Is TIG Welding the Strongest Weld?

Welding is one of the most efficient ways of joining parts together. Part manufacturers choose it over different types of rivets because welding creates a permanent and strong joint. It is also suitable when working on weight-sensitive applications. Because of the popularity of TIG welding, many often wonder if it creates the strongest weld. 

TIG welding results in strong and high-quality welds that are aesthetically pleasing. However, there is no universal strongest weld because the success of a welding process depends on many factors including base metal properties, type of joint used, and welding parameters. This article will compare TIG welding to other common welding processes in terms of strength and explain how to TIG weld to get a strong and durable joint.

What is TIG Welding

TIG welding, also known as Gas Tungsten Arc Welding, is a precise and high-quality technique. It uses a non-consumable tungsten electrode and a shielding gas made up of argon or helium to protect the weld area. An electric arc forms between the base metal and electrode that generates heat that melts the metal and fuses it after solidification. 

Note that the tungsten electrode gets hot but it doesn’t melt and become part of the weld pool. In some instances, you may be required to add a separate filler material to reinforce the weld joint. TIG welding is compatible with many metals such as aluminum, steel, titanium, nickel alloys, copper and its alloys, and magnesium. TIG welds are strong, clean, and may not require further finishing. You have autonomy over the process and you can weld from different directions. 

How to Carry Out TIG Welding

Follow the simple steps below to get strong welds using the TIG welding technique.

Prepare the Workpiece

• The first step is to clean the base metals using a solvent-soaked rag. 
• You then place them close to each other. You should consider clamping very large workpieces to avoid unnecessary vibrations and welding defects. 

Prepare the Electrode

• Now, choose the right size and type of tungsten electrode. You can go for pure tungsten or any number of tungsten alloys based on the type of metal you are working with. 
• Thereafter, grind the electrode to make the tip sharp and rounded. 
• Then insert carefully into the TIG torch. 

Adjust Settings

• Choose the right welding parameters including type and intensity of current, speed, arc voltage, and shielding gas flow rate. 

Consider the material properties, thickness, and the desired weld quality.

Start Welding

• Find a steady position and hold the touch at an 80-degree angle from the workpiece. 
• Weld at a constant speed and ensure the electrode does not touch any part of the workpiece to avoid contamination. 
• Use the foot pedal to control the temperature as you weld. 

One Last Check

• Carry out a final check to ensure the size and quality of the final weld meet specifications. If it is not up to standard, adjust as required.

Factors Affecting Weld Strength

The following factors determine the strength of the final weld in TIG welding 

Material Properties

The intrinsic properties of different metals affect the strength of the final weld. Thermal conductivity, tensile strength, and melting point all play a role. Thermal conductivity describes how fast and well a metal dissipates heat. Metals with low heat conductivity result in higher weld strength because a slower cooling rate reduces residual stresses and enhances weld penetration. Furthermore, metals with high melting points and strength will produce stronger welds that are less likely to crack.

Filler Metal

When TIG welding, there is a wide range of welding rods you can use as filler metals. These include aluminum, mild steel, copper, and nickel. The mechanical properties of the filler metal must match that of the base metal to produce a strong weldment. Additionally, consider the thickness of the workpiece when deciding on the size of the filler metal. 

Type of Joint

The type of weld joint you are using is another crucial factor. The joint type affects weld penetration, heat distribution, and stress concentration. Butt joints result in the highest weld strength because the weld is in line with the force direction. Lap and corner joints offer moderate strength. Hence, they require careful considerations like ensuring proper fit and making sure the workpieces are as flush as possible. 

Welding Parameters

You must also be skilled and experienced in TIG welding to be able to control the welding parameters such as heat input, travel speed, and travel angle. Using too little heat will cause incomplete fusion and penetration. Too much heat will lead to excessive melting and burn-through. Furthermore, the travel speed and angle will affect weld penetration and heat distribution. You need to optimize all these factors to get the desired weld strength and quality. 

Type and Quality of Shielding Gas

The content of the shielding gas also plays a role. When TIG welding, go for pure argon gas. Argon is inert and is denser than air. This implies that it will displace air and maintain a stable electric arc leading to a higher weld strength. You can also use an argon-helium mixture as the shielding gas. Helium increases penetration and is important for applications that need a higher heat input. 

