The Research Of Laser Cladding Technology On The 20CrMnTi Gears For Crack Control

It has been researched in this paper that laser cladding is applied to the repairing of 20 CrMnTi gear by optimize parameters.Here is the research design of this paper: make the single track cladding layer on 20 CrMnTi board to obtain the optimized parameter combination and technology,the repair the 20 CrMnTi gear by laser cladding.The experimental study shows that choosing appropriate beam size,beam position,scanning technology,and technological parameter was the key to get smooth,non-cracking,non-caving,non-collapsing coating on gear tooth.Obtained relative excellent width,height and hardness of cladding layer,and investigated the technological parameter's effect on the cladding layer through the analysis of variance(ANOVA).In the situation of same thickness of powder the results show that the laser power has the largest impact on the width of cladding layer and the off-focus amount has the largest influence on the height and hardness,while the power has the most influence on cracking rate.The optimal technological parameter of results show the laser power is 3.0 KW,the scanning speed is 3mm/s,and the off-focus amount is 25 mm.Comparing the way of synchronous delivering powder and the way of presented powder by making overlap joint cladding layer on 20 CrMnTi steel surface to research the influence of overlap rate on crack.Found the method to how to choose the overlap rate after confirmed the width of coating and the diameter of laser beam.The results show that way of synchronous delivering powder is better for major coating,and the overlap joint cladding layer which chose 40% of overlap rate is more sooth than others.Designing the best cladding process when repairing the tooth space of helical gear,the gear should rotate an angle as same as helical angle of the gear,and keep the laser beam irradiate the tooth space perpendicularly,then make the scanning trace overlap with the midcourt line of tooth space.When repairing the tooth surface of helical gear,the laser beam shouldn't irradiate adjacent tooth,and reduce the slant angle of tooth surface to make incident angle as same as possible and to obtain cladding layer with similar size and quality.The optimal technological parameter of results show the best parameter combination of gear slots cladding is laser power 1200 W,scanning speed 3.5mm/s,the off-focus amount 25 mm,and the thickness of powder is 1mm.Then the best parameter combination of gear surface cladding is laser power 1000 W,scanning speed 5mm/s,the off-focus amount 30 mm,and the thickness of powder is 1mm.