Full Annealing

Full annealing treatment is often needed in order to minimize the risk of cracking or warping 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 certified to AMS 2750 for temperature uniformity and accuracy requirements.  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 machined parts is performed by taking the parts 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 ferritic microstructure.  Full annealing may be performed in open fire, endothermic gas, or vacuum atmospheres depending upon part cleanliness requirements.  Most machined parts should be annealed in endothermic gas or vacuum atmospheres.


We often recommend full annealing prior to hardening operations for parts which have been welded or heavily machined.  Welding and machining produce stresses in materials which can manifest during heat treatment as warping and cracking.

The materials for which ThermTech has most commonly run full annealing treatments include:

  • 4140 steel
  • 1045 steel
  • 4150 steel
  • 4340 steel
  • 8620 steel

Depending on individual product needs, ThermTech offers several alternative annealing processes. For machined parts 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 machined products, please contact a sales representative today!