Unstable Wire Feeding in CO2 Gas Shielded Welding
CO2 gas shielded welding often results in poor wire feeding and uneven wire output during welding, which can cause difficulties in welding and directly affect the welding quality. The weld seam should be divided into several sections to be welded at once. The following experience is for reference only.
The welding wire has a hard bend
Cause of occurrence
The welding wire does not produce hard bending during production, but is only damaged during transportation, causing the welding wire on the wire reel to fall off, or this phenomenon occurs when the scattered welding wire is manually wrapped around the wire reel.
Causing phenomena
Welding wire with a hard bend will be blocked before entering the welding gun after entering the wire feeding wheel. If entering the welding gun, it will also be blocked by the wire feeding hose or conductive nozzle, making welding impossible. When the welding current and voltage are too high, the conductive nozzle will also be burned.
matters needing attention
When opening the packaging and installing the welding wire, carefully inspect the welding wire reel to confirm that it is intact and neatly wrapped before use. When handling welding wire, be sure to handle it carefully to avoid damaging the wire reel and causing it to scatter. When rewinding the scattered welding wire onto the wire reel, wear gloves and wrap it carefully to avoid hard bending.
The welding wire is corroded
Cause of occurrence
The packaging of the welding wire is damaged during transportation, the welding wire warehouse is too humid, the humidity exceeds the standard, the storage time is too long, and the welding wire is stored after being touched by hand.
Causing phenomena
When welding, if the corroded welding wire enters the wire feeder, the clamping wheel will slip, affecting normal wire feeding. When welding wire with corroded parts enters the welding gun, due to the increase in wire diameter, it will be blocked by the conductive nozzle and unable to weld. When the current is too high, it will burn the conductive nozzle, resulting in poor weld formation and surface debris. matters needing attention
matters needing attention
When opening the packaging of welding wire, check whether the welding wire is rusted, and replace the rusted welding wire in the welding wire warehouse in a timely manner. The packaging of welding wire shall not be damaged, and the humidity of the welding wire warehouse shall be controlled. The welding wire shall be stored 300mm away from the ground and walls, and the welding wire purchased first shall be used first. It is strictly prohibited to touch the welding wire opened for use with hands.
Uneven thickness or burrs of welding wire
Cause of occurrence
When producing welding wire, it is caused by unqualified wire drawing equipment.
Causing phenomena
When welding, welding wire with uneven thickness or burrs entering the wire feeding hose of the welding gun will generate friction and vibration with the hose wall. As the vibration gradually approaches the welding gun and enters the conductive nozzle, it will cause unstable wire feeding, intermittent welding, or jamming.
matters needing attention
If intermittent welding still occurs after replacing the new conductive nozzle, use a matching model of conductive nozzle to inspect the welding wire before welding. When it is found that the welding wire that has not been tightened by the welding machine does not pass smoothly through the matching conductive nozzle, it must be due to uneven diameter and thickness of the welding wire, and the welding wire should be replaced.
Improper use of wire feeding compression wheel
Cause of occurrence
The clamping wheel of the wire feeder should be matched with the welding wire when used. Steel wheels should be used for solid carbon steel welding wire, and ceramic wheels should be used for flux cored welding wire. The wheel groove model should match the diameter of the welding wire. The pressure should be adjusted according to the usage requirements, and should not be too loose or too tight.
Causing phenomena
When using ceramic wheels for carbon steel solid core welding wire, it can cause the ceramic wheels to wear out too quickly. When steel wire feeding wheels are used for flux cored welding wire, the wire will be compressed and cracked, causing the flux to leak out and unable to weld. When the diameter of carbon steel solid welding wire is larger than the diameter of the wire feeding wheel groove, it is easy to produce indentation on the welding wire, causing deformation of the circular section of the welding wire. The welding wire with indentation will be stuck when passing through the conductive nozzle. When the diameter of the welding wire is smaller than the diameter of the wire feeding wheel groove, the friction between the wire feeding wheel and the welding wire is insufficient, and the wire cannot be fed normally. When the wire feeding wheel matches the diameter of the welding wire, the pressure of the wire feeding machine's clamping wheel should also be appropriate. When the pressure on the wire feeding wheel is too high, it can cause deformation of the welding wire; When the pressure of the wire feeding wheel is too low, the friction between the wire feeding wheel and the welding wire is too small. When the welding wire encounters resistance inside the wire feeding hose or on the conductive nozzle, unstable wire feeding may occur.
Matters needing attention
Use steel or ceramic wire feeding wheels as required. The groove model of the wire feeding wheel should match the diameter of the welding wire. The pressure of the wire feeding wheel should be moderate, and the groove of the wire feeding wheel should be cleaned regularly.
The welding gun bends too much or too quickly during use
Cause of occurrence
When welding, being too casual or the spatial position of special welds causes excessive bending of the welding gun.
