Everyone knows how to perform a hardness test, or do they? Hardness testing is made more complex by such real world factors as a hard case over a soft core, hard particles, soft inclusions, and soft layers over hard cores to name a few. Part size, shape, and weight are other test challenges. Selection of the best test method, use of proper procedures, and a keen awareness of what and where to test are needed.

Hardness testing is one of the most common quality control checks performed. It is often used to determine the success or failure of a particular heat treatment operation or to understand the material’s current condition. Hardness testing is one of the easiest tests to perform on the shop floor or in the laboratory, but it can be one of the hardest tests to do properly. READ MORE By Alan Stone and Daniel H. Herring.

Ion nitriding can be used in many applications, but some are so unique that they can be called “the best” applications, where the competitive treatments such as salt bath and gas nitriding cannot easily duplicate the unique results of ion nitriding.

Ion, or plasma, nitriding has been studied and used industrially for more than 40 years [1-8], but the technology has not been used to its full potential. Ion nitriding/nitrocarburizing is a low temperature (800-1100˚F, or 430-595˚C) process, which results in little or no distortion of the treated parts even if significant residual compressive stress is induced to the surface layer of the treated products. The ion nitriding process also has been referred to by other surface treating characteristics including plasma, vacuum, diffusion, low nitriding potential, passive surfaces activating, easy-to-control structure and pollution-free processes. These process characteristics with the exception of the low nitriding potential concept are discussed in the literature. READ MORE by E. Rolinski and G. Sharp

Vacuum is used to control the environment in many heat treatment processes and the vacuum pumping systems used may be simple or complex. This article offers practical recommendations to handle operational issues that can arise with these systems to optimize performance, reliability and safety.

The application of vacuum in industrial processes is widespread with the heat treating industry using vacuum in a broad range of processes, many of which place particular demands on the vacuum pumps. Today, there are many types of vacuum pumps available, from traditional oil-sealed rotary vane pumps to the so called “dry” pumps developed for use in the semiconductor industry, and which have found their way into industrial processes. READ MORE by Dick Amos and Simon Bruce

Martensite development is critical to many heat-treatment processes. This paper examines the conditions under which austenite is retained and the problems associated with its presence, with detecting it and with measuring it.

Depending upon the carbon content of the parent austenite phase, either lath (low-carbon) or plate (high-carbon) martensite may form, as well as mixtures of the two. In general, lath martensite is associated with high toughness and ductility but low strength, while plate martensite structures are much higher strength but may be rather brittle and non-ductile. READ MORE by George F. Vander Voort

Quenching is an integral part of any metal alloy heat treating application. It helps define the metal’s microstructure and is a critical step in determining whether a part will meet specifications and properties after tempering. Having a full understanding of the types of quenchants available and in what applications they are best used will improve a heat treater's overall operation.

Everyone who has ever seen a movie about medieval life is likely familiar with the image of a sweaty, soot-covered blacksmith pounding away with his hammer on a sword. When finished, he lifts the bright red, heated blade from the anvil and plunges it into a nearby bath. Most audiences probably think the water was meant just to cool the hot blade. But as any metallurgist or heat treater knows, the blacksmith was forging and heat treating the sword and using the water bath to quench it. READ MORE by Michael Edens

Counting molecules is a job for vacuum gauges. Depending on the type of vacuum systems and the required operating vacuum level, different vacuum gauges are required, often in combination with one another, to accurately determine and/or control the vacuum level of the chamber at any given moment in time. By Daniel Herring