Thread Elongation Gauge 1% scale 8 TPI

Description

The thread elongation gauge can be used to check whether the thread of a bolt is plastically deformed due to excessive tension. Tension is mainly caused by excessive temperature changes and dynamic stresses. The check consists of measuring the stretch on the middle part of the tread.

The thread elongation gauge is designed in such a way that it is possible to immediately determine the percent extension and whether it is reject or approval. All gauges are supplied according to ASME & DIN.

When using normal quality bolts and nuts for fasteners up to M30 (1 inch) diameter, the use of new bolts and nuts is recommended when force multiplier tools, such as hydraulic torque and tensioning equipment, are deemed necessary. For larger diameters, it is recommended that the cost of cleaning, deburring and overhauling be compared to the replacement value when evaluating critical flange assembly problems.

The 0.2% yield strength (or proof stress) is the stress at which 0.2% plastic deformation occurs. This yield strength is according to ASTM, while 0.1% and 0.5% are also used in industry. In essence, the 0.2% yield strength method provides attainable values that can be measured. However, it is an approachable measure, accepted in an engineering sense, and proceeds from the transition form elastic to the onset of plastic deformation.