5 Underwater Welding Information Essentials to a Career

Underwater Welding Information

Photo courtesy of Hydroweld.

Learning about underwater welding information can feel like you’re drowning in a sea of the unknown.

It’s a field mixed with rumors, technicalities and bizarre stories.

So what do you need to know to help you determine if this is a good career choice?

Let’s set the record straight:

Top 5 Underwater Welding Information Facts

We’ll highlight the underwater welding information you must know:

1. Becoming an Underwater Welder: Length of Time

It takes a minimum of 2.5 years to become an underwater welder. On average, it takes closer to 4 – 6 years to begin practicing underwater welding.

The length of time depends on several variables:

  • Surface welding practice and application (if any)
  • Acceptance and and program length of underwater welding school
  • Earning certification
  • On-the-job experience

2. Treasure Chest: Underwater Welders’ Yearly Salary

Underwater welders make a mean income of $54,340, but it ranges from $25,000 – $80,000 depending on your experience and projects.

Some earn even more, to the tune of $300,000.

But remember:

Many welder-divers don’t work year-round.

Some may earn their annual paycheck within 6 months, then live off of it for the rest of the year.

Money management and consistent professional networking are key to maintaining financial success.

3. Risks of Underwater Welding: Is it Dangerous?

The danger of underwater welding information is what you don’t know.

Lethal incidents through drowning, explosions and decompression sickness make underwater welding dangerous. Injuries can occur from electric shock and cold temperatures.

But most divers and surface teams approach each job with the necessary precautions.

Safety is first priority.

With safety measures in place, incidents rarely occur. And when they do, underwater welders are prepared.

4. How Underwater Welding is Possible

Underwater welding is possible because of the gaseous bubble that protects the electric arc. That bubble shields the weld from surrounding water.

It’s made up of three components: hydrogen, carbon monoxide and carbon dioxide.

That’s the jist. But it’s not quite that simple.

Learn what separates underwater welding from surface welding (with a bonus at the end):

5. Wet & Dry: Underwater Welding’s Best Kept Secret

Underwater welding information covers two types of applications.

Many tropical places in the world have two seasons: wet and dry.

Underwater welding works the same way.

Welder-divers can learn both types in their trainingwet welding and dry welding. As technology has progressed, wet and dry welding have undergone major changes in research and application.

Let’s define wet and dry welding.

Wet welding: Welding with water directly surrounding the welding site in a wet environment.

Dry welding: Welding at higher pressure with insulation from water around the weld site. The welder works partially or fully inside of a habitat in a dry or semi-dry environment.

When someone brings up underwater welding, most people picture a diver floating in clear water with a gentle glow at the end of one’s electrode. In reality, very little underwater welding takes place directly exposed to water (wet welding). Most is done in habitats (dry welding).

Every underwater welding project requires a decision by the engineers and managers to determine which type of weld would best suit their needs. We didn’t include hyperbaric welding income in the chart, as that’s more affected by the underwater welder’s skill than welding type.

Here’s a breakdown of the advantages and disadvantages of each.

Underwater Welding Information: Average Wet & Dry Comparisons

[chart]
Type,Cost,Danger,Visibility,Accessibility,Weld Strength,Use
Wet,Low,High,Low,High,Medium,20%
Dry,High,Medium,High,Low,High,80%
[/chart]

Wet Welding

Wet welding works a lot like playing the drums – easy to learn, difficult to master. In fact, the American Welding Society (AWS) has a set of Class “A” tests set aside for only the most skilled of underwater welders. And few succeed in passing them.

Water Wonderland: How it’s Done

In general, welder-divers treat welds below water the same way they treat welds on dry land. Both require the same basic welding equipment and techniques. That’s why the best underwater welders get their welding experience above the water’s surface first.

Underwater wet welds use arc welding to create an electric arc between the electrode and the metals. After preparation and planning with their team, welder-divers will dive down to the correct depth, in full diving gear, usually using surface-supplied air. They wear rubber suits and gloves to create more insulation between their bodies and the electricity generated by their surface power supply.

