The term "fire cracking" describes the spontaneous fracture of a wrought article during intermediate or final annealing procedures after cold-working operations. The phenomenon is most commonly associated with nickel silver alloys, which are the base metal components of common white golds. A number of factors contribute to promoting fire cracking. These include alloy formula, metallurgical processing, grain size, residual stress, annealing techniques and impurities. Stereoscopic, metallographic and SEM techniques are documented in the analysis of fire cracking failures of formed strip, shaped wire, ring tube and stamped components. Studies sought to identify the root cause and remedy for an issue that has become more significant with the broader application of white gold in jewelry.

Author: Greg Normandeau, David Ueno