A combined stackup apparatus with a perforated interlayer for resistance spot welding is provided. The apparatus comprises a first metal sheet of a first material and a second metal sheet of a second material. The apparatus further comprising a perforated interlayer disposed between the first metal layer and the second metal layer. The perforated interlayer is made of one of the first and second materials. The perforated interlayer has a plurality of perforations formed therethrough. Each perforation has a perforation size of between about 0.1 mm and about 3 mm.

Provided is a resistance spot welding method wherein main current passage includes two or more electrode force application steps including a first electrode force application step and a second electrode force application step following the first electrode force application step, an electrode force F.sub.1 in the first electrode force application step and an electrode force F.sub.2 in the second electrode force application step in the main current passage satisfy a relationship F.sub.1<F.sub.2, and an electrode force switching point T.sub.f from the first electrode force application step to the second electrode force application step in the main current passage is set to satisfy predetermined relational formulas.

Provided is a resistance spot welding method wherein main current passage includes two or more electrode force application steps including a first electrode force application step and a second electrode force application step following the first electrode force application step, an electrode force F.sub.1 in the first electrode force application step and an electrode force F.sub.2 in the second electrode force application step in the main current passage satisfy a relationship F.sub.1>F.sub.2, and an electrode force switching point T.sub.f from the first electrode force application step to the second electrode force application step in the main current passage is set to satisfy predetermined relational formulas.

An opposing electrode determination method includes a step of inserting a pair of opposing electrodes into corresponding receiving portions, respectively, by holding, between the pair of opposing electrodes, a held member formed with the receiving portions on both sides; a step of measuring the inter-electrode distance between the pair of opposing electrodes; and a step of determining, based on the inter-electrode distance, whether a combination of the pair of opposing electrodes is correct or incorrect. The receiving portions are configured to have different insertion allowances for the opposing electrodes, respectively, according to the tip shape of each of the pair of opposing electrodes.

A cap tip assembly for spot welding is disclosed. The cap tip assembly for spot welding is configured to spot-weld a first base material in which a flange is formed and a second base material overlapping the flange in a vertical direction. The cap tip assembly for spot welding includes a tip body provided in a shape of a rectangular block in which a round-shaped welding section is formed on a front side of a top surface, and a collet member coupled to the tip body to guide a conductive tape to the welding section.

The present invention relates to an electrode assembly, wherein a plurality of electrodes is stacked in the state in which a separator is interposed between the electrodes, electrode tabs protruding from the electrodes are coupled to an electrode lead in a state of forming an electrode tab bundle, the electrode lead includes a first electrode lead coupled to the electrode tabs and a second electrode lead coupled to the first electrode lead, and an electrode lead coupling portion configured to allow the first electrode lead and the second electrode lead coupled to be coupled to each other includes an adhesion portion and a spot welding portion.

The present invention relates to an electrode assembly, wherein a plurality of electrodes is stacked in the state in which a separator is interposed between the electrodes, electrode tabs protruding from the electrodes are coupled to an electrode lead in a state of forming an electrode tab bundle, the electrode lead includes a first electrode lead coupled to the electrode tabs and a second electrode lead coupled to the first electrode lead, and an electrode lead coupling portion configured to allow the first electrode lead and the second electrode lead coupled to be coupled to each other includes an adhesion portion and a spot welding portion.

A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%≤C≤0.22%, 3.5%≤Mn<4.2%, 0.001%≤Si≤1.5%, 0.020%≤Al≤0.9%, 0.001%≤Cr≤1%, 0.001%≤Mo≤0.3%, 0.001%≤Ti≤0.040%, 0.0003%≤B≤0.004%, 0.001%≤Nb≤0.060%, 0.001%≤N≤0.009%, 0.0005%≤S≤0.003%, 0.001%≤P≤0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10{circumflex over ( )}7/mm.sup.2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.

Art for spot welding able to suppress penetration of hydrogen, one of the factors behind delayed fracture, at the time of spot welding, that is, a spot welding method in which at one or both of the surfaces of the steel sheets becoming the facing surfaces of the overlaid steel sheets, a location where the steel sheets contact each other to form a contact part at the time of initial squeezing of the spot welding is worked in advance to form a plurality of lines running through the contact part and connected to the outside of the contact part and the spot welding is performed at the location of the contact part and also a steel sheet in which the plurality of lines are formed in advance at the location becoming a contact part when steel sheets contact each other at the time of initial squeezing in the spot welding.

Art for spot welding able to suppress penetration of hydrogen, one of the factors behind delayed fracture, at the time of spot welding, that is, a spot welding method in which at one or both of the surfaces of the steel sheets becoming the facing surfaces of the overlaid steel sheets, a location where the steel sheets contact each other to form a contact part at the time of initial squeezing of the spot welding is worked in advance to form a plurality of lines running through the contact part and connected to the outside of the contact part and the spot welding is performed at the location of the contact part and also a steel sheet in which the plurality of lines are formed in advance at the location becoming a contact part when steel sheets contact each other at the time of initial squeezing in the spot welding.