Generally, there are three kinds of materials for ultrasonic spot welding head, namely aluminum, titanium and steel. Aluminum alloy is cheap and easy to process, with good acoustic wave transmission characteristics, but its conductivity is easy to decay, and its hardness is not high and easy to wear; Steel has good sound wave transmission, moderate cost and wear resistance, but it is easy to get hot. The machine load is high. Titanium alloy has good sound wave transmission characteristics, good toughness, and is not easy to process. The cost of materials is high, and the wear resistance is not easy to decay