Preparation method of high-tenacity medium-and-high-carbon superfine bainite steel

A technology of bainitic steel and high toughness, which is applied in the field of preparation of high-toughness medium-high carbon ultra-fine bainitic steel. The effects of transformation time, low cost, and wide application prospects

Inactive Publication Date: 2017-03-22
HEBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The production process of these two methods is relatively complicated, and the requirements for equipment and process conditions are relatively high, especially the isothermal transformation time of bainite is too long, and a variety of alloying elements are added, which increases the production cost

Method used

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  • Preparation method of high-tenacity medium-and-high-carbon superfine bainite steel
  • Preparation method of high-tenacity medium-and-high-carbon superfine bainite steel
  • Preparation method of high-tenacity medium-and-high-carbon superfine bainite steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Heat the cast slab obtained by vacuum smelting and pouring to 1170°C for soaking, then hot-forge to a sample with a cross-sectional size of 40×40mm, then keep it at 900°C for 30 minutes, and then cool it to 570-570°C at a cooling rate of 15-20°C / s. Single-pass rolling at 595°C, the deformation is 16.6%, the temperature after rolling is 500-520°C, and then quickly put it in a salt bath furnace at 340°C for 0.5 hours, and then transfer it to a salt bath furnace at 270°C for constant temperature 2h, and finally air-cooled to room temperature. The chemical composition of the slab is shown in Table 1.

Embodiment 2

[0029] Heat the slab obtained by vacuum smelting and pouring to 1170°C for soaking, then hot forge to a sample with a cross-sectional size of 40×40mm, then keep it at 860°C for 30 minutes, and then cool it to 460~460~ at a cooling rate of 15~20°C / s. Perform single-pass rolling at 490°C, the deformation is 15.9%, and the temperature after rolling is 410-430°C, then quickly put it in a salt bath furnace at 310°C for 0.5 hours, and then transfer it to a salt bath furnace at 230°C for constant temperature 4h, and finally air-cooled to room temperature. The chemical composition of the slab is shown in Table 1.

Embodiment 3

[0031] Heat the slab obtained by vacuum smelting and pouring to 1170°C for soaking, then hot-forge to a sample with a cross-sectional size of 40×40mm, then keep it at 870°C for 30 minutes, and then cool it to 525~525~ at a cooling rate of 15~20°C / s. Single-pass rolling at 560°C, the deformation is 17.3%, the temperature after rolling is 480-500°C, and then quickly placed in a salt bath furnace at 330°C for 0.5 hours, and then transferred to a salt bath furnace at 245°C for constant temperature 2h, and finally air-cooled to room temperature. The chemical composition of the slab is shown in Table 1.

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Abstract

The invention provides a preparation method of high-tenacity medium-and-high-carbon superfine bainite steel. The high-tenacity medium-and-high-carbon superfine bainite steel comprises, by mass, 0.48%-0.78% of C, 1.5%-2.5% of Si, 0.6%-1.2% of Mn, 0.8%-1.4% of Cr and the balance Fe and inevitable impurities. The preparation method of the high-tenacity medium-and-high-carbon superfine bainite steel comprises the following steps that vacuum melting is conducted on the above ingredients, so that an alloy steel casting blank is obtained, after the casting blank is forged, heat preservation is directly conducted on the casting blank at the temperature of 850-910 DEG C for 0.2-1.0 hour, and then the casting blank is taken out; the taken-out casting blank is cooled to the temperature of 450-600 DEG C at the cooling rate of 10-20 DEG C/s, then rolling deformation is conducted, and the deformation is 15%-33%; then, two-step isothermal treatment is conducted on the deformed steel material, and finally the high-strength high-tenacity superfine bainite steel is obtained. According to the obtained bainite steel, it is guaranteed that the superhigh strength and the good plasticity are achieved, and meanwhile compared with the impact toughness of the superfine bainite steel prepared through an existing method, the impact toughness of the obtained bainite steel is improved by 2-5 times. The preparation method of the high-tenacity medium-and-high-carbon superfine bainite steel has the advantages of being low in production cost and short in production period.

Description

technical field [0001] The invention belongs to the technical field of ultra-fine bainite steel, in particular to a preparation method of high-toughness medium-high carbon ultra-fine bainite steel. Background technique [0002] The strength of steel increases with the increase of carbon content, but its plasticity and toughness decrease. How to achieve a good match between strength and plasticity has become an important issue to improve its performance and tap its potential. Compared with martensitic steels or bainitic / martensitic multiphase steels, bainitic steels with ultra-fine lath bainitic ferrite are favored for their better strong-plastic matching, impact toughness and fatigue strength. Widespread attention. [0003] Ultra-fine bainitic steel was proposed by Bhadeshia, University of Cambridge, etc. (US Patent US6884306). By using the inhibitory effect of Si on carbide precipitation, the ingot is austenitized and isothermal at a temperature slightly higher than the ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/34C22C38/04C21D8/00
CPCC22C38/34C21D8/005C21D2211/002C22C38/04
Inventor 刘宁张昕冯建航殷福星丁静
Owner HEBEI UNIV OF TECH
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