6.1 This guide presents techniques on the use of thermocouples and associated equipment for measuring temperature in creep and stress-rupture testing in air at temperatures up to 1800°F (1000°C). The duration of a creep test ranges from a few hours to several thousand hours or more at elevated temperatures, at least partially unattended by operators. Such tests are normally ended before test specimen failure. Stress-rupture tests may operate at higher stresses, higher temperatures, and for shorter times than creep tests, but they normally continue until the specimen has achieved its required life or has failed.

6.2 Since creep and stress-rupture properties are highly sensitive to temperature, users should make every effort practicable to make accurate temperature measurements and provide stable control of the test temperature. The goal of this guide is to provide users with good pyrometric practice and techniques for precise temperature control for creep and stress-rupture testing.

6.3 Techniques are given in this guide for maintaining a stable temperature throughout the period of test.

6.4 If the techniques of this guide are followed, the difference between indicated temperature and true temperature, as used in E139, E292, and E21 will be reduced to the lowest practical level.