ZAM薄板激光焊接性能研究与防锈补偿

Laser Welding Performance of ZAM Sheet and Anti-rust Compensation

针对免处理涂镀锌基系板材在钣金应用中焊接接头性能差、烧蚀发黑、焊缝及切口易生锈问题,研究了ZAM薄板的激光焊接性能,和焊接接头及切口的耐腐蚀补偿工艺。研究表明:采用激光自熔焊接1.2 mm ZAM薄板,预留0.1 mm对接间隙,并以10 L/min的流速充Ar防护,可获得较小的热影响区。焊接接头的正面焊缝成形轻微凹陷,反面熔合区烧蚀发黑,焊缝强度不低于母材强度。焊接接头正火区晶粒细化明显,熔合线的近焊缝区有贝氏体,远离熔合线的焊缝组织中有块状铁素体、片状珠光体及魏氏组织。焊接接头硬化明显,与母材相比,焊缝处硬度增大30%以上。同时发现,焊接接头及冲裁切口处失去涂镀层保护,仍具有一定的耐腐蚀能力。对焊接接头处冷镀锌处理,对切口处浸涂防锈油处理,其耐盐雾能力显著提升。最后展望了激光焊接免处理涂镀锌基系薄板在钣金制品中的应用前景。

Aiming at the problems of poor performance of welded joint, ablation blackening, easy rusting of weld and notches in sheet metal application of non-treatment galvanized base plate, the laser welding performance of ZAM sheet and the corrosion-resistant compensation technology of welded joint and notch were studied. The results show that 1.2 mm thick ZAM sheet is welded by laser self-melting with 0.1 mm butt gap and Ar protection of 10 L/min flow rate, smaller heat-affected zone can be obtained. The front weld of welded joint is slightly dented, the reverse weld is ablated and blackened, and the strength of the weld is not lower than that of base metal. The grain refinement is obvious in the normalizing zone of welded joint, and bainite is found in the weld zone near weld line. There are massive ferrite, flake pearlite and Widmanstatten structure in the weld far from the fusion line. The welded joint hardens obviously, and the hardness of the weld zone is more than 30% higher than that of the base metal. At the same time, it is found that the welded joint and punching notches lost coating protection, but they still have certain corrosion resistance. Cold galvanizing treatment for the welded joint and soaking anti-rust oil treatment for the notches improve their salt spray resistance significantly. Finally, the application prospects of laser welding non-treatment galvanized sheet metal in sheet metal products were prospected.