Spot welding principle
It refers to the welding method of forming a solder joint between the contact surfaces of two lap workpieces by using a columnar electrode.
Spot welding, the first pressure to make the workpiece close contact, then connect the current, the workpiece contact melting under the action of resistance heat, after cooling the formation of solder joint.
Spot welding main applications
(1) lapping of sheet stamping parts, such as automobile cab, carriage, harvester fish scale screen, etc.
(2) thin plate and shaped steel structure slimming and skin structure, such as carriage side wall and ceiling, carriage towing plate, combine harvester funnel, etc.
(3) screen and space frame and cross reinforcement, etc.
Spot welding characteristics
(1) The heating time of the connection area is very short during spot welding and the welding speed is fast.
(2) Spot welding only consumes electricity, and does not need filling material, flux, gas, etc.
(3) spot welding quality is mainly guaranteed by spot welder. Simple operation, high degree of mechanization, automation, high productivity.
(4) low labor intensity, good working conditions.
(5) Because the welding is energized in a very short time, need to use large current and pressure, so the process of program control is more complex, welding machine electric capacity is large, the price of equipment is high.
(6) It is difficult to conduct non-destructive inspection of solder joints.
Spot welding operation
Before welding to clean the surface of the workpiece, the commonly used removal therapy is pickling removal, that is, pickling in the concentration of 10% heated sulfuric acid, and then washing in hot water. The specific welding process is as follows:
(1) Put the workpiece joint into the spot welding machine between the upper electrode and the lower electrode and clamp;
(2) electrify, make the contact table of two workpiece and be heated, partial melting, forming nugget;
(3) maintain the pressure after the power is cut off, so that the nugget cools and solidifies under the action of pressure to form a solder joint;
(4) remove the pressure and remove the workpiece.
Safety precautions for spot welding
(1) The foot switch of the welding machine should have a firm protective cover to prevent accidental start.
(2) The working point should be equipped with a baffle to prevent the work spark from splashing.
(3) Welders should wear flat protective glasses during welding.
(4) The place where the welding machine is placed should be kept dry, and the ground should be covered with anti-skateboards.
(5) After the welding work, the power supply should be cut off, the cooling water switch should be extended for 10s before closing, and the water in the waterway should be excluded to prevent freezing when the temperature is low.铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods