DATIAN (DT) Fastener is famous for producing quality heavy hex nuts. We, one of the professional heavy hex nut manufacturers, have a in house full line heat treatment machine used to improve the hardness and mechanical properties of heavy hexagonal nuts in order to serve different high requirement areas. The heavy duty hex nuts standard we listed below are most ASTM A194/A563 and ANSI/ASME B18.2.2 heavy hex nuts. Compare to finished hex nuts, the heavy hex nut carry higher grade and slightly wider and thicker diameters to meet the greater length of thread engagement and better resistance to stretching or widening. Contact DT Fastener, a professional nuts and bolts manufacturing company, for more info now! less