Multi-response assessment for carbon emission and hardening effect in laser surface quenching

Laser surface quenching (LSQ) is gaining popularity in engineering applications, but it generates non-negligible carbon emissions. However, existing research mostly focuses on quenching performance. Little attention has been paid to carbon emissions of LSQ process. In this study, we build an experimental platform including fiber laser system (IPG YLR-4 kW) and carbon emission measurement system for a synergistic study of environmental impacts and processing quality in LSQ. Based on the L 16 (4 3 ) Taguchi matrix, LSQ experiments are conducted on the shield disc cutter. The influences of laser power, scanning speed, and defocusing distance on carbon emissions and hardening effects are studied. The carbon emission efficiency of LSQ is analyzed and compared with the competitive technology. The geometry and the maximum average hardness ( MAH ) of LSQ high-hardness zone (HHZ) are studied. A comprehensive evaluation considering carbon emissions and hardening effects is conducted. The results show that the maximum value of carbon emission is 1.4 times the minimum value. The maximum depth and width of HHZ are respectively 0.507 and 3.254 mm. The maximum MAH is 3.5 times the hardness of base metal. Compared to the average experimental responses, the experiment with the highest comprehensive score respectively increases by 26.4%, 17.1%, and 30.3% in depth, width, and MAH of HHZ, and reduces by 5.8% in carbon emissions.