Precipitation Hardening

Heat treatment for increasing strength.

Precipitation hardening is the general term used to describe the reheating of a material following some type of annealing or austenite conditioning procedure and a quench. Sometimes referred to as “age hardening,” precipitation hardening is a technique used with many materials including maraging steels, aluminum, some stainless steels, superalloys and others. It is intended to increase a material’s resistance to increase strength.

Whereas the annealing process is meant to dissolve a material’s constituent phases into a solution for ease of machinability, precipitation creates new phases in a material that help to increase strength.

Precipitation or age hardening is usually distinguishable from tempering by the fact that precipitation hardening requires the material be held at high temperatures for far longer than tempering. This is not the case for all materials, however, as some stainless materials will be held at the higher temperature for the same amount of time. Heat treating professionals must take care to avoid “overaging” while conducting precipitation hardening, though, which is an overall reduction in hardness that results from continuing the precipitation hardening process for too long.

Paulo’s approach to precipitation hardening

Finding the right atmosphere to protect your parts is a critical part of the process. At Paulo, we have custom-designed furnaces that can handle air, argon, hydrogen and helium atmospheres – plus vacuum and water-quench furnaces. We have the industry’s widest range of computer-controlled furnaces running 24 hours a day, delivering the precise temperature control your project demands, no matter the delivery schedule.

Paulo’s precipitation hardening delivers unmatched part quality with:

  • Computer-controlled heating rates, soak temperatures and times and cooling rates
  • Multiple thermocouples to ensure uniform temperatures across entire lots
  • One-cycle solution treat and age, decreasing handling time and improving turnaround
  • Fast cooling in high-pressure quenching vacuum furnaces to maintain desired microstructures
  • Vacuum furnace design to eliminate oxidation, alloy depletion, carbon pickup and surface contamination
  • Specialized fixturing to eliminate eutectic melting, surface contamination, distortion and recrystallization
Heat treating 101: An introduction to heat treating procedures