Process of preparing carbon steel with superfine heterogeneous structure

A carbon steel and ultra-refining technology, which is applied in the field of preparing ultra-refined multi-phase structure materials, can solve the problems of high strain rate, low carbon content, and inconspicuous characteristics of large-angle grain boundaries, and achieves the effect of simple process

Inactive Publication Date: 2007-10-03
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

However, from the final structure given by the above report, there is no sufficient evidence that the average grain size of ferrite is less than 1 μm due to the inconspicuous high-angle grain boundary features in the ferrite matrix
The main reasons for the inconspicuous high-angle grain boundary features in the ferrite matrix are: due to the low carbon content (cementite content) (low

Method used

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  • Process of preparing carbon steel with superfine heterogeneous structure
  • Process of preparing carbon steel with superfine heterogeneous structure
  • Process of preparing carbon steel with superfine heterogeneous structure

Examples

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Embodiment 1

[0017] The material used is ordinary eutectoid steel with a carbon content of 0.80%, and the content of other alloy elements is within the usual range of ordinary carbon steel. Its A 1 The temperature was 724°C. The deformation process is shown in Figure 1: the sample is heated to A 1 850°C (T1) within the range of 50°C to 300°C above, heat for 10 minutes (t1) and then water quench to obtain martensite, and heat the obtained martensite at a heating rate (R) of 30°C / s with an induction heating device 0.1s immediately after reaching 650°C (T2) in the range of 600-650°C -1The strain rate is deformed, and the deformation adopts unidirectional compression deformation. After deformation, it is cooled to room temperature at a cooling rate (C) of 100°C / s in the range of 2-200°C / s. The deformed structure when the strain amount reaches 0.69 is shown in Figure 2. The deformed structure basically has the characteristics of the aforementioned ultra-fine multi-phase structure: the averag...

Embodiment 2

[0019] The material used is the same as in Example 1, and the strain rate in Example 1 is increased to 1s -1 , when the strain amount is 1.60, the deformation structure is shown in Fig. 5. The deformed structure has the characteristics of the above-mentioned ultrafine multi-phase structure with a bimodal distribution of cementite particle size: the average grain size of ferrite surrounded by high-angle grain boundaries is 0.58±0.13μm, distributed in the ferrite grain boundaries The average size of the submicron cementite particles on the surface is 162±71nm, and the average size of the nanoscale cementite particles inside the ferrite grains is 43±19nm.

Embodiment 3

[0021] The material used is ordinary medium-carbon steel with a carbon content of 0.48%, and the content of other alloy elements is within the usual range of ordinary carbon steel. Its A 3 The temperature is 760°C. The deformation process is shown in Figure 1: the sample is heated to A 3 950°C (T1) in the range of 50-300°C above, keep warm for 5 minutes (t1) and then water quench to obtain martensite, and use an induction heating device to heat the obtained martensite at a heating rate (R) of 20°C / s 0.01s immediately after reaching 600°C (T2) in the range of 600-650°C -1 The strain rate is deformed, the deformation adopts unidirectional compression, and after deformation, it is cooled to room temperature at a cooling rate (C) of 50°C / s in the range of 2-200°C / s. The deformed structure when the strain value is 1.60 is shown in Figure 6. The deformed structure has the characteristics of the aforementioned ultra-fine complex phase structure: the average grain size of ferrite s...

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Abstract

The present invention is process of martensite heat deformation preparing carbon steel with superfine heterogeneous structure. The process includes controlling the carbon content in carbon steel, austenitic state before quenching and heat deformation parameters, heating the martensite structure in heating speed of 20-100 deg.c/s to 600-650 deg.c, deforming immediately after heat soaking in the strain rate of 0.01-10/s and strain amount of 0.6-2.0, and cooling in the cooling speed of 2-200 deg.c/s to room temperature, so as to prepare superfine heterogeneous structure comprising superfine crystalline ferrite matrix and cementite grains. The present invention has simple technological process, low power consumption and low cost.

Description

technical field [0001] The present invention relates to a method for preparing ultra-fine multi-phase structure materials, in particular to a method for preparing ultra-fine multi-phase structure carbon steel (with a carbon content between 0.35-0.8%, mass fraction) by using Martensitic temperature deformation . Background technique [0002] Refining the structure is an effective means to improve the strength and maintain plasticity of steel materials, but when the grain size is reduced below submicron, on the one hand, the strength of the material increases significantly, on the other hand, the strength-to-yield ratio also decreases rapidly, and the plasticity (especially Is the most important ductility index - uniform elongation at room temperature) decreased. Reasonable phase control has been proven to effectively increase the strength-to-yield ratio and improve the level of toughening. The research shows that the microstructure is an ultrafine microstructure in which su...

Claims

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Application Information

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IPC IPC(8): C21D8/00C21D1/18C21D1/56C21D1/42
CPCY02P10/25
Inventor 孙祖庆李龙飞杨王玥谭洪锋
Owner UNIV OF SCI & TECH BEIJING
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