Resistance Spot Welding System

A technology of resistance spot welding and welding parts, which is applied in the direction of resistance welding equipment, welding equipment, welding power supply, etc., can solve the problems of a lot of time and cost, and the deviation of electrode wear development state, and achieve the effect of stabilizing the nugget diameter

CN105073326BActive Publication Date: 2018-01-30JFE STEEL CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-01-30

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Abstract

A resistance spot welding system, which is provided with: a mechanism that calculates and stores the time change of the instantaneous heat value. The time change of the instantaneous heat value is based on the constant current control to energize and form a suitable nugget during trial welding. Calculated from the electrical characteristics between the electrodes during welding; based on the time change of the instantaneous heat value stored above and the input from the outside after the trial welding, the energization method is divided into multiple steps, and the values ​​of each step are A mechanism that stores the time change of the instantaneous heat value and the accumulated heat value as a target value; an adaptive control mechanism that starts welding based on the time change curve of the instantaneous heat value stored as a target value during main welding and adjusts during welding The welding current or voltage is used to generate instantaneous heat and accumulated heat. When the time variation of the instantaneous heat deviates from the target time variation curve in any step, the adaptive control mechanism adjusts the difference during the remaining power-on time of the step. Compensate so that it is consistent with the target accumulated heat value for this step. It effectively copes with the wear of the electrode front end and the existence of external interference, and obtains a good nugget.
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Description

technical field

[0001] The present invention relates to a resistance spot welding system in which energization is carried out in two or more stages, and in particular to a resistance spot welding system capable of forming a suitable nugget by applying adaptive control welding in each step. Background technique

[0002] In joining overlapping steel plates, resistance spot welding, which is a type of overlap resistance welding, is generally used.

[0003] This welding method is a method of sandwiching two or more overlapping steel plates, applying pressure from above and below with a pair of electrodes, and passing a high-current welding current between the upper and lower electrodes in a short period of time to join. This method utilizes resistance heating generated by the flow of high-current welding current to obtain spot-shaped welded parts. This point-shaped welded part is called a nugget, and is a portion where the two steel plates melt and solidify at the contact porti...

Examples

Embodiment 1

[0089] As the workpiece to be welded, mild steel (thickness: 1.6mm) was prepared. In addition, the welding current is carried out in two stages of energization.

[0090] Two pieces of the workpiece to be welded are superimposed, and welding is carried out under constant current control in a state where there is no diversion to the gap or the welded point, and the welding conditions for obtaining an appropriate nugget diameter are obtained. Use an inverter DC resistance spot welder for the welding machine, and use a chrome-copper electrode with a DR-shaped front end diameter of 6mm for the electrode. In addition, regarding the welding conditions, the applied pressure is constant at 3.43kN (350kgf), the energization time is constant at 16cyc (50Hz (afterwards, the unit of time is the number of cycles of 50Hz)), and the welding current is changed in various ways to obtain the obtained melting point. Core diameter: (t: plate thickness) current value. In this example, a suitabl...