| CHEN Xiang,ZHANG De-qiang,SUN Wen-qiang,WANG Yi-chen,ZHANG Ji-qing.Microstructure and Red Hardness of WC/Co Coating on M2 High-speed Steel Cutter Surface Prepared by Laser Cladding[J],48(11):236-243 |
| Microstructure and Red Hardness of WC/Co Coating on M2 High-speed Steel Cutter Surface Prepared by Laser Cladding |
| Received:February 02, 2019 Revised:November 20, 2019 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2019.11.025 |
| KeyWord:laser cladding M2 high-speed steel WC/Co powders red hardness microstructure microhardness |
| Author | Institution |
| CHEN Xiang |
1. a. Engineering Training Center, Liaoning University of Technology, Jinzhou , China |
| ZHANG De-qiang |
1. b. School of Mechanical Engineering and Automation, Liaoning University of Technology, Jinzhou , China |
| SUN Wen-qiang |
1. a. Engineering Training Center, Liaoning University of Technology, Jinzhou , China |
| WANG Yi-chen |
2.Wonder Auto Group Limited, Jinzhou , China |
| ZHANG Ji-qing |
3.Shandong Steel Rizhao Fine Steel Base, Rizhao , China |
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| Abstract: |
| The work aims to study the change rules of microstructure and cutting properties and the strengthening mechanism of WC/Co coating on the surface of M2 (W6Mo5Cr4V2) high-speed steel cutter by laser strengthening technique. A series of single-pass cladding layers were fabricated on the surface of common M2 HSS cutter by IPG fiber laser system. The microhardness, macro-morphology, microstructure, phase composition and red hardness of the cladding layer were analyzed by the microhardness tester, scanning electron microscope (SEM), energy disperse spectrometer (EDS) and X-ray diffraction (XRD). When the laser power was 1.1 kW, the powder feeding voltage was 14 V and the scanning speed was 3 mm/s, a few pores appeared at the cross section of the cladding layer and the cracks appeared at the left and right boundaries. The main phases were Fe3W3C, WC, W2Cb and M6C hard phases and interstitial carbides. The upper structure was finer and mainly composed of the tungsten carbide and the tungsten-cobalt compound. The middle and lower tissues were distributed in the cladding layer in the form of dispersion and the main structures were Fe3W3C and tungsten carbide. The microhardness of the cladding layer was obviously higher than that of the substrate, and the highest microhardness reached 1411HV, which appeared in the sub-surface area of about 0.4mm from the apex of the cladding layer. The red hardness of the cladding layer reached more than 60HRC at 600 ℃, and it reached more than 50HRC at 1000 ℃. When the temperature increased from 600 ℃ to 1000 ℃, the grain boundary strengthening of the cladding layer decreased gradually after red hardness, and the preferred orientation strengthening was obvious. Cladding WC/Co coating on the surface of M2 HSS can effectively improve the microhardness and red hardness of the cutter material. The maximum microhardness of cladding layer can be increased by 1.64 times as much as that of the cutter substrate, the red hardness is much higher than that of the HSS substrate at 600 ℃ and the red hardness is close to the requirement of cemented carbide at 1000 ℃, which is 2.94 times higher than that of the substrate. The carbide hard phase and gap carbides play major roles in improving the microhardness and red hardness of the cladding layer. |
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