Fasteners, manufactured in hot condition are termed as Hot Forged Fasteners. Most of the times either bolt head or any protruding complex shapes are hot forged and followed by machining in cold condition. Hot forging is preferred mode of manufacturing fasteners when other conventional methods are feasible or the quantity isn't sufficient. Often large size fasteners or small fasteners with fewer quantities are produced economically with hot forging techniques. The overheads on hot forming methods are fewer in most cases. Most of the times, raw material unavailability of proper form of raw material if the main cause which demands the use of hot forging method for producing fasteners.
Products like heavy hex bolts, hex bolts, socket head bolts, eye bolts, eye nuts, countersunk bolts are commonly produced in hot forged condition. Hot forming methods for producing fasteners are used for all known industrial alloys.
Bar stock are cut into pieces of suitable dimension. The end piece of the small cut size bar stock is then heated via induction or any other conventional method. Once the head piece is heated to a temperature, appropriate for hot forming, it is pressed under a manual or automated screw press under a preload. After the head is formed, the raw piece is then taken into machining and threading. The product is then taken into heat treatment for reinstate the mechanical properties or further improve.
Metric size hot forged fasteners from M10 to M100 & imperial size fasteners from 3/8" to 4".