Process for making double peak grain size distributed superfine grain structure from hyposteel

A technology of grain size and hypoeutectoid steel, which is applied in the field of engineering steel structure control technology, can solve the problem of obtaining ultra-fine grain and nanocrystalline structure with bimodal grain size distribution, and achieve high ductility

Inactive Publication Date: 2005-06-29
YANSHAN UNIV
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Problems solved by technology

So far, there is no report on the process of obtaining ultra-fine grain and nano-grain structure with bimodal grain size distribution in engineering steel

Method used

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Examples

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Embodiment

[0009] Example: A 20CrMnTi steel cylindrical sample with a size of φ12×16mm was subjected to 80% compression deformation at 770°C with a Gleeble-3500 thermomechanical simulation test machine, quenched immediately, and then subjected to 40% room temperature compression deformation on a hydraulic press, and then Anneal at 550°C for 30min. After treatment, observe the microstructure with a transmission electron microscope, measure and count the grain size distribution, and obtain a bimodal grain size distribution structure, in which the volume fraction of grains below 200-50nm accounts for 50%, and the volume fraction of grains below 1-2μm accounted for 30%, and the volume fraction of grains in other size ranges accounted for 20%.

[0010] In this way, 20CrMnTi steel is subjected to 770°C compression 80% deformation quenching + 40% room temperature compression deformation + 550°C × 30min recrystallization treatment, and a double peak mainly composed of grains with a diameter of 5...

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Abstract

The invention discloses a process method for obtaining a bimodal grain size distribution ultra-fine grain structure of hypoeutectoid steel. The method obtains an ultra-fine grain structure through a control process method. The ultra-fine grain structure is characterized by: The distribution of medium grain size has bimodal characteristics, that is, there are relatively large grains with a fractional size of 1-3 μm in the ultra-fine grain matrix with a diameter of 0.4 μm or less; the composition characteristics of this type of engineering steel are containing Hypoeutectoid steel with carbon mass fraction less than 0.4%. The invention can be combined with the controlled warm rolling technology to economically produce ultra-fine grain steel plates and strips with high ductility.

Description

technical field [0001] The invention relates to the technical field of structure control technology of a class of engineering steel. technical background [0002] Due to the low work-hardening ability of ultrafine-grained or nano-crystalline materials, the uniform elongation and total elongation at room temperature are much lower than those of coarse-grained materials. Wang Shenggang et al. (Hardware Science and Technology, 2003, (12): 36) had only 6% elongation of the nano industrial pure iron plate prepared by deep rolling+400°C annealing. Y.T.Zhu (J.Mater.Res., 2003, 18: 1908) in the study of nanostructured Ti and H.Jin (Scripta Materialia, 2004, 50: 1319) in the study of ultrafine-grained Al-Mg alloys reported that they are prone to plastic instability. This greatly limits the processing and practical application of ultrafine or nanocrystalline materials as structural materials. Therefore, it is an urgent problem to explore a method of bulk ultrafine / nanocrystalline s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/78
Inventor 王天生
Owner YANSHAN UNIV
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