Common Welds

  • Shielded Metal Arc Welding (SMAW): The most common type of welding in the underwater and topside industry, it is used 90-95% of the time in wet welding. Many refer to it as “stick” welding, because welders use a long, thin cylinder (electrode) and an electrical arc to accomplish their work. Application for stainless steel, aluminum and other metals.
  • Flux-cored Arc Welding (FCAW): Contains a spool that provides a continuous feed of filler metal for welders. Application for nickel-based alloys, cast iron, and other metals.
  • Friction Welding (FW): Fuses metal together through high friction and heat. Material melting does not occur. Application for metals and thermoplastics.

Surface welders keep their metal clean before placing their bead, and it works the same way under the waves. Once underwater welders have reached their weld point, they’ll scope out the area and make sure no obstructions or safety hazards surround it. They may do this several days before they perform the weld. Once the welder-divers are ready, they’ll place their electrode on their starting point and signal their team to flip the switch.

[responsive_video type=’youtube’ hide_related=’0′ hide_logo=’0′ hide_controls=’0′ hide_title=’0′ hide_fullscreen=’0′ autoplay=’0′]https://www.youtube.com/watch?v=Z0oTOEBZ7wI&feature=youtu.be[/responsive_video]

Typically, wet welds will be executed with a power supply generating 300-400 amps of electricity, always using direct current (DC). Direct current is a constant, one-way ticket. It creates a safer, more effective weld in the surrounding water than alternating current (AC).

Until recently, the wet welding process has always been considered “patchwork” and a temporary fix. New electrode technology has changed wet welds in some types of repairs.

Challenges under Pressure

Welder-divers face numerous complications when they wet weld.

Here’s a list of the most common ones:

  1. Arc constriction
  2. Steaming
  3. Deposition Rate
  4. Bubbling Effects
  5. Electrode Diameter
  6. Underwater Welder Position

The troubling part of wet welding comes into play with deposition rate and bubbling – no matter how much our technology improves, these factors will always hurt the strength of welds exposed to the surrounding water. More specifically, wet welds experience hydrogen embrittlement, a process where large amounts of hydrogen (formed from surrounding water vapor) dissolve into the weld.

Now that I’ve soaked you with hyperbaric welding information, let’s explore our dry counterpart.

Dry Welding

“Dry welding” is commonly called hyperbaric welding or habitat welding.

All refer to the same basic process.

Let’s take a look in how it works:

Underwater Dry Welding Chamber

Photo courtesy of AYSAN Hyperbaric Chambers

All dry welds involve a hyperbaric chamber or habitat that seals around the structure needing welded. After sealing, connected hoses push all water out of the hyperbaric chamber and fill it with a gaseous mixture such as helium and oxygen. The chamber is then pressurized to the correct depth.

Just like wet welding, dry welding is a specialized field populated by expert welder-divers. just because they’re in a dry environment, dry welders still have many more variables to work with than surface welders such as different atmospheric gas, pressure, equipment and limited space. Dry welding includes several methods, depending on the repair, cost and other factors.

Dry Welding: One Type, Four Methods

Here’s the four types of techniques that welder-divers use.

As you’ll see, the last three methods are almost identical to each other except in the size of habitat used. It’s a tier system that keeps shrinking.

  1. Pressure Welding: Working in a pressure vessel measuring one atmosphere unit of pressure (same as pressure at sea level).
  2. Habitat Welding: Using a chamber in ambient pressure (same as surrounding pressure at working depth) about the size of a small room to weld. Before entering, the chamber displaces its water into the surrounding ocean or lake.
  3. Dry Chamber Welding: Think habitat welding, but with a smaller chamber. The chamber holds the head and shoulders of a welder-diver (dressed in diving gear) and is open at the bottom for the diver to fit in.
  4. Dry Spot Welding: Now think even smaller. The habitat shrinks to the size of about the welder-diver’s head, and it’s completely clear. It’s placed on the weld site and the welder-diver inserts his or her electrode inside the habitat, which seals around it.

[responsive_video type=’youtube’ hide_related=’0′ hide_logo=’0′ hide_controls=’0′ hide_title=’0′ hide_fullscreen=’0′ autoplay=’0′]https://www.youtube.com/watch?v=JO6IA7QHN9Q&feature=youtu.be[/responsive_video]

Habitat, dry chamber and dry spot welding all work on the basis of ambient pressure, and the deeper down you go the harder it is to create a good weld.

