| ZHANG Xin,LIU Yi,LOU Li-yan,LIU Kang-cheng,LI Cheng-xin,LI Chang-jiu.Microstructure and Properties of Stainless Steel Coatings by High Power Ultra-high Speed Linear Spot Laser Cladding[J],52(1):336-345 |
| Microstructure and Properties of Stainless Steel Coatings by High Power Ultra-high Speed Linear Spot Laser Cladding |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.01.034 |
| KeyWord:linear spot ultra high speed laser cladding overlapping ratio cladding efficiency |
| Author | Institution |
| ZHANG Xin |
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi' an , China |
| LIU Yi |
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi' an , China |
| LOU Li-yan |
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi' an , China |
| LIU Kang-cheng |
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi' an , China |
| LI Cheng-xin |
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi' an , China |
| LI Chang-jiu |
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi' an , China |
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| Abstract: |
| Ultra high speed linear spot laser cladding is of great potential to effectively deposit thin metal coatings at an ultra-high speed to be applied to different industrial fields. However, the quality of the cladding layer depends on the design of the linear spot laser cladding powder feeder head design and the optimization of processing parameters. The objective of this study is to design a powder feeding nozzle for ultra-high speed linear spot laser cladding, examine the cladding efficiency and overlapping rate of the ultra-high speed linear spot laser cladding, and the microstructure and properties of the cladded FeCr-based alloy coating in comparison with those by circular spot laser cladding. The simulation method based on the simulation of flow field and particle trajectory within the powder feeding nozzle is used for optimizing the design of a special powder feeding nozzle for ultra-high speed linear spot laser cladding. FeCr alloy thin coating was prepared by the ultra-high speed linear spot laser cladding using 1 mm×10 mm line spot on 27SiMn substrate at 10% overlapping rate and cladding efficiency of 4.5 m2/h. FeCr alloy coating was also prepared by the ultra-high speed circular spot laser cladding using 2 mm circular spot under the cladding efficiency of 0.2 m2/h for comparison. The microstructure of FeCr alloy coatings prepared by both linear spot and round spot laser cladding was analyzed by SEM and XRD. The microhardness of the coatings was also compared. Results show that uniform powder particle distribution and moderate particle flight velocity were obtained through the single channel powder feeding nozzle with a beam angle of 25°-27°. The comparative study shows that ultra-high speed linear spot and circular spot laser cladding coatings present dense microstructure without cracks and pores. The plane crystals followed by columnar crystals and equiaxed crystals are observed from the bottom of cladding layer towards the surface of cladding layer. The hardness of the coatings cladded by linear spot and circular spot laser claddings is 700-800HV. However, the hardness distribution in the linear spot laser cladded coating is more uniform. Moreover, the surface roughness of FeCr alloy coating by ultra-high speed line spot laser cladding can be as low as Ra< 4 μm. The overlapping rate can be as low as 10%, and the cladding efficiency of the linear spot laser cladding is much higher than that of circular spot laser cladding. In this study, it can reach 4.5 m2/h. As the conclusion the ultra-high speed linear spot laser cladding can prepare a dense thin coating with high surface finish. The microstructure, phase composition and hardness of the coating are similar to those by the circular spot laser cladding. However, the primary surface roughness of the ultra-high speed laser cladded coating is lower than that of spot laser cladding, and the cladding efficiency can reach 20 times that of the circular spot laser cladding. |
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