Heat Treatment

Heat Treating

& Hardness Testing

Heat treatment is a high temperature tempering procedure that increases strength and wear resistance of stainless steel and aluminum aerospace investment castings.

During the heat treatment method, investment castings are heated above their critical temperature, then quenched to fast cool the part, building a more uniform and structurally reliable part.

Depending on the alloy, an aging process may follow to further strengthen the investment casting.

After heat treating is done, hardness testing is achieved to validate the level of surface hardness that was obtained through the heat treatment process.

Workers doing heat treating with machinery


performs most Heat treatments in-house according to customer specifications.

Close view of workers cooling down pieces during heat treatment

Alphacasting also use certified, external resources when needed. We are proud to be NADCAP HEAT TREAT certified since 2014.

See all our certifications

NADCAP Accredited Heat Treatment

for Investment Castings

To save you time and money, Alphacasting manages special process operations in-house like heat treatment, to avoid production delays associated with transit and shared queue times.

Our part-specific instructions, tight procedure controls, preventive maintenance, certified personnel, and routine compliance audits also assure that your aerospace investment cast parts are treated in strict accordance with all contractual requirements.

We are NADCAP accredited for the following heat treating and supporting operations:

  • Precipitation Hardening
  • Rockwell Hardness and Tensile Testing for in-house Heat Treat
  • T4, T430, T6, T61
  • Anneal

Worker looking at a sheet of paper

Aluminium casting heat treatments

Heat treatment helps enhance the physical and mechanical properties of aluminum investment castings by rising strength and hardness, and improved machinability. Aluminum casting heat treatments furnished by our casting foundry are in accordance with AMS-2771 and include:

  • T4 Heat Treatment Process: a natural aging process where the alloy is solution heat treated and then naturally aged until it reaches a stable condition. This heat-treating method is usually followed by an additional process such as T6 or T61.
  • T6 Heat Treatment Process: alloys are solution heated at low temperatures and then artificially aged until the material becomes stable.
  • T61 Heat Treatment Process: uses solution heat treating to heat the alloy to a precise temperature, then holds the material at that temperature for a specified time before rapidly cooling it. The alloy is then artificially aged to stabilize the material.

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Heat treatments applications

In the steel processing industry, heat treatments are often applied after production processes such as rolling, casting, welding and deformations, thus influencing the structure and the associated mechanical properties of the material. After the production process, proper heat treatment improves and generates the desired mechanical properties and structures, and considerably lengthens the lifespan and quality of the components. In general, heat treatments are used to:

  • rectify the undesired effects of a previous production process (homogeneous annealing, re-crystallising annealing, low-tension annealing, or solution annealing)
  • make the crystal structure more homogeneous (normal annealing)
  • make the steel softer, e.g. for further processing (soft annealing)
  • make the steel harder/stronger and more wear-resistant (hardening, tempering or refining)

External heat treatments

Alphacasting works with a large network of approved and trusted qualified suppliers specialized in certain heat treatments, and oversees their reliable and regularly audited processes, all at extremely competitive rates.

We can help you find the right heat treatments through these suppliers, such as solution annealing, hardening, refining, precipitation hardening, homogeneous annealing, re-crystallising annealing, nitro-carburising, inductive hardening, carbonate treatments, vacuum hardening or nitriding.

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Tight procedure controls = ALPHACASTING Solution