For a long time, titanium was seen as a material with far too many advantages to becoming widely used. But we’re not ones to shy away from the hard stuff. We’ve been using it in our products for years now, and it’s only scratched the surface.
Unfortunately, however, titanium is also notoriously tricky to work with when it comes to welding. Nevertheless, with the right equipment and some handy tips, you can learn how to weld titanium easily and efficiently at home.
Over the last 25 years, titanium has become an increasingly popular, commercially-useful metal. As a result, all types of welders have had to learn how to efficiently and effectively weld this exceptional metal.
Titanium is an extremely strong, corrosion-resistant metal. Maintaining its strength while being welded requires great skill, but it isn’t impossible. In this article, we will show you how to weld titanium.
Titanium is a metal that comes in many forms. It has very high melting points and, as such, can be used to create simple shapes without the use of extreme heat. However, due to its high melting point, it is not highly resistant to heat and can be easily melted by fire.
In addition, while it is considered a metal, titanium is also a metaloid. This means it takes on some of the characteristics of metal and some found in non-metallic elements.
Titanium is the ninth most abundant element found in the Earth’s crust, though it can only be extracted from large amounts of ore through a process called a conversion. It is used for jewelry and watches, and many industrial applications.
In the United States, the most common use of titanium is for dental implants and hip replacements due to its strength and durability at high temperatures. NASA also uses it in spacecraft due to its low weight compared to metals like steel and aluminum.
Considerable material and equipment research has achieved a high level of welding success in titanium. For example, modern pulse arc, gas tungsten arc, and plasma arc welding processes for titanium are very effective for many applications.
Improperly made welds in the as-welded condition can be embrittled and less corrosion resistant than the base metal. Welds can be as resilient as the rest of the metal when conditions are right.
These tests show that properly made welds in the as-welded condition are ductile and corrosion-resistant as the base metal when subjected to specific environments.
Titanium is a high-performance material that requires accurate joint design, fabrication techniques, and cleanliness during welding.
The final product should be as free from porosity, defects, and contaminants as possible. Because titanium reacts with most of the gases found in welding fumes, it must be welded with an inert gas shielding atmosphere.
The molten titanium weld metal can be contaminated by air when used without some form of protection. Low-melting-temperature alloys must not be heated above 800°F (427°C).
These alloys are generally incapable of being post welded hardened, and if hardened, would lose strength and flexibility.
It is not possible to weld titanium with most welding processes. Most modern welding processes used to weld other types of metals cannot be used to weld titanium because titanium forms brittle intermetallic compounds with most other metals, and these compounds lower the strength of the finished welds.
Titanium can only be welded by using an arc welding process that does not form intermetallic compounds. Carbon arc welding cannot be used to weld titanium because it forms low-strength cementite that limits the cross-section of the finished weld.
Shielded metal arc welding (SMAW) can only be performed in mobile garages or well-ventilated indoor workshops because SMAW produces a large amount of hydrogen gas when welding thin titanium sections.
If this hydrogen comes in contact with oxygen, spontaneous combustion can occur. In SMAW, the tungsten electrode can be replaced by a non-consumable tungsten electrode that has three times the melting area and similar electrical properties.
While the precautions that must be taken to weld titanium make it appear daunting to the welder, many fabricators are routinely and economically welding titanium at the sound, ductile levels comparable with many other materials.
This white paper will first review the unique characteristics of titanium from a fabrication standpoint. It will then discuss how titanium can be welded successfully and cost-effectively and provide tips for successful arc welding of titanium.
Your weld surface is an integral part of the process for successfully completing a titanium weld. By properly preparing the weld area, you will be able to better control heat input during welding, prevent unwanted effects from taking place, and yield an overall higher quality weld with less effort.
No.
