The use of butt welder

1. According to the working principle of butt welding machine, butt welding process can be divided into resistance butt welding and flash butt welding.


Resistance butt welding is to heat the end joint of steel bar to plastic state, then cut off the power supply, and then heat up to plastic connection. This welding process is easy to produce oxidation and slag inclusion in the joint, and requires the steel bar section to be smooth and smooth, while welding consumes a lot of electricity, requires a large welding machine power, so it is seldom used.


Flash butt welding refers to the process of welding, from the end of the steel bar joints where melted metal particles, showing sparks (flash). It is widely used in butt welding, especially for low carbon steel and low alloy steel.


2. Attention should be paid to the following items when using the welder.


Adjust the distance between the two jaws. The nipple spacing should be the difference between the total elongation and the extrusion of the two weldments when the adjusting screw is rotated so that the control rod is at the left limit. When the control rod is in the right limit, the distance between the nippers should be the total elongation length of the two weldments plus 2-3 mm, the original position before welding.


Adjust the short-circuit limit switch, so that it can automatically cut off the power supply at the end of welding (reach the predetermined extrusion).


Adjust the jaws according to the shape of the welds and place the two jaws at the same level, then clamp the weldments.


To prevent transient overheating of the weldments, the series of adjustment should be added step by step and proper secondary voltage should be selected. For flash butt welding, a higher secondary voltage should be used.


To avoid overheating during welding, the cooling water valve must be opened before water can be welded. For convenience of inspection, a funnel is arranged in front of the left side of the welder to observe the flow of water directly, so as to check whether there is cooling water flowing through the welder.


3. Operation points of reinforcing bar butt welding machine


Operators of butt welding machines must undergo professional training, be familiar with butt welding machine structure, performance, operating procedures, and master the selection of process parameters, quality inspection specifications and other knowledge.


Before operation, it is necessary to check whether the welding machine is sensitive and reliable, whether the electrical system is safe, whether there is leakage in the cooling water pump system, whether the lubrication parts are well oiled, etc.


It is strictly forbidden to weld the steel bar that exceeds the specified diameter. The main reinforcement must be welded before cold welding. In order to ensure welding quality, cleaning, rust removal and correction should be carried out within the range of 150 mm of the sensing end.


Operators must wear colored protective glasses and hats to prevent the arc light from irritating the eyes and burning the skin with molten metal.


The butt welding machine should be parked in a clean, dry and ventilated place. The butt welding machine used on the spot should be equipped with a rain-proof, moisture-proof, sun-proof shelter, and equipped with fire-fighting equipment. Flammable materials should not be piled up within the welding range.


The butt welding machine should be equipped with a special wiring switch and installed in the switch box. The capacity of the fuse should be 1.5 times that of the machine. The welder housing must be grounded properly.


After welding, the joint should be properly upsetting without cracks and obvious burns. The crankshaft of the joint axis is not greater than 6 degrees, and the offset is not greater than 1/10 of the diameter of the steel bar, and shall not exceed 2mm.


After the operation to clean up the site, extinguish fire seeds, winter also compressed air blowing cooling pipe water, cut off the power supply.