What’s your Welding Problem?

Posted by BOC

Most welders will be familiar with imperfect welds; poorly fused or distorted joints, spatter, or unwanted holes in a finished job.

The good news is that most of these welding issues are easy to diagnose—and with a little extra care, can be prevented quite easily.

In this blog, we take a look at some of the most common problems you’re likely to encounter and the steps you can take to deal with them.

Common welding issue 1: Spatter

Spatter — the small droplets of molten metal generated during MIG welding that can stick to surfaces and accumulate in the welding nozzle—can cause a variety of problems, as well as create a messy welding area. It can increase costs by wasting welding material and creating extra time to clean off, and even cause a burn hazard if the right PPE isn’t worn.

Spatter that has occurred when welding mild steel

Lack of Fusion that has occurred when welding mild steel

Common welding issue 2: Lack of fusion

Do you struggle to fully fuse your weld metal with the side walls of the joints, or to join your weld beads together? Left untreated, lack of fusion can cause serious cracks or reduce the load carrying capacity of your joint.

It usually occurs when the welding conditions are too low, but there are a number of other steps that can be taken to mitigate its effects.

Common welding issue 3: Porosity

Porosity, or holes in your welds, occur when bubbles of gas are trapped in the weld pool as it solidifies. It can take several forms; the more common rounded version is known as ‘spherical’ porosity, while it can also take the form of elongated holes, or ‘wormholes’.

The size, amount of porosity and its location can usually help to identify the cause.

Porosity that has occurred when welding mild steel

Distortion that has occurred when welding mild steel

Common welding issue 4: Distortion

Distortion effectively means any kind of change in the welded joint or surrounding material —either shrinkage, a change in the angle, or buckling.

It can be particularly damaging, at a minimum, affecting the appearance of a weld, and at worst, preventing it from being assembled with other parts or stopping the finished piece from performing its purpose.

Common welding issue 5: Lack of penetration and root fusion

Lack of penetration and root fusion are two similar imperfections. Lack of penetration happens when both sides of the root fail to fuse to the weld; for example, when the groove of the metal is not filled completely. Lack of root fusion meanwhile, is a problem commonly associated with a high deposition rate. For both problems, prevention is far better than cure.

Common welding issue 6: Overfill, underfill and undercut

Overfill is a very common problem and simply occurs when the welded metal exceeds the amount that’s required for the job. Underfill, as the name suggests, is the exact opposite, and occurs when not enough weld metal is deposited. Undercut meanwhile, is a slightly different issue, appearing as a narrow, underfilled groove on the base metal, adjacent to the weld metal along its edge. Undercut, like underfill, can cause stress during fatigue loading.

How to deal with these common issues

There are a number of reasons that you could be experiencing all of these issues. Check the following as a first step:

1. Keep your welding area, parent metal and consumables clean

Rust, paint, grease or other contaminants on your wire, torch nozzle and in your work area can create poor quality welds. Take time to prepare your work area before starting to weld.

2. Choose your shielding gases and shielding gas flow rate carefully

The shielding gases you choose can have a positive, or adverse effect on the weld you produce, depending on each job. Make sure you consider your shielding gases carefully and consider using a flowmeter at the torch nozzle to ensure your gas flow remains at the recommended rate (for more on choosing the right shielding gas click here)

3. Check your welding conditions/settings

Using the incorrect settings for your voltage, current and wire feed speed can have an adverse effect on your weld. Take time to fine-tune your wire feed until you achieve a smooth arc. If your wire feed is erratic, check for dirt and kinks/loops in your torch cables and make sure you’re using the correct tip and wire for your job.

4. Focus on your technique

Poor weld technique can be a major cause of welding issues. A bad torch angle, inconsistency with your weld speed, torch to workpiece distance or even over welding can all create poor quality welds. Make sure during set up, that you are using the right technique for each job.

Visit the Welder’s Toolkit

You can find more detailed information on dealing with all of these common welding problems, as well as advice on your welding processes, equipment and health and safety guidance in the Welder’s Toolkit—our new online resource for the welding community.