When you think of welding, doing it underwater may not be the first image that comes to your mind. Yet, underwater welding is a vital part of many of the infrastructures and technologies that we use on a regular basis. While many of us have seen exciting underwater welding scenes in movies and video games, the job carries within itself life-threatening challenges and requires serious expertise on the subject.
Here, we will explore how does underwater welding work and how you can get started in underwater welding as a profession.
What Is Underwater Welding?
Simply put, underwater welding is the act of connecting metal with metal underwater through an electrical arc discharge.
However, unlike regular welding, it requires a much more sophisticated technique or training and a lot more weld experience. It is a highly risky task that can have fatal consequences if done improperly.
How Is Underwater Welding Done
There are two main ways welders can carry out underwater welding –
- Wet welding
- Dry welding
We will briefly discuss these methods.
This is the older of the two methods and the most commonly used one. Shielded Metal Arc Welding (also known as stick welding) method is generally used for wet welding.
Other methods that may also be used are friction welding and flux-cored arc welding. Shielded Metal Arc Welding process uses waterproof electrodes and condensed gas bubbles to protect the welder from electrocution.
The gas bubbles are created externally around the welding surface. The electric arc from the electrode is protected from water as the bubbles continuously push up against the water and repel it.
And the gas bubble is also vital to the formation of the welding metal beads. The pressure levels inside the bubble allow the melted bits of metal from the electrode to coagulate on the welding surface material and form the strong bonds needed.
Moreover, the welder must also make sure to be very precise with the speed and the length of the welding arc, as fluctuations can cause the gas bubble to dissipate and expose the welder to being electrocuted.
Furthermore, the limitations of this method are that it cannot be properly utilized deep underwater. Immense pressure in the deep will certainly not allow gas bubbles to form and hold up.
It is also not advisable for steels with higher amounts of carbon, as that may cause hydrogen-induced cracks under the beads.
This method is also known as hyperbaric welding or habitat welding. It was invented in 1932 and has been used on a commercial scale since 1965.
As the name suggests, this process involves creating a hyperbaric chamber near or around the structure. From the inside of the hyperbaric chamber, all water is pumped out and replaced with light gasses such as helium, argon, and oxygen.
The chamber also needs to be pressure balanced for the safety of the welder, as long exposure to pressure imbalance can cause severe health issues.
And the pressure balancing depends on how deep underwater the chamber is. Moreover, the most common method used in dry welding is Gas Tungsten Arc Welding.
It uses a non-consumable tungsten electrode and a protective inert gas like helium or argon. Welds made through gas tungsten arc welding tend to be more durable and lasting.
Dry welding is the most suitable method for welding in high depths (up to 1000 meters). It is also best for precision welding and welding on non-ferrous metals (metals with high carbon content).
Depending on the size and depth of the chamber, the specification of the work, and the type of metal – professional welders can choose between these approaches to dry welding.
- Habitat welding
- Pressure welding
- Dry spot welding
- Dry chamber welding
- Shielded metal arc/stick welding
- Flux-core arc welding
How Do I Get Started in Underwater Welding?
If you wish to become an underwater welder professionally, you will require a diverse array of skills. These skills range from being a proficient diver to an authorized welder.
In the United States, you may also require certifications in this craft to be qualified as commercial divers, based on your state’s laws. Here is a list of skills and certificates you will need.
- Underwater diving
- Underwater photography and videography
- Diving gear safety checking and maintenance
- Professional welding skills
- Underwater cutting skills and rigging expertise
- Welding safety procedure knowledge
- Diving certificate (acquired from a diving school)
- Professional welding certificate
- ASNT NDT Level II certification
To learn more, Underwater Welding Careers Guide.
What Are the Dangers of Underwater Welding?
As we have discussed previously, underwater welding can be a very dangerous activity if all safety standards are not adequately met. Underwater welding has an extremely high fatality rate at around 15%, which makes it one of the riskiest jobs on the planet.
In the United States, underwater welding accidents caused fatality averages to range from 6 to 8 deaths per year. There are other safety hazards and probable causes of injuries related to commercial diving and welding.
It’s the most common cause of injuries and deaths among underwater welders and cutters. It can result from faulty equipment or from a lack of caution. Wet welds are more prone to electrocution.
Drowning can occur without any fault of the divers. Faulty diving equipment or improper rigging, accidental leaks can lead to drowning.
Welding underwater might cause small pockets of flammable gas mixtures, especially when working on enclosed structures, such as pipes. If not properly vented, they may cause explosions when heat from the welding arc reaches these pockets.
If divers are exposed to a high-pressure environment for too long or surface too quickly after a deep water weld, the pressure imbalance in the nitrogen gasses in your bone joints can cause fatigue, severe joint pains, breathlessness, etc.
Hypothermia and Hearing Loss:
Other causes of injury to underwater welders are hypothermia due to the extremely cold temperatures of the water and hearing loss from excessive pressure in the deepest waters.
Future of Underwater Welding
Even though there are dangers involved, underwater welding can have an exciting career prospect. The demand for experts in this field is always high and is expanding every day.
As we use more technologies and are expand our infrastructures to connect with the world, we venture deeper into the seas for building bridges, pipelines, submarine internet cables, offshore oil drilling rigs, deepest seaports, and countless other constructions. And all of these ventures require expert welders.