How to Control Distortion in Welding? Causes & Types


Updated: 20 Feb 2024

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Welding is a crucial process in various construction, manufacturing, and industrial applications, and due to its popularity, welders often face some hurdles, including distortion in the welding project. Typically, by applying heat, pressure, or a combination of both, metals make the welding works unique and flexible.

However, if the welders do not follow the basic skills and techniques, it will cause issues in the welding process. Some strategies were used to control distortion, such as the Pre-heating technique, avoiding over-welding, and welding passes to minimize distortion.

Here, we will cover the different causes of distortion and how we tackle them through multiple methods.

Distortion in Welding: Let’s Dive Inside.

How to control distortion in welding

Distortion in welding refers to unwanted or undesirable deformation due to heat applied during welding. This phenomenon affected the aesthetic of the welded structure and, most importantly, its structural integrity and dimensional accuracy.

Causes of Welding Distortion 

There are different causes of distortion in welding, but here, we will discuss the leading causes.

Heat Expansion and Contraction:

welding distortion heat affected zone

During the welding process, the heat expands in the metals on the welded side, and after welding, the welded area is cooled, obviously contracting. These contractions and expansions are different at the local area of welding, which will degrade the welding structure.

Material Properties:

Regarding material properties in welding, there are some factors like the coefficient of thermal expansion, thermal conductivities, and yielding strength of the metals. It also affects and leads to distortion during welding because the material properties are different in the welding processes.

Residual Stresses:

Without any external loading on metals or forces, uneven change in the shape of the material is caused by the residual stresses after the welded side cooled when welding, which causes distortion.

Welding Sequence and Technique:

The welding sequence also influenced the metals due to residual stresses during welding. The technique and welding order affected the integrity and structure of the materials during improper welding sequences, which can lead to distortion in welding.

Pre-Welding Strategies to Minimize Distortion

So before starting a project, one should apply pre-welding techniques to end the project without creating any issues, and distortion is one of them.

Joint Design and Preparation:

In welding processes, the most important things to do are to make the joint design and prepare them to control distortion in welding materials. The typical design also impacts the structure of the welding during the welding process.

butt welding joint

Material Selection:

Material selection is essential in any welding process because when skilled welders select welding material, it will affect the structure and durability, creating more issues for them or making the process easier to cover it perfectly. Choosing a suitable material for the welding project would be best—for example, suitable welding metals, correct gas selection, and proper heat input.

Fixture and Clamp Design:

Some critical tools, such as fixtures and clamps, were used to fix or maintain alignment and prevent movement during welding. These tools supported the workpieces during the welding process to minimize shrinkage.

Techniques to Control Distortion During Welding

All the above steps were for those in the initial stage or starting the welding process. But if you are facing the distortion issue on the spot or in mid-stage, then we have compiled some welding techniques to cover your loss.

Heat Input Management:

The fundamental concept of welding involves controlling the heat applied during welding. When too much heat is used, it causes the welded component to undergo rapid temperature changes, ultimately altering its shape.

Weld Joint Design:

In weld joints, including butt, lap, corner, etc and the location of the weld has a significant impact on distortion. In welding, the weld joint makes proper design to have a low chance of distortion.

Use Minimum Weld Passes:

The best technique to follow by the welder is to use minimum welded passes to maintain the form and structure of the materials, which is necessary for weld quality and strength. The minimum passes will help in the welding process to reduce the welding defects.

Avoid Over Weld:

One of the worst causes of distortion is over-welding, which means welding a piece of metal more than once to make it robust, which causes the process to be distorted. To avoid over-welding, one should follow the parameters such as current, voltage, and filler metal size to achieve the best-welded structure. So, one should avoid excessive use of material during the welding process to avoid distortion.

Intermittent Welding:

Continuous welding may cause distortion. However, the intermittent welding technique can make your process easier to control distortion. Intermittent welding is a welding process that is applied with a period rather than continuously to avoid shrinkage. A welder must use welding beads in short segments with some space to control distortion.

Post-Welding Techniques

Suppose you have done the welding process successfully, and still, you have a fear of distortion. In that case, we have compiled some post-welding techniques that can minimize the risk of distortion after the completion of the welding process.

Stress Relief Techniques:

Stress relief techniques reduce or eliminate residual stresses that develop in welded components during welding.

If not appropriately addressed, these leftover stresses could result in warping, fracturing, or early malfunction.

Heat Sink or Backing Bar Removal:

Taking out the heat sinks or backing bars from the welded joint post-welding enables the structure to cool down in a controlled manner, thus minimizing the chances of distortion.

Waiting for the welded component to cool adequately before removing the heat sinks or backing bars is crucial to avoid premature distortion.

Mechanical Straightening:

In cases where distortion has already occurred, mechanical straightening techniques can be used to restore dimensional accuracy.

It may involve applying controlled force to deform the welded component in the opposite direction of distortion, effectively realigning it to its intended shape.

The Future of Distortion Control in Welding

The new advancements in welding make it more accessible to control distortion due to innovations such as computerized scanners and robots used in mega-welding projects, which have less chance of distortion in welding projects. Speculate on how these advancements could further aid in distortion control.

Queries or FAQs

Why does distortion occur in welding?

Distortion occurs during the expansion and contraction of the weld and base metals during the heating and cooling cycle. It means that the welded component fails to maintain its original shape and may result in shrinkage.

Does joint design play a role in welding distortion?

Both butt and filet joints are prone to distortion. It can be minimized in butt joints by adopting a joint type that balances the thermal stresses through the plate thickness. 

Can fixtures and jigs be used to control distortion?

Yes, fixtures and jigs play a crucial role in distortion control by providing proper alignment, support, and restraint management during welding.

What are a few common mistakes to avoid in distortion control?

Welders need to steer clear of common mistakes that could make the problem worse. By avoiding errors discussed in the above paragraphs and implementing effective measures to manage distortion, they can minimize distortion and uphold the strength and accurate dimensions of welded structures.

Conclusion

In conclusion, every successful project in welding aims to be completed successfully, but in the welding process, the primary defect faced by the welders is distortion. This damages the overall structure of the welding, so avoiding this damage requires innovative, skilled, careful planning before and during the welding process.

The welders should follow the technique to ensure the welding project’s success. If distortion occurs, then welders navigate the causes and control them or minimize them by using such strategies as avoiding overwelding and using minimum welding passes to prevent distortion.


Abu Bakar

Abu Bakar

Hello, Abu Bakar here, the Mastermind Behind Welding Villa. Test my years of experience through my well-written blogs, where I have covered the overall experience of welding materials and shown all the aspects of Welding, their types and equipment.

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