Making a perfect weld on a section of pipe requires a welder to be aware of and avoid the following common mistakes. All of these frequently made mistakes can each lead to severe functional problems in the welded pipe equipment being produced.
- Not grinding the joint- Once oxyfuel and plasma cutting is done, the accumulated oxide layer needs to be ground away before welding can begin. If the oxide layer is left on, defects in the pipe such as porosity and a lack of fusion could result.
- Taking shortcuts when cutting- An improper cut can lead to problems such as unwanted gaps and a poor fit-up. Cutting mistakes are especially problematic in cases where welders are working with materials like aluminum and stainless steel that are susceptible to distortion.
- Not cutting out and feathering tacks- When tacking, the welder needs to properly cut out and feather so that the resulting weld is consistent. Any defects in the tack could lead to defects in the final weld. In order to cut out and tack properly, a welder needs to know which filler metal should be used to tack the joint.
- Using too much shielding gas- There is a common misconception among some welders that more shielding gas always brings about improvements. In fact, too much shielding gas can cause a variety of problems. These include weld puddle agitation, a convection effect that could cause porosity, and wasted shielding gas.
- Causing drive roll issues- Sometimes, welders use the wrong type of drive roll or work with a drive roll that is the wrong size. A standard V drive roll should always be used with solid wires and a knurled drive roll works with flux-cored wires.
- Using the wrong nozzle size- Welders need to know how to choose the appropriate nozzle type and size depending on the MIG process being used. In the RMD process, tapered nozzles are appropriate. On the other hand, tapered nozzles are incompatible with the Pulsed MIG process. Welders need to be familiar with these rules and standards to avoid issues like improper gas coverage over the weld.
- Using both a dust pad and a cleaning solvent- While using a dust pad before the drive roll system can help get contaminants off the wire, a dust pad should never be used in combination with cleaning solvent or lubrication. Oils like solvent and lubrication can actually make contamination of the wire worse and bring about weld defects.
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