Laser surface treatment of 52100 steel

• Main Author: Lum, Andrew Kian Meng
• Other Authors: Zhou Wei
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74552
• Institution: Nanyang Technological University

Laser hardening is the surface heat treatment of steel to achieve better wear characteristics of the surface without compromising the toughness of the interior. In this project, AISI grade 52100 steel is laser hardened using a IPG Photonics YLR-150/1500-QCW fibre laser with varying overlap of the laser scans. The microstructure, topography, fracture and flexural strength of as-received and laser hardened 52100 steel are then examined using a series of microscopes, a surface profiler and a universal testing machine. Photomicrographs obtained showed as-received 52100 steel with spherical carbides embedded in a ferritic matrix. Laser treated 52100 steel exposed to atmospheric air and CO2 displays different surface characteristics. Analysis of the surface profile presented the laser treated specimen under atmospheric air with 0% overlap of laser tracks with the lowest mean surface roughness Sa value of 0.949μm while the specimen treated with CO2 protection with 50% overlap having the highest Sa value of 3.82μm. 3-point bending results are negligible and inconclusive as cracking does not occur at the overlapping areas, thus values obtained for fracture are similar.