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Source: Cameron Dekker, "What is an Aerospace Welder, And How Do You Become One?" Waterwelders.com, 09 January 2022.

Summary: This article begins by summing up precisely what applications aerospace welding has and why certain welding techniques/processes or materials are needed. Additionally, the article provides a quick overview of different processes and materials commonly used in Aerospace welding. If aerospace welding interests you by the end of this magazine, the article contains a good section on the career path to becoming a certified aerospace welder.

Reflection: This article is needed to understand what exactly aerospace welding is. Most people (including myself) initially think that aerospace welding has a very limited scope or range of uses. In reality "aerospace welding" is a broad term used to describe any welder who works on any type of aircraft, be it airplanes, helicopters, or even space-fairing vehicles, which all necessitate special materials and welding processes.

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Last Updated on

You may have heard the term aerospace welder in airplane manufacturing or space travel. Aerospace is a specific niche within the welding industry.

So, how does one become an aerospace welder? You may be asking this question because you are considering your next career move. Becoming an aerospace welder is no easy feat, but it is attainable.

You must know what you want to do. In this article, we will tell you who an aerospace welder is, and how to become one.

What is Aerospace Welding?

Aerospace welding is a process used in aircraft, and spacecraft construction. It is also known as structural welding. It is commonly used to manufacture large structures used in commercial aircraft and spacecraft.

Aerospace welding differs from other welding processes because the welds are scrutinized for cleanliness. Also, the welds are heated to high temperatures and cooled fast. These high-temperature welds are somewhat brittle, and so they need extra precautions.

Aerospace welding is used to join metallic components and structures. It also provides structural support. Various welding processes are used in aerospace welding including:

Aerospace welding is not a new process but it has recently become more widespread. The benefits of the aerospace welding process over traditional methods include:

Who is an Aerospace Welder?

An aerospace welder welds in aerospace, particularly in aircraft and spacecraft. Most aerospace welders work in one of these three areas:

Most aerospace welders work indoors, at an airport, or in an aircraft factory. Usually, aerospace welders work in hot, noisy conditions.

Aerospace welders perform many unique welding jobs. These highly skilled welders use hot metal. They create high-tech products, such as airplanes, helicopters, rockets, satellites, and spacecraft.

The primary materials they use include:

How to Become an Aerospace Welder

Are you a student or already working somewhere else? Are you curious about the world of aerospace? If yes, you will be surprised to know that one of the most adventurous jobs in this field is aerospace welding. Here, we will tell you how to become an aerospace welder.

Get a High School Diploma or GED

Aspiring aerospace welders must have this diploma. It is the minimum requirement. But most employers will prefer an applicant to have an associate's degree in welding technology or a related field. Welding programs at vocational schools usually need applicants to have a GED or diploma.

Pursue a Four-Year Degree in Welding and Fabricating or Mechanical Engineering

Aerospace welders must earn a four-year degree in welding and fabrication. Welding and fabrication programs teach students how to use various materials, how to apply heat to these materials, and how to construct and repair metal parts.

Take the Exam Required to Get Certified

To work in aerospace manufacturing, you need certification. The certification process is not challenging. All you need is to demonstrate competency by passing a written test and showing your skills.

You must pass an exam administered by the American Welding Society (AWS). The exam is made up of two components. The first is a written exam. The second is a hands-on welding test, which you will complete at the AWS's testing center.

The exam covers a wide range of welding topics. Most welding schools in the United States offer classes that prepare you to take the exam.

Get Hands-On Experience through Internships, Apprenticing, or Working in a Related Field

To get hands-on experience, try an internship. It is a great way to learn about the field and get a taste of what it is like to work in the aerospace field. In most cases, internships are unpaid. But some companies will compensate you by letting you use the welding equipment.

Look for an internship in a welding shop or at a welding training school. If you do not have access to this type of shop, you will have to try something else like getting a job as an apprentice.

An apprenticeship is a formal relationship in which one person agrees to train another person. You will be working for someone else. But you'll be doing most of the work. The benefit is that you will get free training although you will not be paid.

Another way to get experience would be to work in a related field. If you want to be a mechanic, you can get a job repairing cars or trucks. Also, if you aspire to become an aerospace welder, you could get a job as an aircraft mechanic.

Get Licensed

One of the first things you need to do if you want to become an aerospace welder is to get a license. The license is issued by the local licensing agency in your county. For those currently employed in the industry, start by talking to your employer about obtaining a license.

