MECHANICAL TESTING LABORATORY

Due to the very large number of tests offered, descriptions of those most commonly requested have been gathered into the following groups:

ASTM G38 – Standard Practice for Making and Using C-Ring Stress-Corrosion Test Specimens

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This practice covers the features of design and machining, and procedures for stressing, exposing, and inspecting C-ring type of stress-corrosion test specimens. An analysis is given of the state and distribution of stresses in the C-ring.

Stress of principal interest in the C-ring specimen is the circumferential stress because this stress is not uniform. When the specimen is stressed by measuring the strain on the tension surface of the c-ring, the strain gage should be positioned in the middle of the arc in order to indicate the maximum strain. There are also transverse stresses present; however, these stresses may decrease with decreasing width to thickness and increasing diameter to thickness ratios.

Care must be taken during machining so that specimens are not overheated, are not plastically deformed and do not develop residual stresses in the metal surface. Touchstone takes care that the specimens are supported by nothing more than the corrosive medium comes into contacted with the critically stressed area of the specimen. Determination of the cracking time may be subjective due to the visual examination. Touchstone Engineers have experience with Stress-Corrosion Testing and are able to accurately determine when the specimen fractured and obtain a precise cracking time.

Please email info@trl.com or call (304) 547-5800 for information regarding test procedures, results, specimen information, pricing or any other ASTM G38 questions you may have.

To request a quotation for any test email info@trl.com for a prompt reply