According to a survey conducted by the welding industry, up to 35% of welders are unfamiliar with the concept of ‘dross’. Dross is a form of waste material that results from welding operations, which can be anything from particles created during the welding process to slag and oxidized material.
As dross affects the quality of the weld and leads to increased costs and safety hazards, it is important to understand what dross is and how it can be reduced. This article seeks to help familiarize welders with the concept of dross, its effects and the common approaches to dross reduction.
What is Dross in Welding?Dross is a type of waste material that forms on the surface of the weld during the welding process. It is a residue created by the cooling of the molten metal that contains impurities that have been brought up to the surface of the material during welding.
This can occur during arc welding, which is when an electric current is used to weld metals together and during gas welding, which is when a gas flame is used to heat the material.
What Does it Look Like?
The dross is typically composed of a greyish, slag-like material that can often be seen on the surface of the weld. It may also take on the shape of small spheres, or droplets, that form on the surface of the weld. Depending on the type of welding and the materials used, it can vary in colour.
How Does it Affect the Weld?The presence of dross on the weld can lead to a weakened structure and can even cause the weld to fail if it is not removed prior to the welding process.
The dross can also interfere with the electrical current which can lead to problems during the welding process. Finally, the presence of dross can lower the quality of the weld and can interfere with the desired finish of the piece.
How Can Dross Be Removed?
It is important to remove dross from the surface of the weld in order to ensure a strong and reliable bond. Depending on the type of welding, there are a few ways to remove the dross.
- For arc welding, grinding wheels, power tools, and wire brushes are often used to remove the dross.
- For gas welding, sandpaper or a chisel can be used to remove dross.
- A chemical cleaning process may also be used to remove dross.