If you want to work in a different capacity, contact an Aerospace Joint Apprenticeship and Training Committee (AJAC). A representative will determine the licensing requirements for the career path you follow.

Network with Others in the Welding Industry

Networking is one of the most important ways you can advance your career. These days, welding jobs are highly competitive. So, securing a good job is essential, even if it's an entry-level position. Networking will help you comfortably enter the aerospace welding industry.

The first step to networking is establishing contacts with people in the aerospace welding industry. When looking for a job in welding, you should consider joining a union, such as the American Welding Society, which will allow you to meet fellow members and build a network of contacts.

Additionally, you should join professional organizations. These professional organizations usually hold conferences and meetings. They also provide welding resources and publications. Having these contacts will increase your chances of landing a job as an aerospace welder.

Apply for an Aerospace Welding Job

Once you have decided to become an aerospace welder, you need to apply for the job. There are a few things you should do before applying. They include:

The application process usually takes a month or more. During this time, you must provide a resume. Your resume should include information, such as past work experience and education. It should also have your skills and references.

This interview can last 30 minutes or an hour. In the interview, you will respond to questions about yourself.

The background check is done online. Usually, it takes two days to complete. Ensure you disclose your criminal history.

A drug test proves that you do not have illegal drugs or alcohol in your system.

In the welding test, you will be asked to weld a sample. Usually, the test takes about 45 minutes. The test is graded on a pass or fail basis.

Typical Skills of an Aerospace Welder

Throughout an aerospace welder's career, one learns many skills. In every job, you have to think fast and solve problems as they come up.

As an aerospace welder, you need the following skills.

Conclusion

Do you want to become an aerospace welder? If yes, aerospace welding is a skilled trade that needs a combination of aptitude and technical expertise. Aerospace welders join or fuse different types of metals for a wide variety of applications.

Aerospace welders are a crucial component in the production of aerospace products. That is why they are highly sought-after by employers. They have passed extensive training to become part of this industry. If you want to become an aerospace welder, you must be willing to put in the work to get the training you need.

Featured Image Credit: aapsky, Shutterstock

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What is an Aerospace Welder, And How Do You Become One? - WaterWelders

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Last Updated on You may have heard the term aerospace welder in airplane manufacturing or space travel. Aerospace is a specific niche within the welding industry. So, how does one become an aerospace welder? You may be asking this question because you are considering your next career move.

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Source: "Welding Technology in Aerospace Industry" D&H Sécheron, 08 December 2021

Summary: This article explains the challenges that aerospace welders face. This article additionally describes why welding is starting to gain favor over rivets in terms of aeronautical construction.

Reflection: This article perfectly sums up the multitude of restrictive challenges in aerospace welding. The content in this article assists in building a better understanding of why advanced and complex materials and welding processes are used in this industry, especially for those with little knowledge of the industry or welding in general.

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Welding in the aerospace industry has seen some very fascinating and exciting developments in recent years. The ever improving knowledge of welding material, designs and welding as a whole are paving the way for welding being implemented in aeronautics.

Welds have been replacing rivets and bolts since World War 2 and hence, has become a favourite for the military, ship building and the aeronautics industry. This is for the simple reason that welding is cost-effective as compared to rivets, welds require less year-on-year maintenance, welding is structurally sound while being light-weight and rivets simply just add on to the weight of the aircraft or of the project.

Preferred types of welding in this industry are diffusion welding, laser welding and electron-beam welding. There are a few other very promising welding methods which are slowly gaining popularity and establishing quick effects too. These are, friction stir welding and variable polarity plasma welding.

While welding in aerospace is making ground-breaking improvements, there are certain challenges that are posed in the aerospace & defense industry. Let's have a look at those:

Uncommon Materials Materials used in welding for the aerospace and defense industry are often different from the common usage. Why? They need more malleable, ductile yet at the same time sturdy and lightweight metals.

Thus, 'exotic' metals and materials are used in aerospace applications. These are materials like stainless steel, and aluminium to begin with and high-end materials like inconel and titanium are widespread.

Complex Joint Designs

With unique and new structures in this industry, there are many complex joints and designs that have to be aced. Welding is the right choice for it, because rivets cannot do a job as smooth and seamless and very importantly, as lightweight as welding can. This requires efficient processes in the assembly line as well as the best of the best methods of welding.

