Abstract
304 austenitic stainless steel with a thickness of 7.5 mm was welded by high-power fiber laser welding. The effects of main welding parameters, including laser power, welding speed, and defocusing amount, on weld formation were studied in detail. The welding parameters were optimized according to the weld formation. On this basis, the microstructure and mechanical properties of the welded joints were further analyzed. The results showed that depression and hump defects easily occurred once the joints were penetrated. The defects could be effectively avoided when two specific parameters were adopted: namely, high-power laser welding with high speed at the focal position or low speed at the far defocusing position; both could reduce the impact of metal vapor in the keyhole on the molten pool, and meet the requirements of penetration and stability to obtain well-formed welds. High-speed welding obtained nail-shaped weld, and Peanut-shaped weld was obtained by low-speed welding. The microstructure of the welds was mainly composed of massive austenite and a small amount of ferrite, indicating that the solidification abided by the F-A mode according to the pseudo-binary phase diagram. Due to the smaller grain size, the hardness of the Nail-shaped weld (238.8HV0.3) was higher than that of the Peanut-shaped weld (223.4HV0.3). The tensile strength of the Nail-shaped weld joint and Peanut-shaped weld joint were 677 MPa and 689 MPa, which reached more than 95% of the base metal.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.