Further study of laser surface treatment of AISI 1055 steel

• Main Author: Tan, Yan Ming
• Other Authors: Zhou Wei
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/77702
• Institution: Nanyang Technological University

Laser treatment is a surface hardening process used to improve the surface hardness, wear resistance and increase the service life of engineering components. Most laser treatment using continuous wave laser. However, there are inadequate studies done on laser hardening using pulse wave laser. The objective of the research is to study the effects of operating parameters and the change in crystal structure after laser treatment using pulse wave laser on AISI 1055 steel. The laser hardened specimen received was sample preparation for analysis. Hardness test was done to the specimen to study the hardness profile. Optical images and scanning electron images were taken to study the change in the crystal structure. Hardened depth and width increase when a higher laser power output is used. While average hardness value decreases as laser power increases. Hardened depth and width do not deviate much with a change in scanning speed. Average hardness value increases as scanning speed decreases. In the crystal structure of high laser power treated area, martensite was found in most area. Bainite was also found in the middle section of the cross-section area. Multiple zones and defects such as surface melting, thermal cracks and voids were observed in high laser power treated area. In the crystal structure of low laser power treated area, micro-dimpling was found. Micro-dimpling has engineer application like self-lubrication properties. Further research can be done on micro-dimpling with laser hardening treatment.