Adapting Orbital Processes for Ship Construction and Welding


If you have ever been on a cruise, then you can visualize the sheer size of the largest ships in production today. The single largest ship, the Symphony of the Seas, a part of the Royal Caribbean fleet, measures 1,188 feet long and 238 ft tall. This enormous maritime vessel is similar in size to the largest class of naval ships in the world—aircraft carriers—many of which measure over 1000 feet in length. Ships of this size can require more than six years to build, with much of that time devoted to welding the hull, piping system, and other metal assemblies.

The principal consideration for ship construction and welding is safety—whether for passengers (which may number in the thousands) or for shipbuilders. Welding standards and regulations for ship construction are provided by OSHA. Specific standards can be found under 29 CFR 1910, 1915, 1917, 1918, 1926 and other publications such as notices and directives that add clarification for particular requirements. 

The OSHA regulations are comprehensive and address everything from employment, training, and documentation to various welding processes. For example, these regulations are intended to apply whether you employ an arc welding, gas welding, or resistive welding process; however, determining which welding process is best for your project rests with you. To help you with this decision, let’s take a look at commonly applied processes, the challenges associated with ship construction and welding, and whether an orbital process may be the best option.

Conventional Ship Construction and Welding

The shipbuilding process is conventional with respect to other types of construction. One unique aspect of shipbuilding is it occurs in shipyards that perform both terrestrial and in-water assembly. As a result, ships can be tested before they set out to sea. In assembling ships and their inner systems, many welding processes have become standard.

Typical Welding Processes Used for Ship Construction

Common welding processes used to build ships can be classified as one of three types.

Ship Construction Welding Processes

1. Arc Welding Processes

  • Shielded Metal Arc Welding (SMAC)
  • Submerged Arc Welding (SAW)

2. Gas Welding Processes

  • TIG Welding (GTAW)
  • MIG Welding (GMAW)

3. Resistance Welding Processes (ERW)

  • Butt Welding
  • Flash Butt Welding
  • Spot Welding
  • Projection Welding
  • Seam Welding

The basic processes are listed above, but there are also variations. For example, flux-cored arc welding (FCAW) is very similar to MIG; however, it utilizes a different shielding technique. Other welding processes that are commonly used in shipyards are laser, plasma, friction stir, and thermit. The number of different processes above indicates the wide range of welding applications that exist in shipbuilding, as each process can be advantageous in meeting specific challenges in ship construction today. 

The Welding Challenges for Building Ships

Welders have always been an integral part of an expanding economy, as construction (building and otherwise) is a leading indicator of economic growth. Today, the quality requirements for welded structures, especially on high-spec projects, can be daunting for companies seeking to bid competitively on jobs. Additionally, finding professionals with the requisite expertise can also pose a major problem. The challenges of meeting high-quality standards and employing the number of skilled welders needed pose a significant concern throughout industries—like shipbuilding—that rely on welding.

Meeting Ship Welding Quality Requirements

The use of welding for ship construction has produced many benefits. For example, smooth surfaces that cannot be created using bolts and rivets are readily crafted with welding processes. This capability alone results in smooth hulls, less resistance to movement, and lower material requirements. Additionally, vessels are safer and require less maintenance. Issues persist, though, and defects that occur during welding must be overcome.

Common Ship Construction Weld Defects

  • Overlaps – low welding speed can cause weld material to flow over or overlap the base material surface without cooling.
  • Undercuts – occur when the weld results in a loss or reduction of base material area. This degrades the overall strength of the weld.
  • Underbead cutting – is when a crack or fault occurs near the weld, but is not filled by the weld material. This weakens the joint and can lead to a significant crack or breakdown.
  • Weld pool not deep enough – insufficient weld depth is another cause for weakening that can lead to a crack or break.
  • Slag in weld pool/entrapment – slag, which is the solid flux that forms over a weld to protect it, can become trapped within the weld pool and threaten structural integrity.
  • Gas in weld pool/entrapment – for shield gas welding processes, the gas (argon or helium, usually) shields the weld pool until it cools and hardens. However, a lack of shielding gas can allow oxygen, nitrogen, or hydrogen to become trapped within the weld pool.
  • Lack of fusion – means the base material and weld material do not bond and fill in the joint opening. The weld does not fully penetrate the base material, and the joint can still be seen by x-ray, ultrasound, or visually.
  • Excessive reinforcement – occurs when the weld is too big and excess stress is created at the joint.
  • Insufficient reinforcement – the opposite of excessive reinforcement is insufficient reinforcement. Here, the weld deposition is not sufficient.
  • Lamellar tearing – is tearing or cracking that occurs in the base metal, usually outside of the heat-affected zone (HAZ).
  • Crater cracking – is typically caused by operator error. For example, crater cracking can occur when a welder stops before completing a full pass. Likewise, crater cracking can occur if proper downslope and crater fill techniques are not implemented.