For the purposes of overcoming the challenge of joints and uncommon designs of megastructures, electron-beam welding and laser welding are the best choices to weld two complicated parts and metals.

Airtight Sealing

In case of both aerospace as well as military counterparts of it, airtight sealing is required to protect sensitive material, both electronic and otherwise. Expensive gear that has to be uncompromised at all points, without any other failures and at all costs need this hermetic approach to be followed through.

This would not be possible without welding, and thus welding is not just a great choice, but also a must.

High thermal conductivity

Most metals, alloys and materials used in these industries have a very high thermal conductivity. Along with this, these materials also have a high crack sensitivity which makes it challenging for the welder.

The materials are difficult to weld with the common methods of welding since high standards of quality, airtight sealing and more is required of them. Therefore, more advanced ways of welding like electron-beam welding and laser welding are the preferred methods.

These are a few among the many challenges that one faces in the aerospace industry while welding. But it's a vast universe in itself, and a very interesting one at that!

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Welding Technology in Aerospace Industry | D&H Secheron

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Welding in the aerospace industry has seen some very fascinating and exciting developments in recent years. The ever improving knowledge of welding material, designs and welding as a whole are paving the way for welding being implemented in aeronautics.

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Source: "New Trends Emerge in Aerospace Welding Technology" Thomasnet.com, 07 December 2018

Summary: This article provides brief summaries of different welding processes, including conventional forms of arc welding along with lesser known advanced methods such as friction or laser beam welding. The article also mentions how welding processes are advancing as the materials to be welded become more complex and harder to work with.

Reflection: I chose to keep this article in because I think it provides a good introduction into the more advanced and specialized welding processes while also explaining the basics of common industry arc welding. It is important to realize too that the world of aerospace welding is always advancing as new materials, such as the magnesium alloys mentioned in the article, become more common within the industry.

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Welcome to Thomas Insights - every day, we publish the latest news and analysis to keep our readers up to date on what's happening in industry. Sign up here to get the day's top stories delivered straight to your inbox.

Aerospace manufacturers rely on aerospace welding processes such as arc welding to efficiently assemble large, intricate end products. Because of the complexity of aerospace design, major challenges including low unit production, high unit costs, high safety standards, and severe operating conditions consistently drive new welding technology and innovations in the field.

Manufacturers in the aerospace welding industry must follow strict quality standards to ensure strong, safe, and reliable parts for all their aircraft components. Stringent regulations set by the National Aerospace and Defense Contractors Accreditation Program (NADCAP) govern aerospace welding.

To comply with these regulations while delivering the most efficient products possible, aerospace manufacturers have adopted four main manufacturing techniques in their facilities:

Laser beam welding

Laser-arc hybrid welding

Friction stir welding

Electron beam welding

Trends in Aerospace Welding Processes

In recent years, magnesium alloys have seen massive growth as a durable replacement for aluminum in aerospace products. This recent explosion in the use of magnesium results from several developments in the arc welding field to improve process efficiency.

More recent research indicates that solid-state friction stir welding and high-energy density lasers are the most promising joining techniques for magnesium alloys. These techniques reduce and, in some cases, eliminate defects that occur during conventional arc welding processes and are discovered during weld inspections.
Arc Welding
Conventional arc welding operates by forming an electric arc between the workpiece and a consumable wire electrode, heating two metal elements to their melting points so they can fuse together. This process creates strong, solid joints once the metal cools.

Arc welding has many different forms, including metal inert gas (MIG) welding, which uses a consumable electrode, and tungsten inert gas (TIG) welding, which uses a nonconsumable electrode together with a filler metal to join different alloys. Both techniques use various shielding gasses to prevent contamination.

Similar to TIG welding, plasma arc welding techniques such as variable polarity plasma arc welding construct airframe structures and fabricate external space shuttle tanks. This technology is also known as friction technology, further discussed below.
Laser Beam Welding
Also known as keyhole or deep-penetration welding, laser beam welding (LBW) requires relatively low heat input. This makes it ideal for welding components that require minimal thermal distortion.

Aerospace manufacturers typically use LBW to weld aircraft fuselage panels as it works with a number of different materials including steel, aluminum, and nickel alloys. LBW also boasts high weld quality, low weld distortion, and high volume production.

