Arc Welding and its uses in Industrial, Military and Civilian application with comparisons.

1. Arc Welding is

Arc Welding Is one of many common manufacturing and industrial processes used to fuse or join two pieces of metal, this is achieved by applying very high temperatures produced by an arc of electricity at the joint between two parts causing the parts to melt and intermix at the point of desired joining. Commonly Arc Welding is done with an intermediate molten filler material which upon cooling and solidification creates a metallurgical bond between the 2 work pieces, since the fusing is an intermixture of the 2 materials the final weld potentially has the same strengths as the metals in the work pieces. The Arc is formed between the work piece and an electrode that is manually or mechanically guided along the join. The electrode can be one of 2 types: 1. An inert electrode that’s purpose is to guide the arc between the tip and the surface of the join or 2. A specially engineered and designed electrode that also acts as the filler material that melts into the join during the welding process. Arc welding is used in many different fields of engineering and manufacturing with different applications needing either of the types of electrode.

1.1 Consumable electrode Arc Welding

Consumable electrode Arc Welding has many applications from repairing to construction and equally have many different methods that range from Gas Metal Arc Welding (GMAW/MIG Welding) to Shielded Metal Arc Welding (SMAW/Stick Welding) but all of these have an electrode that is used during the welding process that needs to be replaced as the electrode is melted and replaces the filler metal in the whole process. This type of weld is very versatile as it requires very little operator training and inexpensive equipment, However the overall weld times are rather slow due to the electrode needing to be replaced when depleted and the flux that coats the electrode turning into slag during the welding process needing to be scrapped of the surface of the weld. Generally, Arc Welding is normally restricted to welding only ferrous metals, However Special more expensive electrodes can be used to weld other metals such as aluminum and copper.

Consumable Arc Welding is used in all sorts of companies from the automobile industry to construction and even home use with many engineers and hobbyist owning or using MIG welders.

1.2 Non-Consumable electrode Arc Welding

Non-consumable techniques such as Gas Tungsten Arc Welding (GTAW/TIG welding) use an electrode made of tungsten, carbon or similar material, in conjunction with an inert or semi-inert gas mixture such as Argon and filler material to create a weld. While this is a less versatile method due to its higher operator skill and slow weld times it is often used for when higher quality welds are needed or when the work pieces are thin, this is due to a very stable arc that can create stronger and higher quality welds. Non-Consumable Arc Welding is also able to weld nearly all weldable materials but is most commonly used on stainless steel and other light metals.

Industries that need high quality welds such as aircraft, naval and bicycle companies use this method despite the slower manufacturing speeds, higher quality of training needed and their subsequent higher costings.

The Increased cost and experience needed to operate Non-Consumable Arc Welding make it a less common method among engineers and smaller companies.

2. Safety

Operating any sort of welding equipment should be done with all safety requirements met and risk assessments having been done to ensure that no damage is caused to personnel or the work pieces involved, Even more so with Arc Welding as it can be extremely dangerous if handled incorrectly leading to severe injury or in the worst-case scenario death.

2.1 Instillation of Arc Welder.

The first port of call for all welding safety is the correct set up and instillation of the welding machinery. The first part of this is making sure that the system you are using the welder in can handle the increased electrical load on the system, failing to do so can cause fires to break out or equipment failure. To prevent the failure of equipment it’s important to ensure that: A. the frame and the case of the welder is properly grounded, B. an emergency stop button or switch to be installed near the machine to cut off power and C. The welder to be protected by appropriately sized fuse, trip switch or circuit breaker on an independent circuit. Following all of these during setup will enable a safe as possible operation of machinery.

2.2 Ventilation

One of the key points in the safe operation and usage of an arc welder is the appropriate ventilation during use. The operator and the welder itself should be situated in an area of adequate ventilation, although most of the metals that are normally arc welded are considered non-toxic and non-hazardous, a system of around 2000 cubic feet per minute is still required. However, many materials, especially coated or galvanized metals are considered hazardous and to prevent the buildup of toxic materials and oxygen deficiency a larger volume of fresh air is needed. This is to prevent injury or danger to not only the operator of the welder but to anyone in close proximity to the site of the welder. When welding or cutting hazardous materials anyone close to the welder and the operator should wear a supplied air type respirator or specially designed respirators to filter out any toxic fumes.

2.3 Fire prevention and electrocution

The arc welder contains a live circuit and produces arcs that reach high temperatures that can cause large uncontrollable fires and severe burns to the operator and any bystanders as well as electrocution. To reduce the chances of these dangers occurring many safety steps and decisions must be made, the first is the construction and manufacture of the welding machine itself, having to pass the appropriate industry standard (ie ISO, BS, etc) to guarantee the safe manufacture of the welder. This includes everything from the correct insulation in the machine to the ease of cleaning the machine after use. The second is a high level of training on the operator as well as the correct protective gear when in use of the welder. Following these steps will ensure that the user and any bystanders as well as the machinery shouldn’t be damaged by fire or electrical discharge.

