Can You Weld Titanium? What You Need to Know!
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Yes, titanium can be welded. In fact, welding is one of the most common ways to join titanium components together. However, note that welding titanium is not the same as welding other materials. It is one of the most difficult metals to weld. It has several properties that make it unique, and these need to be taken into account when welding.
It has a very high melting point and is also very reactive. This means that it is hard to create a good weld joint with it. In addition, titanium is also susceptible to corrosion. This means that it is important to use the right welding technique, such as Gas Tungsten Arc Welding (GTAW) and the Gas Metal Arc Welding (GMAW) processes.
In this article, we delve deeper into the practice of welding titanium, the drawbacks as well as the precautionary measures to get a good titanium weld.
What Makes Titanium Difficult to Weld?
We have already established that titanium can be welded, though it’s quite challenging for the reasons outlined below.
- It is a very reactive metal, which means it can easily form oxides and other compounds when exposed to air. This can make welding difficult, as the oxide layer will prevent the weld from taking properly. To avoid this, it’s important to use an inert gas (such as argon) to shield the titanium from the air.
- It has a very high melting point, which means it can be difficult to weld without using specialized equipment. In particular, you’ll need a welder that can generate enough heat to melt the metal.
- Titanium is also a very strong metal, which means it can be difficult to weld without causing damage. You’ll need to be careful not to overheat the metal, as this can cause it to warp or crack.
- Finally, titanium is a very lightweight metal, which means it can be tricky to work with. This is because it’s easy to overweld and cause the metal to become distorted.
With all these things in mind, it’s important to be careful and take your time when welding titanium. If you’re not experienced in welding, it’s best to leave it to a professional.
How to Prepare and Handle Titanium for Welding
The first step in preparing titanium for welding is making sure that you have suitable equipment such as an argon gas torch or a plasma arc welder.
Also, you need protective clothing and breathing gear. With this, you’ll not be harmed by exposure to fumes while working with titanium.
When you’re ready to start welding titanium, ensure you know what piece of titanium you’re working on and the welding technique you’ll need for that particular job.
Some pieces may need different types of welds because of different thicknesses. Others may need more than one type of weld, depending on their shape or size.
Also, consider how thick each piece of metal is before starting any welding task involving titanium. If it’s too thin, it will break during use.
If you want to create a high-quality titanium weld, ensure the area you’re working on is clean. If grime or grease contaminates your titanium weld, you’ll not get a high-quality weld.
How to Weld Titanium
Titanium welding is like aluminum welding. You must remove the oxide layer before you start welding. It’s also like welding stainless steel because it needs to be back purged.
Here are brief steps to follow:
1. Remove the Oxide Layer
The first step when welding titanium is removing the oxide layer on its surface. The oxide layer acts as a barrier between the weld and the base material. It prevents proper bonding between them.
Use an abrasive cloth or a chemical cleaning agent such as trichloroethylene (TCE) or acetone to remove this oxide layer.
2. Maintain Enough Gas Coverage
Titanium reacts with oxygen while being heated in the arc of your torch. The reaction can cause sparks and splatter, which can ignite flammable materials nearby.
Maintain proper gas coverage throughout the arc to prevent this from happening. Then, shield off the area around your weld joint.
3. Back Purge the Titanium Section
When you back purge titanium before welding, you’re getting rid of all unwanted vapors and gasses from your welding surface. You’ll replace all these gasses with argon.
If you back purge, your weld will be free from contamination. It’ll produce clean, smooth welds.
4. Weld Titanium with a Broad Diameter Cup
Titanium has a high melting point. So, you need an arc welder that can produce this temperature for the best results when welding titanium parts together.
A wide diameter cup gives you more power when striking an arc. It also gives you more control over where heat is applied during the process.
Types of Inert Gas Shielding Used When Welding Titanium
The most common shielding gasses used for welding titanium are argon and helium. The shielding gas prevents contamination by air.
Gas shielding is carried out in three stages:
Primary shielding is used when welding titanium to other metals. This type of shielding uses argon gas. It protects the nearby metal from contamination by the weld, which would weaken it.
The argon also protects the welder from breathing in any contaminants in the air. In other words, it provides the primary coverage needed to protect the weld puddle. Ensure you use a water-cooled torch with gas lenses and a ceramic cup in primary shielding.
Secondary shielding comes from trailing shields. It protects the zones affected by heat until it attains a temperature of 427ºC (800ºF) or less. Also, it protects the solidified titanium weld metal.