LBW produces a concentrated heat source that allows for more efficient welding processes and safe production even in open environments. Because it reduces corrosion and is lighter, cheaper, and considerably stronger than traditional rivets, LBW is particularly beneficial for Airbus A318 and A380 design.
Laser Arc Hybrid Welding
Laser Arc Hybrid Welding (LAHW) incorporates arc welding and LBW, resulting in faster welding speed and penetration depths to improve weld stability.

MIG, TIG, and plasma arc welding are the three main types of LAHW. In particular, NASA values MIG welding for its ability to perform well in both high- and low-pressure environments.
Friction Technologies
Friction welding offers a melt-free alternative to traditional welding techniques. This solid-state process heat treats engineered materials to produce high-strength end products; because it expends less heat energy, it requires less preparation to join pieces. These benefits also make it a safer welding technique than other methods.

Because friction stir welding (FSW) efficiently joins dissimilar materials, it is an optimal way to weld high-strength steel to light-weight aluminum. FSW can also be used with thermoplastics, adding to its versatility as a welding process, and is the preferred welding technique for the construction of space shuttles.

Boeing has invested more than $15 million in FSW. High-end business jets such as the Eclipse 500 saved up to $7,000 per lb. after incorporating FSW, whose ability to work with lighter material also increased their range by 4%. FSW also manufactures A380 planes, making them stronger and faster while experiencing less corrosion and wear and tear.
Electron Beam Technologies
Recent improvements to the electron beam welding (EBW) process, which operates using a concentrated heat source, have increased its popularity for the large-scale fabrication of steel structures. However, the process must be conducted in a vacuum.

Aerospace manufacturers primarily use EBW to weld low-alloy grade F22 steel and titanium.

Welding Specialization to Increase Efficiency

New advances in aerospace welding techniques have significantly expedited the manufacturing process and moved beyond the capabilities of basic welding methods, creating increasingly specialized manufacturing sectors to enable more efficient mass production.
Image credit: safakcakir / Shutterstock.com
More from Industry 4.0

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New Trends Emerge in Aerospace Welding Technology

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Welcome to Thomas Insights - every day, we publish the latest news and analysis to keep our readers up to date on what's happening in industry. Sign up here to get the day's top stories delivered straight to your inbox. Aerospace manufacturers rely on aerospace welding processes such as arc welding to efficiently assemble large, intricate end products.

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Source: Ben Smye, "Aluminum Alloys for Aerospace" aerospacemanufacturinganddesign.com, 04 October 2018

Summary: This article contains a great deal of information about the types of aluminum used in aerospace welding, as well as the pros and cons of each type. In addition, it contains a very brief history of the first usage of aluminum in an aerospace application and some history of the different types of aluminum contained in the article.

Reflection: I chose this article because when most people think of aircraft, they think of aluminum. It is important to understand just how important aluminum is, especially in the aerospace industry. Without aluminum we would not have aircraft as we know them today. The lightweight yet strong characteristics of the metal are just so versatile that the material is used somewhere in every aircraft currently constructed.

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A brief introduction (or refresher) on the lightweight metal's history, applications, and future.

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Source: Vern Lewis Welding Supply, "An Overview of Welding With Titanium" vernlewis.com, 27 December 2021

Summary: This article gives us a quick explanation of what titanium is and what its primary uses are. In addition, we receive information about challenges and quirks to consider when welding titanium, some tips on welding titanium, and some ways to analyze the efficacy of welds.

Reflection: This article gives a nice bit of information on titanium. Titanium is a newer material seeing expanded use in the aerospace industry. It is important to grasp how difficult titanium can be to work with. In my life I have seen the difficulties in machining it, and welding is equally as difficult.

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An Overview of Welding With Titanium - Vern Lewis Welding Supply, Inc.

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Ethan Bale, "Welding Magnesium - Here's How To Do It Effectively" mewelding.com, 29 October 2021

Summary: This article provides a description of the qualities of magnesium and potential alloying elements. The article goes into detail about the dangers of welding magnesium, how to properly clean and prepare it, and how to weld it either using TIG or MIG.

Reflection: This article serves to demonstrate that magnesium has properties that make it a useful metal. Magnesium is similar to titanium in that it is a new arrival to the aerospace industry, but shows great promise with its material properties. It is important to understand that welding any material has some form of unique challenge, and that magnesium provides unique challenges due to the material's inherent flammability.

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Magnesium is a white, very lightweight, machinable, corrosion-resistant, high strength metal. It can be alloyed with small quantities of other metals, such as aluminum, manganese, zinc, and zirconium, to obtain desired properties. It can be welded by most of the welding processes used in the metalworking trades.