2.4 Personal Protection

Personal protection equipment is key in the safety of the operator using the welder, this is due to the potentially lethal consequences in accidents and misuse of the machine. Correct safety equipment includes but is not limited to: Safety shoes, clean fire-resistant clothing, face shield or mask, fire resistant gauntlet gloves and no excess material on the clothing such as pockets or cuffs. These specific safety clothing items enable the user to stay as safe as possible, keeping them grounded to the earth to prevent electrocution and making fires and burns an unlikely occurrence. Always avoid clothing with: tears, rips, snags or worn spots as these can be easily ignited by sparks and the arc produced. Eye protection is key, and the face shield used should be at least shade #10 for general welding up to 200 amps, however certain welding operations should have a darker face shield used.

2.5 Safe Operation

It is crucial that anyone operating the welder has had enough training on the welder by a qualified teacher or welder. Because of the violent nature of arc welding serious consideration needs to be made when deciding that arc welding is the correct method for the materials being welded. The correct placement of the operating area is key, welding should be conducted on firebrick surface at a comfortable operating height. The machine should be kept grease and oil free by regular scheduled cleaning and the welding should be done in a well-ventilated area to prevent the buildup of steam that can cause an explosion.

3. Corrosion

Many materials used in the arc welding are susceptible to corrosion, metals notably high-strength steel, aluminum and titanium alloys can be affected by hydrogen embrittlement. During the welding process contaminants may get onto the surface or the electrodes of the welder, if damp electrodes are used the water decomposes in the heat of the weld causing free hydrogen ions to enter the structure of the welding cause brittleness. New electrodes can be used immediately but if any moist concerns arise electrodes should be baked in a drying oven at around 550oc to 850oc. flux used in the process also needs to be kept clean and dry away from other materials in the workshop.

During the welding of stainless steels, a contaminant may form, this contaminant, chromium carbide, forms from the process called sensitization which corrodes the point of welding. This process happens when the chromium content of the stainless-steel drops below 12%, at these levels the chromium can no longer form a complete film over the entire steel structure meaning the areas not covered are susceptible to corrosion via intergranular attack.

Sensitization can be minimized by post-weld high-temperature annealing and quenching. This dissolves the chromium at the grain boundaries and prevents the formation of chromium carbide during the cooling process.

3.1 Prevention of corrosion

There are many different ways to protect from and prevent corrosion during arc welding:

•  Material selection – during the material selection process attention to matching materials and consumables will reduce the chance of corrosion by reducing the micro and macro differences.
•  Surface Preparation – before the start of the weld the surface of the work material must be cleaned of oils and contaminants to prevent contaminants entering the weld and causing deformities and corrosion.
•  Weld Surface Finishing - It is essential to inspect the weld deposit immediately after the welding process. For maximum resistance to corrosion, the surface must be smooth, uniformly oxidized and free of irregularities and other foreign particles. Grinding may be used to even out the roughness and weld spatter, while a wire brush may be used to smooth out the surface
•  Correct welding process – the operator of the welder must insure to use the equipment correctly from start to finish, including the clean up of the weld to the correct shielding of the weld.

4. Environmental

The main environmental impact created from the welding procedure is air pollution and its adverse effects on animal and plant life. In all types of welding a considerable amount of air pollution is created in the form of gases and fumes. These are created due to the extreme high temperature of the arc vaporizing materials and contaminants in the air into these fumes. Welding fumes are incredibly small and if inhaled can cause serious long term and short-term damage to human lungs as well as many other respiratory systems of other species. With gases however the most common gases are ozone and, nitrous oxide and carbon monoxide as well as phosphine and phosgene being produced in small quantities. Carbon monoxide and phosphine gases are extremely bad not only on health but cause considerable damage to the environment, with phosphene leading to acidic rain and CO causing damage to our atmosphere. Furthermore, produced waste during the welding processes results in undesirable impact on the work or natural environment. To protect the welding region and prevent oxidation, inert gases like carbon dioxide and argon are used because of their availability and low cost. Along side these hazards there are the inputs and outputs of the entire welding process that all use energy, from the large amount of energy needed to create the arc to the energy needed to transport waste to landfill.

All these factors however in the last 2 decades have been worked on and improved upon to lessen the impact of arc welding and all other welding on the environment and health.

5. Costs

There are many costs involved with the usage and production of arc welding. These include: operator costs, overheads, materials and design costing.

These costs are dependent on the practices of the business and/or user of the welder. They comprise factors such as rent, materials, bank interest, cost of workers. In addition, other accounting may affect the decisions on which is the most cost-effective joining method.

One of the most significant costs is that of labor and this varies with industry, time and country. The costs mentioned above cannot generally be influenced by the decisions made by a welding operator but rather by larger companies such as supplies or government bodies imposing taxes on supplies.

There are many costs, other than the cost of depositing weld metal that will affect the price of a welded fabrication itself.

