The Purdue Heat Treating Consortium works to advance the science of heat treating by turning new technologies into practice. Over the past three years, the consortium has delivered results on projects for new sustainable and environmentally friendly austempering oils and processes, as well as lifecycle analysis of carburization heat treatments.

This article compares heat treat processes and furnace types that are typically used to harden gears.

Tests conducted on vacuum carburized and quenched shafts identify variables that increase distortion and the magnitude of residual stresses.

Application of heat treat simulation using the finite element method is ideal to troubleshoot, improve, and design heat treating processes. This article presents examples of heat treating simulation used in the design of a tooling component and in refining a low-pressure carburizing process.

Process optimization and optimal component performance can be achieved when multiple variables are measured and studied as a whole. In the investigation described in this article, fatigue performance of AISI 8620 H steel was characterized as a function of carburization case depth, hardness, residual stress, and retained austenite to demonstrate that an optimized carburization process could be engineered to meet specific application requirements.

In this article, the authors demonstrate the use of simulation software to optimize low-pressure carburizing (LPC) processes for high-alloy steels with strong carbide-forming elements.

This article focuses on five common reasons for distortion and cracking during heat treatment and recommended remediations: (1) Nonuniform and uncontrollable heat transfer during heating and cooling; (2) Structural changes during phase transformation; (3) Residual stresses in the part that occur due to forming, welding, or machining before heat treatment; (4) Macro or micro steel structure; and (5) Fixturing and loading errors.

Stringent pressure control and gas species type both play an important role in minimizing the evaporation rate of not only copper, but other elements susceptible to evaporation in vacuum systems. The article describes a study investigating the effect of temperature, pressure, and carrier gas species on the amount of copper evaporation that occurs from copper foil test samples in low pressure carburizing.

Emissivity is a term used to define the ability of a surface to emit and absorb radiation. At any given temperature, the emissivity of a body (or surface) equals its absorptivity. Development work on a vacuum carburizing process revealed the need to better understand the effect of workload surface emissivity and the proper use of dummy thermocouple test blocks. This article reports on the findings from this research effort.

There is growing interest in steels microalloyed with titanium, niobium, and molybdenum for use in high-temperature carburizing applications. This article describes methods for control of grain coarsening and work to commercialize microalloyed coarsening-resistant steels.

Manufacturing data together with heat treating knowledge can be synthesized with physics and data-based modeling approaches in a closed loop to provide insight for improving process efficiency and product quality for overall reduction in operating and energy costs. This article provides case studies of data analytics for coil batch annealing and batch carburizing.

Low-temperature surface hardening of stainless steel by means of gaseous processing provides a high degree of tailorability of the hard surface case without affecting corrosion resistance. This article covers the fundamental and technological aspects of the process and examines the effect of different LTSH treatments on 304 and 316 austenitic stainless steel.