Usually, trailing shields are tailor-made to fit a specific welding torch and operation. They allow an even distribution of the inert gas used when welding titanium.
Backup shielding provides inert gas shielding to the affected heat zones and the root side of welds. It creates a backing-gas flow around the weld puddle. To do this, attach a gas hose to your torch, then turn on the flow control valve on the torch to create an even gas flow around the weld area.
Once you have established a steady flow, turn off your main gas supply and begin welding using only backup shielding.
The advantage of using backup shielding is that it reduces spatter from entering the atmosphere because the hot melt does not have direct access to air.
Tips to Remember When Welding Titanium
Titanium is one of the best choices for any welding job because it resists corrosion. But it can be tricky to weld because it expands and contracts.
These tips will help if you’re working with titanium in your welding shop.
The Shielding Gas Is Crucial
Titanium doesn’t need preheating before you begin welding it. It needs a shielding gas for proper protection from oxidation during the welding process.
When using the shielding gas, the fumes will go through the torch tip and onto the surface of your workpiece. They won’t cause any damage or contamination.
The shielding gas protects the weld from becoming brittle and cracking during cooling. Usually, argon is used because it does not react with oxygen or hydrogen in air or water. It will not cause any corrosion on the metal surface you’re welding.
Cleanliness Is Key
Titanium reacts fast to contaminants such as paint, oils, dirt, and body oils from your hands, leading to weld embrittlement or localized corrosion.
Always use clean work areas and keep your welding equipment and materials clean. You’ll reduce airflow by doing this. Also, you’ll avoid interrupting the shielding gas that safeguards the weld pool.
Wipe down the area you’re welding with an alcohol swab before beginning your project. The alcohol will remove grease, oil, dirt, and other contaminants that would contaminate your weld joint.
Choose the Correct Tungsten Electrode and Filler Metal
If you choose to weld titanium using the Gas Tungsten Arc Welding (GTAW) process, always use a 2% lanthanated or ceriated tungsten electrode.
These are the sizing applications and the amperage you should use.
|Tungsten Electrode Size||Suitable Amperage|
|1/16-Inch||Below 90 amps|
|3/32-Inch||Between 90 and 200 amps|
|1/8-Inch||Above 200 amps|
Titanium has a high melting temperature and needs a high current to melt it. It means that tungsten electrodes have a higher melting point than those used on other metals.
The filler metal you select should have the same characteristics as the base metal. Otherwise, it can cause porosity in the weld joint.
Select the Right Welding Equipment
Titanium is an expensive material. So, use tools designed for working with it. For example, use argon shielding gas for GTAW processes rather than helium or hydrogen-based shielding gasses.
When welding, use a dual-process machine. It can handle both AC and DC. It will allow you to switch between tungsten electrode wire and gas tungsten arc welding (GTAW). It also gives you more flexibility in choosing how your weld joint will look.
Challenges You May Face When Welding Titanium
Titanium can react with oxygen at high temperatures and form trace amounts of titanium dioxide. It can cause embrittlement and alter the mechanical properties of the material.
This reaction also generates hydrogen gas during welding operations. It can also cause porosity in welds.
The titanium also has a low thermal conductivity compared to other metals. So, it needs higher temperatures for fusion than stainless steel or aluminum alloys.
It has a low hydrogen absorption capacity to make matters worse. It takes more heat input to achieve fusion than other metals do. It means that welders must use higher amperage levels on their machines. It’ll melt the filler metal and achieve fusion through the weld joint area.
Also, titanium welders must shield the liquid weld and the surrounding metal. It’s a challenge for even the most experienced welders.
Benefits and Drawbacks of Welding with Titanium
- Titanium is corrosion-resistant. Titanium pipes are used in marine applications because they’re resistant to salty water.
- It has a better strength-to-weight ratio than steel or aluminum.
- It has low expansion and thermal conductivity.
- It is lighter than steel.
- It has an operating temperature of about 900ºF.
- You can use it in many industries, such as marine and aerospace, for constructing structural frames.
- It’s stiffer compared to magnesium or aluminum.
- Titanium’s tensile strength reduces as the temperature increases.
- It’s less soft than steel.
- If it’s in powder form, it is flammable in ordinary air.
Though it can be welded, titanium is among the most challenging metals to weld. It’s important to be aware of its unique properties. In particular, use an inert gas to shield the metal from the air, and be careful not to overheat it.
It’s difficult to weld it without harming the integrity of the metal. So, take every necessary precaution.
Featured Image Credit: aon168, Shutterstock