Evaluation of austenitic stainless steels fatigue state by non-destructive method of measurement of magnetic property of metal – coercive force

Solomakha, R.N.; CM Diagnostics; Ukraine

Bezliudko, H.Y.; Special Scientific Engineering; Ukraine
Gopkalo, O.P.; Special Scientific Engineering; Ukraine
Nekhotiaschiy, V.A.; Special Scientific Engineering; Ukraine
Savluk, S V.; Special Scientific Engineering; Ukraine
Solomakha, R.N.; CM Diagnostics; Ukraine

ID: ECNDT-0272-2018
Session: Materials Characterization - Magnetic Techniques 1
Room: J2
Date: 2018-06-14
Time: 14:10 - 14:30

Results of cyclic and static (tensile) destructive stand tests of austenitic stainless steel samples are presented in the report. The tests were accompanied with non-destructive coercimetrical control. These actions were aimed to justification of possibility of practical non-destructive in-service control of fatigue state of industrial equipment made of stated above metal and forecast of its outstanding service life. Austenitic state maintaining corrosion resistance combining with appropriate mechanical properties is inherently radically unstable in operating temperature range. Various processing and metallurgical technics are applied for its limited stabilization. Austenite gradually and unavoidably transforms through several intermediate phases (in accordance with classical phase equilibrium diagram) to ultimate stable phase – ferrite, being affected by operating factor’s combination. With this transformation metal loses its corrosion resistance and mechanical strength. Simultaneously with phase transformations accumulation of microdamages takes place. This transformation takes place under influence of external factors and internal stresses due to phase transformations. Such multiparameter fatigue degradation of metal can be controlled reliably by combination of laboratory research of batch of samples cut out from operating equipment only. That is the reason of application of such control for investigation of accidental failures reasons only, but not as monitoring instrumentation of equipment current state, its deterioration rate and possible becoming failures prevention.