For many heat treaters, the use of oil gives the best value based on a number of factors including:

• Overall performance (cooling rate or quench severity)
• Economics/cost (initial investment, maintenance, upkeep, life)
• Minimization of distortion (quench-system performance) Variability (controllable cooling rates)
• Environmental concerns (recycling, waste disposal)

One additional factor – performance over time – should be added to the list since we are always looking for ways to extend the life of our quenchants without sacrificing their performance. By Daniel H. Herring

Cooling curves, cooling-rate curves and oil analyses are provided by suppliers to help heat treaters better control an important process variable – quenching. Unfortunately, in many cases these reports are not well understood or, worse yet, filed to be used merely as ISO documents. It’s time to pull them out of the file cabinet and learn how to interpret them so we know what it is we are being told. By Daniel H. Herring

Nadcap is the leading worldwide cooperative program of major companies designed to manage a cost-effective consensus approach to special processes and products and provide continuous improvement within the aerospace and automotive industries. The not-for-profit Performance Review Institute (PRI) administers Nadcap. By Arshad Hafez

Tempering, also known as “drawing,” is one of the most common heat-treatment processes – and one that is all too often taken for granted. We all know it’s important, yet we spend little time focused either on the process or on the equipment in which it is performed. By Daniel H. Herring

For anyone involved with heat treating of tool steels, it is critical to remember that there is no such thing as acceptable short-cuts in the heat-treatment process. As such, applying best practices for preheating, austenitizing, quenching, deep-freezing and tempering is mandatory. by Daniel H. Herring

Maintenance of oil diffusion pumps is key to optimal vacuum furnace performance. The following describes the workings of oil diffusion pumps and indicates the best investment of limited maintenance resources. A small in-vestment in planned maintenance can yield a high return in the ongoing high-level performance of your vacuum system. by Varian, Inc., Vacuum Technologies