Radiant Heat Treating

DN Staff

June 1, 2001

4 Min Read
Radiant Heat Treating

All information and opinions presented in this paper are the authors. Design News online did no editing or confirmation of the information provided.

A new, cost-effective technology to heat treat ferrous materials promises higher quality, reduced cycle times and more applications than other comparable methods. Radiant Heat Treating, or RHT, offers numerous advantages over other localized heat treating services, such as induction, flame, laser and electron beam.

Heat Treat Comparison Chart


Radiant Heat Treating


Suitable Material

Carbon, alloyed, tool, and martensitic stainless steels; cast irons

Mostly limited to steels with .30% to .60% carbon

Part Geometry

Flat, round and many complex shapes

Limited to flat or round shapes

Hardening Depth


.010-.250" depending on power source operating frequency and coil characteristics

Process Tooling

No part specific tooling required; flexible source-to-part distance allows broad air gaps of .25 -5"

Induction coil require; narrow coil-to-part gap .06-.08"

Heating Rate

Adjustable heating ramp & soak sequence; can be faster than induction

Rapid heating rate

Heating area

Up to several square feet or more

Up to several square inches

Adaptive Coating Technologies, LLC, Waunakee, Wis., developed RHT as part of a Small Business Innovation Research (SBIR) award, and the company plans to offer the RHT service in December. The primary applications are heat treatable mechanical components having simple or complex geometries.

RHT can heat treat most carbon steel and steel alloys, as well as tool steels and martensitic stainless steels. A variety of heat treatments, including stress relieving, quenching and tempering, austempering, martempering, and annealing can be performed to produce the desired hardness range and/or microstructure.


RHT can heat treat selective areas or entire surfaces of flat, cylindrical or complex shapes. Parts may measure more than several square feet. See Figure 1, "Typical Part Geometries and Heat Treat Patterns."

  • The hardening depth can be adjusted to heat treat from .010 to more than .500 inches deep. Flat parts with a wide variation in cross sectional thicknesses or cylindrical parts with several different diameters can be heat treated.

  • With RHT, a part may be heat treated without damaging a nearby temperature sensitive coating, joint or adjacent material.

  • RHT permits simultaneous localized heat treating of not only similar or identical part geometries but also individual or multiple parts.

  • Parts can be heat treated in a variety of environments, including open air, protective or vacuum, to accommodate a wide range of part requirements.

  • Due to excellent process repeatability, RHT should provide consistent high quality parts.


Whether the part shape is flat, cylindrical or complex, most ferrous parts can be heat treated with Radiant Heat Treating. Using RHT may result in cost reductions and quality improvements.

Adaptive Coating Technologies, or ACT, is currently using RHT for a Phase II Small Business Innovation Research (SBIR) project on armor plate fabrication. In Phase I, ACT successfully heat treated 1/2" thick titanium/steel plates to a hardness of 60Rc. Numerous commercial applications for RHT exist in the agricultural, mining, pump, oil, aerospace and automotive industries.

Red depicts possible RHT shapes. Areas can be heat treated individually or in any combination.


ACT, with trained technicians and experienced materials engineers, offers this cost effective heat treating service for a variety of applications. For further information about this new service, fax or mail drawings and specific requirements to John Krebsbach, Chief Engineer, Adaptive Coating Technologies, LLC, 315 Raemisch Road, Building H, Waunakee, Wis., 53597, 608-849-1908. Or e-mail us at [email protected].

If you want to contribute a technical paper, please send a hard copy and IBMelectronic format (.txt file, .jpg file, or .gif file only). For more information, e-mail [email protected].

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