Full Annealing

Due to the nature of the casting process, full annealing is often needed in order to improve machinability and also minimize the risk of distortion during any subsequent hardening or machining processes.


ThermTech runs full annealing treatments in batch-type furnaces for optimum process and lot control. All of these furnaces are in full compliance the temperature uniformity and accuracy requirements of AMS 2750.  Our largest furnace capable of performing the full anneal process has a working dimension of 86” x 51” x 182”.


The process of full annealing steel castings is performed by taking the castings above the critical eutectoid temperature in the 1475F to 1650F range for a length of time commensurate with the cross section size and then slow-cooling them to promote a uniform microstructure composed primarily of ferrite and coarse pearlite.  This process creates a product with maximum ductility, uniform properties, and improved machinablility.


We often recommend the full annealing process to customers with castings which are too hard due to rapid cooling during the casting process,  common occurrence  with castings poured  from any of several commonly used alloys.
The materials for which ThermTech most commonly runs full annealing treatments include:

  • 4140 steel
  • 4145 steel
  • 4150 steel
  • 4340 steel
  • 8620 steel

Depending on individual product needs, ThermTech offers several alternative annealing processes. For castings bound for intense machining, ask us about our spherodize anneal treatment. We also recommend asking about any other product needs you might have; ThermTech prides itself on its ability to meet any property and/or hardness requirements!

For a quote, a schedule, or more information about how our full annealing process can benefit your casting products, please contact a sales representative today!