Because this metal oxidizes rapidly when heated to its melting point in the air, a protective inert gas shield must be provided in arc welding to prevent destructive oxidation.

Magnesium possesses properties that make welding it different from the welding of steel. Many of these are the same as for aluminum. These are:

1. Magnesium oxide surface coating, which increases with an increase in temperature.

2. High thermal conductivity.

3. Relatively high thermal expansion coefficient.

4. Relatively low melting temperature.

5. The absence of color change as temperature approaches the melting point.

6. The normal metallurgical factors that apply to other metals apply to magnesium as well

The welds produced between similar alloys will develop the full strength of the base metals; however, the strength of the heat-affected zone may be reduced slightly. In all magnesium alloys, the solidification range increases, and the melting point and the thermal expansion decrease as the alloy content increases.

Aluminum added as an alloy up to 10 percent improves weldability since it tends to refine the weld grain structure. Zinc of more than 1 percent increases hot shortness, which can result in weld cracking. The high zinc alloys are not recommended for arc welding because of their cracking tendencies.

Magnesium, containing small amounts of thorium, possesses excellent welding qualities and freedom from cracking. Weldments of these alloys do not require stress relieving. Certain magnesium alloys are subject to stress corrosion.

Weldments subjected to corrosive attack over a period of time may crack adjacent to welds if the residual stresses are not removed. Stress-relieving is required for weldments intended for this type of service.

Cleaning. An oil coating or chrome pickle finish is usually provided on magnesium alloys for surface protection during shipment and storage. This oil, along with other foreign matter and metallic oxides, must be removed from the surface prior to welding. Chemical cleaning is preferred because it is faster and more uniform in its action.

Mechanical cleaning can be utilized if chemical cleaning facilities are not available. A final bright chrome pickle finish is recommended for parts that are to be arc welded. The various methods for cleaning magnesium are described below.

WARNING

The vapors from some chlorinated solvents (e.g., carbon tetrachloride, trichloroethylene, and perchloroethylene) break down under the ultraviolet radiation of an electric arc and form a toxic gas. Avoid welding where such vapors are present. These solvents vaporize easily, and prolonged inhalation of the vapor can be hazardous. These organic vapors should be removed from the work area before welding begins.Dry cleaning solvent and mineral spirits paint thinner are highly flammable. Do not clean parts near an open flame or in a smoking area. Dry cleaning solvent and mineral spirits paint thinner evaporate quickly and have a defatting effect on the skin. When used without protective gloves, these chemicals may cause irritation or cracking of the skin. Cleaning operations should be performed only in well ventilated areas.

Grease should be removed by the vapor degreasing system in which trichloroethylene is utilized or with a hot alkaline cleaning compound. Grease may also be removed by dipping small parts in dry cleaning solvent or mineral spirits paint thinner. Mechanical cleaning can be done satisfactorily with 160 and 240 grit aluminum oxide abrasive cloth, stainless steel wool, or wire brushing.

WARNING

Precleaning and postcleaning acids used in magnesium welding and brazing are highly toxic and corrosive. Goggles, rubber gloves, and rubber aprons should be worn when handling the acids and solutions. Do not inhale fumes and mists. When spilled on the body or clothing, wash immediately with large quantities of cold water, and seek medical attention. Never pour water into acid when preparing solution; instead, pour acid into water. Always mix acid and water slowly. Cleaning operations should be performed only in well ventilated areas.

Immediately after the grease, oil, and other foreign materials have been removed from the surface, the metal should be dipped for 3 minutes in a hot solution with the following composition.

The bath should be operated at 70°F (21°C). The work should be removed from the solution, thoroughly rinsed with hot water, and air-dried. The welding rod should also be cleaned to obtain the best results.

Joint Preparation. Edges that are to be welded must be smooth and free of loose pieces and cavities that might contain contaminating agents, such as oil or oxides. Joint preparations for arc welding various gauges of magnesium are shown in figure 7-13.

Safety Precautions

CAUTION

Magnesium can ignite and burn when heated in the open atmosphere.

Goggles, gloves, and other equipment designed to protect the eyes and skin of the welder must be worn. The possibility of fire caused by welding magnesium metal is very remote. The temperature of initial fusion must be reached before solid magnesium metal ignites. Sustained burning occurs only if this temperature is maintained.

