YAG激光毛化技术进展

二十世纪八十年代,当比利时冶金研究中心(CRM)开发出CO_2激光毛化冷轧辊技术后,尝试用YAG激光进行轧辊毛化一直吸引着众多的研究者,这是因为YAG(1.06μm)激光波长比CO_2(10.6μm)激光波长短一个量级,材料

Development of YAG Laser Texturing Technology

Calculations showed that 5 mJ energy was enough to vaporate materials in a pit of 100μm diameter and 10μm depth. When a laser pulse with duration 600ns and energy 10mJ shoot on the surface of metal, the power density is 108 W/cm2 if it was focused on a region of 100μm diameter. This energy was well enough to evaporate iron within 6. 37ns, while plasma plumb was produced. So it was clear that most of laser energy was absorbed by plasma. It was found that major loss of laser energy was inverse bremsstrahlung absorption by plasma. To lower the e-lectron density of plasma, an unique technique was developed to modified laser waveform. When high repetition frequency pulse laser beam radiated on the roller surface, a number of micro-pits were formed, in which metal was melt and solidified. We say the roller was textured. Experiments showed that the tensile strength σb of laser-textured steel sheet increased 4 - 7% than that of shoot-peening steel sheet, and the yield strength σ0. 2 of laser-textured steel sheet decreased 6— 7 than that of shoot- peening steel sheet，the stretchability艿1O increased 6— 1O ．Another advantage of laser— texturing sheet was its good lubricity comparing with shot— peening steel sheet．