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An economical tempering-free strengthening and toughening process for low-alloy high-strength steel products

A process method and high-strength steel technology, which are used in the manufacture of low-alloy high-strength steel products, and the field of economical strengthening and toughening hot processing technology, can solve the problems of restricting the application of Q-P-T process, the difficulty of distribution-tempering time, and the uniform temperature inside and outside the workpiece, etc. problem, to achieve the effect of suitable for large-scale production, good impact toughness, good strength and toughness

Active Publication Date: 2016-08-24
攀枝花贝氏体耐磨管道有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the Q-P-T process, due to the short distribution-tempering time (in seconds), the internal stress in the quenching process is not fully released, and the impact toughness is very low; on the other hand, from the perspective of large-scale production, when the workpiece size When it is large, this short quenching + distribution process cannot make the temperature inside and outside the workpiece uniform, resulting in inconsistency in phase transition, from the quenching temperature to the distribution-tempering temperature immediately, and the extremely short distribution-tempering time in the large difficult to achieve in production
These shortcomings restrict the application of Q-P-T process in mass production

Method used

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  • An economical tempering-free strengthening and toughening process for low-alloy high-strength steel products
  • An economical tempering-free strengthening and toughening process for low-alloy high-strength steel products
  • An economical tempering-free strengthening and toughening process for low-alloy high-strength steel products

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) According to the following ingredients, smelt and refine, then continuous casting or die casting into billets or ingots, or forging into billets. The steel composition is: C: 0.45wt.%, Mn: 3.0wt.%, and the rest is Fe.

[0024] (2) Heat the aforementioned steel slab to 1280℃ to keep it fully austenitized, then perform hot rolling or use controlled rolling to control the corresponding deformation and finish rolling at about 850℃ to produce a certain thickness of plate , Cool down after rolling.

[0025] (3) The steel plate obtained in step (2) is controlled to cool to 420℃ in water, and then the cooling rate is changed, so that the workpiece is slowly cooled to 280℃ within 180 minutes, and then air-cooled to room temperature. The above method reduces the tensile strength of the workpiece 10% or more.

[0026] The temperature change trend is like figure 1 Shown.

Embodiment 2

[0028] (1) According to the following ingredients, smelt and refine, then continuous casting or die casting into billets or ingots, or forging into billets. The steel composition is: C: 0.21wt.%, Mn: 2.3wt.%, Cr: 1.0wt.%, Si: 0.5wt.%, Mo: 0.40wt.%, V: 0.2wt.%, Nb: 0.04wt .%, the rest is Fe.

[0029] (2) The aforementioned steel billet is heated to about 1250°C to keep it fully austenitized, and then hot-rolled. Using controlled rolling, the corresponding deformation is controlled and finally rolled into a certain thickness of plate at about 900°C. Cool down after rolling.

[0030] (3) The steel billet obtained in step (2) is controlled to be cooled to 250°C in water, and then the cooling is interrupted; then the workpiece is kept at 250°C for 120 minutes, and then air-cooled to room temperature. The above method reduces the tensile strength of the workpiece by 10% the above.

[0031] The temperature change trend is like figure 2 Shown.

Embodiment 3

[0033] (1) According to the following ingredients, smelt and refine, then continuous casting or die casting into billets or ingots, or forging into billets. The steel composition is: C: 0.6wt.%, Mn: 6.5wt.%, and the rest is Fe.

[0034] (2) Heat the aforementioned steel slab to 1280℃ to keep it fully austenitized, then perform hot rolling or use controlled rolling to control the corresponding deformation and finish rolling at about 850℃ to produce a certain thickness of plate , Cool down after rolling.

[0035] (3) The steel plate obtained in step (2) is controlled and cooled to 420°C in air, and then the cooling rate is changed, so that the workpiece is slowly cooled to 210°C within 180 minutes and kept for 60 minutes, and then air-cooled to room temperature. The above method Reduce the tensile strength of the workpiece by about 15%.

[0036] The temperature change trend is like image 3 Shown.

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Abstract

The invention discloses an economical tempering-free strengthening and toughening process for low-alloy high-strength steel products, which includes three steps of steel smelting and forming, high-temperature heating, heat preservation and cooling, and isothermal treatment. The process is suitable for C-Mn It is a low-alloy high-strength steel. Compared with the prior art, the present invention provides a preparation process of low-alloy high-strength steel products with simple process, suitable for large-scale production and good strength-toughness coordination, which is characterized by controlled cooling and interrupted cooling at high temperature and A strengthening and toughening manufacturing process for thermal insulation at the cooling end temperature. Compared with the traditional quenching and tempering process, this process simplifies the process of quenching to obtain martensite and martensite + bainite multiphase structure, and then tempering. Compared with the Q‑P‑T process, this process The process has operability more suitable for large-scale production, simplifies the process of immediately heating up from P process to T process, and makes production easier to operate.

Description

Technical field [0001] The invention belongs to the technical field of low-alloy steel processing, and relates to a method for manufacturing low-alloy high-strength steel products, in particular to a saving-type strengthening and toughening heat for low-alloy high-strength steel hot-rolled plates, pipes, rails, bars or castings Processing method. Background technique [0002] Low-alloy steel products such as high-strength hot-rolled plates, pipes, rails, bars, etc. are widely used in construction machinery, vehicle manufacturing, petroleum, slurry pipelines and bridge engineering. In order to obtain ideal strength and toughness, reasonable alloying and corresponding heat treatment processes are generally adopted. Quenching-tempering is a common heat treatment process for strengthening and toughening steel materials. This process refers to heating the workpiece to austenitic After the body single-phase zone is kept for a period of time, it is quenched to room temperature, and the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/20C21D6/00
Inventor 刘文利黄维刚黄雪飞刘鑫席建
Owner 攀枝花贝氏体耐磨管道有限公司