A composite hard-surface material preparation method and a composite hard-surface material prepared thereby, the preparation method comprising: dispersedly fixing a plurality of cemented carbide sheets (2) to a surface of a metal substrate (1); and surfacing the cemented carbide sheets (2) and the metal substrate (1) with a solder (3) to obtain a composite hard-surface material, the solder (3) comprising nickel-based alloy powder, tungsten carbide particles and boron nitride powder. The solder (3) used in the preparation of the composite hard-surface material comprises nickel-based alloy powder, tungsten carbide particles and boron nitride powder, wherein the nickel-based alloy powder can increase fluidity and corrosion resistance, the tungsten carbide particle can improve hardness, and the boron nitride powder can effectively reduce friction coefficient. The present solder has good fluidity, high hardness and good solderability, using said solder, the obtained composite hard-surface material may enjoy good wear resistance.

A method for producing a resistance-welded member made of three or more sheets including a plated steel sheet includes: a main energizing by performing energization with a first current value while compressing the steel sheet with a first compressive force to form a nugget; a subsequent energizing by performing, after the main energizing, energization such that the current value gradually decreases from the first current value while compressing with a second compressive force greater than the first compressive force; and holding an electrode while maintaining the second compressive force after the subsequent energizing. The second compressive force and a total sheet thickness, compression rise delay time, and a downslope time and an electrode holding time satisfy respective predetermined conditions.

A method for producing a resistance-welded member made of three or more sheets including a plated steel sheet includes: a main energizing by performing energization with a first current value while compressing the steel sheet with a first compressive force to form a nugget; a subsequent energizing by performing, after the main energizing, energization such that the current value gradually decreases from the first current value while compressing with a second compressive force greater than the first compressive force; and holding an electrode while maintaining the second compressive force after the subsequent energizing. The second compressive force and a total sheet thickness, compression rise delay time, and a downslope time and an electrode holding time satisfy respective predetermined conditions.

A spot welding apparatus includes a stationary frame having a housing formed therein. An upper welding gun is mounted to a length direction of a pressing unit disposed in the housing of the stationary frame. A plurality of lower welding guns are mounted on an outside of the stationary frame and ends of the plurality of lower welding guns selectively face one end of the upper welding gun in a length direction of the lower welding guns by the plurality of lower welding guns. A plurality of actuators are mounted on the outside of the stationary frame. A plurality of link units are disposed between the actuators and the lower welding guns, connect the actuators and the lower welding guns, respectively, and rotate as the actuators are operated.

Described herein is a single-sided welding head including a first welding electrode and a second welding electrode, where the first and second welding electrodes are carried by a body of said welding head. The first welding electrode is movable relative to the body of said welding head at least along a first coordinate of motion. The second welding electrode is movable relative to the body of said welding head at least along a second coordinate of motion; where said first coordinate of motion is a coordinate of angular motion that develops about a first axis of rotation, and said second coordinate of motion is a coordinate of linear motion that develops along a first axis of translation.

Resistance spot rivet welding systems, subsystems, and methods of use thereof are provided.

An electronic device includes an inlet including a ground terminal having a first surface and a second surface opposite from the first surface, a first casing metal plate configured to hold the inlet and contacting the first surface of the ground terminal, and a second casing metal plate contacting the second surface of the ground terminal.

A method for producing a coated steel sheet having a tensile strength TS of at least 1100 MPa, a total elongation TE according to ISO standard 6892-1 of at least 12%, the product TS×TE of the tensile strength by the total elongation being at least 14200 MPa %, and a hole expansion ratio HER according to ISO standard 16630:2009 of at least 25%, the method including the following successive steps: providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15%≤C≤0.23%, 2.0%≤Mn≤2.7%, with C+Mn/10≥0.420%, 0≤Cr≤0.40%, with Mn+Cr≥2.25%, 0.2%≤Si≤1.6%, 0.02%≤Al≤1.2%, with 1.0%≤Si+Al≤2.2%, 0≤Nb≤0.035%≤Mo≤0.1%, the remainder being Fe and unavoidable impurities, annealing the steel sheet at an annealing temperature T.sub.A so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite, quenching the sheet from a temperature of at least 600° C. at a cooling rate comprised between 20° C./s and 50° C./s down to a quenching temperature QT between 200° C. and 270° C., heating the sheet up to a partitioning temperature PT comprised between 400° C. and 480° C. and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50 s and 250 s, hot-dip coating the sheet at a temperature less than 515° C., cooling the coated sheet down to the room temperature,
the steel sheet having a microstructure consisting of, in surface fraction: between 3% and 15% of retained austenite, at least 30% of tempered martensite, at most 5% of fresh martensite, at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, and between 5% and 35% of ferrite.

A method for producing a coated steel sheet having a tensile strength TS of at least 1100 MPa, a total elongation TE according to ISO standard 6892-1 of at least 12%, the product TS×TE of the tensile strength by the total elongation being at least 14200 MPa %, and a hole expansion ratio HER according to ISO standard 16630:2009 of at least 25%, the method including the following successive steps: providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15%≤C≤0.23%, 2.0%≤Mn≤2.7%, with C+Mn/10≥0.420%, 0≤Cr≤0.40%, with Mn+Cr≥2.25%, 0.2%≤Si≤1.6%, 0.02%≤Al≤1.2%, with 1.0%≤Si+Al≤2.2%, 0≤Nb≤0.035%≤Mo≤0.1%, the remainder being Fe and unavoidable impurities, annealing the steel sheet at an annealing temperature T.sub.A so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite, quenching the sheet from a temperature of at least 600° C. at a cooling rate comprised between 20° C./s and 50° C./s down to a quenching temperature QT between 200° C. and 270° C., heating the sheet up to a partitioning temperature PT comprised between 400° C. and 480° C. and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50 s and 250 s, hot-dip coating the sheet at a temperature less than 515° C., cooling the coated sheet down to the room temperature,
the steel sheet having a microstructure consisting of, in surface fraction: between 3% and 15% of retained austenite, at least 30% of tempered martensite, at most 5% of fresh martensite, at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, and between 5% and 35% of ferrite.

A spot welding electrode and a method of using the electrode to resistance spot weld a workpiece stack-up that includes an aluminum workpiece and an adjacent overlapping steel workpiece are disclosed. The spot welding electrode includes a weld face having a multistep conical geometry that includes a series of steps centered on a weld face axis. The series of steps comprises an innermost first step in the form of a central plateau and, additionally, one or more annular steps that surround the central plateau and cascade radially outwardly from the central plateau towards an outer perimeter of the weld face. The weld face has a conical cross-sectional profile in which a periphery of a top plateau surface of the central plateau and a periphery of a top annular step surface of each of the one or more annular steps are contained within a conical sectional area.