Finely divided magnesium particles such as grinding dust, filings, shavings, borings, and chips present a fire hazard. They ignite readily if proper precautions are not taken. Magnesium scrap of this type is not common in welding operations. If a magnesium fire does start, it can be extinguished with dry sand, dry powdered soapstone, or dry cast iron chips. The preferred extinguishing agents for magnesium fires are graphite-based powders.

Tungsten Inert Gas (TIG) Welding Magnesium

Because of its rapid oxidation when magnesium is heated to its melting point, an inert gas (argon or helium) is used to shield metal when TIG welding Magnesium. This process requires no flux and permits high welding speeds, with sound welds of high strength. Direct current machines of the constant current type operating on straight polarity (electrode positive) and alternating current machines are used with a high-frequency current superimposed on the welding current.

Both alternating and direct current machines are used for thin gauge material. However, because of better penetrating power, alternating current machines are used on material over 3/16 in. (4.8 mm) thick. Helium is considered more practical than argon for use with direct current reverse polarity.

However, three times as much helium by volume as argon is required for a given amount of welding. Argon is used with alternating current. The tungsten electrodes are held in a water-cooled torch equipped with required electrical cables and an inlet and nozzle for the inert gas.

The two magnesium alloys, in the form of sheet, plate, and extrusion, that are most commonly used for applications involving welding are ASTM-1A (Fed Spec QQ-M-54), which is alloyed with manganese, and ASTM-AZ31A (Fed SPec QQ-44), which is alloyed with aluminum, manganese, and zinc.

In general, less preparation is required for welding with the alternating current than welding with the direct current because of the greater penetration obtained. Sheets up to 1/4 in. (6.4 mm) thickness may be welded from one side with a square butt joint. Sheets over 1/4 in. (6.4 mm) thickness should be welded from both sides whenever the nature of the structure permits, as sounder welds may be obtained with fewer warpages.

For a double V joint, the included angle should extend from both sides to leave a minimum 1/16 in. (1.6 mm) root face in the center of the sheets. When welding a double V joint, the back of the first bead should be chipped out using a chipping hammer fitted with a cape chisel. Remove oxide film, dirt, and incompletely fused areas before the second bead is added. In this manner, maximum soundness is obtained.

The gas should start flowing a fraction of a second before the arc is struck. The arc is struck by brushing the electrode over the surface. With alternating current, the arc should be started and stopped by means of a remote control switch. The average arc length should be about 1/8 in. (3.2 mm) when using helium and 1/16 in. (1.6 mm) when using argon. Current data and rod diameter are shown in table 7-24.

When welding with alternating current, maximum penetration is obtained when the end of the electrode is held flush with or slightly below the surface of the work. The torch should be held nearly perpendicular to the surface of the work, and the welding rod added from a position as nearly parallel with the work as possible (fig. 7-14). The torch should have a slightly leading travel angle.

Welding should progress in a straight line at a uniform speed. There should be no rotary or weaving motion of the rod or torch, except for larger corner joints or fillet welds. The welding rod can be fed either continuously or intermittently. Care should be taken to avoid withdrawing the heated end from the protective gaseous atmosphere during the welding operation.

The cold wire filler metal should be brought in as near to horizontal as possible (on flatwork). The filler wire is added to the leading edge of the weld puddle. Runoff tabs are recommended for welding any except the thinner metals. Forehand welding, in which the welding rod precedes the torch in the direction of welding, is preferred.

If stops are necessary, the weld should be started about 1/2 in. (12.7 mm) back from the end of the weld when welding is resumed. Because of the high coefficient of thermal expansion and conductivity, control of distortion in the welding of magnesium requires jigging, small beads, and a properly selected welding sequence to help minimize distortion.

Magnesium parts can be straightened by holding them in position with clamps and heating to 300 to 400°F (149 to 204°C). If this heating is done by local torch application, care must be taken not to overheat the metal and destroy its properties. If cracking is encountered during the welding of certain magnesium alloys, starting and stopping plates may be used to overcome this difficulty.

These plates consist of scrap pieces of magnesium stock butted against opposite ends of the joint to be welded as shown in 'A', figure 7-15. The weld is started on one of the abutting plates, continued across the junction along the joint to be welded, and stopped on the opposite abutting plate. If a V groove is used, the abutting plates should also be grooved.

An alternate method is to start the weld in the middle of the joint and weld to each edge (B, fig. 7-15). Cracking may also be minimized by preheating the plate and holding the jig to 200 to 400°F (93 to 204°C) by increasing the speed of the weld.

