The importance of knowing what material you’re welding

If you didn’t know what metal you had to weld, how would you determine the type and grade of welding material you're working with?

Well, try to weld metals if you don't know what it is, as critical parts could fail, resulting in injury or worse. So a compelling reason why material identification is required is to understand what and how you are going to weld.

Welding material identification

You probably already know that welding some metals with improper welding procedures can result in defects in the base metal, the weld, or both. As a result, welding material identification, characterisation, and verification are critical for businesses to ensure their materials or products are manufactured to the correct alloy grade and meet all the necessary codes and standards. However, that might not be required for welding repair if you understand the welding metal family.

What kind of metal is it?

A basic evaluation can narrow down the possibilities if you're frequently asked to weld an unknown material. As a welder, you could examine the material's surface to determine its weight. Then, looking at the welding material, you should be able to categorise it as carbon or low-alloy ferrous material, stainless steel or nickel alloy, or aluminium alloy.

When evaluating the area where you'll need to weld, you can find important clues. Can you tell if the part was welded during its original production? This is a good indicator of weldability. However, look carefully for evidence to see if a welding repair was already attempted. If previous repairs have failed, this is a red flag.

To ensure safety and success, it is critical to ask questions. Check the nameplate, call the original manufacturer, and inquire about the material used, as they will most likely keep records and use the same grade of material each time. For example, handrails are typically made of 6061-grade aluminium. If you still can't figure it out, research the materials commonly used to create specific items to narrow down your choices.

Welding metals that produce small chips are likely to be free machining grades prone to hot cracking when welded. Conduct spark tests on steel and cast iron. This may give you an idea of how much carbon is present in the material. Chemical spot testing can also determine the presence of specific alloying elements.

In addition, a chemical analysis could provide some of the best information to help identify the material grade, and several businesses will do this for you. Submit machining chips from the material for analysis or remove a small 25mm square piece. In addition, most testing labs offer chemical analysis of metals, which in many cases costs far less than injury or defect claims. Metal chemical analysis is used for various purposes, including manufacturing quality control, reverse engineering, and to investigate failures.

Earn the respect of your customer, who should be willing to pay for tests to ensure that you get it right the first time. Spending time and money to get a good idea of what material you will be welding with is essential if you want to make a safe and long-lasting repair.

Alphabetical list of metals that can be welded.

• Aluminium is one of the most challenging metals to weld because of its properties and the type of equipment required to weld it.
• Brass can be difficult to weld depending on the type of brass.
• Bronze is a more difficult metal to weld and requires a hotter weld.
• Cast iron is a complex metal to weld and may require you to heat it before welding. Stick welding is usually the best way to weld stainless.
• Copper is difficult to weld and is usually done by soldering or brazing.
• Galvanised metal is not difficult to weld, but the gas produced by the zinc coating can be extremely dangerous and harmful.
• A36 mild steel is the most common and easiest type of metal.
• Nickel welds easily and similarly to stainless steel. You can use arc welding, MIG, or TIG for a good weld when welding nickel.
• 304-grade stainless steel welds fairly easily but has a tendency to wrap if heated too much.
• Titanium is difficult to weld, but if you understand your tools and metals, it's not that difficult.