How Do You Measure Weld Depth?


The ability to measure and calculate with precision is one of the abilities that set a good welder apart from a great one. There are just so many values you must track actively to ensure everything turns out well, and weld depth is certainly one of them. But how do you measure weld depth exactly?

There are destructive and non-destructive ways to measure weld depth. The destructive and common way is by cutting through the weld seam and inspecting your job with your naked eyes, while the no-destructive method is through an x-ray examination.

In this article, you’ll learn how you’ll likely come across weld depth and why it’s an important part of welding. I’ll also show you how to measure the weld depth of a weld if it’s possible, and how you can calculate it if you can’t get the weld depth directly.

What Is Weld Depth?

Weld depth, also popularly known as weld penetration depth, is a very important indication of weld quality, as it’s one of the values that determine the strength of the welded parts. It has come to replace the cut-check quality testing technique, which is unnecessarily destructive and wasteful.

While measuring weld depth is possible without having to destroy your metal, there’s still no automatic way to do it effortlessly. You have to either measure it manually or pick up a pen and paper to calculate it from known values.

Regardless of what kind of welding you’re carrying out, the weld depth remains the most reliable value to calculate strength. There are many different standards for calculating weld depth, but we’ll go over most of them in this article.

In most types of welding, the root of the weld usually has the deepest weld depth, making it the most accurate place to measure or calculate the depth. Before trying to get the weld depth, you should try learning the industry standards, as your values will be useless without those.

With that said, the next sections will explain how you can explain weld depth for both fillet welds, fillet welds, and many more.

How to Calculate Throat Thickness for Butt Welds

Thanks to the advancement of technology, you no longer need a pen and a determine the weld depth, it also helps to isolate many other faults in your fillet or butt weld.

If there are any faults in your weld, the x-ray can help identify its precise location to make it easier to fix. Due to its numerous disadvantages, it’s the preferred method of measuring weld depth in aerospace, transportation, power, and also the military.

However, radiography may not be the most cost-effective way to measure weld depth, especially when you’re working with small jobs. In that case, you may have to go hands-on, cutting through the metal to see the actual depth.

Since this method is undoubtedly destructive, you should avoid it at all costs. It should only be used as a last resort whenever there are no better and non-destructive options.

If you’ve decided to cut through the weld, cut from the perpendicular of the seam and inspect the cut to determine if it’s of acceptable weld depth. While this may work well, x-rays have been proven to be better than your naked eyes way too many times to even try this in an industrial environment.

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