In the context of fasteners, the coefficient of friction (CoF) refers to the frictional resistance between contact surfaces in a fastening assembly – primarily the threads of a bolt/nut and the underside of the bolt head or nut face. This seemingly simple property plays an outsized role in how bolts, screws, and other fasteners perform during installation and in service. When a fastener is tightened, friction in the threads and under the head consumes the majority of the tightening effort. In fact, typically only about 10–20% of the applied tightening [...]

Salt spray testing is conducted in a chamber where specimens are continuously exposed to a fine mist of saltwater solution. This accelerated test is commonly used to evaluate corrosion protection, especially for coated metals. Purpose and Methodology of Salt Spray Testing Salt spray testing (typically per ASTM B117 or ISO 9227) is an accelerated corrosion test that exposes materials to a constant fog of salt solution in a heated chamber. The standard neutral salt fog uses about 5% sodium chloride at ~35 °C, with specimens placed at an angle so [...]