An induction hardening process model to assist sustainability assessment of a steel bevel gear

Abstract

The manufacturing industry is beginning to make production and design decisions informed by principles of sustainability. This means balancing economics with environmental and social performance. In order for design and manufacturing engineers to make these types of decisions, they need to measure product sustainability performance at the process level. The purpose of this research is to develop an induction hardening unit manufacturing process model to assist in product sustainability assessments. Physics and engineering principles are used to construct the underpinning induction hardening mathematical models. The models are functions of process and design parameters to quantify the appropriate economic, environmental, and social metrics. The induction hardening model is demonstrated for hardening the teeth of a representative steel bevel gear. Bevel gear alternatives made from AISI 4340, 4140, and 4150 steel alloys were chosen to analyze the influence of material properties on the sustainability metrics. A tempering process model was incorporated into the sustainability assessment to obtain functional equivalence of the components. It was found that the electrical resistivity greatly impacts the electrical energy consumption of the induction hardening process, while the austenitizing temperatures of the three steel alloys have a lower effect. The differences in the steel alloys had a low impact on the operating cost and did not affect the social metrics. Constructing unit process models improves the accuracy of product sustainability assessments that are used to help decision makers investigating tradeoffs in process and design parameters.