Underwater Welding |Equipment |Career |Salary |Pros |Cons |Applications

What is Underwater Welding?

The type of welding which takes place at an elevated pressure normally under water is known as underwater welding.

Underwater welding can take place either in wet condition i.e. in the water or dry condition i.e. inside a specially constructed enclosure called as “habitats”.

Difference between wet & dry (hyperbaric) Welding

When welding is carried out in a dry environment inside specially constructed enclosures i.e. habitats then it is called dry or hyperbaric welding. Special diving chambers are used to dry out the air around the welding work.

When welding is carried out in a wet environment like inside water then it is called as an underwater wet welding. Diver’s equipment is carried out by the welder to weld required area.

dry and wet welding

Why underwater welding?

Underwater welding is required on off-shores in some sort of heavy machinery which can’t be weld on the surface. It is also required in shipwrecking and ship maintenance underwater.

Surely, we are not in a condition to take out this big fan from the water attached to the ship, then guess what?.

How we are gonna achieve this?

That’s when underwater welding comes handy.

We need some alternate solution to weld the fan. This can be achieved only with the help of an underwater welder.

Underwater welding needed

Welders having various physical & mental skills are the best choice for underwater welders because it is one of the toughest jobs in the world. Secondly, it depends on the experience of the welders as well.

underwater welder

Why underwater welding is difficult?

Tell you what, people are so afraid of this underwater welding but it is only the hype. Though, it is difficult but not as much as it is considered to be. Certain precautions & you are good to go.

Various reasons behind the difficulty of underwater welding include

  1. High pressure underwater
  2. Very low temperature underwater
  3. Wet environment
  4. Dissolved gases in the water
  5. Marine life can affect the welding

Underwater welding Invention & History

This welding was invented by Konstantin Khrenov a Russian metallurgist in 1932. He performed underwater welding in a lab test.

First practical work was carried out on underwater welding in 1946 in British to seal the leaking ship rivets underwater. Waterproof electrodes were made in Holland.

Later in the 1970s, a qualified underwater wet welding procedure was introduced to the “American Welding Society (AWS)”.

How underwater welding works

  • In all of the welding techniques, welding power supply is connected to the welding equipment with the help of cables and hoses.
  • Mainly this process is useful for low carbon equivalent steels only when depth is slightly higher. Also, there are high chances of cracking due to the hydrogen.
  • If stick electrode is being used then wet welding is carried out in the same way as dry welding only electrode holders are designed for water cooling and are insulated heavily.
  • If these electrodes are used out of the water then they will be overheated.
  • Direct current is used with a heavy duty isolation switch in the cable at the control surface position to disconnect the welding current when not in use.
  • The operator at the surface is given instruction to make and break the connection as required.
  • Contact should be closed when actual welding is being carried out and should be opened when the electrode is being changed.

Underwater welding electrodes

Each underwater welder uses his own equipment preferred brand electrode.  One of the main challenges for the electrode manufacturers is to make it waterproof when being used for underwater welding.

Waterproof electrode

Electrodes are copper coated graphite/carbon electrodes which are specially made for underwater welding. Special electrode holders are used for water cooling & are heavily insulated.

Direct current is used for powering the electrodes in case of wet welding. But in the case of hyperbaric (dry) welding, both direct and alternating current can be used.

Dry (Hyperbaric) Welding

In dry hyperbaric welding, the weld is carried out at a raised pressure in the chamber which is filled with gas mixture & gas is sealed around the welding structure.

Chambers/Habitats

Chambers which are also known as “habitats” can occupy 2-3 people if their size is large enough.

Larger habitats are used only in major projects like oil rigs because of the high cost.

Types of habitat

Habitats can be in 2 different sizes depending upon the requirement of the weld are

  1. Mini Habitat
  2. Large Habitat

Underwater welders also use small enclosures as well; they include the ones which only fit the upper body or those which only enclose the electrode itself.

The design of the habitats is simple due to this reason they are sometimes cheaper as well.

For example, if spot welding is carried out in the habitat then the only requirement is “water needs to be displaced with the air” so in this case there is no need of breathable environment for welders.

These habitats have almost similar pressure to the surface level. The slight increase in the pressure provides continuous air in the chamber for underwater welder diver to work.

