Source Errors

Welding Defects and Suggested Solutions:

Welding defects can arise not only from common causes but also from complex and hidden factors. This situation can lead to the root cause of the problem being overlooked. Since welding defects can result from one or more causes occurring simultaneously, it is important to examine each defect individually and evaluate possible causes separately for each welding method.

Spatter

1. Excessive Welding Current:
   The welding current must be properly adjusted.
2. Excessive Arc Length:
   The arc length should be adjusted according to the wire diameter.
3. Incorrect Polarity:
   To prevent issues such as arc blow, verify that the polarity is set according to the product specifications.
4. Insufficient Gas Shielding:
   The type and flow rate of the shielding gas must be checked. Nozzle cleaning should not be neglected, and the angle of the torch relative to the plate should be increased to hold it more vertically.

Welding Defects and Recommended Solutions:

1. Inappropriate Welding Sequences:
   The joint should be welded as symmetrically as possible from both sides. Welding can begin from the center and proceed in opposite directions.
2. Excessive Number of Very Thin Weld Beads:
   This typically occurs when the electrode diameter is selected too small, resulting in excessive heat input. An electrode of the appropriate diameter for the design should be selected, and a high-efficiency electrode should be used.
3. Weak or Incorrect Pre-Welding Joint Designs:
   Workpieces must be joined to accommodate the anticipated shrinkage, and angles should be designed accordingly.
4. Insufficient Clamping of Plates:
   Plates must be clamped securely at a sufficient number of points.

Arc Blow Welding Defects and Recommended Solutions:

1. Magnetic Deviation:
   As a result of magnetic effects, the workpiece may be positioned in the opposite direction of the grounding clamp (chassis). Welding should be performed at a point at an appropriate distance from the chassis connection. Additionally, you can try splitting the chassis connection and connecting it to both sides of the part before welding.
2. Magnetic Field:
   Heavy and large workpieces have their own unique magnetic fields. This field becomes more pronounced at the edges and corners of the workpiece.
3. Ground Cable Connection:
   The ground cable connection must be positioned to counteract the magnetic effects of heavy workpieces. The arc distance should be kept as short as possible.
4. Electrode Selection:
   Choosing an AC (alternating current) electrode may offer an alternative solution to this problem.

Longitudinal Cracks in ITAB: Welding Defects and Recommended Solutions

1. Base Material Prone to Hardening:
   If the base material is prone to hardening due to high carbon content or other alloying elements, a material that is easier to weld and not prone to hardening should be selected, if possible. If this is not possible, a procedure involving preheating, slow cooling, and monitoring the temperature between passes should be implemented.
2. Rapid Cooling:
   If the weld cools too quickly, preheating should be performed at higher temperatures or for a longer duration.
3. Hydrogen Sources:
   Hydrogen sources within the weld may result from damp material, an improperly cleaned weld joint, incorrect electrode selection, or damp welding consumables. Moisture in the weld area must be removed, and low-hydrogen, properly packaged welding consumables should be used. Products from opened packages should be re-baked to dry them before welding.

Ignition Difficulties: Welding Defects and Recommended Solutions

1. Low Welding Amperage:
   The welding amperage may be too low. In this case, the current should be adjusted according to the electrode diameter, welding position, and the manufacturer’s recommendations.
2. Low Arc Voltage:
   If the arc voltage is too low, the line voltage may fluctuate or remain low in certain areas. The appropriate voltage should be obtained using an external power source.
3. Insufficient Ground Connection:
   The ground connection may not be properly secured or may not be making sufficient contact. Therefore, the condition of the ground connection should be thoroughly checked, and the contact surface should be cleaned.
4. Uneven Coating:
   The coating on the tip of the covered electrode may be uneven, or the ignition tip may remain closed due to a previous ignition. In this case, check whether the ignition tip is open and whether the coating is even.

Solidification Cracks: Welding Defects and Recommended Solutions

1. Elements with Low Melting Points:
   Elements such as P, S, and Cu from the base metal can form phases with low melting points during welding. To prevent this, base material or a buffer plate with metallurgically cleaner P, S, and Cu content should be preferred.
2. Inappropriate Joint Geometry:
   If the width-to-depth ratio is less than 1, the weld groove angle should be set higher, and welding should be performed at lower currents.
3. Large Weld Pool:
   A weld pool that is too large or wide can cause cracking. A smaller-diameter electrode should be selected, and lower current values should be used. The oscillating welding technique should be avoided.
4. High Welding Speed:
   If the welding speed is high, the cooling lines in the weld bead may take on an arrow-like shape. The welding speed should be reduced until the cooling lines take on a more elliptical shape.
5. Insufficient Clamping:
   Even when the parts are clamped, tack welds or root passes that are not strong enough to withstand expansion and contraction forces may cause cracks. More durable tack welds and root passes should be applied.

Insufficient Fusion Defects: Welding Defects and Recommended Solutions

1. Low Heat Input:
   Heat input may have been too low. To prevent this, welding parameters should be increased and the welding speed slowed down.
2. Large Weld Pool:
   If the weld pool is too large and is running ahead of the arc, the metal deposition rate should be reduced and/or the welding speed increased.
3. Low Joint Angle:
   The joint angle (weld groove) may have been set too low. A weld groove with a higher angle should be designed.
4. Incorrect Electrode or Torch Angle:
   The electrode or torch angle may be incorrect. This angle should be positioned to ensure complete fusion of the plate or material surfaces.
5. Inappropriate Weld Bead Sequence:
   Weld beads must be sequenced at the correct angles relative to each other and to the plate/material surfaces.

Crater Cracks: Welding Defects and Recommended Solutions

1. Abrupt Termination of Welding:
   Abruptly terminating the weld or withdrawing the electrode from the weld pool too quickly can lead to crack formation due to solidification shrinkage.
2. Closing the Crater Area:
   When terminating the welding process, the crater area can be slightly closed by backing up 3–5 mm.
3. Caution During Root Pass Welding:
   During root pass welding, the arc bath should be quickly moved to the edge of the plate and exited at the end of the weld.
4. Crater Closing Feature:
   If your welding machine has a crater closing feature, the duration of this feature can be increased.

Undercut: Welding Defects and Recommended Solutions

1. High Voltage Setting:
   A voltage setting that is too high can cause welding defects. An appropriate voltage setting should be selected.
2. Long Arc Length:
   If the arc length is too long, the arc distance can be reduced.
3. Incorrect Torch or Electrode Angle:
   The torch should be approached at an angle between 30° and 45° relative to the workpiece.
4. Use of Excessively Large-Diameter Electrodes/Wires:
   Electrodes or wires with a diameter that is too large for the workpiece thickness may be used. Consumables with smaller diameters should be preferred.
5. Low Welding Speed:
   If the welding speed is too low, it should be increased slightly.