Attributes
Explanation
1
Material type
Titanium
2
Welding process
Gas tungsten arc welding (GTAW), Gas metal arc welding (GMAW), Laser welding, Electron beam welding
3
Welding Technique
Shielded metal arc welding, Tungsten inert gas welding, Keyhole welding
4
Welding temperature
4000-7000 degree fahrenheit
5
Welding speed
Slow to moderate
6
Welding time
30-70 seconds per inch
7
Welding preparation
Surface cleaning, oxide removal, filler metal selection
8
Weld joint type
Butt joint, Lap joint, T-joint and Corner joint
9
Welding Gas
Argon, Helium
10
Welding filler
ERTi-2, ERTI-5, ERTI-9
11
Welding defects
Porosity, cracking, wrapping, distortion
12
Welding equipment
Tungsten electrodes, Gas shield, Welding torch
Note: The above table is not exhaustive and may vary based on the specific welding conditions and techniques used.
Surface Cleaning
Titanium must be cleaned before welding to ensure the titanium weld metal has the proper mechanical and corrosion resistance properties. There are three important considerations in cleaning the titanium surface:
mill scale must be removed;
dirt, dust, grease, oil, moisture, or other potential contaminants must be removed; and
The cleanliness of the welding wire is also important.
To protect against possible contamination, it is a good practice to clean all surfaces prior to welding. For example, scrub with a cleaning compound and follow with hot water to clean a joint.
You can use a wire brush to remove rust if necessary and then scrub with household cleaners or detergents for base plates. Wire brushes are also used on frames and other side rails before being painted. After cleaning, make sure all dust has been wiped off surfaces to the point where no dirt is left on the surfaces.
The cleaning of surfaces is an important factor in successful coating bonding. Welding and heat-treated surfaces must be free of scale, grease, oil, and other foreign matter.
Unfortunately, titanium is a wonderful material that has virtually no corrosion resistance of its own. When exposed to water (in the air or when underwater), it oxidizes or rusts and tarnishes.
Moreover, it reacts in yet another unsightly manner when exposed to common household chemicals, such as those in some cosmetics, cleaners, and lotions. And if that weren’t bad enough, titanium can also be easily scratched by conventional abrasive cleaners and steel wool, ruining the finish completely!
Chlorinated solvents cannot be used on titanium because dichloromethane is readily absorbed by the metal and has an adverse effect on the corrosion resistance of titanium.
Instead, the surfaces of titanium weldments must be cleaned by wire brushing, without fail! Solvent cleaning with acetone, toluene, or MEK is acceptable, provided no grease or oil remains.
The heating of stainless steel in the temperature range 600°-800°F (316- 427°) will cause the formation of a light oxide film. 90% of accumulated surface scale normal to stainless can be removed rapidly and easily through the use of a Hard-Wire Brush. It is said that the best tool for the job is the one that you will use.
A well-characterized pickle bath of 35 vol.% nitric and five vol.% hydrofluoric acids at room temperature is the first step in the cleaning process of titanium weldments.
A minimum immersion time of 1 to 15 minutes (depending on the activity) is recommended to ensure that all dirt, oxides, and other contaminants are removed.
A blast of cold water does the job of cleaning off-scale from high-temperature heat treatment. The water should be enough to flood the surface and rapidly lift as it recedes.
A hot rinse, usually at the same temperature as the treatment, is desirable to facilitate drying. Mechanical cleaning methods do not remove, or even partially remove, the acid that penetrates all surfaces, and therefore after the metal is completely rinsed off with water.
So a pickle impregnated with an acid that can dissolve metallic oxides is used to remove all such traces of acid, both for safety reasons and for appearance purposes.
Choose the Right Filler Wire
Titanium arc welding is an excellent process for joining titanium and its alloys. It provides high levels of strength, toughness, and impact resistance, and the weld obtained by arc welding has the same basic characteristics as the base material.
This is why welding titanium is preferred over brazing or soldering. Before you begin to weld, we recommend choosing a filler wire primarily composed of the same or similar alloy as the base material.
