M20 Form 'B' Flat Washers Zinc Plated

• Form B flat washers are thinner than the heavier duty form A type washers.
• They are zinc plated for resistance to corrosion, and conform to BS4320 standards.
• Washers provide a smooth surface for the nut or bolt to bear on, making it less likely to loosen as a result of an uneven fastening surface.
• The main purpose of a washer is to distribute the load under a bolt head or the nut face.

Zinc coatings prevent oxidation of the protected metal to create a longer lasting finish. It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged. Zinc oxide is a fine white dust that (in contrast to iron oxide) does not trigger a breakdown of the substrates surface integrity as it is formed. The zinc oxide, if left intact, can act as a barrier to further oxidation, in a way similar to the protection afforded to aluminum and stainless steels by their oxide layers.