Glossary

Terms denoting a formal program for monitoring product quality. The denotations are the same, but QC typically connotes a more traditional postmachining inspection system, while QA implies a more comprehensive approach, with emphasis on “total quality,” broad quality principles, statistical process control and other statistical methods.

Fracture of a metal during quenching. Most frequently observed in hardened carbon steel, alloy steel or tool steel parts of high hardness and low toughness. Cracks often emanate from fillets, holes, corners or other stress raisers and result from high stresses due to the volume changes accompanying transformation to martensite.

1. Hardening alpha-beta alloys (most often copper or titanium alloys) by solution-treating and quenching to develop a martensite-like structure. 2. In ferrous alloys, hardening by austenitizing and then cooling so that austenite transforms to martensite.

Rapid cooling of the workpiece with an air, gas, liquid or solid medium. When applicable, more specific terms should be used to identify the quenching medium, the process and the cooling rate.

Cutter holder that permits rapid tool changes. Generally associated with automatic or semiautomatic machining operations. See toolholder.