In some cases, however, the welder may select a filler wire that falls in the same category but one grade below the base material.
Filler wire selection is crucial when welding unalloyed titanium as filler metals that are too strong can cause microcracking of the weld metal.
Instead, use a filler metal that is lower in yield strength than the base metal but still high enough so that it will have sufficient toughness and ductility to meet the requirements of the application.
For example, if you are welding a Ti-6AL-4V base, your filler wire should be selected to have yield strength of at least 180,000 psi.
When welding titanium from the Ti-5A1-2.5Sn and Ti-6A1-4V classifications, filler wire that contains unalloyed Ti has proven adequate for most welding applications. The marking of filler wires is dependent on the intended use of the wire.
When a metal alloy has a relatively high concentration of certain elements, these elements can be responsible for unwanted microstructure in the base metal and its alloys, particularly at elevated temperatures.
Conversely, when a metal alloy has a relatively high concentration of certain elements, these elements can be responsible for unwanted microstructure in the base metal and its alloys, particularly at elevated temperatures.
The first thing most people learn about welding is that melting the filler metal always turns it into a big mess. This is because, in the process of making the filler molten and welding it to the base metal, its alloying elements also get melted.
Since most of these alloying elements are not needed at the weld junction and are not required by industry standards as filler material additives, you can opt for an alloy, some percentages of which are close to zero. Suppose a person in high school does well at math.
In that case, he or she might consider selecting a filler metal with lower percentages of oxygen, nitrogen, hydrogen, carbon.
It’s possible to solve the problem of a high percentage of alloying contents by using a filler metal with lower percentages of other alloying contents than the base metal. The result will be much cleaner welds without any loss of strength.
In addition to alloying additions, this option may include adjusting the additive or diluent elements and/or the volume of the second phase particles to achieve the desired microstructure in the base-metal weld zone.
In addition to alloying additions, this option may include adjusting the additive or diluent elements and/or the volume of the second phase particles to achieve the desired microstructure in the base-metal weld zone.
But why do we need a shielding gas, then? This is because the purpose of the gas is to protect the weld puddle from contact with the atmosphere.
The atmosphere is filled with oxygen, and that’s exactly what we want to keep away from our weld puddle.
Unfortunately, when non-pure Argon is used as a shielding gas, it has the tendency to burn away fairly quickly, and it doesn’t provide the proper protection needed for optimal welding conditions.
The best way to use Argon as a shielding gas is to use only very pure Argon itself. Anything less will compromise your weld.
There are several different shielding gases that you can use. While most will work, some are better than others.
Typically you want to look for a gas that does not have any damage to the quality. Poor gas will cause problems with welds, including discoloration and mottling.
In addition, if you use a shielding gas that is impure or slightly incomplete coverage, it can lead to blue tinting and mottling that is just as bad.
So that, When you are looking to achieve a proper shielding gas mix of Argon and helium for tig welding, you will want to make sure that you only get this gas from trusted suppliers.
In addition, you will want to ensure that you’re getting enough helium and don’t get any impurities in your mix, as it can severely affect the quality of the finished welding project.
The correct choice of shielding gases is essential when welding titanium, which is exceptionally hard to weld. The front of the weld needs good coverage; an argon/helium mix may help protect both the back and front of the weld.
The backside of the weld is particularly important as this will be seen on a finished job when carved or machined. Argon has several benefits as a shielding gas for welding titanium.
It costs more than helium but less than a helium/argon mix. It may give better coverage with smaller amounts of gas.
Several types of shielding gases are used to protect parts from radiant energy and contamination. First, use an inert gas such as Helium, Argon, or Nitrogen.
For small parts or short times, enclosed compartments made out of glove boxes can be used.
With the aid of a purge gas system, they can be created with nearly perfect seals. These enclosed compartments are filled with inert gas, which must then be purged with an inert gas after work is done to eliminate any surface contamination prior to opening the compartment.
