Analysis of Microstructure and Performance of Cr<sub>3</sub>C<sub>2</sub>/Ni60A Coating on 45 Steel for Laser Cladding Piston Rod
This study investigates the preparation of a high-performance Cr<sub>3</sub>C<sub>2</sub>/Ni60A coating on 45# steel through laser cladding technology. The microstructure, residual stress, phase composition, hardness, and wear resistance of the coating are analyzed. The resul...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Crystals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4352/15/1/93 |
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| Summary: | This study investigates the preparation of a high-performance Cr<sub>3</sub>C<sub>2</sub>/Ni60A coating on 45# steel through laser cladding technology. The microstructure, residual stress, phase composition, hardness, and wear resistance of the coating are analyzed. The results reveal that the solidification structure of the molten pool exhibits a progression from coarse columnar crystals and dendrites near the interface with the substrate to equiaxial crystals at the coating surface. The coating primarily consists of Fe-Ni solid solution, Cr<sub>7</sub>C<sub>3</sub>, and Cr<sub>23</sub>C<sub>6</sub> phases. As the Cr<sub>3</sub>C<sub>2</sub> mass percentage in the Cr<sub>3</sub>C<sub>2</sub>/Ni60A composite powder increases, the formation of the Cr<sub>7</sub>C<sub>3</sub> and Cr<sub>23</sub>C<sub>6</sub> phases is suppressed. A pronounced stress concentration occurs at the interface between the coating and the substrate, leading to an increased dislocation density and localized grain deformation. When the Cr<sub>3</sub>C<sub>2</sub> mass percentage reaches 45% and 55%, the coating surface exhibits a higher density of induced cracks due to the combined effects of microstructural changes and thermal influences. The maximum microhardness of the coating ranges from 520 HV<sub>1</sub> to 556 HV<sub>1</sub>, approximately three times that of the substrate. The wear resistance of the coating initially increases and then decreases with increasing Cr<sub>3</sub>C<sub>2</sub> content. The wear resistance is optimal at a 35% Cr<sub>3</sub>C<sub>2</sub> mass ratio, with a wear loss of 0.15 mg—five times lower than that of the substrate. The primary wear mechanism is abrasive wear, although localized fatigue and adhesive wear are also observed. |
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| ISSN: | 2073-4352 |