【作者】 申晓龙；

【导师】 陈根余；

【作者基本信息】 湖南大学 ， 机械制造及其自动化， 2006， 硕士

【摘要】 高强度镀锌钢具有良好的机械性能、耐蚀性能和抗冲撞性能,因而被广泛应用在汽车车身及安全件制造上。激光焊接的焊接速度快、生产效率高。基于大功率激光小孔效应基础上的深熔焊的焊缝深宽比大、被接焊材料不易氧化、焊缝窄、热影响区小,适用于焊接变形小的精确焊接。本文对高强钢(DOGAL 800DP)进行激光焊接的质量和缺陷进行研究。试验所用激光器为自行研制的PHC-1500折叠式准封离型CO2激光器;得到影响高强度镀锌钢激光焊接焊缝质量的影响因数和变化规律。论文工作首先在CO2激光焊接1.5mm厚高强钢板深熔焊接试验基础上,系统地研究了激光焊接参数(光束质量、激光功率、焊接速度、离焦量、光致等离子体浓度等)对高强钢材料焊接可行性的影响。利用正交法优化设计试验,并确定试验方案与研究方法,讨论了高强度镀锌钢材料的激光焊接质量的影响因素。其次在全面分析激光深熔焊接研究的基础上,采用理论分析高功率CO2激光焊接过程,研究了高强度镀锌钢连续激光焊接过程不稳定性的特征与产生机理,分析了影响高强钢激光焊接稳定性的原因,建立了高强度镀锌钢激光焊接稳定性的临界曲线。接着在理论分析指导试验研究的前提下,综合考虑焊接速度、离焦量、激光功率以及侧吹保护气体角度和流量等因素对高强度镀锌钢激光焊接焊缝拉伸强度、韧性的影响。最后根据组织决定性能这一道理,通过对激光焊接试样取样,进行了焊接接头SEM分析;焊缝金相组织和显微硬度;焊缝盐水腐蚀试验等多种焊缝质量的检测方法。同时分析了高强度镀锌钢焊缝质量与常见缺陷,确定了保证高强度镀锌钢激光焊接质量的措施。更多还原

【Abstract】 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.更多还原