Neutral Hardening

Neutral hardening is performed on steel alloys with sufficient hardenability to attain designated surface and core hardness, without surface treatments (carburizing or carbonitriding). When neutral hardening in an atmosphere controlled furnace, the furnace atmosphere’s carbon potential is matched to the heated part’s carbon concentration; thus the heated part surfaces are not enriched or decarburized.

After heating in a neutral atmosphere, parts are quenched into furnace-integral, temperature controlled and agitation controlled oil baths. Quenching in oil fully hardens the parts; tempering is necessary after quenching to relieve stresses in the part from the heat treat process and to reduce part hardness to the designated hardness range.

Carbon Restoration

The carbon restoration process restores partial or fully decarburized part surfaces. During the hardening process, the carbon potential of the furnace atmosphere is maintained at a level slightly in excess of the carbon content of the material being processed. After the desired surface carbon content is achieved, the parts may be quenched and tempered, or slow cooled.

IST’s metallurgical lab facility evaluates the case depth and hardness of each heat treat load, and certifies results.

Endothermic Gas Generator

Rack Heat Treat

Hour Mesh Belt

Neutral Harden

Controlled Atmosphere Neutral Hardening and Carbon Restoration Capabilities

Part Length Range

0.25 mm to 762 mm

Loading Methods

Bulk Loading
Rack Loading


Batch – load size: 36″ x 72″ x 36″
Continuous Mesh Belt Systems
Data log heat treat attributes
Integral oil quench, or slow cool in protective atmosphere
Integral pre and post-washing systems
Integral tempering systems
Nine-position Continuous Row – load size 36″ x 36″ x 30″ high

Customer Process Specifications

Caterpillar 1E2225, IE0060, IE0106, 1E0107, 1E0672, 1E1042, 1E2203
Chrysler PS-1, MS-6149, MS-6179
Clark Components International 1X-1
Cummins 70315
Dana SHAES174
Eaton TES-003
Ford W-HTX, W-HT2-8, WD-956
GM GM6217M, GM280M, GM275M
Haliburton 70.94179
Harley Davidson ES805-41100

Trained/Competent Workforce

To attain operational excellence, IST fosters employee development by diversifying each employee’s capabilities, enhancing skill sets and creating a climate for action. Certified/cross-trained employees understand all aspects of the heat treat process, and our customer’s needs. Certified/cross-trained employees are capable of receiving, heat treating, inspecting and shipping.

Technology and Knowledge Management

To best manage our customer’s needs, IST continually refines the knowledge management process and improves information technology resources. We utilize best practices to facilitate the transfer of knowledge to all levels of the organization; employees understand our customer’s requirements and act in their best interests.