Slow Strain Rate Testing (SSRT)

Definition - What does Slow Strain Rate Testing (SSRT) mean?

Slow strain rate testing (SSRT) is used in testing materials for corrosion, usually metals. In this test, the specimen is put under elongation within a constant degree.

The load differs in order to maintain a persistent rate of extension. While under extension, the material under testing is exposed to various factors like certain fluids and temperature.

Slow strain rate testing is also known as constant extension rate tensile (CERT) testing.

Corrosionpedia explains Slow Strain Rate Testing (SSRT)

SSRT is a method that helps evaluate the behavior of corrosion on materials such as metals in a particular environment. This test gauges the effects of atmospheric conditions on stress corrosion cracking (SCC) or material fracture susceptibility.

For the test to be successful, the selected extension rates should be within the proper range. The selection process is highly important since cracking susceptibility may not be apparent from test results conducted at a strain rates that are too high or low.

In different environment systems, a standard strain rate is used. However, cracking absence at that certain strain rate should not be looked upon as proof of immunity to cracking, since there are cases where stress corrosion cracking susceptibility can become evident at higher strain rates.

The strain rate that can most quickly produce stress corrosion cracking for a particular environment is referred to as the critical strain rate. There are known standard values for the critical strain rate for metals in certain environment systems, such as stainless steel in chloride or water in high temperature, copper alloys and magnesium alloys in nitrite solutions, and others.

Overall, this test is ideal for mechanistic studies as well as the evaluation of SCC susceptibility of various alloys.

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