This difficulty is due to the pressurized gases surrounding the weld site and the electrode arc. Thinner gases cause the arc “roots” to contract and the flow and behavior to increase dramatically. It’s like throwing a frisbee on a windy day: It’ll go further, but you won’t have any accuracy.

Common Welds:

  • Shielded Metal Arc Welding (SMAW): Previously defined.
  • Flux-cored Arc Welding (FCAW): Previously defined.
  • Gas Tungsten Arc Welding (GTAW): Also known as “TIG,” is achieved with an electrode made of tungsten, non-consumable. Heat is applied with an electric arc. Application for stainless steel, aluminum, and other metals.
  • Gas Metal Arc Welding (GMAW): Also known as “MIG,” this welding process is done with a shielding gas running through the welding gun around the electrode. Known for its diverse metal transfer methods. Application for aluminum and other non-ferrous metals.
  • Plasma Arc Welding (PAW): Uses an electric arc but constricts the arc, like pressurized water in a small hose. It allows for high arc (plasma) speed and intense heat to the weld site. Application for stainless steel, aluminum, and other metals.
Underwater Hyperbaric Welding Information

Hyperbaric Welding Habitat. Photo courtesy of Oxylance, Inc.

If welder-divers must perform an extensive weld deep underwater in a large hyperbaric habitat, they’ll usually work in pairs of two.

Looking at hyperbaric welding information, here’s how it works:

First, operators will lower the habitat chamber down to the weld site and fill it with gas.

Then, the underwater welders will drop in a diving bell to the same depth, where they will swim over into the chamber to start work. Since there is two of them, they’ll be able to trade off and work six to eight-hour shifts.

This method also allows for surveillance by surface technicians for safety reasons. Also, welder-divers can perform non-destructive testing to make sure the weld will hold for years down the road.

Hyperbaric Welding Facts: Choosing Wet or Dry

As you can see, all underwater welding is not created equal.

Both wet and dry types have their advantages and disadvantages, and there’s no formula to decide which type of welding gets used in a given situation. Several key factors influence which welding process is applied:

  • Welder-diver skill
  • Project budget
  • Safety concerns
  • Location and depth
  • Project time length

Offshore has increased largely in the past decade, and the demand for skilled underwater welders will always be present.

Most dry welding takes place in extremely shallow waters, especially in offshore operations.

Overall, companies have limited underwater weld operations to 400 meters or less. Further depths have shown to dramatically increase safety concerns for underwater welders. Some welding simulations have actually shown that dry welding can be done at close to 2,500 meters, but those were under controlled conditions.

New Technology in Hyperbaric Welding

Let’s look at the future of underwater welding information.

Advances are being made.

The automation of the welding process underwater has given a boost to the industry.

“THOR’s (TIG hyperbaric orbital robots)” have changed the way underwater welders do things.

Once they’ve reached the weld site, the welder-diver must simply install the track, orbital head and pipefit. Afterward, THOR takes over the rest of the weld.

In addition, Subsea Global Solutions, a maritime company, has applied wet welds that meet the standards set by the AWS 3.6 underwater welding code.

This means that underwater welders now have the capability to create permanent wet welds.

Which type seems harder to you to perform, wet or dry welding? Let me know in the comments below!

Updated: September 26, 2016 — 6:52 pm

4 Comments

  1. will the bubble act as a shield in underwater friction welding?

    1. Hey Vikrant, because friction welding is more similar to forging than welding, the weld area is not protected in the same way. Underwater, these types of welds cool faster and are prone to cracking. To counteract this, many welder-divers surround the weld site with foamed plastics: http://www.twi-global.com/technical-knowledge/faqs/process-faqs/faq-can-friction-welding-be-carried-out-underwater/

  2. dry welding seems harder to perform

    1. Amit, certainly preparation is more difficult since it requires greater resources and planning around the use of a small or large hyperbaric chamber. Once that’s in place, though, dry welding is arguably easier than its wet welding counterpart. Or at least accompanied with a higher success rate.

Comments are closed.