The team at the surface pumps air into the habitat either from ceiling or sidewalls. The habitat draws air from the ceiling/walls with the help of fans and pipes.

New air is pumped in and the old air is pumped out with the help of fans and pipes to make sure that no toxic fumes are build up in the habitats, which can cause the welders to suffocate.

For pressurizing purposes diver team uses helium mixtures at greater pressures.

Equipment & Circuit diagram of Dry Welding

Equipment and circuit diagram used in dry welding vary from that used in wet welding. Electric cables are insulated only once. Both direct current (DC) & alternating current (AC) can be used in dry welding.

Circuit Diagram of Dry Welding

Dry underwater welding circuit diagram

Equipment

Following equipment is used in dry underwater welding.

  • AC/DC power source
  • Electrode
  • Electrode holder
  • Return lead
  • Workpiece

Welding techniques Used in Dry (hyperbaric) Welding

Mostly arc welding processes are used in hyperbaric welding.  Gas Tungsten Arc Welding is the most commonly used technique in hyperbaric welding.

Following techniques are carried out in dry hyperbaric welding.

  1. Shielded metal arc welding (SMAW)
  2. Flux cored arc welding (FCAW)
  3. Gas Tungsten Arc Welding (GTAW)
  4. Gas Metal Arc Welding (GMAW)
  5. Plasma Arc Welding (PAW)

These techniques can be carried out at hyperbaric pressures but when the pressure increases all are suffered.

When pressure increases a significant change in the capacity and efficiency of welds occur.

Work is being done to use laser welding technique in underwater welding as well.

Welding Depth

Using some special techniques it has been made possible to weld under a depth of 2500 meter in the laboratory but keeping in view the physiological capability of divers it has been limited to weld at 400-meter depth only due to high pressure.

Advantages & Disadvantages of dry (Hyperbaric) welding

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Pros
  • Welder safety
  • High-quality welds are formed
  • Surface monitoring Testing is non-destructive
  • Both A/C & D/C current can be used
  • Before and after weld heat treatment is possible
  • Presence of habitat increases control of the welding
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Cons
  • Time taking process
  • High process & training cost
  • Costly equipment is required in the high ratio
  • More energy required if the depth increases
  • Welding difficulty, if the area to be weld is very small
  • Chamber fabrication changes for different applications

Underwater Wet Welding

In wet underwater welding, welder and welding electrode is directly exposed to the water and surrounding elements. Direct current that is used for powering the electrodes varies from 300-400 amperes.

Heat Distribution on the weld area

In wet welding, the heat of the electrode needs to be distributed in the weld area with extreme care. Heat on the weld area is controlled through the charged electrons.

Areas of Heat Movement

Heat movement takes place in the following 3 areas

  1. Weld area which acts as an anode
  2. The electrode which acts as a cathode
  3. Gaseous cylinder from where electric arc travels as a plasma

When arc strikes the underwater weld area electrons from the cathode (which is negatively charged) travel down toward the anode (which is positively charged). Ions move towards the cathode.

This particle movement occurs in a larger amount which causes a greater amount of heat & energy to be produced. The temperature of the arc heats up to 5000 oC.

This heat doesn’t distribute uniformly, more than 60% of the heat goes to the anode while the other heat stays at the cathode tip.

Protection of wet weld area

Wet weld area can be protected with the help of forming a gaseous bubble around the arc. The mixture of gases is used to compose the bubbles.

How Bubbles are formed?

Following three gases are mostly used to produce a gaseous bubble.

  1. CO2, Carbon dioxide (25%)
  2. CO, Carbon monoxide (25%)
  3. H, Hydrogen (70%)

The electrode which is used in underwater wet welding is waterproof. “Flux” which is a thick material is coated on the surface of the electrodes.

When the electrode burns, a chemical reaction takes place due to the presence of the flux and gas bubble is formed around the weld area which is used for protection. The bubble is formed only around the small area of the weld.

Drawbacks of the bubbles formation

A unique challenge that is faced by the underwater welders is the excessive formation of the bubbles around the weld area because of the chemical reaction taking place due to the presence of the flux.

Excessive bubbles produce following 3 challenging problems

  1. Visibility hindering
  2. Rapid movement of the Weld puddle
  3. Risk of electric arc collapsing

These problems can be reduced with ease only when experienced underwater welders are doing the job.