Filler rods must be of the same composition as the alloy being joined when arc welding. One exception is when welding AZ31B. In this case, a grade C rod (MIL-R-6944), which produces a stronger weld metal, is used to reduce cracking.

Residual stress should be relieved through heat treatment. Stress relief is essential so that lockup stresses will not cause stress corrosion cracking. The recommended stress relieving treatment for arc welding magnesium sheet is shown in table 7-25.

The only cleaning required after arc welding of magnesium alloys is wire brushing to remove the slight oxide deposit on the surface. Brushing may leave traces of iron, which may cause galvanic corrosion. If necessary, clean as in b above.

Arc welding smoke can be removed by immersing the parts for 1/2 to 2 minutes at 180 to 212°F (82 to 100°C), in a solution composed of 16 oz (453 g) tetrasodium pyrophosphate (Na ₄P ₂O ₇), 16 oz (453 g) sodium metaborate (NaBO ₂), and enough water to make 1 gallon (3.8 1). Welding procedure schedules for Gas Tungsten Arc welding (GTAW) of magnesium (TIG welding) are shown in table 7-26.

The MIG welding process is used for the medium to thicker sections of magnesium. It is considerably faster than TIG welding. Special high-speed gear ratios are usually required in the wire feeders since the magnesium electrode wire has an extremely high melt-off rate. The normal wire feeder and power supply used for aluminum welding are suitable for welding magnesium.

Different types of arc transfer can be obtained when welding magnesium. This is primarily a matter of current level or current density and voltage setting. The short-circuiting transfer and the spray transfer are recommended. Argon is usually used for gas metal arc welding of magnesium; however, argon-helium mixtures can be used.

In general, the spray transfer should be used on material 3/16 in. (4.8 mm) and thicker, and the short-circuiting arc used for thinner metals. Welding procedure schedules for Gas Metal Arc Welding (GMAW) of magnesium (MIG welding) are shown in table 7-27.

Other Welding Processes. Magnesium can be welded using resistance welding processes, including spot welding, seam welding, and flash welding. Magnesium can also be joined by brazing. Most of the different brazing techniques can be used. In all cases, brazing flux is required and the flux residue must be completely removed from the finished part.

Soldering is not as effective, since the strength of the joint is relatively low. Magnesium can also be stud welded, gas welded, and plasma-arc welded.

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Welding Magnesium - Here's How To Do It Effectively

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Magnesium is a white, very lightweight, machinable, corrosion-resistant, high strength metal. It can be alloyed with small quantities of other metals, such as aluminum, manganese, zinc, and zirconium, to obtain desired properties. It can be welded by most of the welding processes used in the metalworking trades.

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Source: Jeff Grill, "Friction Weld Process" weldguru.com, 12 December 2019

Summary: This article provides a description of what friction welding is and how it is performed. It includes several videos demonstrating the process in action. The potential list of materials that can be friction welded is included too.

Reflection: Several times in other articles within this blog has friction welding been mentioned. It is a way of joining similar or dissimilar metals together faster, without filler metal, and with less heat input than conventional welding methods, making it ideal for aerospace applications. This is a specialized welding process, typically something like this would not be used for day-to-day welds, but would be used for something far more specialized necessitating less heat and less potential human error.

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Friction welding is a solid state welding process which produces coalescence of materials by the heat obtained from mechanically-induced sliding motion between rubbing surfaces. The work parts are held together under pressure.

This process usually involves the rotating of one part against another to generate frictional heat at the junction. When a suitable high temperature has keen reached, rotational notion ceases. Additional pressure is applied and coalescence occurs.

There are two process variations:

1. In the original process, one part is held stationary and the other part is rotated by a motor that maintains an essentially constant rotational speed. The two parts are brought in contact under pressure for a specified period of time with a specific pressure. Rotating power is disengaged from the rotating piece and the pressure is increased. When the rotating piece stops, the weld is completed. This process can be accurately controlled when speed, pressure, and time are closely regulated.

2. The other variation is inertia welding. A flywheel is revolved by a motor until a preset speed is reached. It, in turn, rotates one of the pieces to be welded. The motor is disengaged from the flywheel and the other part to be welded is brought in contact under pressure with the rotating piece. During the predetermined time during which the rotational speed of the part is reduced, the flywheel is brought to an immediate stop. Additional pressure is provided to complete the weld.

