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A method of preparing 24crnimo bainite alloy steel by laser selective melting technology

A technology of laser selective melting and alloy steel, which is applied in the field of materials, can solve the problems of complex heat treatment process, complex phase and phase transition, long production cycle, etc., and achieve a good matching relationship between strength and toughness, excellent mechanical properties, and fast cooling speed. Effect

Active Publication Date: 2019-07-30
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

24CrNiMo alloy steel is used to manufacture high-speed rail brake discs. Traditional manufacturing methods mainly use casting, forging, subsequent heat treatment, and finishing. There are problems such as long production cycle, high manufacturing cost, and complicated heat treatment process. At the same time, the core technology is monopolized by foreign countries. Formed related technology protection
[0004] In recent years, the research and application of laser selective melting technology on iron-based alloys include 316L and 304 stainless steel. After rapid forming, all or most of the structure is austenite, the tensile strength at room temperature is 500Mpa, and the elongation reaches 30%. , with a strong plasticity of 15GPa·%; and applied to 18Ni-300 martensitic precipitation hardening steel and H13 high-speed steel, most of the structure after rapid forming is composed of martensite. Although the tensile strength can reach 1200Mpa, the elongation is only About 6%, the strong plastic product is only 7.2Gpa·%. In addition, due to the large structural stress brought by the martensitic transformation, cracks and other defects are easy to occur during the selective laser melting process.
At the same time, there are few researches and applications on laser additive manufacturing of low-alloy high-strength structural steel, which is the most used in national economic construction. Complicated
In particular, there is no report on the laser selective melting process, microstructure and properties of 24CrNiMo alloy steel.

Method used

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  • A method of preparing 24crnimo bainite alloy steel by laser selective melting technology
  • A method of preparing 24crnimo bainite alloy steel by laser selective melting technology
  • A method of preparing 24crnimo bainite alloy steel by laser selective melting technology

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Effect test

Embodiment 1

[0052] The 24CrNiMo bainite alloy steel high-speed iron brake disc is prepared by laser selective melting technology. The laser selective melting equipment used in it includes semiconductor lasers, computer systems for forming control, powder spreading device forming cylinders and atmosphere protection devices. The details are as follows Steps to implement:

[0053] Step 1: Raw material powder preparation:

[0054] (1) 24CrNiMo alloy steel powder material, the powder contains the following elements in mass percent (Wt%) content: C: 0.27%, Cr: 0.97%, Ni: 0.98%, Mo: 0.50, Mn: 0.91%, Si: 0.52 %, O: 0.02%, the balance is Fe; the sum of the mass percentages of the above elements is 100%;

[0055] (2) Sieve the above-mentioned alloy steel powder, and the particle size distribution range is preferably 15-53 μm; before use, heat it at 80° C. for 5 hours in a vacuum drying oven, and perform drying treatment;

[0056] Step 2: Formulation of scanning path and laser process parameters ...

Embodiment 2

[0079] Utilize laser selective melting technology to prepare 24CrNiMo bainite alloy steel metal sample, preparation method is the same as embodiment 1, wherein difference is to change the powder pretreatment drying temperature and time in (2) of step 1, step 2 (1) The layer thickness of the three-dimensional model in layered discrete processing, the laser selective melting process parameters in (2), the thickness of the 24CrNiMo powder layer in (2) in step 3, and the volumetric energy density in (3) in step 3, specifically:

[0080] Drying temperature and time of powder pretreatment: before use, heat it in a vacuum drying oven at 100°C for 8 hours for drying treatment;

[0081] Layer thickness during layered discrete processing of the 3D model: construct the 3D model of the part to be formed, use the programming software that comes with the laser to perform layered discrete processing of the 3D data of the part to be formed, the thickness of each layer is uniform, and the thick...

Embodiment 3

[0099] Utilize laser selective melting technique to prepare 24CrNiMo bainite alloy steel metal sample, preparation method is the same as embodiment 1, wherein difference is to change the powder pretreatment drying temperature and time in (2) of step 1, step 2 (1) The layer thickness of the three-dimensional model in layered discrete processing, the laser selective melting process parameters in (2), the thickness of the 24CrNiMo powder layer in step 3 (2) and the volume energy density in step 3 (3), specifically:

[0100] Drying temperature and time of powder pretreatment: before use, heat it in a vacuum drying oven at 90°C for 7 hours for drying treatment;

[0101] Layer thickness during layered discrete processing of the 3D model: construct a 3D model of the part to be formed, use the programming software that comes with the laser to perform layered discrete processing of the 3D data of the part to be formed, the thickness of each layer is uniform, and the thickness is set to ...

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Abstract

The invention provides a method for preparing 24CrNiMo bainite alloy steel by laser selective melting technology. The method includes scanning the 24CrNiMo alloy steel powder spread on the substrate according to the preset laser selective melting scanning path until the powder is melted. A step of. In the present invention, by optimizing the process parameters and using the effects of alloy elements such as C, Cr, Ni, Mo, etc., the bainite alloy steel with uniform structure is obtained under the high cooling rate of laser selective melting, and the average microhardness of the obtained bainite structure is It reaches 330-346HV, the tensile strength is 962-978Mpa, the elongation is 16.4-17.6%, and the strong-plastic product reaches 16.1-16.9Gpa·%. The tissue has excellent strength and toughness matching. The method and process are mainly used for laser selective melting manufacturing of 24CrNiMo alloy steel high-speed rail brake discs.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a method for preparing high-strength and toughness 24CrNiMo bainite alloy steel by using laser selective melting technology. Background technique [0002] Cr-Ni-Mo series low-alloy high-strength steel has good strength, toughness and high heat resistance, and is currently commonly used steel for high-speed train brake discs. 24CrNiMo alloy steel is used to manufacture high-speed rail brake discs. The traditional manufacturing methods mainly use casting, forging and subsequent heat treatment, finishing and other manufacturing methods. There are problems such as long production cycle, high manufacturing cost, and complicated heat treatment process. At the same time, the core technology is monopolized by foreign countries. Related technology protection has been formed. [0003] Laser selective melting technology is a brand-new manufacturing technology integrating comp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/105B33Y10/00C22C38/44C22C38/02C22C38/04
CPCC22C38/02C22C38/04C22C38/44B33Y10/00C21D2211/002B22F10/00B22F12/30B22F10/34B22F10/28B22F10/36B22F10/366B22F10/32Y02P10/25
Inventor 陈岁元魏明炜刘常升郭快快梁京崔彤
Owner NORTHEASTERN UNIV LIAONING
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