Oil&Gas - Automotive 

The Slow Strain Rate Test (SSRT) performed in tensile mode make the specimen elongate at low speed. The load change during the test, while the strain rate is kept constant, but much slower compared to a standard tensile test: typically from 10^-5/s up to 10^-6/s. 

While the material deflects, it is exposed to a particular environment (corrosive fluid, high temperature etc.). 

This method lets us compare the behaviour of different materials in a defined environment. On the other hand it lets us determine if the behaviour of the materials is more or less influenced by a defined environment.

The picture shows an example of application of the method: is this case the test is performed with the aim of evaluating the effect of the hydrogen embrittlement. A small system of "cathodic protection" produces Hydrogen (H), through water electrolysis, around the material subjected to tensile; the migration of the H atoms in the material is at the origin of its embrittlement. 

The test is performed at the speed of  3x10^-6/s, in order to allow the material to charge up of hydrogen and to be exposed to the embrittlement effect/risk during the test. On this basis, the difference between the tests performed with and without the H production is significant: it is evident a reduction of the ductility that leads to a reduction (by 3 times) of the elongation after fracture and consequently on the duration of the test.