt%, N 0.01-0.013wt%, Ni 0.03-0.06wt%, and the rest are Fe and unavoidable impurities.

[0046] When reheating the steel slab, the steel slab was heated to 1100°C.

[0047] The start rolling temperature of the rough rolling is 950°C, and the finish rolling temperature of the rough rolling is 890°C.

[0048] The start rolling temperature of the finish rolling is 850°C, and the finish rolling temperature is 770°C.

[0049] Normalizing heat treatment: Due to the use of microalloying, in order to ensure th...

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Abstract

The invention belongs to the technical field of ferrous metallurgy and steel rolling, and particularly relates to a production process for controlling surface cracks of micro-alloyed hot-rolled roundsteel. The production process comprises the following steps that molten steel is continuously cast to obtain a steel billet, and the steel billet is sequentially subjected to reheating, rough rolling,finish rolling, normalizing treatment and cooling. The main process parameters are that the initial rolling temperature of finish rolling is 800 DEG C-850 DEG C, and the final rolling temperature is750 DEG C-770 DEG C; and in the normalizing heat treatment, microalloying is adopted, and the normalizing heat treatment is carried out at the temperature of 620 DEG C-650 DEG C for guaranteeing sufficient solid solution of alloy elements. By controlling process parameters in the rolling process, grain boundary precipitation plays a role in precipitation strengthening, the strength is improved, and it is guaranteed that the mechanical property is qualified; and through normalizing treatment, the cracking tendency of a component is reduced, cracks on the surface of the casting blank are effectively reduced, and the product quality of the casting blank is improved.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy and steel rolling, in particular to a production process for controlling surface cracks of micro-alloyed hot-rolled round steel. Background technique [0002] Reinforcement bars are currently the largest type of steel produced and sold in China. The quality level of steel bars has approached the international advanced level, but there is still a certain gap between the use strength and developed countries. my country's hot-rolled ribbed steel bars are divided into three strength grades of 400, 500 and 600 according to their strength grades. After years of popularization and application, HRB500(E) has been widely used in key engineering projects such as nuclear power and landmark buildings. With the issuance and implementation of GB 1499.2-2018, the new standard puts forward higher requirements for the internal organization of national standard steel bars, and puts an end to the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/12C22C38/08C21D8/06C21D1/28B21B3/02B21B37/74
CPCB21B3/02B21B37/74C21D1/28C21D8/065C22C38/001C22C38/02C22C38/04C22C38/08C22C38/12
Inventor 张新文江宏亮轩康乐孙智伟孟祥岩
Owner JIANGSU LIANFENG ENERGY EQUIP
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