Thursday, March 31, 2022

How Do You Distinguish Between Different Metal Alloys For Welding?

Rolls of metal sheeting in a warehouse

It is important to know what type of metal you are working with before welding. Some metals are weldable, others are not - but knowing the type will help you determine the proper technique and methods needed for successful welding. 

The more you work with metals and the greater experience you have, you may easily come to recognize what is in front of you. Until then, we’ve got some tests to help you distinguish between different metal alloys for welding. 

Common Ways to Test Metal Alloys

There are 7 general tests that can help you distinguish between metal alloys, including: 

  • Visible surface appearance

  • Spark test

  • Chip test

  • Magnetic test

  • Torch test 

  • Chemical test

  • Hardness test

Let’s take a closer look at each. 

Visible surface appearance. Familiarizing yourself with the visible appearance of metal alloys as well as their common applications, you can get an idea for the type of alloy you are working with - or at least narrow it down. 

Spark Test. You can determine the type of metal you are getting ready to weld by determining whether or not there is a spark when holding it against a grinding wheel. If there is, you may be dealing with stainless steel, cast iron, wrought iron, nickel, etc. Otherwise, you won’t find sparks with metals such as bronzes, coppers, brasses, lead, aluminum alloys, and zinc alloys.  

Chip Test. Using a chisel to chip a small piece off of the metal can give you some insight. The size of the chip, whether its edges are smooth or sharp, the grain, and so on can all be important key aspects of identification. For example, copper chips are smooth with sawtooth-like edges. Brass and bronze have the same characteristics. The differing factor is that copper chips in a continuous strip while the latter has smaller, more brittle chips. 

Magnetic Test. Ferrous metals are magnetic, nonferrous metals are not. All you need is a small magnet to perform this test. You will find that steel, nickel, and iron alloys are strongly magnetic. Copper alloys, aluminum alloys, and zinc alloys are not. 

Torch Test. By firing up a torch and heating the metals, welders are able to better distinguish between them. This is done by visibly inspecting the melted metal as well as paying attention to how fast it melted. Each metal will react a little differently to the heat. For instance, brass and bronze melt rapidly and turn red before they do. Brass may give off white flumes. Copper requires a larger flame to melt and its color becomes very pronounced just before it melts. It does so slowly and may tend to bubble if close to the flame. 

Chemical Test. Certain chemicals can be used to determine the metal you are using. Of course, it is important to have an understanding of what you are doing before you attempt these tests. An example is putting a few drops of 45% phosphoric acid onto stainless steel - if it bubbles, then it is stainless steel. There are a few different tests for various metals that you can use. 

Hardness Test. This test can be done in different ways, but it involves pressing a specific object known as the indenter into the surface of the metal. Its hardness can be determined based on the depth of the penetration or the size of the impression. By understanding the hardness of common metals, you can narrow down which one you may be confronting. 

Learn More About Metal Alloys at AtlasBronze

There are quite a few different metals and metal alloys so it can be tough to always know exactly which is which. But, if you are a welder, it is important to know the properties of each of the metals you are using at all times. 

If you are looking for the right metal for your application - or you aren’t sure which one is best - the experienced professionals at AtlasBronze can help. Contact us at (800) 478-0887 or reach out to us online. 

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