Spot welding

About: Spot welding is a research topic. Over the lifetime, 12491 publications have been published within this topic receiving 89845 citations. The topic is also known as: Spot_welding.

Method for welding thin layer iron nickel base alloy carbon steel composite tube

Abstract: The invention relates to a method for welding a carbon steel composite pipe of a thin iron-nickel-based alloy. The method comprises: processing a step on the end part of the composite pipe; adopting the surfacing of argon arc welding on the surface of the step and trimming the surfacing layer; processing a groove; adopting tungsten electrode argon arc welding to carry out three-point positioning of spot welding evenly around a welding seam, and adopting the tungsten electrode argon arc welding to carry out back welding on the root; and adopting manual electric arc welding to carry out fillingwelding and overlay welding on the upper part of a second layer of back welding. The chemical compositions of a welding material by weight percentage: 0.02 to 0.1 percent of C, 0.2 to 1.0 percent of Si, 1.0 to 2.2 percent of Mn, 20.0 to 31.5 percent of Cr, 40.0 to 60.0 percent of Ni, 8.0 to 14.5 percent of Mo, 0.5 to 2.5 percent of Cu, 0 to 5.0 percent of Co, 0.3 to 4.2 percent of Nb, and the balance being Fe. The welding seam has the characteristics of no sensitivity to offset, favorable corrosion resistance, high strength and favorable plastic toughness.

Method of ensuring the maintenance of constant quality of spot welds

Abstract: A method of improving the reproducibility of the welds in an electric spot welding machine comprises prior to the initiation of a welding operation passing a preheating current of lower magnitude than the welding current through the parts to be welded. When either the total electrical workpiece resistance of the parts to be welded has fallen below a given limit or when its rate of decrease is slower than a predetermined limit the changeover from preheating current to welding current is effected.

Quantifying the link between crack distribution and resistance spot weld strength reduction in liquid metal embrittlement susceptible steels

Abstract: Zinc-coated advanced high-strength steels (AHSS) used in the automotive industry are vulnerable to liquid metal embrittlement (LME) during welding. In this work, a “crack index” is used to link LME crack distributions in resistance spot welds to the weld performance. Other commonly used LME metrics, such as maximum crack length, are unable to predict an effect on weld performance. Because both crack size and location have been established as critical characteristics for loss in weld strength, both of these factors must be taken into account when characterizing LME severity. The crack lengths measured in LME-affected welds were observed to fit a lognormal distribution; therefore, the lognormal median is used as the parameter to account for crack size. Long cracks are more likely to adversely impact mechanical performance. Number of cracks can be used to account for the probability that a crack will be found in a critical location. These parameters are multiplied together and divided by the sheet thickness to produce the crack index. A large crack indicates that LME cracks in the weld are likely to impact the mechanical performance of the weld. A simpler version of the crack index may be calculated using the normal median.

Corrosion performance and mechanical properties of joined automotive materials

Abstract: The automotive industry envisions that an optimized vehicle in terms of performance and cost can be achieved only by using different materials at different vehicle locations in order to utilize the functionality of the different materials to a full extent. Currently, steel and aluminum are the most important construction materials for the mass production of automotive structure. However, other materials such as magnesium alloys and stainless steel are also used. The use of dissymmetric assemblies of materials in the automotive industry has also led to the development of joining technologies other than spot welding and arc welding such as clinching, adhesive bonding, laser welding, and MIG brazing. However, and despite the development of these new joining technologies, there are still important gaps of knowledge with regards to the corrosion performance of different joint populations using dissymmetric and symmetric materials. Materials commonly used in the automotive industry including steel and aluminum-based susbtrates were assembled with different combinations using various joining techniques in order to evaluate their corrosion performance as well their mechanical properties after cyclic accelerated corrosion tests. The results indicated a relationship between the corrosion inside the confined joint and the decrease of the mechanical properties of the assemblies.

Image-based electrode tip displacement in resistance spot welding

Abstract: The paper presents a new image processing-based algorithm for electrode tip displacement measurement. Its accuracy is evaluated by a comparison with a conventional optical sensor. The results show a clear advantage of the proposed image processing algorithm. A special program was written in order to analyze the algorithm. The electrode tips are detected by the program. It also determines the size of the reference areas on the electrode tips and tracks these areas during the welding process. Due to a multi-thread implementation of the algorithm the execution time was reduced significantly as compared to previously presented work. Consequently this approach is now applicable for control-related resistance spot welding purposes.