Surface Preparation

Surface preparation is another important factor that affects the strength of the final weld. The surface of the workpiece may be contaminated with grease, moisture, dirt, and rust. These contaminants can interfere with the welding process and lead to pores in the final weld. It is essential to properly prepare the workpiece surface by pickling, blasting, and cleaning with solvents. This will help improve penetration and maintain consistent weld quality.

Comparison of Welding Processes

Let’s compare TIG with other welding techniques in terms of strength. 

TIG Welding Vs Shielded Metal Arc Welding (SMAW)

SMAW forms an electric arc between a consumable flux-coated electrode and the workpiece. The arc heats the electrode tip and fills the joint to create a weld pool. The flux coating then creates a gas cloud around the arc to protect the weld from atmospheric contamination as it cools and solidifies. 

TIG welding produces cleaner and stronger welds when compared to SMAW under the same conditions. TIG welding uses an external shielding gas and has a lower tendency to cause welding defects. 

TIG Welding Vs Laser Welding

Laser welding uses a highly focused beam of light to join metal parts together with or without a filler material. It can handle both thin and thick metals with high accuracy and precision. 

Just like TIG welding, laser welding uses an external shielding gas. The most common gases used for laser welding are argon, helium, and nitrogen. Laser welding has a smaller heat-affected zone and produces stronger and higher-quality welds. However, it is expensive and needs careful consideration when working with highly reflective metals.

TIG Welding Vs MIG Welding

MIG welding describes the process of using a consumable wire electrode that is continuously fed through a torch. An electric arc melts the workpiece and fuses it with the metal electrode. Because the electrode is continuously fed, MIG welding is fast and results in a shorter lead time. However, TIG welding has more penetration and produces stronger welds than MIG welding. Additionally, the welds are cleaner with a lower tendency of holes and cavities. 

TIG Welding Vs Flux Cored Arc Welding (FCAW)

FCAW uses a consumable tubular wire electrode with a flux-filled inner core to fuse metal parts. It is a semi-automatic process that can be performed without or without a shielding gas depending on the type. Just like MIG and TIG welding, FCAW also requires an electric arc to heat the workpiece and electrode. This technique is perfect for outdoor and heavy-duty applications. In terms of strength, TIG welding has an edge over FCAW. TIG welds are stronger, cleaner, and of a higher quality.

Industries that Require High-Strength Welds

TIG welding is used in many industries for manufacturing and repair applications. The following industries depend on high-strength welds to function 

Building and Construction

The building and construction sector rely on strong welds to firmly hold components together. It is used for building bridges, heavy-duty cranes, and skyscrapers. The welds must be able to withstand heavy loads to prevent collapse which can be detrimental. They should ensure safety and structural integrity. 

Pipeline and Pipe Welding

Welding is a crucial aspect of the pipeline system for many reasons. Strong welds prevent leakage of fluids and gasses from pipes because they handle vibrations better. Additionally, it preserves the integrity and purity of the substance being transported. This makes welded pipes suitable for use in both extreme hot and cold conditions. 

Aviation Industry

Aircraft part manufacturers prioritize welding over riveting because welds are permanent and do not add extra weight. Strong welds are important when manufacturing engine mounts, exhaust systems, wing structures, and landing gears. They ensure components are perfectly secured to each other to prevent damage and ensure passengers’ safety.

Automotive Industry 

Welding is a critical part of the automotive industry. You can use it to create a strong connection when manufacturing sheet metal parts and structural body components. Additionally, welding is suitable for repairing cracks and fixing damaged panels. The final welds must be strong to be able to resist impact, ensure durability, and enhance overall performance.

Conclusion

TIG welding is an efficient way to join two or more parts together. It results in a strong, clean, and durable weld. To get a consistent and excellent result, you must optimize welding parameters, properly prepare the base metals, and use a high-quality shielding gas. If the external parameters are constant, TIG welds are usually stronger than others produced from MIG and similar arc welding processes. However, laser welds are stronger because they use high-powered laser beams and result in a small HAZ.