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Saving-type tempering-free strengthening toughening method for low-alloy high-strength steel products

A process method and high-strength steel technology, applied in the field of low-alloy steel processing, can solve the problems of restricting the application of Q-P-T process, the difficulty of realizing distribution-tempering time, uniform temperature inside and outside the workpiece, etc., to achieve suitable for large-scale production, good impact toughness, The effect of good strength and toughness

Active Publication Date: 2014-09-03
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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  • Saving-type tempering-free strengthening toughening method for low-alloy high-strength steel products
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  • Saving-type tempering-free strengthening toughening method for low-alloy high-strength steel products

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Experimental program
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Effect test

Embodiment 1

[0023] (1) According to the following ingredients, it is smelted and refined, and then continuously cast or molded into billets or ingots, or forged into billets. The steel composition is: C: 0.45wt.%, Mn: 3.0wt.%, and the rest is Fe.

[0024] (2) Heat the aforementioned billet to 1280°C and keep it warm to make it completely austenitized, then carry out hot rolling or use controlled rolling method to control the corresponding deformation and finish rolling at about 850°C to make a plate with a certain thickness , cooling after rolling.

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

[0026] The temperature trend is as figure 1 shown.

Embodiment 2

[0028] (1) According to the following ingredients, it is smelted and refined, and then continuously cast or molded into billets or ingots, or forged into billets. Steel composition: 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) Heat the aforementioned steel billet to about 1250°C and keep it warm to make it completely austenitized, and then carry out hot rolling, adopt the method of controlled rolling, control the corresponding deformation and finally roll it into a plate with a certain thickness at about 900°C, Cool after rolling.

[0030] (3) Controlly cool the billet obtained in step (2) to 250°C in water, and then interrupt the cooling; then keep the workpiece at 250°C for 120 minutes, and then air-cool to room temperature. The above method reduces the tensile strength of the workpiece by 10% above.

[0031] The temperature trend is as figure 2 shown.

Embodiment 3

[0033] (1) According to the following ingredients, it is smelted and refined, and then continuously cast or molded into billets or ingots, or forged into billets. The steel composition is: C: 0.6wt.%, Mn: 6.5wt.%, and the rest is Fe.

[0034] (2) Heat the aforementioned billet to 1280°C and keep it warm to make it completely austenitized, then carry out hot rolling or use controlled rolling method to control the corresponding deformation and finish rolling at about 850°C to make a plate with a certain thickness , cooling after rolling.

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

[0036] The temperature trend is as image 3 shown.

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Abstract

A disclosed saving-type tempering-free strengthening toughening method for low-alloy high-strength steel products comprises smelting and moulding of steel, high-temperature heating and warm keeping and cooling, and isothermal treatment. The method is applicable to C-Mn series low-alloy high-strength steel. Compared with the prior art, the preparation technology for the low-alloy high-steel steel products with good cooperation of strength and toughness is simple in technology and suitable for large-scale production, and is characterized in that the technology is a strengthening toughening manufacturing technology which comprises cooling control and cooling interruption under a high-temperature condition, and warm keeping at a cooling-termination temperature. Compared with conventional quenching and tempering technologies, the technology simplifies quenching for obtain martensite and martensite-bainite multiphase structures, and then tempering processing is performed. Compared with a Q-P-T (quenching-partitioning-tempering) technology, the technology has the maneuverability relatively suitable for large-scale production, helps to simplify the process of raising the temperature for replacing the P (partitioning) technology by the T (tempering) technology for processing, and enables production to be relatively easy 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 an energy-saving strengthening and toughening heat treatment for hot-rolled low-alloy high-strength steel plates, pipes, rails, bars or castings. Processing method. Background technique [0002] Low-alloy steel products such as high-strength and toughness hot-rolled plates, pipes, rails, and bars 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, among which quenching-tempering is a common heat treatment process for strengthening and toughening steel materials, which refers to heating the workpiece to Austenitic After holding for a period of time in the single-phase region of the ...

Claims

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Application Information

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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