Tough wear-resistant strengthened layer and preparation method thereof

A strengthening layer and strong toughness technology, which is applied in coating, metal material coating process, etc., can solve the problems of poor toughness of coating, complex process, and difficulty in industrialization implementation

Inactive Publication Date: 2021-07-16
OCEAN UNIV OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is equivalent to sequentially cladding laser cladding sheets containing different ceramic phases together. In fact, it is an artificially prepared coating whose performance changes along the gradient, which increases the wear of the peeling layer, and the coating has poor toughness. Moreover, the process is complex, and industrialization is difficult to implement, so it cannot be used on high-speed rail brake discs

Method used

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  • Tough wear-resistant strengthened layer and preparation method thereof
  • Tough wear-resistant strengthened layer and preparation method thereof
  • Tough wear-resistant strengthened layer and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Step 1: Powder preparation

[0030] Raw materials for laser cladding are divided into medium-entropy alloy powder and strengthening phase powder. The selected medium-entropy alloy Ni, Co, and Cr powders have a particle size of 45-75 μm, and the powder ratio is the molar ratio Ni:Co:Cr=1:1: 1. The particle size of WC powder in the strengthening phase is 35-45 μm, and the particle size of TiC, ZrC, NbC, VC, etc. is 10-20 μm. According to the mass ratio of the powder, the medium entropy alloy powder is 80%, the ceramic powder is 20%, and the WC powder accounts for 100% in the ceramic powder, and the rest TiC, ZrC, NbC, VC, etc. account for 0%.

[0031] Step 2: Substrate surface pretreatment

[0032] First, use a grinding wheel to grind the surface of 24CrNiMo steel to remove oil and oxides and increase the roughness. If it is not cleaned and used directly, it will affect the quality of cladding, then degrease with absolute ethanol and dry in the air. During the grinding ...

Embodiment 2

[0038] In addition to the powder preparation in step 1, the medium entropy alloy powder is 50%, the ceramic powder is 50%, and the WC powder accounts for 80% in the ceramic powder, and the remaining TiC accounts for 20%. The thickness of the laser cladding powder in step 3 is 10mm; Run the laser cladding equipment, the experimental parameters used are: laser power is 1500W, scanning speed is 7mm / s, and the average surface hardness of the sample after treatment in step 4 hardness and friction and wear test can reach 900HV 0.1 , the friction and wear test was carried out on the sample, and the wear volume loss was 0.3×10 8 μm 3 , coating abrasion resistance is more than 3 times of substrate, and all the other are identical with embodiment one.

Embodiment 3

[0040] Except step 1 powder preparation, medium entropy alloy powder is 65%, ceramic powder is 35%, and WC powder accounts for 90% in ceramic powder, and all the other VC accounts for 10%, other is the same as embodiment two. Carry out hardness and friction and wear tests on the sample, and the average surface hardness of the sample after treatment can reach 1100HV 0.1 , the wear volume loss is 0.2×10 8 μm 3 , The wear resistance of the coating is 5 times that of the substrate.

[0041] figure 2 It is a phase composition diagram of the cladding layer of the present invention, which shows the phase composition of the cladding layer with the addition of WC powder in the system being 25wt%. It can be seen from the figure that under suitable laser process parameters, the WC particles Partially dissolves, decomposes to different degrees, and forms W with hardness between WC and FCC matrix 2 C.M 23 C 6 , M 7 C 3 , M 6 C and other compounds. For the sake of comparison, the...

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Abstract

The invention discloses a tough wear-resistant strengthened layer and a preparation method thereof. According to raw materials of the tough wear-resistant strengthened layer, 50wt%-80wt% of Ni-Co-Cr medium-entropy alloy powder is added, 20wt%-50wt% of strengthening phase ceramic powder is added according to the proportion of the medium-entropy alloy powder, the Ni-Co-Cr medium-entropy alloy powder and the strengthening phase ceramic powder are mixed to obtain mixed powder, and a 24CrNiMo matrix is clad with a composite coating through laser cladding; and the ceramic powder at least comprises WC powder, WC ceramic particles of the powder can be decomposed to different degrees in the laser cladding process to form W2C, M23C6, M7C3 and M6C compounds with the hardness between the hardness of a WC matrix and the hardness of an FCC matrix, and the compounds cooperate with externally-added ceramic strengthening phases to form an echelon strengthening effect on the FCC matrix of the medium-entropy alloy Ni-Co-Cr. The problems of surface layer high-temperature wear and thermal fatigue failures brought by high-speed emergency braking of an existing high-speed rail brake disc are solved.

Description

technical field [0001] The invention relates to the technical field of metal material surface processing, especially for the strengthening of high-speed rail brake discs, axles, wheel rails, etc., which are repeatedly stretched and compressed during service, thermal fatigue occurs on the friction surface, cracks are generated, and the surface loss is serious. . It specifically relates to a method of using laser cladding surface strengthening technology to prepare medium-entropy alloy Ni-Co-Cr composite coatings with different contents of ceramic strengthening phases. The ceramic phase forms a "wear-resistant network" and forms a "gradient strengthening" for the medium-entropy alloy matrix. This method not only greatly improves the wear resistance of the surface of parts such as brake discs, but also improves the strength, toughness and thermal fatigue resistance. ,Extended service life. Background technique [0002] China's high-speed rail leads the new trend of high-speed...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C24/10C22C30/00C22C32/00
CPCC22C30/00C22C32/0052C23C24/103
Inventor 崔洪芝毕勇马国梁宋晓杰满成崔中雨逄昆张宏伟
Owner OCEAN UNIV OF CHINA
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