A bright idea: General Industry Coverage

In the world of precision metal parts, aesthetics can be everything. For example, metalworking professionals expect precipitation hardenable stainless steel to look bright silver. “When they hear ‘stainless steel’ and then see something other than silver, the immediate question in their minds is ‘is this really stainless steel?’ ” said Don Jordan, vice president of R&D and corporate metallurgist for Solar Atmospheres, which specializes in vacuum heat treating.

The process to anneal and bright age-harden PH stainless steels in a vacuum furnace typically requires the heat treater to cool the metal below the ambient temperature after annealing by placing it in a refrigerator before the age-hardening step, Jordan explained. That requires exposing stainless to air, which causes it to discolor—oxidize—to a golden blue hue during age hardening. “You’re breaking the vacuum,” he said, adding that the discoloration doesn’t negatively impact material properties but people interpret that it does.

Courtesy of Solar Atmospheres

Solar Atmospheres’ heat-treat process to anneal and bright age-harden PH stainless steels avoids discoloring the metal.