If you want to achieve a thoughtfully-considered level of coverage when you’re welding, you should choose between helium and argon gas.
You need to follow three steps to determine which of these shielding gasses is going to be best for your project.
Choosing the right shielding gas is necessary to protect the weld from air contamination. The shielding gas is the most important equipment for welding.
It provides primary, second, and even third protection to weld puddle and molten metal. We suggest that you equip your torch with a broader cup to better protect the weld.
Primary Shielding
Primary shielding gases are used to protect the area immediately surrounding the weld. The shielding gas is usually supplied from a standard, water-cooled torch with a ceramic cup and gas lenses. The larger the cup, the broader the coverage and protection of this primary shielding gas.
Secondary Shielding
Choose a trailing shielding gas when you need secondary protection from contamination due to dirty gases. Trailing shields are available on most of our torch heads to provide secondary protection for flame, heat, and smoke.
With most zones protected from contamination, the trailing shields allow for longer sealing, faster heating, and less clean-up time.
This secondary protection can be easily attached to the welding process and offers a sense of security for welders. Upgrade your torch today!
Backup Shielding
A backup shield can be placed behind the work, under the tip of the flame, to act as a blinder. They are used when a welder is too far from their work or is unable to shield their eyes from intense light, and for those doing indoor welding.
They are also used to help increase shielding gas flow to the weld area, much like a trailing shield.
The technique is the most important variable to consider when welding titanium. The attention to detail at the beginning of a job is critical to ensuring a successful weld. Properly preparing your equipment, using the correct parameters, and shielding gasses will ensure a quality weld every time.
The section on arc starting covers a basic but important topic that, when done correctly, will improve the quality of welds produced. The method described is confirmed by a number of articles written by welding industry experts and laboratory tests.
This article emphasizes using high-frequency arc starting whenever possible because it minimizes tungsten inclusions by virtually eliminating metallic contamination of the weld pool.
This is achieved because electrode-tungsten contact lengths are kept extremely short, reducing the time when metallic impurities may dissolve in the molten weld pool.
At this time, the operator must continue torch shielding until the weld metal cools below 800°F. Preheat the surfaces to 150°F (66°) for about 30 minutes.
Use a slightly oxidizing flame on the welding surface. Maintain neutral gas flow (no extra argon added) and keep the shielding gas (100% argon) flowing throughout the weld.
For best results in welding titanium, the arc length should be about equal to the electrode diameter. Arc length may require adjustment for variations in combined metal thicknesses and to accommodate the desired weld penetration.
For a given current, a longer arc increases the depth of fusion; however, weld quality may be adversely affected by excessive arc length and inadequate travel speed.
For example, when using a 3/32-in.-diameter electrode on 1/2-in.-thick base metal and 1/8-in.-thick cover metal, maximum arc length should be about 1-1/2 times the electrode diameter.
The addition of filler metal to titanium requires a maximum welding arc length of three times the electrode diameter. The intermittent dipping technique can create turbulence in the molten weld pool, which may result in contamination of the hot end of the welding wire.
By clipping back the end of the wire, about 1/2-inch reduces turbulence and allows for a smoother flow. Clip off the end of the wire and then reinsert it into the gas shield after each dip.
When welding thin material, the arc cannot be used up to the edge of the metal. Instead, use a series of short, advancing passes until the entire weld is completed.
Use a skilled hand to match the arc length for each successive pass to avoid undercutting (digging into) the edges of the joint. Cleaning between passes by grinding off a discolored weld bead is not necessary if the bead remains bright and silvery.
It is sometimes difficult to see whether or not the weld bead has cooled on thicker materials before advancing. When this happens with steel or pre-alloyed materials, try using a perforated filler rod, which cools quickly and can be easily vacuum-picked between passes.
The following techniques are considered by many to be the “best practices” for most welding applications. Using these techniques will increase your performance and help produce quality welds.
