The significance of double pulse of energy storage spot welding machine

What is a double pulse Weld?

Double-pulse welding schedule was employed in the process. Under the second pulse current, the central temperature in the weld was higher than Ac3, and the second nugget was formed. The weld including two nuggets with different size and same center was obtained under the optimized process.

What are the mechanical properties of double pulse welding?

The double pulse welding using highest secondary current led to the best mechanical properties with peak load of 31.59 kN and energy absorption of 30.28 J. The failure mode was gradually transformed from IF to PT-PP, which is discussed in the following sections. Fig. 13.

What is a double pulse welding schedule?

For the double-pulse welding schedule, the first stage current was the same as the current of single-pulse schedule. To insure the nugget with same size, enough cooling time between the two pulses was necessary. Different welding joints were obtained by changing the second pulse current. The resistance spot welding parameters were shown in Table 1.

Does double pulse resistance spot welding affect mechanical properties of q&p 980 steel?

In this study, the effect of double pulse resistance spot welding processes on mechanical properties and fracture process of Q&P 980 steel were explored. The following conclusions can be drawn: Q&P 980 steel was susceptible to liquation crack formation. Martensite was the predominate microstructure in the weldment.

What is the peak load and energy absorption of double pulse welding?

It can be seen that the peak load and energy absorption first remain unchanged and then increased, having the same trend with nugget diameter. The double pulse welding using highest secondary current led to the best mechanical properties with peak load of 31.59 kN and energy absorption of 30.28 J.

What is double-pulse welding process compared to dual-Nugget RSW process?

Similar to dual-nugget RSW process, double-pulse welding process were used as shown in Table 1: electrode force 4.4 kN, welding current of the 1st pulse 6.0 kA, welding time 375 ms; the current of the 2nd pulse from 2 kA to 4.5 kA, 2nd pulse time 375 ms.