Laser surface alloying with carbon on 15-5PH steel for improved wear resistance

ABSTRACT

Supersaturated carbon alloying layer was prepared on the surface of 15-5PH stainless steel using laser surface alloying technology with carbon powders as alloying materials. XRD, optical microscope, scanning electron microscope, microhardness test and wear test were performed to characterize the microstructure and wear resistance of substrate and alloying layer. Results showed that the alloying layer was rapidly solidified dendritic structure with phase compositions of high-carbon austenite and a small amount of martensite and M₇C₃ carbides. Microhardness of the alloying layer reached about 510 HV, which was 38.7% higher than that of the as-deposited substrate (375 HV). Carbon supersaturated solid solution strengthening and microstructure refinement strengthening were the main reasons for a substantial increase in alloying layer microhardness. After direct aging treatment, microhardness of the alloying layer further increased to nearly 640 HV. Wear test results showed that the mass loss of the aging alloying layer was about 60% lower than that of the aging substrate, which meant significantly improvement of wear resistance.

KEYWORDS:

• Laser surface alloying
• 15-5PH steel
• microstructure
• microhardness
• wear resistance

Acknowledgements

This work was supported by National Key R&D Program of China (grant number 2018YFB2002000 and 2018YFB1105800), CHINA RAILWAY R&D Program (grant number 2017G003-C) and National Science and Technology Major Project (grant number 2017-VII−0003-0096).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Key R&D Program of China: [grant number 2018YFB2002000 and 2018YFB1105800]; National Science and Technology Major Project: [grant number 2017-VII-0003-0096]; CHINA RAILWAY R&D Program: [grant number 2017G003-C].