Pulse fiber laser welding of AISI 321-AISI 405 stainless steel thick plates butt joints

摘要

Pulse fiber laser welding was used to directly join AISI 321 to AISI 405 stainless steel thick plates in a butt joint configuration. The effect of pulse parameters and rear groove on the weld shaping, microstructure and mechanical properties of weld joints was investigated. Frequency was the most important affecting weld penetration, while waveform and rear groove had great influence on the porosity. Excellent joints were produced with the trapezoidal waveform, 400-600 Hz frequency and 30-50% duty cycle. Microstructures of weld consisted of a variety of complex martensite-austenite-ferrite mixed structure, and resulted in that microhardness was significantly greater than other zones of the weld joint. The average high-temperature tensile strength of the butt joint decreased by approximately 20% compared to that at room temperature, and the tension specimens ruptured at the AISI 405 HAZ near the fusion line.