Flange nuts are a type of fastener with a wide bottom circular flange. Their washer like base helps in distributing the load pressure of the nut uniformly over a large surface area. Class 10 nut grading is similar to the grade 8 classification, which is used in with Class 10.9 bolts. This is a medium strength nut. Phosphate and black oxide finishes have low corrosion resistance and are a good choice for indoor, automotive and industrial applications.