... helical shape. This causes the washer to exert a spring force between the fastener's head and the substrate ... Manufacture→Quality Contol→Package a.The Material of the washer: spring steel - 65Mn & #70 stainless steel b.Quality Control ... of business: washersspring lock washers, double spring lock washer, flat washerpinscotter pins, split pins, spring pins, spring cotters, lynch pinsBolts& nutshex bolts, ...