The difference between pressure welding and flash welding

The core difference between pressure welding and flash welding lies in the heating method: flash welding generates resistance heat through electric current, while pressure welding relies on the flame from gas combustion for heating.

I. Heating Method
Flash welding: Heats the workpiece using resistance heat generated by electric current, with welding temperatures exceeding 1600℃.
Pressure welding: Heats the rail ends with a flame from gas combustion, reaching a temperature of approximately 1200℃.
II. Comparison of Advantages and Disadvantages
Flash welding:
Advantages: High degree of automation, stable process, excellent welding quality, mechanical properties close to the rail base material, and high production efficiency.
Disadvantages: High requirements for equipment and power supply, and high initial investment.
Pressure welding:
Advantages: Low initial investment, no need for high-power power supply, short welding time, and good welding quality.
Disadvantages: Strict requirements for the treatment of the weld joint cross-section, requires longitudinal movement of the rail during welding, and is difficult for welding ultra-long rails.
III. Application Scenarios

Flash welding: Widely used in the manufacturing and on-site welding of long rails, with joint straightness controllable to the millimeter level.

Pressure welding: Mostly used for joint welding, but requires strict process control.