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.

In conveyor oven applications, product testing is critical to determine the part heatup time and therefore the oven length. This article is a case study of how product testing was performed for a hydrogen embrittlement relief process of fasteners to determine oven design parameters.

This article discusses the implementation of a stationary induction hardening process for crankshafts and camshafts and the measures taken to maximize production rates while controlling part distortion.

A temperature management system is essential to accurately monitor and control the heat treating process for maximum productivity and product quality.

Computer modeling is used in the design and development stages of induction hardening to optimize the process and to improve component quality including hardness, beneficial stress distributions, and reduced distortion.

Induction heating is used to produce high quality, reliable aerospace components as well as unique combinations of engineering characteristics.

Induction hardening parts with small grain size achieves higher fracture strengths, but close control of thermal cycles is required to prevent grain growth.

As a regular contributor to the HTPro eNewsletter, Professor Induction answers a wide variety of questions regarding induction heating and heat treating. Included here are three recent challenges and solutions.

Professor Induction answers a wide variety of questions regarding induction heating and heat treating. This article addresses differences between auto-tempering and self-tempering.

Coupling a high magnetic field environment with an applied induction elevated temperature capability can achieve stronger, more durable components and materials with improved performance. This article describes work to develop high magnetic field processing technology.

Induction Heating and Heat Treatment, Volume 4C of the ASM Handbook, was developed to serve as a comprehensive resource on induction thermal processes to meet the needs of the induction heating and heat treating communities. This article reviews the topic coverage of the volume.

This article demonstrates how FEA-based tools are used to model residual stress and distortion in a full-float truck axle induction hardened and cooled at different rates. The effect of cooling rate on axial displacement is discussed.

A novel brazing approach for joining SiC-based fuel cladding is a promising technology for enhanced accident-tolerant nuclear fuels.

Variable valve timing (VVT) plates are part of a system designed to optimize engine performance by changing the lift, duration, and timing of valve lift events. This article reviews a case study involving cracking of AISI 1045 steel VVT plates after heat treating.

Modern, high quality induction heat treating equipment must be readily available and flexible enough to allow for easy retooling and reprogramming to process a variety of parts. This article focuses on the technical revolution taking place in induction heating, which for the first time enables preprogramming of induction equipment to change frequency and power during the heating cycle in the same manner manner as machinists have been programming CNC machines for years. This is illustrated through a case study of induction hardening a shaft-like component.

The Industrial Internet of Things (IIoT) has tremendous potential in many areas of industry, and the opportunities in heat treating cannot be overlooked. Large amounts of process and operational data can be gathered in heat treating. The potential for predictive processes, maintenance, and productivity will be fully realized as the heat treat industry combines data from multiple sources and focuses on evaluating, and acting on, both real-time and historical data that is readily available.

A new welding process known as hybrid induction arc welding (HIAW) or high deposition arc welding (HiDep) uses a hybrid approach to reduce—or even eliminate—weld distortion and greatly increase productivity. Operating directly in front of the arc welding torch, a portable induction coil heats the surfaces of the weld to, or near, the melting point. Heat generated by the welding arc is primarily used to melt the welding wire. This novel process operates at speeds two to four times faster than conventional arc welding and substantially reduces weld distortion.

Heat shields help protect vehicle-critical components that could delaminate and fail if exposed to high temperatures for any length of time. This article describes a solution that features ceramic platelets applied via plasma spray onto a metal substrate to create a heat shield that adds additional temperature resistance in comparison to standard pressed aluminum versions.

The application potential of magnesium alloys as lightweight structural materials in aerospace and especially inside the aircraft cabin are hindered by their high surface reactivity at increased temperatures with particular concerns of ignition and flammability during a potential contact with a flame or other heat source. This article describes global efforts to develop ignition-resistant and nonflammable magnesium alloys. A widely explored avenue involves microalloying magnesium with rare earth metals and other elements having a high affinity to oxygen. As demonstrated by experimental alloys, this approach allows shifting the ignition temperature well above the liquidus, not only easing requirements on protective atmospheres during liquid-state processing, but also increasing the safety margin for possible aerospace applications.

This work describes the development of a model to simulate the compound layer growth kinetics for nitriding AISI 4140 steel based on a customized Lehrer diagram. The model can be used to calculate concentration profiles of nitrogen as a function of time and position during the nitriding process and to predict the thickness of the compound layer. Winner of the 2012 HTS-Bodycote Best Paper in Heat Treating Award endowed by Bodycote Thermal Process-North America.