Both methods utilize frictional heat and produce welds of similar quality. Slightly better control is claimed with the original process. The two methods are similar, offer the same welding advantages, and are shown by figure 10-79 below.

There are three important factors involved:

1. The rotational speed is related to the material to be welded and the diameter of the weld at the interface.

2. The pressure between the two parts to be welded. Pressure changes during the weld sequence. At the start, the pressure is very low but is increased to create the frictional heat. When the rotation is stopped, the pressure is rapidly increased so forging takes place immediately before or after rotation is stopped.

3. The welding time is related to the shape and the type of metal and the surface area. It is normally a matter of a few seconds. The actual operation of the machine is automatic. It is controlled by a sequence controller, which can be set according to the weld schedule established for the parts to be joined.

Normally, one of the parts to be welded is round in cross-section. This is not an absolute necessity. Visual inspection of weld quality can be based on the flash, which occurs around the outside perimeter of the weld. This flash will usually extend beyond the outside diameter of the parts and will curl around back toward the part but will have the joint extending beyond the outside diameter of the part.

If the flash sticks out relatively straight from the joint, it indicates that the welding time was too short, the pressure was too low, or the speed too high. These joints may crack.

If the flash curls too far back on the outside diameter, it indicates that the time was too long and the pressure was too high.

Between these extremes is the correct flash shape. The flash is normally removed after welding.

Welding Variables

Rotational Speed

Heating pressure

Forging pressure

Time for heating

Time for braking

Time for forging

Types of Friction Welding

Spin Welding

Spin Welding Video

Spin welding involves a rotating chuck along with a flywheel. After reaching the required speed the motor disengages with the flywheel.

Linear Friction Welding

Linear Friction Welding Video

In linear friction welding, an oscillating chuck is used. It is applied to non-round shapes as compared to spin welding. The material welded has to have high shear strength.

In linear friction welding, an oscillating chuck is used. It is applied to non-round shapes as compared to spin welding. The material welded has to have high shear strength.

Friction Surfacing

Friction surfacing is a surface coating process. The coating material is Mechtrode, which is rotated under pressure over the substrate.

Friction Stir Welding

Friction stir welding is a cylindrical shouldered tool with a profiled probe. A pin or nib is used. Friction is created between the metal being worked, the nib and the shoulder.

There are a wide variety of metals that can be joined. The process can also be used to join different metals.

Advantages and Disadvantages of Friction Welding

Advantages:

1. Can produce high-quality welds in short cycle time.

2. No filler metal is required and flux is not used.

3. The process is capable of welding most of the common metals. It can also be used to join many combinations of dissimilar metals. Friction welding requires a relatively expensive apparatus similar to a machine tool.

4. Easy to operate equipment

5. Not time-consuming

6. Low levels of oxide films and surface impurities

7. When compared to resistance butt welding creates better welds at a lower cost and higher speed, lower levels of electric current are required

8. Small heat affected zone when comparing the process to conventional flash welding.

9. When compared to flash butt welding, less shortening of the component.

10. No need to use gas, filler metal or flux. No slag that can cause weld imperfections.

Disadvantages:

1. Process limited to angular and flat butt welds.

2. Only used for smaller parts.

3. Complicated when used for tube welding.

4. Hard to remove flash when working with high carbon steel.

5. It requires a heavy rigid machine in order to create high thrust pressure.

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Affiliate Disclaimer: This post may contain links that will earn us a commission at no cost to you. This helps keep Weldguru a free resource for our readers. Friction welding is a solid state welding process which produces coalescence of materials by the heat obtained from mechanically-induced sliding motion between rubbing surfaces.

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Source: TWI, "What is Electron Beam Welding?" twi-global.com, Date unknown

Summary: This article details what electron beam welding is and how it is performed. It also lists several important advantages of electron beam welding over conventional welding.

Reflection: Again, electron beam welding has been mentioned before as an important developing technique becoming more common in the aerospace welding industry. The minimal amount of heat generated from this process allows for sensitive components to be manufactured, even when the joints are close to other components, meaning that it is important for assembling complicated aircraft such as space fairing vessels.

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What is Electron Beam Welding? Process Definition and Advantages

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Electron beam (EB) welding is a fusion welding process whereby electrons are generated by an electron gun and accelerated to high speeds using electrical fields. This high speed stream of electrons is tightly focused using magnetic fields and applied to the materials to be joined.