| LI Yong,MIAO Xingxu,ZHANG Chengjia,JIANG Heming,WANG Kun,WANG Xiaojin.Effect of Laser Surface Melting Treatment on Microstructure and Properties of P20 Die Steel[J],53(9):209-215 |
| Effect of Laser Surface Melting Treatment on Microstructure and Properties of P20 Die Steel |
| Received:April 18, 2023 Revised:October 14, 2023 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.09.020 |
| KeyWord:P20 die steel laser surface melting melted layer microhardness microstructure friction and wear |
| Author | Institution |
| LI Yong |
National Collaborative Innovation Center of Laser Manufacturing and Materials Technology, Zhejiang Industry & Trade Vocational College, Zhejiang Wenzhou , China |
| MIAO Xingxu |
National Collaborative Innovation Center of Laser Manufacturing and Materials Technology, Zhejiang Industry & Trade Vocational College, Zhejiang Wenzhou , China |
| ZHANG Chengjia |
National Collaborative Innovation Center of Laser Manufacturing and Materials Technology, Zhejiang Industry & Trade Vocational College, Zhejiang Wenzhou , China |
| JIANG Heming |
National Collaborative Innovation Center of Laser Manufacturing and Materials Technology, Zhejiang Industry & Trade Vocational College, Zhejiang Wenzhou , China |
| WANG Kun |
National Collaborative Innovation Center of Laser Manufacturing and Materials Technology, Zhejiang Industry & Trade Vocational College, Zhejiang Wenzhou , China |
| WANG Xiaojin |
National Collaborative Innovation Center of Laser Manufacturing and Materials Technology, Zhejiang Industry & Trade Vocational College, Zhejiang Wenzhou , China |
|
| Hits: |
| Download times: |
| Abstract: |
| The work aims toimprove the surface hardness and wear resistance of P20 die steel. The surface of P20 die steel was strengthened by laser surface melting technology. The hardness distribution characteristics and wear resistance of the laser surface melted layer were evaluated by the hardness gradient test and friction and wear test. In addition, the morphology of the laser surface melted layer and wear marks were analyzed by optical microscope and scanning electron microscope. With the laser output power of 500 W, the spot diameter of 2.5 mm, the focusing lens distance of 40 mm, the scanning speed of 6 mm/s and the lap rate of 45%, the microstructure of the laser surface melted layer obtained by nitrogen protection laser surface melting process was fine, without decarbonization, distortion, crack and other defects, and the laser surface melted treatment quality was high. According to the microstructure and hardness distribution characteristics of the melted layer, from the surface layer to the matrix, the laser surface melted layer could be divided into laser melted zone, heat affected zone, overlapping affected zone and non-affected zone which was named the matrix zone. In the process of laser surface melting, the single-channel laser surface melted layer presented a semi-elliptical distribution, and the maximum depth was about 610-620 μm. After laser surface melting treatment, the surface hardness increased significantly. The hardness distribution of the laser surface melted layer was related to the location of the layer. The depth of the laser surface melted layer with high hardness and stable hardness was about 400 μm. Beyond this depth, the hardness of the melted layer tended to decrease. The maximum hardness of the single laser surface melted layer could reach 460-480HV, and the maximum hardness of the overlapping affected zone, namely the double melting zone, was between 540-560HV, namely that the hardness of laser surface melted layer was generally more than 60% higher than that of matrix. The hardness of the double melted zone was about 17% higher than that of the single laser melted layer, which indicated that the surface hardness of the laser melted layer could be improved by moderately increasing the bonding rate. The wear weight loss data showed that the wear mass loss of P20 die steel treated by laser melting was about 1.03 mg, while that of P20 die steel without laser melting was about 2.63 mg. The wear weight loss of P20 die steel after laser melting treatment was reduced by about 61% compared with that of untreated samples. The friction and wear test also showed that the average friction coefficient of laser melted P20 die steel was about 0.85. The wear mechanism was mainly characterized by abrasive wear and a small amount of adhesive wear or peeling off. Laser melting treatment can significantly improve the surface hardness and wear resistance of P20 die steel. The laser melting process used in the test can obtain high hardness and stable and reliable melted layer depth of about 400 μm on the surface of P20 die steel, which can increase the surface hardness and wear resistance of P20 die steel by more than 60%. |
| Close |
|
|
|