... the purpose of welding.Welding advantages:1, welding material does not melt, non-fragile metal properties.2, then after the ... short, without any flux, gas, solder.5, no welding sparks, environmental protection and safety.Local advantages:1, using phase-locked ... sheets of mutual melting.7, the metal tube end sealing, cutting can be water, gas-tight.the sample effectionULTRASONIC THEORY Ultrasonic metal ...