From Blueprint to Maiden Voyage: Welding’s Integral Role in Shipbuilding Projects

December 13, 2023 · Leave a comment · Red-D-Arc
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Welding plays a vital role in ship construction. The ship’s structural elements are only as strong as their weakest point. So, the welds joining the hull plates and other critical components must be produced to meet the strength requirements and stringent codes, standards, and client specifications. 

Since welding technologies enable modern shipbuilding projects, welding is one of the key drivers of the developments in the shipbuilding industry. Any improvements made during the various welding processes during the ship construction can significantly contribute to productivity, safety, inspection pass rates, and profitability.

Critical Welding Applications In Shipbuilding

Welding is applied in almost every step during the shipbuilding process. From structural steel to supportive piping systems and decking, welding processes ensure the integrity and safety of every modern ship. 

Considering the cyclical and unpredictable nature of waves, the structural ship components must be produced with maximum quality. Ships are exposed to significant dynamic loading due to unpredictable buoyancy forces and wave configurations. Every ship must respond to these forces with transverse, longitudinal, torsional, and local strengths. But to do that, all structural components must have exceptional weld quality. 

Some of the most critical structural components of a ship are: 

  • Keel – a ship’s backbone that runs along the center plane at the bottom of the ship.
  • Framing – transverse members running continuously from the keel to the deck. Commonly referred to as “ribs.”
  • Plating – the outer-most structure of the ship that provides a watertight layer. Depending on the position, plating is referred to as bottom, side, or deck plating.
  • Longitudinal – girders parallel to the keel on the bottom of the ship that provide longitudinal strength of the bottom hull.
  • Stringers – girders on the side of the ship placed against plating.
  • Deck beams and girders – the deck frame’s longitudinal and transverse structural members.

Welding Processes Employed In Shipbuilding

“Welding is applied in almost every step during the shipbuilding process”

Shipbuilding requires the use of industrial welding processes, like submerged arc welding, and highly sophisticated welding processes, like orbital TIG welding. Since ships are complex structures, they rely on multiple sophisticated systems, not just structural framing. For example, hydraulic line systems are critical for the ship’s functionality and require orbital TIG welding for maximum joint precision and quality.

MIG Welding

MIG welding offers exceptional productivity and travel speed, especially for welding aluminum. Any in-door welding is likely to benefit from the MIG welding process. The equipment is easy to set up and use, and the process is easy to master. The filler metal wire is continuous, which significantly improves productivity compared to stick and TIG welding, where the welder needs to stop to replace the electrode/wire. 

Advanced MIG welding processes, like pulsed MIG, allow for an additional productivity boost. Pulsed spray transfer improves penetration, deposition rate, and travel speed, and it’s especially beneficial for MIG welding aluminum. High-speed boats and ships, like those used by coastguards and leisure vessels, must cut weight wherever possible, making aluminum a preferred choice for various structural members. Still, welding aluminum is tricky, but not when using the pulsed MIG welding process.

Shipbuilding requires welding many challenging steel and aluminum alloys. So, not every welding machine is the most productive choice. But, specialized pulsed MIG welders, like the Extreme 360 MAP, can handle almost any job, including the hard-to-weld aluminum alloys used in shipyards. 

Depending on the application, you can also benefit from specialized, high-power multi-process welders. The FX650 Red-D-Arc welder supports MIG, TIG, SAW, FCAW, and stick arc welding with a maximum output of 750A at 60% duty cycle and 650A at 100 duty cycle, allowing you to weld extremely thick structural members for as long as necessary.

There are many specialized MIG welding power sources in our arsenal that can specifically benefit shipbuilders. The MIG welding process is one of the most productive manual welding processes for in-shop welding or outside when there is no wind draft. But you’ll benefit the most when choosing powerful MIG machines with features suitable for alloys and thicknesses used in ship construction. 

Flux Cored Welding

Flux-cored arc welding uses the same equipment as MIG, but it can run with or without a shielding gas. Since some ship parts are welded in open shipyards, contractors benefit from using self-shielded flux-cored wires because they don’t need a shielding gas and offer many of the MIG’s benefits. In addition, FCAW can provide a higher deposition rate and deeper penetration than MIG. Since the FCAW wire is tubular, it has a smaller cross-sectional area compared to solid MIG wire. As a result, the FCAW wire carries a higher current density and melts at a faster rate, resulting in a higher deposition rate. 

FCAW welding is best applied to thick structural steel where you must deposit a lot of metal to fill the joint. It’s one of the most productive manual welding methods, especially when working outdoors.

Submerged Arc Welding

Submerged arc welding is better than MIG and FCAW at welding thick structural steel because it has a higher deposition rate, better weld quality, and can operate at extreme amperages (above 1000A). Like MIG and FCAW, SAW welding equipment is readily automated to produce precise joints when welding extremely thick steel. But thanks to SAW’s immense deposition rate and ability to weld extreme thicknesses, it’s the best choice for welding a ship’s framing, girders, and other structural members.

The SAW is best applied when making long, straight welds. You can use a seam welding machine in combination with a SAW system and a SAW welding power source to automate your structural steel welding and significantly improve productivity and weld quality. 

