Method of making a chain

Abstract

In a method of making a chain, in particular a round steel chain of tempered steel, a chain strand is produced in a conventional manner and subject to the usual heat treatment of normalizing, hardening and annealing. Annealing is implemented at a low temperature level of below 200° C. A tempered steel is used having a microstructure which, after hardening and annealing, has a stable residual austenite content between 3% and 10%. After the final calibration process, the chain strand is subjected to a thermal aftertreatment at a temperature between 190° C. and 250° C. This relieves stress resulting from the calibration process and the associated work-hardening. In this way, the notch impact energy capacity is enhanced.

Dependencies are inferred from the claim text.