It is critical to eliminate all inclusions and pollutants when preparing a material’s surface for welding and during interpass and postweld cleaning. Removing as little material as possible between weld passes saves time and money since any material removed will ultimately need to be replaced via the most expensive consumable—the filler metal. Removing too much of the base material during preweld surface preparation can also affect weld penetration, impacting the strength and integrity of the finished weld.
For these reasons, always choose the best surface preparation and cleaning tools for the job. The right solution provides efficient, effective performance—and allows you to spend more time welding and less time cleaning and making repairs.
Common Tools in Welding Applications
Three common tool categories are used for surface preparation and cleaning in welding applications:
- Bonded abrasives/grinding wheels
- Coated abrasives/flap discs
- Wire brushes and wheels
What you should choose depends on the requirements of the application and, of course, your personal preference.
Abrasive products and wire brushes differ in their performance and purpose. Abrasive products are designed to remove base material, whereas wire brushes are not. When surface preparation or weld cleaning requires that you remove slag or mill scale, a wire brush is generally recommended. Note, heavy mill scale sometimes can be too much for even the most aggressive wire brush. In these instances, choose an abrasive product. Abrasive products are specifically designed for applications such as stock removal, edge beveling, chamfering, and weld grinding and blending. Conversely, if an application requires that you preserve the base material during surface preparation and weld cleaning, a wire brush is still your best choice. Here’s how these products work.
Bonded Abrasives/Grinding Wheels. A combination of the grain type, grain size, and bonding agents (resins and additive fillers) determines the performance of each. Bonded abrasives are generally more aggressive and remove material faster, requiring a skilled operator who knows how to prevent damage, gouging, and undercutting. Wheels are constructed of abrasive grains, including aluminum oxide, silicon carbide, zirconia alumina, ceramic alumina, and combinations of these grains. A resinoid (organic) bonding agent is mixed with the abrasive grains. Finally, this mix is molded and combined with fiberglass reinforcement layers for durability and strength.
Aluminum oxide (AO) wheels are the most popular and are good for many general-purpose applications. Products made with a combination of ceramic and zirconia alumina cost more, but typically provide a better overall life and material removal. They are a good choice for materials such as armored steel, structural steel, cast iron, and INCONEL® alloys.