The work done by the designer in designing the most cost-effective joint is key in reducing the costings for large welding jobs as this can save on material and labor hours. For example, the type of joint preparation the designer selects; a single or double-V preparation can be flame cut, a J-preparation must be machined and is generally far more expensive.

Costs that are directly affected by decisions made before any welding is done in addition to the cost of depositing weld metal, are therefore; joint preparation, assembly time, cleaning the weld, removal post weld heat treatment and cost of repairs.

6. Comparisons

6.1 Industrial

Arc welding in the industrial setting is used in construction, electrical applications, ship building, mechanics and equipment. Arc welding is used in these fields due to its welding properties, these are creating strong bonds between the weld pieces and ensuring a long and useful life of the final product.

Arc welding is fundamental to the construction industry, with thousands of projects daily using arc welding to ensure strong bonds and connections in everything from steel framed skyscrapers to metal-based bridges.

For harder more rugged applications arc stud welding is used to provide the control and strength necessary to firmly bond heavier pieces together, this is key in the automotive industry to weld heat shields, exhaust systems and hydraulic lines to the chassis and in the furniture industry with metal desks, filing cabinets and ventilation and air conditioning units.

For over a century arc welding has been used in the traditional ship building industry ensuring that the external surface of the boat is water tight as well as for securing hatches, fluid lines, control panels and many other critical and key components.

Arc welding has many more applications in the industrial setting from medical uses in hospitals to the assembly lines of many factory’s and workshops. Without arc welding there would be substitutions for the process but none as cost effective or have as many applications and uses, this would lead to slower production times and higher costs as well as draw backs in many other areas like safety.

6.2 Military

Arc welding and often GTAW welding is used in many military applications, mainly aircraft, vehicles and ships but is also used in the engineer corps of many militaries for on base and off base construction and repairs, for example bridge building over rivers and repairing of armor and fortifications of military camps and bases.

The main use of the arc welder in most militaries is the production and maintenance of ships, armored vehicles and aircraft as GTAW welders works well with aluminum and exotic alloys that are used to reduce the weight and fuel consumption of aircraft and vehicles.

To be an army welder requires a lot of training as the quality of your work can be life and death, whether it be emergency repairs on a tank to welding shut a fuel leak. Without the flexibility of arc welders or the experience behind the user the military would have to invest a lot of money and time into finding alternative solutions which could cause deaths among civilians and soldiers.

6.3 Civilian

There is a huge number of day to day services and products that everyone uses in there lives in one form or another, whether it is the buildings you visit and work in to the method of transport you use, arc welding is one of the most common you will come into contact with without even knowing it. Arc welding is used in: Infrastructure, public and private transport, theme parks and attractions, public services and products that you purchase. Unless you live a off the grid sheltered life you will come in contact with arc welding almost everyday and without it life would be not only harder but more expensive and possibly more dangerous.

“Welding is used in almost all manufacturing of Metal products. Without welding, our lives would not be as interesting. We wouldn’t have airplanes, trains, space shuttles or most buildings. Additionally, welding provides high paying jobs.” – Alan Saul.

Not only is arc welding key to our day to day lives its also taken up as a vital career path for many people with an estimated 40-80 thousand of these jobs in the UK alone, with many thousands more trained in welding and using there training on a regular basis but not as there main job, Arc welding and welding in general is a key skill to have with many companies employing people for workshop jobs with welding experience. Across the globe there are hundreds of thousands of workers who arc weld with over 400,000 welders in the US and many more crucial to the manufacturing heart of many countries, from the automotive industry to the aerospace industry and many more.

Alongside all of this enthusiast and hobbyist alike have picked up and use arc welding in their own homes and private workshops, with groups across the globe meeting at engineering, hobby and welding events and conventions to share there experiences and work with MIG welding being shared and voted as the most beginner-friendly starting point for many people.

Not only is Arc welding so prevalent in our day to day lives but the running of countries, the impact on businesses and economy’s but also a great adventure and hobby for many people.

Conclusion

In conclusion the world without arc welding and welding in general would be far different, we may have never built skyscrapers, trains and railway lines or even the cars we drive in to work.

Life would have had to evolve and changed very differently all the way back since the industrial revolution. Maybe the world would have been a completely different place, but it could have been far less exciting and more dangerous.

Arc welding in my opinion greatly impacts everyone’s lives for the better, providing money to workers and economies and allowing us to build amazing superstructures and infrastructure as well as achieve many great technological advances and improving everyone’s day to day live for the better.

As for business they would have to find an alternative method that would be more expensive and certain products and services would be impossible, as for existing industries like automotive the entire cycle would have to change completely from design to the actual making of the vehicles themselves.

Arc welding has been tried and tested for over a century with millions and millions of pounds/dollars invested into perfecting and evolving the method for many uses and while there would be alternatives if welding didn’t exist it would take many years and much more money to create anything close to as efficient as welding.