Flash butt welding

Flash butt welding This is a type of resistance butt welding and is classified as pressure welding. This type of welding emerged approximately 90 years ago. Flash butt welding is an effective method for joining metals with a cross-sectional area of up to 100,000 mm²It is used to connect pipelines, reinforcement of reinforced concrete structures, and for joining profile steel. This method is very effective for producing seamless railway tracks and anchor chains.

Flash butt welding

Flash butt welding is as follows:

• The parts are cleaned of dirt, oil stains, and oxidation. The ends of the workpieces to be welded are prepared for precise contact;
• the parts to be welded are fixed in welding electrodes;
• from the transformer, high current and low voltage are supplied to the parts;
• the mating surfaces are heated to a plastic state;
• then the workpieces are compressed with increasing force, and the current is turned off until the upsetting is complete.

Flash butt welding Allows for the joining of workpieces at the atomic level. The crystallization process of metals creates a strong weld.

Flash butt welding modes

Flash butt welding modes This method has the following features:

• Explosive joining of parts. This is caused by the high current density at the ends of the workpieces, which greatly heats the part. When joining, an explosive effect occurs. As a result, some of the heat is dissipated into the atmosphere as metal splashes, while the rest accumulates in the joint. This creates a liquid metal layer. The parts are then quickly brought together. When joining the parts, some of the liquid and solid metal is forced out of the weld zone, creating a burr.
• It is carried out by continuous and intermittent melting.

The characteristic of continuous melting is the gradual convergence of the workpieces. Their ends touch only at certain protrusions. But this is sufficient for rapid heating and melting, causing some of the metal to explode and fly off. The convergence continues, and new contacts melt, forming a liquid layer of metal. Now the ends are quickly brought together with force, and the parts are welded.

The intermittent flash welding method involves alternately compressing and separating the parts with gentle force. Since this process occurs with the current on, the ends of the parts are heated by the welding current during compression. During separating, an electrical discharge is generated between the ends. This discharge melts the surface of the metals. After several such repetitions, the metal melts, and the workpieces are compressed.

There are a wide variety of flash welding machines available and each has its own specifications and flash butt welding modesThe MSGU-300 and MSGU-500 machines have identical specifications but differ in power. They are used for welding rods up to 70 mm in diameter using continuous flashing, as well as preheating. The rod is clamped using a pneumatic-hydraulic clamp. The upsetting mechanism is hydraulically driven, and the welding transformer has a contactor stage selector switch.

The MS-2008 welds 60 mm diameter rods using continuous flash welding. Semi-automatic welding is performed using flash welding with heating. The upsetting drive is electromechanical, the clamp frame has a pneumatic device, and the welding transformer has a step switch. The Chaika FBWM-60 machine performs flash welding of knives, strips, and band saw blades of high-carbon and alloy steel, followed by heat treatment. It is equipped with computer control, automatic heat treatment, a modern clamp design, and rapid weld quality control. Each of these machines complies with flash butt welding modes For a strong connection of workpieces. This results in a high-quality weld.