Technology 1) Program-controlled voltage reduction flas […]
1) Program-controlled voltage reduction flash soldering This soldering method is characterized by a high secondary no-load voltage at the beginning of the flash to facilitate the excitation of the flash. When the temperature of the end face rises, the low-voltage flash is used and maintained. The flash speed is constant to increase thermal efficiency. When approaching the upset, the secondary voltage is increased to make the flash strong to increase the self-protection.
Compared with preheated flash butt welding, the program-controlled voltage reduction butt welding has the advantages of short welding time, low power consumption and uniform heating.
2) Pulse flash butt welding This welding method is characterized in that, in the stroke of the moving clamp, a reciprocating vibration stroke is superimposed by the hydraulic vibration device, the amplitude is 0.25-1.2 mm, and the frequency is 3-35 Hz uniform. Tune. Due to the vibration, the end faces of the weldments are alternately short-circuited and pulled apart, thereby generating a pulsed flash.
Compared with ordinary flash butt welding, pulse flash butt welding, because there is no spontaneous blasting of the lintel, the spattered particles are small and the crater is shallow, so the thermal efficiency can be more than doubled, and the upset forging can be reduced to 2/3-1/ 2.
The above two methods are mainly to meet the needs of flash butt welding of large-section workpieces.
3) Rectangular wave flash butt welding This welding method can significantly improve the stability of the flash compared with the power frequency AC sine wave flash butt welding. Because the sine wave power supply will cause the flash to be interrupted instantaneously when the voltage is close to zero, the rectangular wave can produce a flash evenly over the entire period. Independent of voltage phase.
The number of flashes per square time of the rectangular wave power supply is 30% higher than that of the power frequency communication. The metal particles sprayed are fine, the fire mouth is shallow, and the thermal efficiency is high. The rectangular wave frequency can be adjusted in the range of 30-180 Hz. This method is mostly used for continuous flash butt welding of thin plates and aluminum alloy wheels.