The Research On Laser Welding Quality Of High Strength Steel

High strength galvanized steel is widely used in vehicle body and safety part manufacture for well mechanical performance, erosive- resistant performance and impact-resistant performance.The deep-penetration laser welding based on high-power laser keyhole effect has characteristic of large depth-width ratio welding line, oxidation-resistant characteristic of material, narrow welding line and small area of welding heat influence for high speed and high efficiency. This subject has background of the laser welding project of Laser Institute of Hunan University; this article focus on the quality and limitation of laser welding of high strength galvanized steel recur to the self-develop laser of PHC-1500, and try to find the influence factor and variated rule of laser welding quality.First of all, This article systemic study on the influence of high strength galvanized steel feasibility caused by laser welding parameters (beam quality, laser power, speed, distance of away from focus, density of photo-plasma etc.) based on the deep-penetration laser welding experiment on high strength galvanized steel with a depth of 1.5mm. Discussing the quality influence factor of laser welding of high strength galvanized steel after optimized designing the experiment by the orthogonal test design, and confirming the experimental scheme and research method.Secondly, based on full analysis of deep-penetration laser welding, study on the unstable characteristic and mechanism of process that laser welding of high strength galvanized steel, analyze the reasons that influence the high strength steel welding stability, form the critical curve of stability about laser welding high strength galvanized steel.Then based on the precondition of experimental research under theoretic analysis, analyze the factors of velocity, distance of away from focus, power and angle and flux of protect gas that influence the extend strength and tenacity of laser welding high strength galvanized steel.Finally, according to form decide performance, after sampling laser welding, analyzing the energy spectrum of welding tie-in SEM; gold organizes and rigidity;brine corroding proof etc., analyzing the welding line quality and limitation of high strength galvanized steel, confirming measurements of laser welding quality of high strength galvanized steel.