Cooling of the Weld Area

Proper cooling of the weld is necessary because it provides more efficient and high-quality welds.

When the welder moves the arc on the weld area a metal liquid is left behind which is called “SLAG”. This slag covers the top of the seam which provides proper time to cool the weld.

More resistant flux is created which allow the slag to drip more evenly and for the consistent burning of the electrode for a better control of underwater weld.

Equipment & Circuit diagram of Wet underwater Welding

Underwater wet welding uses electric cables that are insulated twice. Only direct current is used in wet welding. Negative polarity is incorporated in wet welding. A knife switch is also added in the wet underwater welding. The knife switch is used to turn ON & OFF the power supply.

Circuit Diagram Wet Welding

Wet underwater welding circuit diagram

Equipment

Following equipment is used in the wet underwater welding

  • DC power source
  • Electrode
  • Electrode holder
  • Knife switch
  • Welding lead
  • Workpiece
  • Return lead

Welding techniques Used in Wet Welding

Varied forms of arc welding are used in wet welding.

  1. Shielded metal arc welding (SMAW) employed with a variation of a waterproof electrode
  2. Flux cored arc welding (FCAW)
  3. Friction welding

Advantages & Disadvantages of Wet welding

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Pros
  • Welder safety
  • High-quality welds are formed
  • Surface monitoring Testing is non-destructive
  • Both A/C & D/C current can be used
  • Before and after weld heat treatment is possible
  • Presence of habitat increases control of the welding
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Cons
  • Both welder & electrode exposed to the water
  • Higher risk of electric shocks
  • Alternating current (A/C) cannot be used due to high risk of safety
  • Reduced visibility underwater
  • Chances of Hydrogen cracking
  • -Ve polarity is used

Risks Associated with underwater welding

Shark attacks

Sharks and other marine life are not one of the big threats in underwater welding. Most of the times they can get in the way of welding and can cause a delay in the work. As the delay increases the time spent underwater also increases which mean the risk is also increased.

 Safety measures to reduce Shark attacks

The welding team should explore the area of work before starting the welding so that they can remove any sort of complications and sharks if found in the area.

Electric shock

Welding divers go through the risk of electric shock whether it is wet or dry underwater welding. Even though there is more chance of electric shocks in wet underwater welding since they are completely exposed to the water. This risk further increases if you are working in flash zones & are bound to hold your position while you are working.

 Safety measures to reduce Electric shocks

Direct current is a must for wet underwater welding. Its precautions include the following

  • Make sure to wear a rubber suit and gloves
  • Cables should be insulated twice in case of wet underwater welding
  • Waterproofed electrodes which are fully insulated must be used
  • Never change the electrode when power is live
  • Knife switch should be opened only when the diver is ready to power the electrode
  • The power supply should be placed on insulating materials like rubber or wood

Decompression Sickness

Most of the time underwater welding process is being carried out at a depth of a hundred meters; welders also go through pressure changes as well. This pressure change can cause damaging effects on the body of the welder.

Decompression sickness which is also known as “the bends ‘takes place when the diver moves up to the surface very quickly, during this dissolved gases are pushed onto the other parts of the body.

Fatigue, pain, and itching in different parts of the body like lungs, ears, joints, are the symptoms of Decompression sickness.

Safety measures to Decompression sickness

Risk of decompression sickness can be decreased when the diver moves up to the surface he should avoid

  • Quick ascending after a deep dive
  • Becoming dehydrated
  • Drinking alcohol
  • Continuous underwater dives in a small duration

Drowning

Failure of the breathing equipment which contains oxygen tank and breathing mask can cause severe consequences, most of the time death can occur.

When divers are working deep in the water and are unable to come to the surface quickly precautions should be taken seriously, since underwater welder relies on the surface supplied oxygen.

Safety measures to Drowning

If your oxygen supply is stopped & you are not aware of the cause then you should take following precautions

  • Don’t panic
  • Follow the directions of the surface team
  • Try to keep your head calm
  • Breathe slowly
  • Use emergency SCUBA supply if available
  • Make sure to check your helmet for any sort of malfunctioning

Gas explosions

There are greater chances of gases explosion (Oxygen & Hydrogen) if air is trapped in the chamber for a longer duration. Even Surface welders must take precautions as well. The surface welder should possess proper ventilation in the shop to keep the air moving. Proper ventilation removes the danger of any explosive gases to get collected.

