Posted to News on 7th Nov 2006, 00:00
Steel nuts stand up to salt spray
A groundbreaking finishing process developed by Profil UK and applied to its standard range of steel nuts has resulted in the fasteners being able to withstand more than 1000 hours' automotive testing without red rust (RR) appearing. This represents a significant move forward for the automotive industry as a typical zinc electroplated zinc and yellow passivation steel surface withstands salt spray for just 96 hours without RR.
A major supplier of pierce fastening technology to the automotive industry, this is the first time Profil has used the Magni finish, which has been developed in conjunction with the US motor industry and is available under licence in Europe and the UK. Because fasteners are used on all parts of vehicles, different coatings are required to protect against corrosion and control the amount of torque needed to tighten them.
Profil worked with a Magni supplier in Germany to develop the finish which prevents bi-metallic corrosion between nut and panel and consists of two layers: 565 - an inorganic zinc-rich basecoat - and a B18 organic pigmented topcoat. The function of the nuts and pre-piercing the holes in the panels ensures the plating is not damaged or altered while the nuts are inserted.
Exceptionally high torque and pull-through loads have also been achieved when Profil's Magni-plated standard steel nuts inserted into aluminium panels have been subjected to the 1000-hour salt spray test. For example, an RND 8 nut in 3.00mm thick material achieved a maximum torque to failure of 87.1Nm and a nut pull-through load of 29 tonnes.
