Shot blasting is an abrasive ‘blast’ surface treatment that uses round metal shots that are propelled under high velocity, commonly to polish a metal substrate, to strengthen it, or to repair damaged metalwork by closing cracks or tiny tears. The force required to propel the particles is achieved using a centrifuge or wheel, spun at high revolutions-per-minute – hence the alternative name of ‘wheel-blasting’. Often offered as a service alongside grit blasting, shot blasting is distinct for the spherical particles that it uses, whereas the grains used in grit blasting are angular. The function and purpose of shot blasting is also distinct from grit blasting. Here are three ways shot blasting can improve the quality and strength of metalwork.
1) Polishing Metal
Shot blasting can be an effective way to polish metal prior to application of a finishing coating, or to achieve an attractive shine in the absence of a coating (e.g. stainless steel railings). The shot impacts help in several ways, from removing surface scratches to blending tool marks and creating a uniform appearance across the metal. When used for polishing, shot blasting normally follows one or more sessions of grit blasting – a process used to remove old paint residues, rust, and grime from a surface.
2) Strengthening Metal
It’s important for metal to be as strong as possible, so shot blasting can be effective in increasing strength and reducing ductility. Shot peening – the process of improving the physical properties of metal using shot blasting – is a cold working method that manipulates metal at room temperature, by subjecting it to high velocity particulate shots. When blasted over the surface of the metal, shot peening can be invaluable in strengthening the workpiece. This applies as much to restoration pieces – e.g. vintage cars or agricultural plant – as it does to new fabrications, each of which benefits from improved strength and durability.
3) Repairing Damaged Metal
Shot blasting is an effective way of repairing and restoring surface defects and weaknesses. The impacts level the area and close many of the cracks or micro-tears that can weaken the surface. With defects identified and repaired, the metal will enjoy increased flexibility, durability and strength, and greater resistance to corrosion and heat. Please note that shot blasting isn’t appropriate for metalwork intended for non-destructive testing (NDT), as the process can temporarily cover up and mask the damage that NDT is designed to identify!
Contact Us For Your Shot Blasting Project
At GLW Engineering, we offer a range of shot blasting services to prepare metal objects for a consistent, impressive finish. We use a variety of shot media depending on the desired outcome, whether you need a smooth, textured, or shaped surface.
For more information about our shot blasting services, take a look at our free-to-download Guide to Shot Blasting and Powder Coating, or give us a call today.
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