Heat Treating

Duraloy Heat Treating


Spiral retorts are used to heat treat a variety of parts such as ball bearings, coins, nuts and bolts, and fasteners. The internal flights are cast integrally with the outer shell of the retort to eliminate hours of welding. Common alloys for spiral retorts include HT, HU, HW and MO-RE 15®. The carbon content of these alloys makes them stronger than their wrought-fabricated equivalents at high temperatures. 

Radiant Tube Assemblies

Duraloy produces a variety of straight, “U” and “W” radiant tube assemblies. Duraloy can manufacture complete assemblies that include bung plates, bellows, and insulation. Radiant tubes are manufactured in alloys ranging from ASTM grades HK, HT and HU to high temperature proprietary grades like MO-RE 1®, Super 22H® and MO-RE 2®. R&D 100 award winning TMA-4701® can be used in some applications as an upgrade over HK, HT and HU with little to no increase in cost. 

Calciner Tubes

Calciners are used for the heating and drying of powdered products. Typical calciner applications include the manufacture of pigments, dyes, and chemicals. The product is fed into one end of a rotating calciner, which is being heated on the outside while maintaining a very precise atmosphere inside. As the product moves through the calciner, heat is transferred through the calciner wall to achieve the desired temperature in the product. These assemblies can be manufactured in a wide variety of alloys like HK, HT, MO-RE 1® and Super 22H® depending on operating conditions. Manufacturing these centrifugally eliminates the longitudinal seam welds that are required for fabricated calciner tubes. Integrally cast internal lifters can also reduce fabrication time and defects by utilizing proprietary casting techniques and unique tools to integrally cast lifters to the inside of the calciner. Lifters are used to tumble the product during the heating cycle.

Furnace Rolls

Small diameters rolls as shown above can be placed close together to provide support for material with low strength at high temperatures. This is a common issue with material such as aluminum and glass. 


Duraloy Technologies produces heavy duty circular baskets and grids for pit carburizing furnaces. These baskets withstand frequent temperature cycling from a high temperature bath the parts are placed in. Duraloy has worked with our customers to modify the design to improve life and wear resistance.