Method for enhancing strength of low-carbon and medium-carbon steel through nano carbide precipitation

A low-carbon steel, high-strength technology, applied in the field of metallurgy, can solve the problem that the strengthening effect is not very obvious, and achieve the effect of improving the strength

Inactive Publication Date: 2013-10-09
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Patent CN02115101.6 proposes a method of strengthening low-carbon steel by using nanoparticles, but it does not clearly point out that the strengthening particles are cementite, and the strengthening effect is not very obvious

Method used

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  • Method for enhancing strength of low-carbon and medium-carbon steel through nano carbide precipitation
  • Method for enhancing strength of low-carbon and medium-carbon steel through nano carbide precipitation
  • Method for enhancing strength of low-carbon and medium-carbon steel through nano carbide precipitation

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The thickness of the carbon steel slab used is 70mm, and the composition is C 0.17%, Si 0.19%, Mn 0.7%, P 0.002%, S0.002% by weight percentage, and the balance is iron;

[0027] Heat the carbon steel slab to 1200°C and keep it warm for 1h;

[0028] The heated carbon steel slab is hot-rolled at 1100°C with a rolling mill, the cumulative reduction is 90%, and the final rolling temperature is 890°C to obtain a hot-rolled slab;

[0029] The hot-rolled slab is water-cooled to 500°C at a rate of 100-120°C / s by using an ultra-rapid cooling method;

[0030] Using a rolling mill, the water-cooled hot-rolled slab is subjected to single-pass plastic deformation at 500°C, with a deformation of 7%, and then kept at 500°C for 60 minutes, and then air-cooled to room temperature to obtain high-strength carbon steel. Its structure is uniform lath bainite, and its morphology is as follows: Figure 4 As shown, the volume fraction of nano-cementite particles reaches 10%; nano-cementite p...

Embodiment 2

[0034] The thickness of the carbon steel slab used is 80mm, and the composition is C 0.19%, Si 0.3%, Mn 0.7%, P 0.002%, S0.004% by weight percentage, and the balance is iron;

[0035] Heat the carbon steel slab to 1200°C and keep it warm for 1h;

[0036] The heated carbon steel slab is hot-rolled at 1100°C with a rolling mill, the cumulative reduction is 90%, and the final rolling temperature is 890°C to obtain a hot-rolled slab;

[0037] The hot-rolled slab is water-cooled to 450°C at a rate of 100-120°C / s by means of ultra-rapid cooling;

[0038]Using a rolling mill, the water-cooled hot-rolled slab is subjected to single-pass plastic deformation at 450°C, with a deformation of 6%, and then kept at 500°C for 20 minutes, and then air-cooled to room temperature to obtain high-strength carbon steel. Its structure is bainite, and dispersed nano-scale cementite particles are precipitated in the structure of the material, with a particle size of 5-30nm; the yield strength of high...

Embodiment 3

[0040] The thickness of the carbon steel slab used is 40mm, and the composition is C 0.15%, Si 0.23%, Mn 0.7%, P 0.003%, S0.002% by weight percentage, and the balance is iron;

[0041] Heat the carbon steel slab to 1200°C and keep it warm for 1h;

[0042] The heated carbon steel slab is hot-rolled at 1100°C with a rolling mill, the cumulative reduction is 90%, and the final rolling temperature is 880°C to obtain a hot-rolled slab;

[0043] Using ultra-rapid cooling method, the hot-rolled slab is water-cooled to 600°C at a speed of 150-200°C / s;

[0044] Using a rolling mill, the water-cooled hot-rolled slab is subjected to single-pass plastic deformation at 600°C, with a deformation of 7%, and then kept at 600°C for 20 minutes, and then air-cooled to room temperature to obtain high-strength carbon steel. It is mainly a degenerated pearlite structure, in which dispersed nano-scale cementite particles are precipitated, and the particle size of the cementite particles is 5-50nm; ...

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Abstract

The invention discloses a method for enhancing the strength of low-carbon and medium-carbon steel through nano carbide precipitation, belonging to the technical field of metallurgy. The method comprises the following steps of: (1) heating a carbon steel plate blank to 1100-1250 DEG C, and preserving the heat for 1-2 hours; (2) carrying out hot rolling at the temperature of 1000-1100 DEG C to obtain a hot rolled plate blank, wherein the accumulated reduction amount is 70-95%; (3) carrying out water cooling on the hot-rolled plate blank to 400-600 DEG C at the speed of 100-200 DEG C/s in a super rapid cooling way; (4) carrying out plastic deformation at the temperature of 400-600 DEG C, then, preserving the heat of 400-600 DEG C for 10-120 minutes, and then, carrying out air cooling to the room temperature, wherein the deformation amount is 2-10%. The method has the advantages that the traditional laminated structure of a pearlite in a common carbon steel tissue is changed through changing a process on the premise that no any microalloy elements are added, the nano carbide precipitation is realized, a uniform dispersed distribution effect is formed in the whole tissue, a remarkable enhancing effect is achieved, and the requirement for the strength of part of microalloy steel is met or exceeded.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for improving the strength of medium and low carbon steel by utilizing nano carburizing and precipitation. Background technique [0002] Since the 1970s, the mainstream development method of iron and steel materials based on Fe-C alloys is to strengthen by adding trace alloy elements such as Nb, V, Ti and controlling the phase transformation. However, with the deterioration of the global environment and the emergence of resource crises, the cost of alloys in the production process of the iron and steel industry has increased year by year, while corporate profits have declined sharply. Therefore, iron and steel enterprises expect to further reduce the addition of microalloying elements in steel. Seek for more economical and green strengthening phases to meet the development requirements of reducing production costs and saving alloy resources. Among them, c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/02C22C38/04
Inventor 刘振宇王斌周晓光王国栋
Owner NORTHEASTERN UNIV
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