Resistance spot welding method and manufacturing method of welded member

Abstract

A resistance spot welding method and a manufacturing method of a welded member, performing the main welding and the trial welding before the main welding, in the post-welding energization of the trial welding, the average value of the voltage between the electrodes of the main energization for the trial welding: Vtm and The average value Vtp of the voltage between electrodes energized after welding, when tc<800ms: satisfy the relationship of 0.5≤Vtp / Vtm≤2.0, and in the case of 800ms≤tc<1600ms: satisfy 0.5‑0.3×(tc‑ 800) / 800≤Vtp / Vtm≤2.0‑0.5×(tc‑800) / 800, in the case of tc≥1600ms: under the condition of satisfying the relationship of 0.2≤Vtp / Vtm≤1.5, through constant current control In the main energization of the above-mentioned formal welding, adaptive control welding is performed. In the post-welding energization of the above-mentioned formal welding, the current value of the post-welding energization of the above-mentioned trial welding is set as Itp, and the post-welding current value of the above-mentioned formal welding is When the current value of energization is Imp, energization by constant current control is performed under the condition that the relationship of 0.8×Itp≦Imp≦1.2×Itp is satisfied.

Description

technical field [0001] The present invention relates to a method of resistance spot welding. In particular, the object is to ensure the diameter of the nugget stably even under the condition of a plate group including a high-strength steel plate under the condition that the influence of disturbance such as a flow diversion and a plate gap is large, And can improve joint strength. Background technique [0002] Usually, the resistance spot welding method, which is one of lap resistance welding methods, is used to join the stacked steel plates. [0003] In this welding method, two or more overlapping steel plates are clamped and pressed from above and below with a pair of electrodes, and a high-current welding current is energized between the upper and lower electrodes for a short time to join. The resistance heat generated by the high-current welding current produces spot-like welded parts. This spot-shaped welded portion is called a nugget, and is a portion where both steel...

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Problems solved by technology

[0020] However, in the techniques described in Patent Documents 1 and 2, the appropriate welding conditions vary depending on the presence or absence and magnitude of disturbances.

For this reason, there is a problem that, when more than expected plate gaps and shunts occur, the desired nugget diameter cannot be ensured without occurrence of splash points.

[0021] In addition, the techniques described in Patent Documents 3 and 4 have the following problems: In order to estimate the temperature of the nugget based on a heat conduction model (heat conduction simulation), etc., complex calculation processing is required, which not only complicates the structure of the welding control device, but also causes the welding The controls themselves become more expensive

[0022] In addition, the technologies described in Patent Documents 1 to 5 have the following problem: no discussion is made on the method of improving the joint strength of the welding of the plate group including the high-strength steel plate.

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