Safety measures to reduce Gas explosions

  • Use vent tubes to move explosive gases from underwater to the surface
  • Check out parts of the equipment that can trap gases
  • Always start welding from the highest point and end at the lowest point
  • The electrode shouldn’t cross a specific temperature limit usually above 10,000 o

Underwater welding salary

The most important question everyone interested to be an underwater welder would love to get answered is “How much we can earn”? Right

Here you go then.

If you are an underwater welder and commercial diver then your salary depends upon various factors that include,

  • Your employer
  • Past experience
  • Underwater welding Equipment
  • Diving depths
  • The location where you are working
  • Certification
  • Dive methods
  • Offshore distances

These are the factors that are going to determine how much you are going to get paid for your work as an underwater welder or commercial diver.

Diving experience and location are the top 2 parameters of the underwater welder salary.

Diver welders on the list of top 10% make roughly 83,700$ to 90,000$ per year, while those on the list of the bottom 10% make around 30,700$ per year.

 

According to Commercial divers and global statistics, the average salary of an underwater salary is around 53,990$ per year and they charge almost 25.96$ per hour.

 

Saturation divers can make up to 500,000$ per year. Saturation divers receive extra 1$-4$ per foot.  Up to the depth of 100 feet, they charge 1$ then it keeps on increasing after this depth.

 

Underwater welding as a career

Underwater Welding Career

Underwater welder or commercial diver as a career may seem rewarding to you but it’s not for everyone, because it is quite challenging.

Industry demands total commitment, great work ethics, extensive travel, long hours, and great attitude, if you lack any of these skills then you might find difficulty adapting this as a career.

You should be ready for a mental & physical challenging career if you want to become a commercial diver or underwater welder.

Necessary Skills & Education

If you want to become a commercial diver or underwater welder then you should have following minimum qualifications for a great career.

  • High school diploma
  • Commercial diving certification
  • Mechanical aptitude
  • Ability to swim
  • Certified welding training

Underwater welding certification

An exam is held for the certification of Underwater welding. The conducted test for the certification includes effects of pressure & depths. The test also includes the quality of steel used in underwater welding.

GSI is a registered and recognized body for the certification underwater welders which can carry out this complex and full of risk welding process.

GSI trains the welders according to the required guidelines of DVS 1186.

You should be Certified Diver to obtain a GSI underwater welder certificate.

Underwater welding death rate

It has been clear through the studies that most of the welders die because of “drowning” and “decomposition sickness”. Also, each year 11 underwater welder diver die based on the Population statistics and old fatality rates.

Download Underwater welding PDF from HERE

Download Underwater welding PPT from HERE

 

Underwater welding Applications

It is most commonly used for repairing purposes. The most common material used in underwater welding is “THE STEEL”.

Underwater welding is also used for maintenance and constructions of

  • Docks
  • Waterways
  • Ships
  • Lock installations
  • Dams
  • Hydroelectric power stations
  • Underwater pipelines
  • Offshore oil platforms for ship buildings

Future trends of underwater welding

Underwater Welding Future Trends

Welding underwater is among one of the most difficult jobs in the world not only because of the dangers included but necessary skills and experience are important factors as well. If you are lacking in skills or experience then underwater welding can become troublesome.

As the world process, developments are being made each and every day to reduce human effort. Robotics technologies are helping to reduce human effort especially in risky areas but in underwater welding still, human beings are used as underwater welders. Underwater welders help to maintain the most important components of many industries.

Unless until most advanced robots are designed having multi-variety skills & who are capable of performing most intricate tasks with human dexterity, human underwater welders will be the most common source for most of the industries.

Underwater welding is both physically & mentally a challenging job. In terms of working conditions and risks associated it is not one of the best careers that most of the people would love to adopt. But, if you are physically & mentally strong & want to earn more in less time then underwater welding is a great choice for you.

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Summary
Underwater Welding |Equipment |Career |Salary |Pros |Cons |Applications
Article Name
Underwater Welding |Equipment |Career |Salary |Pros |Cons |Applications
Description
The type of welding which takes place at an elevated pressure normally under water is known as underwater welding. Underwater welding can take place either in wet condition i.e. in the water or dry condition i.e. inside a specially constructed enclosure called as “habitats”.
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The Welding World
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