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Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling

A technology of hot-rolled ribbed steel bars and production methods, which is applied in the production field of high-strength energy-saving construction steel products, and can solve the problem of giving specific indicators for the grain size of ribbed steel bars, not specifying the refinement, and having no final rolling pass strain Accumulation and other issues to achieve the effect of expanding market sales, improving plasticity and welding performance, and significant economic benefits

Active Publication Date: 2014-12-17
MAGANG (GROUP) HOLDING CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Although the 200810233733.4 patent proposes a method for preparing hot-rolled ribbed steel bars, claim 1-A is the conventional composition and production process of hot-rolled ribbed steel bars, and there is no specific requirement for strain accumulation in the final rolling pass during hot rolling. No specific index is given for the grain size of the ribbed steel bar; the patent 200810124722.2 proposes a low-temperature rolling method for the controlled rolling and controlled cooling of the hot-rolled belted steel bar, and the rolling temperature given is obviously lower than that of the present invention. Low-temperature rolling is beneficial to grain refinement, but it is difficult to realize the process due to the limitation of equipment conditions, and no specific indicators are given for the cooling strength and the grain size of the final product; patents 200610125347.4 and 201010183312.2 mainly involve the composition of ribbed steel bars Design, there is no provision for controlled rolling and controlled cooling and surface ferrite grain refinement

Method used

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  • Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling
  • Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling
  • Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Taking the VN microalloyed ribbed steel bar with a diameter of 16 mm as an example, the chemical composition analysis (mass fraction) of the steel bar is shown in Table 1 ①. After smelting, a continuous casting slab of 150mm×150mm is obtained. Put the continuous casting slab into a walking heating furnace, heat it at 800°C-1200°C for 1.2 hours, and start rolling at 1150°C. After 16 passes of rolling, a ribbed steel bar with a diameter of 16 mm is obtained. The deformation temperature and strain of the last 7 passes (10-16 passes) are designed to ensure the accumulated strain of austenite. After the computer-aided design model, the designed 7-pass rolling process is:

[0025] pass

[0026] Design the final rolling pass, that is, the deformation temperature of the 16th pass is 1190°C, the strain rate is 39 / s, and the corresponding critical strain of austenite dynamic recrystallization is 0.532, which is 95% of the critical strain. The cumulative strain of the...

Embodiment 2

[0028] Taking the VN microalloyed ribbed steel bar with a diameter of 25 mm as an example, the chemical composition analysis of the steel bar is shown in Table 1 ②. After smelting, a continuous casting slab of 150mm×150mm is obtained. Put the continuous casting slab into a walking heating furnace, heat it at 800°C-1200°C for 1.2 hours, and start rolling at 1050°C. After 16 passes of rolling, a ribbed steel bar with a diameter of 16 mm is obtained. The deformation temperature and strain of the last 7 passes (10-16 passes) are designed to ensure the accumulated strain of austenite. After the computer-aided design model, the designed 7-pass rolling process is:

[0029] pass

10

11

12

13

14

15

16

critical strain

0.577

0.627

0.640

0.649

0.622

0.631

0.704

Strain accumulation

0.113

0.490

0.630

0.505

0.237

0.427

0.692

dynamic recr...

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Abstract

The invention discloses a method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling. The method is characterized in that: deformation and recrystallization behaviors of the austenite are controlled in the rolling process, so that the deformation accumulation of the austenite after finished rolling is controlled in 80 to 99 percent of an austenite dynamic recrystallization critical strain range, and the cooling strength of spray cooling after rolling is controlled to inhibit the static recrystallization of the austenite. By controlling the deformation temperature, strain speed and rolling reduction of a finished rolling pass, strain accumulation required by strain induced transformation is obtained, and is matched with cooling time from the finished rolling to spray cooling and the spray cooling strength to refine ferrite grains on the surfaces to be 4-7 micrometers; and the method is an advanced process for producing high strength tempered martensite-free hot rolled bars, and has obvious technical innovation.

Description

technical field [0001] The invention belongs to the production technology of high-strength and energy-saving building steel, in particular to the technology of achieving the required mechanical properties through the method of refining grains and cooling speed to control the surface microstructure of steel bars through deformation-induced phase transformation. Background technique [0002] Hot-rolled ribbed steel bar is widely used in concrete structures in engineering construction, and it mainly bears tensile stress in concrete. Due to the role of ribs, the ribbed steel bar has a greater bonding capacity with concrete, so it can better withstand the action of external forces. Ribbed steel bars are widely used in civil engineering construction such as bridges, houses, roads, etc. With the development of these industries, there is a great demand for ribbed steel bars and higher requirements are put forward for the performance of products. In order to make the ribbed steel ba...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D8/08
Inventor 完卫国朱国辉孙维陈其伟隋凤利郭湛郭茂忠曹淑敏
Owner MAGANG (GROUP) HOLDING CO LTD
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