The list above represents the types of errors that occur when welding ships. Welds that display any of these errors are sub-standard and would need to be corrected. These inefficiencies increase costs. In addition to ensuring high-quality welds, ship construction projects must contend with a shortage of experienced welders.

Meeting the Number of Welders Required

Today’s welder shortage is no secret, and the reasons for this shortfall are not complicated.

Primary Causes for the Welder Shortage

  • The expansion of welding processes and applications
  • Loss of experienced welders to administrative positions and retirement
  • The trend away from manual labor career paths

Unfortunately, the discrepancy between the number of skilled welders needed and the number of available welders is projected to grow for the foreseeable future. Solutions, such as increased recruitment and more training, are viable long-term goals. In the short-term, however, advanced technologies may offer a better alternative for ship construction and welding.

Is Orbital a Solution for Ship Construction and Welding?

Building ships is unique because of the variety of structures that require welding. First, there are the large metal assemblies that include the hull and deck. Additionally, many piping systems within ships utilize welding. These include the bilge system, fire protection system, ballast system, engine cooling system, flammable liquids (fuel and gas) system, steam, cargo, sound, and air systems.

The piping network, along with the electrical system, is one of the ship’s most important aspects. And maintaining seaworthiness depends upon the ability to perform pipe welding while at sea, if necessary. The types of contingencies that necessitate welding repair can be life-threatening, and the objective during initial construction is to prevent these situations from occurring.

The best way to achieve this objective is by successfully overcoming the challenges of ship construction: high-quality standards and a shortage of skilled welders. For piping systems, MIG welding offers a fast process; however, top-quality welds are achieved with TIG welding. GTAW requires an experienced welder, but this requirement can be overcome by instituting an automated process like orbital welding.  

Advantages of Orbital Welding

Orbital welding is essentially the automation of tube and pipe welding applications. This implementation has tremendous advantages over manual welding. Moreover, automation makes applying TIG welding easier. Perhaps the most significant advantage of orbital welding is that it lends itself to the use of advanced technology such as remote weld view and process control. By leveraging these enhancements for TIG welding, the following results can be attained.

Attributes of Orbital TIG Welding for Ship Construction

  • Consistent, high-quality welds
  • Greater efficiency
  • Simpler usability

Orbital TIG welding enables shipbuilders to perform high-quality welds while reducing the need for welders with years of experience in ship construction applications. While orbital welding provides today’s solution for assembling ship piping systems, it must be correctly implemented. 

How to Best Apply Orbital Welding to Ship Building

While orbital can be a significant asset to your shipbuilding project, you should consider the following four guidelines to obtain the best results.

Guidelines to Optimize Orbital Welding for Ship Piping Systems Construction

#1 Use the Right Process

GTAW is the best option when quality is a premium concern, such as when building ships. There are two available options:

  • Cold Wire TIG Welding
    Typically used for lower temperature applications and requires a separate power supply
  • Hot Wire TIG Welding
    A common way to significantly increase yield

#2 Use the Right Equipment

Equipment choice is a crucial decision when implementing orbital welding. At a minimum, this equipment includes the power supply, controller, and weld head. These elements must work together seamlessly and should be easy to operate and maintain. For maximum safety, operators should use a remote pendant. Not only does this remove the welder or operator from the weld area and away from harmful gases, but it also enables the process to be performed in tight spaces that could not accommodate a person. 

#3 Use the Right Materials

Weld defects in shipbuilding are often traced back to the materials. Therefore, material choices, such as electrodes, are another serious consideration.

Types of Tungsten Electrodes

#4 Optimize equipment operation

Finally, the best equipment is only useful if it is properly maintained. Therefore, be sure to incorporate the following maintenance regimen to ensure that you receive the best service and also prolong the life of your orbital welding system.


For the best-in-industry orbital welding equipment, materials, and service, you can rely on Arc Machines, Inc.  Since its founding by former NASA engineers in 1976, AMI has continually advanced the technology utilized on projects like ship construction and welding. 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.