Although great strides are being made in the simulation of induction patterns, most of today’s inductor design and validation activities are still done through experience and experimentation. This paper provides a brief overview of how an inductor is designed, fabricated, and prepared for integration into manufacturing. Each aspect of its manufacture is critical to deliver a hardening inductor capable of meeting engineering drawing requirements and to be ready for production. The paper covers determination of requirements, inductor design, fabrication and assembly, process development, inductor characterization, metallurgical validation, and delivery of a production-ready inductor. Each step is described, and important considerations for each are presented.

Several case studies are presented illustrating issues that may be encountered when developing induction heat treating processes. The relationship of how induction heat treating parameters affect the metallurgy of production parts is examined in the form of case studies. These include the importance of normalized versus anneal starting microstructure as it relates to the ability of pearlite to transform to martensite within the short induction hardening process window. The influence of a non-uniform microstructure with proeutectoid grain boundary ferrite is discussed as it relates to prior structure. A team approach to balancing design specification with manufacturing cost and sound metallurgical practice is covered for an AISI 1060 steel channel component with complex inductor design. Another case study addresses how evaluating hardness in the as-quenched versus tempered condition can provide additional detail relating to back tempering in tooth by tooth hardened gears. The final example is the influence of frequency of case depth formation for an AISI 4140 cross roller section.