Plasma arc welding (PAW)
Electron-beam welding (EBW)
Friction welding (FRW)
Resistance welding (RW)
Laser-beam welding (LBW)
Gas-metal arc welding (GMAW) or Metal Inert Gas (MIG)
Gas-tungsten arc welding (GTAW) or Tungsten Inert Gas Welding (TIG)
Friction welding Gas-metal arc welding (GMAW) or Metal Inert Gas (MIG)
Electron Beam Welding
A prominent aerospace company recently dropped an electron beam welder from a ceiling height of 48 feet during an internal quality test, and the weld itself at the joint was unaffected.
Electron beam welding is a fusion process that utilizes a high-velocity electron beam to join two metals together. Electron beams are more precise than laser beams, generate much more heat, and allow the density of the metal to remain constant at the joint, which appears beaded on the surface but is homogeneous internally.
Electron beam welding (EBW) is a process used to weld annealed, cold-worked, or hardened steels or stainless steels. The EBW process uses a beam of electrons to create a low-temperature arc between the workpieces.
This process does not require clamps or a large amount of pressure and heat to create welds of high quality and low contamination levels, making it ideal for welding plates ranging up to 76 mm thick in sizes up to 1,081 mm by 1,551 mm.
Tungsten Inert Gas / GTAW
In Tungsten Inert Gas welding or TIG welding, a non-consumable tungsten electrode is used to protect the weld puddle from contamination. In addition, a constant flow of shielding gas (helium or Argon) prevents the buildup of a carbon dioxide layer on the surface of the weld.
The constant flow of shielding gas prevents contamination of the weld area, which ensures high-quality welds.
The Tungsten Inert Gas process is a widely used process for welding titanium and its alloys. To apply, the weld area must first be preheated in order to help keep the area from cooling down too quickly and cracking.
Using filler metal is required for joint strengths of 4 mm or less. In addition, the filler metal needs to have high impact strength and good rigidity in order to prevent deformation during welding, which could decrease the strength of the welds.
Resistance Welding (RW)
Resistance welding is often referred to as thermo-electric joining because it uses both heat and electricity to join the materials.
The goal of Resistance welding is to place the material in contact with each other, then pass a current of electricity through them, creating a bond while at the same time suppressing the heat outside of the joining area to avoid damaging the rest of the material.
If you want to join metals, then you should know the basics of the Resistance Welding technique. Resistance Welding (RW) is a spot and continuous welding process that can be applied either on a titanium base or on plated steel to produce a local intermetallic phase transformation in the weld seam, as well as to improve the mechanical properties of the welded piece.
The basic principle behind this technique is that when two metal structures are welded together, heat generated during the welding process melts the surface area of both structures.
Laser-Beam Welding (LBW)
Why have a single name when you can have two? LBW is an alternative new fusion welding process that’s set to reduce production time and improve efficiency for many industries and applications.
The LBW Fusion process is unique in that it bonds two pieces of metal together using a laser beam. This technique uses less material in the welding process and creates a stronger, more durable weld.
In addition, a fusion weld is less visible than other welding processes, so that surface preparation for application is minimized. It can be used in equipment and machinery manufacturing, shipbuilding, aerospace, and much more.
In laser beam welding (LBW), intense heat energy is generated by focusing a high-powered laser beam directly onto the surface of the workpiece. Its attributes are a much shorter process time and an improved welder’s view of the weld area, as there is no need for goggles.
However, it has been problematic to weld without shielding gas with a laser beam on titanium, but DuPont [company] has developed a new technology. This enables LBW welding on titanium with the same quality as with electron beam but at a much lower cost.
Plasma Arc Welding (PAW)
Plasma Arc Welding (PAW) is becoming increasingly useful for medical applications due to its ability to create strong, smooth welds with excellent finishes.
Used in manual or semi-automatic modes, the Plasma Arc Welder (PAW) allows for high-precision seam welding of titanium to titanium.
