Craft Study On CO₂ Laser Welding Of Zinc Coated High Strength Steel

With the appearance of high power laser bean, power density of it is improved expressly; the technology of deep penetration laser welding is applied widely in the industry. The keyhole effects are characteristics of deep penetration laser welding and the plasma of the high density always exists above work piece and in the keyhole, so that the interaction relation between plasma and laser energy is one of important studies of the laser and material interaction mechanism.Gived material, thickness, joint mode and diameter of focus facula, central pararameters influencing welding quality are laser power, focal position, protecting gas and welding speed. Based on theory and experimentation in paper, craft research of co₂ laser welding of zinc coated high strength steel to vehicle body is done.First of all, the laser machine and laser welding are introduced in the summarization in the research and apply of the domestic and overseas manufacture. Compared with other welding, characteristics of laser welding are concluded.the paper forecasts that the better apply of the laser machine and facing technology challenge are viewed in the 21th century. Laser welding of zinc coated high strength steel relate to the impact of plasma, grain growth of HAZ.non structural equation of welding joint. Softening HAZ of welding of zinc coated high strength steel and the gas hole. Cleaning function to melting zone of co₂ laser welding is expatiated. Development survey of mathematical model about laser welding is retrospected.In the next place, characteristics of laser welding are recommended and affecting factors of welding quality and development foreground of laser welding technology and facing challenge. The instability essence and characteristics of laser welding are introduced, the four phases of forming keyhole are analysed under the laser bean. based on the heat exchange laser welding and deep penetration laser welding, the paper deems that there is an other welding mode ------an unstable welding mode.The paper introduces the form of welding HAZ and organizing distributing and performance. Consulting the Steen W M's mathematical model of point thermal source and mathematical model of line thermal source, based on the principle of superposition. Temperature mathematical model of a point is got in the work piece and find the analytic untie. Adopting the thermocouple of homemade Pt-Rh10—Pt alloy, the paper has validated the model. Form of plasma and molding of welding and control. The...