Do headed bolds receive heat treatment before or after the heads are forged?
Not all grades of bolts require heat-treating, but those specifications that do are heat-treated after the heads are forged. Heat-treating is performed in a controlled environment using specific quenching and tempering temperatures and durations. The bolts are then tested to ensure the strength of the heat-treated bolts meet the requirements of the given specification. Since we hot forge heads onto bolts in an uncontrolled environment by heating them to approximately 2,000 degrees during the forging process, heading must be performed prior to heat treatment. Otherwise, the mechanical properties on that portion of the bolt will be altered, and they may no longer meet the strength requirements of the specification.