Preventing Metallurgical Problems With AMI Orbital Welding

A common metallurgical problem for piping systems

Some metals contain physical properties that make them fundamental components across a wide variety of industries. These include industrial factories, food processing facilities, energy generation plants, ships, and aviation platforms. Ironically, the same attractive metallic properties can also undermine the strength and resiliency of piping systems used in these industries. 

Undoubtedly, material degradation—caused by exposure to the elements, excessive heat or pressure, or gradual wearing due to the toxicity of transported chemicals—is the most common problem for welded pipes and tubes. This premature failure of piping systems is never acceptable and, in some cases, can be catastrophic. 

However, by applying the best welding process and using advanced equipment and materials from Arc Machines, Inc (AMI), you can address the most common metallurgical problems and confidently assemble reliable systems.

The Most Common Metallurgical Problems for Piping Systems

It is well known that when steel is exposed to the air, the resulting surface oxidation will cause the metal to weaken and become brittle. However, this is only one of several metallurgical problems that can materialize along and within welded piping systems. Additional problems that can arise include the following surface and interior issues:

Pipe Exterior Surface Issues

  • Lack of fusion: Lack of fusion or heat to melt the base materials can result in cracks at the weld joint that minimize the strength of the joint.
  • Porosity: Porosity occurs when the weld pool contains air pockets. The presence of nitrogen in the dissolved oxygen is the primary reason for this inconsistency in the weld.
  • Inadequate shield gas coverage: The shield gas in processes such as MIG and TIG is intended to protect the weld puddle from the environment. Inadequate coverage can result in porosity.
  • Shield gas-base metal mismatch: The shield gas—usually argon—should be matched to both the base material and the pipe interior purity.
  • Lack of or inadequate overlay or OD cladding: Piping systems continually exposed to harmful conditions, such as overland piping, require either a corrosion-resistant base material or an overlay application to mitigate premature failure, leaking, or eruption.

Pipe Interior Surface Issues

  • Lack of purging: Purging is atypical for high-spec projects and may be overlooked due to cost concerns on other jobs. This omission can potentially have a negative impact depending upon the piping system contents.
  • Lack of or inadequate ID cladding: ID cladding is another often omitted tool. However, this omission can result in premature internal wall breakdown for some contents.

The issues listed above are not all-inclusive, yet they represent the types of metallurgical problems that you should address for your piping system assembly. Additionally, many of these issues are simply outside the scope of manual welding—to reliably mitigate them requires a more advanced and controlled process such as orbital welding.

How Orbital Welding Helps Preserve Pipe Surfaces

When comparing manual vs. orbital welding, it is obvious that manual welding places outsized demands on welders. Additionally, each substandard weld or error increases time and cost requirements and decreases project ROI. Therefore, the best option is to leverage the advantages of orbital welding to mitigate metallurgical welding problems.

Advantages of Orbital Welding in Preventing Pipe Surface Issues

Consistent Quality

Implementing an orbital welding process enables welders—even less experienced welders—to generate consistent, high-quality welds.

Process Control

Orbital welding is an advanced form of the craft where the physical demands and safety risks are removed and replaced by enhanced visibility and software technology which simplifies the ability to control the process even from a remote location.

Job Efficiency

In addition to producing consistent and high-quality welds, orbital welding offers a safer and simpler alternative to manual welding. Since operators can run several welding processes simultaneously with virtually no errors, they can use orbital welding efficiency to lower costs and complete jobs faster.

By instituting an orbital welding process, you can successfully address the metallurgical problems that can threaten to limit the lifetime of your piping system or structure. However, optimizing orbital welding usage requires that you also adopt the best process and use the best equipment and materials. 

AMI’s Orbital Welding Solution to Prevent Metallurgical Problems

Your solution to address external and internal metal surface issues is only as good as the process, equipment, and material that you bring to bear on the problem. And the best solution available for creating welds and overlays that extend the life of your assemblies can be found at AMI: a company experienced in dealing with metallurgical issues

The Best Process

AMI M15 TIG welding system in action

Orbital TIG Welding
AMI M15 TIG welding system in action

The Best Materials

AMI high purity ground and polished tungsten electrodes

AMI high purity ground and polished tungsten electrodes

The Best Equipment

AMI Model 2 versatile OD overlay/cladding weld head

OD Cladding
AMI Model 2 versatile OD overlay/cladding weld head

AMI Model 94 weld head

ID Cladding
AMI Model 94 weld head

By employing AMI’s advanced orbital TIG and overlay welding equipment and materials, you can ensure that your piping systems will remain free from metallurgical problems for their expected lifetime or longer.


Arc Machines, Inc. specializes in high-quality, precision orbital welding and has been a leader in advanced welding technology processes and equipment since its founding by former NASA engineers in 1976. We also offer a range of overlay and cladding solutions, backed with superior service and support, to help ensure that your piping systems remain resilient to metallurgical problems throughout their lifetime. For inquiries regarding products, contact For service inquiries, contact Arc Machines welcomes the opportunity to discuss your specific needs. Contact us to arrange a meeting.