Troubleshooting CO2 Gas Shielded Welding: Tips and Solutions


The difference between gas shielded welding machine and other welding machines is that it is a trinity of machine, electricity and gas.

In the process of use, the problems arising from it should be understood, analyzed and solved from three factors.

Generally speaking, can’t weld is caused by circuit failure, hard to weld is caused by mechanical failure, poor welding is caused by process problems or impure shielding gas, gas circuit problems, etc.

Related reading: Manual Arc Welding vs CO2 Gas Shielded Welding

1. Mechanical problems

1. Whether the inlet nozzle, middle nozzle and outlet nozzle are concentric in a straight line.

If it is not in a straight line, it is easy to increase the resistance of wire feeding and cause unstable wire feeding;

2. Whether the wire feed wheel slips.

For the first test run, the anti-rust grease shall be wiped off and the wheel groove shall be cleaned regularly.

Pay attention to wiping with soft things.

Judge whether the groove is seriously worn: generally, let the welding wire expose 1/3 of the groove surface, otherwise replace the wire feed wheel with the corresponding wire diameter.

The wheel groove must be installed correctly according to the welding wire diameter.

3. The wire feeding wheel retainer ring is only used to prevent the wheel ring from falling off or running too fast during wire feeding, and should not be screwed too tightly, otherwise the embedded screw is easy to fall off or loosen;

4. The wire feeding hose (wire guide tube) is full of dust and iron dust due to long use, which will also cause large wire feeding resistance, so it should be cleaned frequently.

When the wire guide tube has been used for a period of time but is still relatively new, it can be cleaned with compressed air (only this method can be used for nylon tube);

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When the wire guide tube is used, soak it with kerosene, gasoline, alcohol and other organic solvents, and then clean it.

When replacing the wire guide pipe, select the appropriate hose according to the welding wire diameter, cut the hose length according to the actual length of the gun, and be sure to remove the burrs at the spiral steel wire pipe orifice;

In addition, during low-speed welding, the thin wire can use a wire guide tube with a diameter greater than the first grade of welding wire, but it is not allowed to use a thin wire guide tube for thick wire.

For example, Φ1.2 wire can use a Φ1.6 wire guide tube, but Φ1.6 wire cannot use a Φ1.2 wire guide tube.

During high-speed welding, the wire feed pipe shall be matched strictly according to the welding wire diameter;

5. If the hole of the conductive nozzle is too large, it should be replaced in time, otherwise the welding process will be unstable or the output current will not be large enough due to the large gap and poor conductivity.

The use of anti spatter during welding can prolong the life of the conductive nozzle, and the spatter in the sheath of the welding gun shall be cleaned in time during welding.

The diameter of the conductive nozzle of steel welding wire shall be 0.1~0.2mm larger than the diameter of the welding wire, and the length shall be about 20~30mm.

For aluminum welding wire, the aperture of the contact tip (0.2~0.3mm larger than the diameter of the welding wire) and its length shall be appropriately increased to reduce wire feeding resistance and ensure reliable conductivity.

The aperture of aluminum contact tip welded with the same wire diameter shall be larger than that of steel contact tip;

6. For the selection of guns, it is recommended to use a standard 3m gun under the condition that the operating radius is met.

The welding torch cable shall not be bent during use, especially at the position adjacent to the welding torch handle and the cable, great attention shall be paid to ensure smooth wire feeding;

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7. The pressing force shall be properly selected.

Generally, tighten the pressure regulating handle at the scale of 2-4, not too tight, so as to avoid the deformation of the welding wire and increase the wire feeding resistance (especially during aluminum and flux cored welding), and also accelerate the wear of the wheel groove;

8. The supporting shaft of the wire feed tray, which is made of aluminum alloy and is worn with the plastic hole for a long time during use, should be cleaned frequently and coated with grease;

9. The welding wire reel shall rotate clockwise instead of counterclockwise.

2. Circuit problems

1. Whether aviation plugs, sockets, secondary cables and ground wires are correctly connected and well contacted.

(1) Correct connection method of aviation plug

When the aviation plug is inserted, it should be correctly aligned with the positioning slot of the plug and socket (width and width correspond to each other), and then it should be locked by right rotation.

At this time, the positioning lock of the socket just enters the positioning lock hole of the plug.

After the plug is removed, it must be handled with care to avoid hard damage.

(2) Phenomenon during virtual connection of aviation plug

A. There is no action response when pressing the gun (solenoid valve and motor do not respond).

B. The normal display range of the power panel is 15~48V, the preset digital scale of the current is 30~280, the abnormal display voltage is 60~70V, and the preset scale of the current is about 400.

The specific value is related to the grid voltage.

C. Current and voltage are not adjustable.

(3) Correct connection method of secondary cable

The connection method of the secondary cable quick connector is to align it with the embedded slot of the secondary output socket on the front panel of the power supply, push it forward and rotate it about 90 ° to the right.

(4) Phenomenon during virtual connection of secondary cables and ground wires

A. Serious heating at the joint, even adhesion;

B. When welding with high current, the corresponding welding voltage exceeds the normal matching range;

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C. Welding process is unstable at low current;

D. The adaptability of trunk elongation decreased (shorter).

2. Treatment of extension wire

Generally, we can lengthen it to 50 m/50mm2.

If it is necessary to lengthen it in case of special requirements, it is recommended to thicken the cross-sectional area of the cable.

However, after the cable is lengthened, the error between the wave control sampling and the arc voltage will increase due to the increased line loss, so the given voltage should be appropriately increased.

3. Arc striking problem (under the condition that the welding circuit is in good condition)

The old models of circuit boards are designed according to 1.6 wires.

When Φ1.0, Φ1.2 and other wires are used, the arc starting current is always high.

The new models of circuit boards have overcome this problem.

3. Protective gas and gas circuit problems

Protective gas and gas path problems (welds are easy to be oxidized, especially when welding aluminum alloys)

1. The purity of CO2 gas

The purity of CO2 gas has a great influence on the compactness and plasticity of weld metal.

The purity of CO2 gas for welding shall not be less than 98% (volume method), and its water content shall be less than 0.005% (weight method).

2. Whether the protective gas flow is sufficient

Check that the gas flow V=(12 ~ 15) L/min, and properly increase the gas flow during high current welding (select according to the current or nozzle aperture).

3. Whether the gas heater works

Check whether the heater works normally.

Wait for 2~3min after starting the machine, and touch the heater with your hand.

If it is not heated, the heater will frost, even block the air flow channel or increase the probability of air holes.

4. Whether the wire guide tube is damaged and whether there is air leakage.

5. Whether the diverter is damaged

If it is damaged, it should be replaced, otherwise it will affect the distribution direction of the shielding gas and cause poor protection.

6. Whether the air pipe is damaged.

7. Check whether all sealing rings in the gun body are normal.

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