Heat Treatment Of Castings

ThermTech processes over 20 million pounds of castings a year.  We process everything from Aluminum to Gray to Ductile to Bronzes to Steels.  Please contact us if you have any questions whether or not we have the capabilities to process yours. 

Casting treatment instructions
ThermTech has run very large loads of stress relieving of castings on our car-bottom furnace that is 15' long x 7' wide x and 4' high.
Image of furnace maintenance
The sub-critical annealing process typically produces a microstructure where existing pearlite dissolves into the ferritic matrix which lowers hardness and strength while improving machinability.
Parts after normalizing
Gray iron and ductile iron castings are typically normalized to move the carbon from being locked in carbides or graphite into more of a pearlitic microstructure.
Parts after full annealing
The full annealing process involves taking a casting to a temperature above the critical eutectoid temperature in the 1475F-1650F range for a length of time commiserate with the cross section size and then slow cooled to promote a ferritic microstructure.
Image of a Vacuum Furnace for Solution Annealing
Solution Annealing stainless steel castings is a process which takes the carbides that have precipitated in the grain boundaries and dissolves then into the surrounding matrix.
Image of product ready for Water Quenching
Many steel foundries cast low carbon or low alloy steels that require a severe water quench to adequately achieve the proper martensitic microstructure and hardness requirements.
Image of Cryo Freezer
Polymer quench hardening of steel castings like 4130, 15B41, 1045, and 5130 is the proper way to balance the necessity for rapid quench rates while minimizing the risk of quench cracking the castings.
Image of part to eventually undergo oil quench hardening
Steel castings made from alloys in excess of 0.40% carbon content can typically be oil quench hardened to achieve their desired mechanical or hardness requirements.
Image of an ADI part
In addition to austempering ductile iron we are also capable of austempering gray irons and several alloys of steel castings.
Image of technician in front of atmosphere furnace
To insure that the steel castings are capable of achieving full surface hardness during subsequent hardening processing the castings may require a carbon restoration of their surfaces and we have several furnaces capable of doing this.
Image of parts being treated with Vacuum homogenization
Most importantly to our customers we are able to run impellars and pump units where minimal oxidation occurs on internal surfaces making clean-up faster and cheaper for them.
Image of a casting after blast cleaning
Currently ThermTech blasts several thousand pounds of castings a day through our 96" diameter table blaster and our 36 cubic-foot tumbleblast unit.
Image of staff member checking quality data
Most austempered ductile iron castings have mechanical requirements due from either industry standards such as ASTM-897 or customer specifications.