Investigation of mechanical and thermal properties of laser spot welding as a replacement to resistance spot welding in automotive assembly applications

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Thesis Type: Postgraduate

Institution Of The Thesis: Bursa Uludağ University, Turkey

Approval Date: 2019

Thesis Language: Turkish

Student: GÖKHAN TEKİN

Supervisor: Gökhan Sevilgen

Open Archive Collection: AVESIS Open Access Collection

Abstract:

In this study; the variables and important parameters of the laser spot source, which is an alternative to the electrical resistance source, were investigated, the mechanical and thermal effects were investigated and the virtual and physical verification criterias were emphasized according to the OEM’s specifications. It has been clearly observed after the researches and trials that the laser spot source will serve the targets of vehicle lightening and energy consumption reduction in the transportation sector, and then it will create significant advantages in other sectors with the spread of the process. There is an average of 4000 spot welds on a passenger vehicle, and about 70% of mechanical failures are around the joint areas. Therefore, the spot-welding process, the most commonly used method in automotive, is the main factor affecting the mechanical strength of the vehicle. In addition to the disadvantage of the present speed of the spot-welding process compared to the laser spot welding in terms of operation efficiency, there are many attempts at commissioning and serious cost of material consumption and scrap costs. In order to investigate the advantages and disadvantages of laser spot welding, products which are frequently used in the automotive sector and which have a significant number of electrical resistance sources have been examined and researches have been carried out on how to increase the process efficiency data obtained from these sectors. Experimental studies have progressed as an optimum parameter setting study on sample materials. During the applications, critical parameters were changed to obtain the most efficient solutions. Combined materials; hardness, tensile and optical experiments were applied metallographically. The effects of these materials on the mechanical and microstructure properties of different laser welding parameters were investigated and compared to determine these properties.