What Does A Good Weld Look Like?

How do you distinguish a good weld from a bad weld? The skill to spot a bad weld can be crucial within your work. This guide will take you through what a good weld looks like on a TIG, MIG and ARC welder, the inspection process and common factors in faulty welds.

Welding on a MIG

One of the most common and easier methods of welding is MIG welding. But what does a good weld look like?

Look out for:

- A smooth consistent weld
- A weld with no discolouration or patterns
- No lumps or dips
- Straight and neat
- No cracks down the middle of the bead
- No holes
- Flat with no concave or convex

Signs of a bad weld on a MIG welder include:

- A thin line or welding bead
- Cracks with the bead
- Undercut
- Crooked or bent line
- Lack of strength in the joined structure
- Spatter

Welding on a TIG

TIG welding is more complex and requires high skills and experience to perform to a good level. It can easily create an illusion of a good weld. Here are some things to look out for.

Signs of a good weld:

- A pattern of beads
- No signs of burnout
- No signs of slag
- Visually pleasing
- No metal particles in the weld
- Neat welds

Look out for signs of a bad weld including:

- No pattern
- Beads out of line
- Flat beads
- Sins of burnout and slag
- Signs of undercutting
- Tungsten in the weld

Welding on a ARC

ARC welding, also known as stick welding, is one of the more versatile types of welding enabling you to work with many materials including carbon steel, iron, nickel and even aluminium. Signs of a good ARC weld are:

- The weld having a consistent thickness
- No breaks or cracks in the bead
- Straight and uniform

Signs of a bad ARC weld may look like:

- Breaks in the beads or cracking
- A bead that looks consistent
- Spatter on the weld
- Undercutting

Welding Inspection

Welding inspections should take place before, during and after the welding process. There are many types of weld testing but visual testing, also known as VT and destructive testing are the most common. Checking your weld before and during the process keeps the welder safe. The welding checks that take place after the welding process keep the user safe, ensuring the weld has been completed to a high standard.

Inspection before the weld

Make sure all the safety precautions have been followed, read and understand the explanation of the job and gather and prepare the tools needed.

Inspection during the weld

Ensure you clean between each weld and keep track of the heat source. Monitor your weld throughout as many problems can be seen once the weld has finished and cooled, which could have been prevented during the welding process.

After the welding process

Carry out visual checks including checking the welding size meets the requirements of the job, testing the weld strength, and looking for the signs mentioned above, in the ‘what does a good weld look like? section. Destructive testing happens after the weld has taken place, it can be done for many reasons but usually a piece of the weld is broken off and assessed for strength and performance.

Common faulty welds

There are many factors that can cause a faulty weld, including:

- Burn through - The welding from one side melts through the parent metal
- Corrosion - Leads to weld failure
- Lack of fusion - Also known as overlap
- Porosity - A gas absorbed in to the weld
- Undercutting - Usually happens if the source is too hot or the arc is too long
- Lamellar tearing - A form of cracking, preheating can reduce the risk of this

In conclusion, it is essential to check your weld before, during and after the process. This will keep you safe and prevents common faulty welds from happening, ensuring you are creating the best weld possible. If you have any further questions, contact our team of welding experts, on hand to help you.