Abstract: A high-strength steel laser welding filler, comprising the following components in percentages by weight: 0.05-0.5% of C, 0.1-2% of Cu, 0.2-2.5% of Cr, 0.5-3.5% of Mo, and 2-10% of Ni, with the balance being Fe and inevitable impurities. The filler is used for laser filler welding of hot-formed steel which has an aluminum-containing coating on the surface thereof, can effectively reduce the adverse effect of the aluminum-containing coating on the surface on the strength of a joint, and enables the strength and plasticity of the welded joint, after hot stamping, to reach 90% or more of those of a base material.

Abstract: An electric resistance welding method for a dissimilar metal joint used for welding a laminated structure, with an outer layer being composed of iron or iron-based alloy, and an inner layer being composed of a metal with a density of less than 5 g/cm3 or a melting point of lower than 800° C. The electric resistance welding method comprises an expulsion stage in which a light metal or low-melting-point metal in the middle of the laminated structure is separated in a splashing mode, so that a connecting structure is directly formed between iron or iron-based alloy layers in a welding interface to complete welding. According to the invention, the formation of brittle intermetallic compounds on the welding interface of the dissimilar joint can be avoided, thereby improving the mechanical properties of the joint and achieving reliable connection between dissimilar metals. The invention further provides a dissimilar metal joint.

Abstract: A resistance spot welding electrode cap contains a groove at the center of the welding contact interface. During welding, because of the groove, the area of contact between the electrode cap and a metal workpiece to be soldered is reduced. In the initial stage, the overall heat generation is concentrated on the outer ring of the weld point and heat dissipation becomes slower, helping a weld nugget to form from the outside to the inside. Due to the presence of the groove, the metal workpiece expands toward the groove at the center of the electrode, thereby increasing the size of the weld nugget and reducing splash and deformation. In comparison with conventional electrode caps, the welding current required to form weld points of the same size is lower, saving on electricity costs, and weld points obtained using the same current have higher strength and stability with fewer welding defects.

Abstract: A resistance spot welding electrode cap contains a groove at the center of the welding contact interface. During welding, because of the groove, the area of contact between the electrode cap and a metal workpiece to be soldered is reduced. In the initial stage, the overall heat generation is concentrated on the outer ring of the weld point and heat dissipation becomes slower, helping a weld nugget to form from the outside to the inside. Due to the presence of the groove, the metal workpiece expands toward the groove at the center of the electrode, thereby increasing the size of the weld nugget and reducing splash and deformation. In comparison with conventional electrode caps, the welding current required to form weld points of the same size is lower, saving on electricity costs, and weld points obtained using the same current have higher strength and stability with fewer welding defects.