Honda Motor Co., Ltd.

Xihao Tan

Hitoshi Saito

Shinya Watanabe

Shinyu Hirayama

Sumitomo Watanabe

Hironori Sawamura

Shogo Nagayoshi

Hiroki Toyoda

Yasuhisa Saito

Takahiro Morita

Provided is a spot welding method capable of reliably welding a metal sheet laminate while suppressing occurrence of expulsion. In the spot welding method, a pulse current is applied in a first current application step and a second current application step by a DC chopping control method. In the DC chopping control method, a pulse waveform of the pulse current is generated by switching between current application and current application stop to a pair of electrodesandby a current switch, a peak current value of the pulse current in the first current application step is set to a value Aequal to that of the pulse current in the second current application step, and a power of the pulse current in the first current application step is set to a value larger than that of the pulse current in the second current application step.

Spot welding method

This spot welding method is a method for joining workpieces being a layered body of three or more metal sheets by supplying welding current. The welding current has a pulse-like waveform wherein a peak state in which the current reaches or is maintained to be within a set peak current range and a non-peak state in which the current is lowered from the peak current range to a set bottom current, and is then increased toward the peak current range again are alternately achieved. In the non-peak state, in the case where an effective value Irms of the welding current is lowered, and reaches a predetermined effective value target range, a current control process for increasing the welding current toward the peak current range is started.

A spot welding method includes supplying a welding current having a pulse-shaped waveform to a workpiece by alternately executing a step of maintaining the welding current within a set peak current range and a step of decreasing the welding current from the peak current range toward a bottom current and then increasing the welding current toward the peak current range when an effective value of the welding current reaches a set target range for a plurality of cycles. The spatter detection method includes measuring a pulse width IW(1), IW(2), . . . in each cycle of the pulse-shaped waveform and detecting the occurrence of spatter when a pulse width difference D(M)=IW(M)−IW(M−1) between a pulse width IW(M) in a target cycle (M-th cycle) and a pulse width IW(M−1) in a cycle immediately before the target cycle exceeds a width threshold value Dth.

Spatter detection method

Provided is a spot welding method by which welding can be successfully performed while inhibiting occurrence of expulsion. First to third metal plates Wto Wwere welded in which ratio of total thickness to thickness of the first metal plate Wis 7. In Example 1, peak current value Ais 14.6 kA, effective current value Ais 7.8 kA, peak duration Tis 0 ms, and no-peak duration Tis 5.9 ms. As a result, in Example 1, lower limit current value Ais 6.9 kA, upper limit current value Ais 8.42 kA, difference Abetween upper limit current value Aand lower limit current value Ais 1.52 kA, peak duration T/no-peak duration Tis 0, effective current value A/peak current value Ais 0.53, and rising time T/falling time Tis 0.79, furthermore, no expulsion occurs, and welding result was determined to be OK.

Provided is a spot welding method by which welding can be performed successfully while inhibiting occurrence of expulsion. First to third metal plates Wto Wwere welded in which a ratio of a total thickness to a thickness of the first metal plate Wis 7. In Example 1, a peak current value Ais 14.6 kA, an effective current value Ais 7.8 kA, a peak duration Tis 0.1 ms, and a no-peak duration Tis 5.9 ms. As a result, a lower limit current value Ais 6.9 kA, an upper limit current value Ais 8.42 kA, a difference Abetween Aand Ais 1.52 kA, T/Tis 59.0, A/Ais 0.53, and rising time T/falling time Tis 0.53, furthermore, no expulsion occurs, and a welding result was determined to be OK.

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Tochigi, Japan

Xihao Tan