It operates at voltages from 6-35 kV and will weld a variety of thicknesses from 0.5 mm to 10 mm in its manual mode.
As it uses an arc between a tungsten electrode and the workpiece, weld quality is similar to that of TIG welding; however, the extra heating time achieved by PAW helps it penetrate further and weld heavier materials.
Compatible with virtually all-titanium classifications, PAW will allow you to make that one-pass plate and save yourself the second pass over. With a single weld, you can make complex shapes with different types of titanium welds.
In addition, the PAW process allows you to use multiple numbers of tungsten electrodes on the same piece of metal while both are held in place by a common potting fixture. A great choice for almost every application.
Metal Inert Gas (MIG) or Gas-Metal Arc Welding (GMAW)
GMAW is the welding process of choice for producing strong, stable welds in applications such as construction and repair. A reliable welding technique, GMAW (Gas Metal Arc Welding), gets its name from the arc that connects the base metal to the filler wire.
The high-frequency flow of current helps in two ways: It ensures a more precise arc length which results in better overall weld quality, and it causes droplets to be carried away from the weldment, and into the surrounding shielding gas, so your weld puddle stays nice and clean.
A more efficient method is available for welding titanium plates. Gas-Metal Arc Welding (GMAW), also called Metal Inert Gas (MIG) or “wire welding,” is one of the methods used to melt and join metal to make a weld.
This welding process uses a consumable wire as a filler material which provides a bond between two pieces of metal. A source of gas is also required for this process, as well as an electrode.
Friction Welding (FRW)
Friction welded tubes are made by joining two tubes using a welding process that is akin to welding two pieces of pipe together. The resulting tubes are seamless and require no additional finishing.
This process does not use any consumable filler material or flux, and the welded pipes are as strong as normal seamless ones.
Is it Possible to Weld Stainless Steel to Titanium?
According to Lincoln Electric, you absolutely can weld stainless steel to titanium. However, it is not recommended. Welding stainless steel to titanium has a number of downsides, especially for someone with little welding experience.
It is also a very challenging task to complete. Welding Stainless steel to titanium requires the use of two different sets of electrodes in order to keep the two materials from ruining each other’s properties.
Furthermore, this type of project requires a certain amount of precision and skill in order to have well-formed metal and an overall good final product.
This technique’s benefit may be provided by a desirable look or resistance against corrosion.
Titanium has a number of applications, both in pure and alloy forms, but is most commonly used as a structural material in aerospace, chemical, and petroleum industries due to its extremely high strength, low density, and good corrosion resistance.
The excellent mechanical properties of titanium also allow it to be used in armor plating. Although it is often used as alloyed material with aluminum, welding titanium to aluminum is not strictly recommended.
Conclusion:
In this article, we covered the basics of welding titanium. Titanium is a very expensive and durable metal that can be hard to work with, but if you have some basic knowledge of how it works, it can be interesting to learn how to weld it.
Welding Titanium is a critical aspect of any industry, no matter how big or small. It can be used in countless planes and projects, because it is extremely sturdy and durable. If you are looking to find out more about how to weld titanium then our article is the best place for you to start.
FAQs
What is the weakness of titanium?
Titanium is a material that has high reactivity. It is reactive with air, water oxidizes and forms a thin layer of titanium dioxide on its surface, so it has to be protected from air during the process. Titanium also reacts with oxygen at high temperatures, so it’s important to control the thermal processing in an inert environment.
Does titanium last forever?
Technically, no substance can last forever. However, titanium is a metal that has a high strength-to-weight ratio, meaning it doesn’t rust or corrode easily. It is also very light so it has wonderful characteristics for making sports and everyday use products such as watches, jewelry and medical devices.
Which welding is suitable for titanium?
Titanium is most commonly joined using a technique known as TIG (tungsten inert gas), which involves using an inert gas shield to protect the weld from oxidation. If you want to experiment with more exotic welding techniques, though, you can try MIG and MAG welding on titanium.
