Trace every bolt lot from wire coil to heat treatment, plating and the customer’s pallet.

A bolt is cheap, yet a vehicle maker will stop a line over one bad lot. Coil chemistry, header setup, thread rolling, hardness after furnace and coating thickness all have to be traceable to the pallet that left your dock, often years later. Customers ask for that trail often.

Fastener makers run many part numbers at high volume, with the furnace and the plating shop in the middle of the route. Coil, lot, heat-treat step and test result share one record. When a customer questions a batch, the answer comes straight from that file.

Wire arrives in coils with a mill certificate, and the stores record the heat number, diameter and coil weight. Planning pairs each order with a part drawing and revision, then picks a coil that suits the grade. The header is set up with dies, punches and a first-off check, and the operator logs pieces per minute and the dies that wear. Stores then tag the coil.

Headed blanks go to thread rolling, where the die set decides the pitch and the finish. Parts then pass through the hardening furnace, tempering and a hardness check, and many lots go out to a coating vendor for zinc flake or plating. On return, the quality team samples for torque, tensile load, coating thickness and visual defects. Packing follows the customer’s label, the lot is closed, and a certificate of conformance goes with the delivery note.