Can DOM Tubing be MIG Welded? A Comprehensive DIY Guide

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Can DOM Tubing be MIG Welded? The answer is yes, but with some critical details and advanced considerations that DIY users need to keep in mind. This comprehensive guide will provide you with the technical specifications, hands-on details, and expert-level insights to successfully MIG weld DOM tubing.

Understanding DOM Tubing and MIG Welding

DOM (Drawn Over Mandrel) tubing is a type of mild steel that is commonly used in various industries, including automotive, aerospace, and construction. MIG (Metal Inert Gas) welding, on the other hand, is a popular welding process that is suitable for joining DOM tubing.

When it comes to welding DOM tubing, the primary concern is the difference in the coefficients of thermal expansion between DOM tubing and chromoly, which can lead to distortion and potential cracking during the welding process.

Selecting the Appropriate Filler Wire

can dom tubing be mig weldedImage source: Mig weld example

To address this challenge, it is recommended to use ER80S-D2 filler wire when welding chromoly to DOM tubing. This filler wire is specifically designed for welding chromoly and has a similar chemical composition to DOM tubing, making it a suitable choice.

However, if the chromoly bungs are not heat-treated, it is possible to use ER70S-6 wire, which is a general-purpose MIG wire. In this case, it is crucial to adjust the welding parameters accordingly to ensure a successful weld.

Preheating the Tubular Parts

Preheating the tubular parts is another important consideration when welding chromoly to DOM tubing. It is recommended to preheat the parts, especially if the bungs have a significant section. This helps to reduce the risk of distortion and cracking during the welding process.

It is worth noting that preheating is not necessary for parts with a wall thickness under 0.095 inches.

Controlling Heat Input

When welding chromoly to DOM tubing, it is essential to control the heat input to prevent cracking. This can be achieved by using a lower welding current, a smaller welding wire diameter, and a shorter welding time.

Additionally, it is recommended to use interpass temperature control, which involves monitoring the temperature of the weldment between welding passes to prevent overheating.

Welding Techniques and Considerations

To ensure a successful MIG weld on DOM tubing, consider the following techniques and considerations:

  1. Weld Preparation: Ensure that the surfaces to be welded are clean, free of any contaminants, and properly aligned.

  2. Welding Position: Depending on the project, you may need to weld in various positions, such as flat, horizontal, or vertical. Adjust your welding technique accordingly.

  3. Welding Parameters: Carefully adjust the welding current, voltage, wire feed speed, and shielding gas flow rate to achieve the optimal welding performance.

  4. Weld Appearance: Monitor the weld appearance during the process and make adjustments as needed to ensure a consistent, high-quality weld.

  5. Post-Weld Inspection: Carefully inspect the weld for any defects, such as cracks, porosity, or lack of fusion, and address them accordingly.

  6. Heat Treatment: Depending on the application, you may need to heat-treat the welded assembly to relieve any residual stresses or improve the mechanical properties.

Conclusion

In summary, DOM tubing can be successfully MIG welded for DIY users, but it requires advanced hands-on details and technical specifications. By understanding the critical considerations, such as filler wire selection, preheating, and heat input control, you can achieve high-quality welds on DOM tubing.

Remember to always prioritize safety, follow proper welding procedures, and consult with experienced welders or industry experts if you have any doubts or concerns.

References

  1. Welding DOM Tubing
  2. MIG Welding Tubing
  3. Welding DOM Tubing
  4. Welding Chromoly to DOM
  5. Welding Chromoly to DOM Tube