Causing phenomena
It will cause excessive obstruction of the welding wire during operation in the wire feeding hose of the welding gun, resulting in difficulty in wire output and unstable wire feeding.
Matters needing attention
During welding, the welding gun should be kept at a straight or large curved angle as much as possible to reduce the running resistance of the welding wire in the wire feeding hose.
Groove is ground inside the welding gun wire feeding spring hose
Cause of occurrence
The welding gun wire feeding spring hose has been used for too long, and when the welding wire passes through the wire feeding hose, grooves are worn out inside the hose.
Causing phenomena
When welding, if the welding wire enters the groove worn out in the feeding spring hose and the bending degree changes due to the movement of the welding gun, it will cause wire clamping in the groove, hindering the normal operation of wire feeding.
Matters needing attention
When the wire feeding spring hose is used for too long and the wire output is not smooth, and the welding gun shakes or blocks the wire feeding hose with the change of welding gun angle, the wire feeding spring hose should be replaced in a timely manner. Try to maintain a large bending angle of the welding gun to reduce friction of the welding wire inside the wire feeding hose. The wire feeding spring hose is too short inside the welding gun, which can cause the welding wire to bend inside the welding gun, resulting in poor wire feeding. When the wire feeding spring hose is too long inside the welding gun, it will bend, which will increase the frictional resistance of wire feeding and cause unstable wire feeding.
The conductive nozzle was not cleaned in a timely manner
Cause of occurrence
When the welding specifications are not adjusted properly or the welding gun is too close to the molten pool, the welding spatter adheres to the conductive nozzle, and the longer the welding time, the more spatter adheres.
Causing phenomena
The more splashing the welding gun's conductive nozzle, the easier it is to block the wire hole of the conductive nozzle, thereby increasing the resistance of wire feeding and causing the welding wire to be blocked or blocked.
Matters needing attention
Adjust the angle of the welding gun and the stretching length of the welding wire as required during welding to reduce the generation of spatter. Regularly use pointed pliers to clean the splashes on the conductive nozzle. After cleaning, extend the welding wire 10-15cm long from the conductive nozzle. Use pointed pliers to bend the welding wire from the base of the conductive nozzle and rotate it clockwise or counterclockwise 3-5 times before quickly releasing it. Use the force of the welding wire rotation to smooth out the wire feeding hole of the conductive nozzle.
Excessive wear on the wire feeding hole of the conductive nozzle
Cause of occurrence
During welding, prolonged wire wear on the conductive nozzle can cause the wire feeding hole to become too large.
Causing phenomena
Excessive wire feeding holes in the conductive nozzle can cause poor conductivity during welding, resulting in discharge between the welding wire and the conductive nozzle. This can cause unstable wire feeding or adhesion with the conductive nozzle, accompanied by the phenomenon of the welding wire swinging back and forth in the molten pool, affecting the formation of the weld seam.
Matters needing attention
During welding, it was found that the welding wire was swinging back after coming out of the conductive nozzle, accompanied by adhesion with the conductive nozzle. A new conductive nozzle should be replaced in a timely manner. The conductive nozzle of the welding gun should match the diameter of the welding wire. If the diameter of the conductive nozzle is too small, it will cause excessive frictional resistance, resulting in the welding wire being blocked or blocked. Excessive conductive nozzle can cause the welding wire to swing back and forth in the molten pool, resulting in poor weld formation.
Voltage and current mismatch during welding
Cause of occurrence
Failure to adjust according to the prescribed welding specifications and lack of experience during welding.
When the current is too high or the voltage is too low, intermittent and unstable welding may occur, with excessive welding spatter and loud and chaotic transition of the welding wire to the molten pool. When the current is too low and the voltage is too high, the welding smoke is too large, the transition sound of the welding wire to the molten pool is small, and the welding wire and the conductive nozzle melt and stick together at the same time, making welding impossible.
Causing phenomena
According to production needs, adjust according to welding specifications to ensure that the welding wire melts in a timely manner when entering the molten pool, and the transition sound of the welding wire to the molten pool is uniform.
Matters needing attention
In addition to the nine reasons mentioned above, there may also be poor quality of the welding machine, unstable operation of the wire feeding motor, loose bonding of the copper plating layer on the welding wire, copper powder falling off, causing blockage of the conductive nozzle and unstable wire feeding. The fixed shaft of the wire feeding machine's wire reel is too loose, which can cause the wire to loosen, and too tight can cause excessive wire feeding resistance and unstable wire feeding. Loose ground wire or untreated rust at the contact area during welding can cause excessive resistance and unstable arc, which can affect wire feeding. The conductive nozzle is not tightened, which can cause unstable welding current and voltage, and also lead to unstable wire feeding.
The above experience can provide judgment basis and solutions for unstable wire feeding during CO2 gas shielded welding operation, thereby improving production and product quality.