As a welder, identifying different types of material to be welded can be a helpful trick up your sleeve.
Identifying metals involves knowing their properties and composition. Once these facts are established, you can choose the proper welding procedure required for your project. First, consider some key components to narrow down your clues.
By plain sight, some metals can be characterized by their colours, like brass, aluminium, copper, and stainless steel.
Some of them develop an oxidized layer when exposed to specific environmental conditions for long periods. Removing the oxidized layer will show its original colour.
Oxidizing and rust are usually found on carbon steel or low-alloy metals that can be welded. In comparison, stainless steel is more resistant to corrosion.
One way of checking if they are weldable is to look for previous welding joints.
When held against a steel grinder, metal sparks say a lot about its characteristics.
To perform the test, set the speed of your grinding wheel to 1525 m/minute and hold your metal piece against your grinder, ensuring that the sparks emanating from the grinding wheel are pointed downwards and away from your eyes. It would be best if you worked in dark areas to observe the sparks’ characteristics easily.
Conducting a spark test is an easy and cost-effective way to identify the material to be welded; however, nonferrous metal does not give out any sparks that set it apart from most steel.
Here are some spark characteristics to note when trying to identify metals:
- Cast iron gives out reddish, short streams instead of carbon or alloy steel.
- Steels create yellow or white long sparks.
- Steel with little carbon content produces long streams that may burst into a sparkle at the end. The more carbon content is present on the metal, the bursting tendency increases. When the carbon content reaches about 1%, you can expect brighter and more intense bursts.
Metals display magnetic reactions in varying degrees. Hence testing for magnetic behaviour is a straightforward and less damaging way to identify them. Furthermore, no fancy equipment is necessary for this test; all it requires is a pocket magnet.
Here is a list of metals and their magnetic characteristics.
- Magnetic metals are iron alloy, low alloy steel, nickel, and martensitic stainless steel.
- Slightly magnet metals have high nickel content like nickel alloys.
- Non-magnetic metals are zinc alloys, copper alloys, precious alloys, aluminium alloys, and magnesium, to name some.
This test involves an expensive device called the spectrometer which identifies the chemical composition of metals.
Since purchasing a spectrometer is a hefty investment, you can consider having a chemical test done by specialized companies that offer chemical analysis.
Types of Metals that can be Welded
Here is a list of weldable metals that can be utilized according to your specific needs.
- Cast Iron
- Galvanized Steel
- Mild Steel
- Stainless Steel
The purpose of identifying metals is to ensure that the material to be welded is appropriate for your project and that it delivers the utmost safety and durability.