Steels used for ship construction can be highly specialized. For example, icebreaker ships must be made with high-strength steel alloys that require specialized welding procedures. Depending on the welded alloys and application, shipbuilders can benefit from advanced submerged arc welding power sources. The Lincoln Electric Power Wave AC/DC 1000 is an excellent example of a sophisticated SAW machine. It includes Lincoln’s Waveform Control Technology, allowing you to control the frequency, amplitude, deposition rate, penetration, welding speed, and other crucial welding aspects. Unlike most traditional SAW machines, Lincoln’s 1000 AC/DC SAW welder can help you fine-tune the submerged arc precisely to the weld specification needs. This makes it easier to achieve inspection-passing welds on critical ship parts made from hard-to-weld steels.

MMA Welding

While MIG, FCAW, and SAW offer significant productivity benefits, depending on the application and operator training, the stick welding process can often be a solution to many shipbuilding problems. First, stick welding doesn’t require a shielding gas, so you can weld in open shipyards and conduct on-sea repairs without worrying about shielding gas coverage. Next, stick welding equipment is very simple to set up, and hundreds of electrode types are readily available. 

Our rugged stick welding gear is more than capable of handling harsh shipyard conditions and on-sea challenges. For example, the Red-D-Arc E500 stick welder utilizes the tubular Pak-Lok-Frame and extreme-duty stainless steel construction. But this welder isn’t just built for harsh environments. It’s made for heavy-duty welding with exceptional arc characteristics. You can weld extreme steel thicknesses with its 650A output and tune your arc for maximum stability and precision. Its arc characteristics are particularly useful when welding with low-hydrogen and stainless steel electrodes. In addition, it reduces spatter and resists pop-outs, which improves productivity and makes it easier to achieve a high-quality weld.

TIG Welding

While manual TIG welding is slower than MIG, FCAW, and SAW and can’t provide a comparable penetration depth, it has many uses in shipbuilding applications. 

The TIG welding method offers the highest level of weld precision, purity, and quality. In addition, the TIG welding process can be used on virtually all metals and alloys, making it the most versatile welding process. 

When you think of shipbuilding, you are probably picturing large structural pieces being welded and assembled together. While structural welding plays the number #1 role in keeping a ship safely afloat, many more ship systems are needed for the proper functioning of a modern vessel. Usually, the more advanced and sophisticated the equipment, the more accurate welds have to be. That’s where TIG welding often comes in with its impeccable arc and weld quality, allowing the production of exceptionally clean and quality welds.

The best example of ships that require highly complex equipment are the floating production storage and offloading vessels (FPSO). These ships receive oil from platforms or produce it themselves by tapping into the subsea oil wells. The FPSO ships are highly complex and can cost up to 1 billion U.S. dollars and require an enormous amount of pipes, pressure vessels, heat exchangers, and other specialized equipment for storing and processing hydrocarbons.

Other examples include but aren’t limited to leisure cruise ships, tankers, submarines, and military warships like frigates and aircraft carriers. These ships can have miles of various kinds of critical pipes and tubes and specialized equipment like nuclear power cores for the ship’s energy. While MIG welding can be applied to many of these systems, TIG welding is a primary choice for critical welds that must pass stringent code requirements.

Red-D-Arc has a large fleet of high-end TIG welding equipment, including the Miller Dynasty and Synchrowave line of industrial-grade TIG power sources. The possibilities with the Miller Dynasty 400 are almost limitless. You can set the amperage output independently for EP and EN parts of an AC TIG, control AC frequency, modify AC balance, and choose up to four AC TIG waveforms. In addition, the Dynasty 400 supports extreme pulsing capabilities, allowing you to pulse weld with up to 5000 pulses per second on DC and 500 PPS on AC TIG. Whatever alloy you need to weld, our equipment has you covered. With this much arc adjustability, you can finely tune the average heat input and get impressive results on stainless steel alloys or adjust the EN, EP, balance, frequency, and waveform for a perfect aluminum weld regardless of the aluminum series. 

Another crucial TIG application for shipbuilding is the automated orbital TIG welding of pipes and tubes. It’s challenging to manually make a sound TIG pipe weld, especially if you need to make hundreds or thousands of these welds for hydraulic, power, steam, water, ballast, fire protection, and other critical lines. Thankfully, using our Axxair orbital weld heads, you can make consistent quality TIG welds in minimal clearances with maximum precision all day long without worrying about operator fatigue and a high amount of rework. Orbital TIG welding can dramatically improve your productivity as a shipbuilder. Welding a ship’s piping systems takes significant time and resources. But orbital welding can make this process far easier and faster, which can directly improve your bottom line.

Rent or Lease Welding Equipment From Red-D-Arc

Whether you are constructing oil barges, military ships, or tourist cruisers, Red-D-Arc has the necessary welding and cutting equipment for every production step, from the keel to the deck. 

Contact us today, and our team of experts will work with you to help you choose the necessary welding equipment rentals for the welded alloys, structural parts, and piping and decking systems you need to fabricate.

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