Weld Overlay Procedures for Interior and Exterior Diameter Applications

automated weld head for overlay procedure

When working on a piping project, simple solutions are key. Take, for example, the important process of protecting pipes. Corrosion presents a serious threat to a piping system’s longevity as it leads to metallic breakdown and separation. To mitigate this undesirable outcome, manufacturers can either opt for a corrosion-resistant material such as stainless steel or perform a weld overlay procedure. 

However, manufacturers are often prohibited from utilizing stainless steel in piping systems due to strength and cost considerations. This can leave piping systems susceptible to oxidation and other problematic environmental factors. In these cases, a weld overlay procedure or cladding can offer the simplest method to raise the pipe surface properties to an appropriate level of corrosive resistance.

Why Weld Overlay and Cladding?

Weld overlay procedures include any process where a welded metal structure, including piping systems, receives a metal overlay that changes the structure’s surface properties to better suit its environment. Weld overlay methods include mechanical processes, such as rolling or deploying explosives, and fusion welding. Though limited to fusion welding techniques, cladding serves a similar purpose. 

When and Where is Weld Overlay Used?

Cladding or weld overlay processes are applied in situations where pipe base materials may be structurally compromised by environmental hazards. This includes external systems where weather or atmospheric conditions can result in oxidation or gradually reduce the effectiveness of any polishing meant to guard the base metal against exposure. Weld overlay is also used for underwater applications and internal environments where seawater and extreme temperatures create significant threats.

In addition to cladding, which is most often used on the outer surface of pipes, weld overlays are also utilized inside pipes and tubes. This inner diameter, or ID cladding, is most often used in applications where internal contents threaten pipe or tube integrity. Pressure vessels, where contents may be at high temperature or pressure, are a major application area for ID cladding.

One of the most important considerations for weld overlay is the type of overlay or cladding material. Alloys such as Monel and Inconel® are good choices as they provide excellent resistance to corrosion. However, there are limitations. For example, Monel should not be used for internal industrial applications. And Inconel can be time-consuming and difficult to perform, especially for ID cladding. Manufacturers must also consider cost. Weld overlay materials are often expensive relative to most base materials. Therefore, it is important to strike the correct balance between cost-effectiveness and reliability for weld overlay procedures.

What is The Most Effective Weld Overlay Procedure?

A good weld overlay process begins with the best cladding material, as discussed in the previous section. Although weld overlay procedures are not intended to join or bond different pipe sections together, this does not reduce the importance of weld strength and quality. In fact, outer and inner base material surfaces provide a much larger area of susceptibility to hazards. Therefore, you should insist on the best welding equipment for your cladding process. Although cold wire cladding can be done, the best results are obtained by utilizing high-quality fusion welding equipment, such as the orbital weld head shown below.

An industry leader for nearly half a century, AMI provides advanced orbital welding equipment, including the Model 2 and Model 94 weld heads for OD and ID, respectively, to aid you in performing weld overlay procedures that rival MIG welding speed while delivering TIG welding’s high quality.

AMI Model 94 weld head


Arc Machines, Inc. has the experience, expertise, and equipment to help your exterior and ID weld overlay procedures meet the highest level of weld quality. Whether you are working on an external pipe system or a hazardous internal environment, you should place your trust in an industry leader who specializes in delivering high-tech, high-quality welding equipment and service. For inquiries regarding products, contact sales@arcmachines.com. For service inquiries, contact service@arcmachines.com. Arc Machines welcomes the opportunity to discuss your specific needs. Contact us to arrange a meeting.