proportional gauge length
The extension of a length called the gauge length is studied during the test. The points that indicate the ends of the gauge length are called the gauge points.
There is a fixed relationship between the gauge length and the cross-sectional area of the test-piece at the reduced diameter.
Rolling the thick strip head is one of the most important techniques in continuous cold rolling process. It directly influences the out-gauge length of finished strips.
In order to save continually having to measure the diameter of the test-piece during the test, the stress is taken to be the force divided by the original cross-sectional area, and strain is taken to be the extension divided by the gauge length.
