Full Annealing

Full Annealing Heat Treatment for Machined Parts & Stampings

Full annealing is often needed in order to minimize the risk of cracking or warping during subsequent hardening or machining processes.


ThermTech runs full annealing heat treatment in batch-type furnaces for optimum process & lot control.

All our furnaces are certified to AMS 2750 for temperature uniformity & accuracy requirements.

Our largest furnace capable of performing the full annealing process has working dimensions of 86” x 51” x 182”.


Full annealing heat treatment of machined parts & stampings is performed by taking 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 that have been welded or heavily machined, as welded or heavily machined parts can produce stresses in the materials which can manifest as warping & cracking during heat treatment.

ThermTech typically runs full annealing heat treatment on the following steels:

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

Depending on individual product needs, ThermTech offers several annealing alternatives. 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!

Contact ThermTech today to find out how our full annealing process can benefit your machined parts or stampings!