PSI - Issue 23

Hugo Wärner et al. / Procedia Structural Integrity 23 (2019) 354–359

359

Hugo Wärner / Structural Integrity Procedia 00 (2019) 000 – 000

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4. Conclusions At relatively low mechanical strain range (Δε mech = 0.4% - 0.3%) the two TMF-test conditions IP- and OP-cycling, performed on the pre-aged austenitic stainless steels Sanicro 25, Sanicro 31HT and Esshete 1250, did not differ that much in hardening behaviour. However, the plastic strain range were in general greater for IP-cycle condition. The OP TMF-test specimens all suffered from inhomogeneous deformation over the gauge length that induced a barrelling effect of the specimens. The barrelling effect was simulated by a simplified finite element analysis (FEA), which showed influence of specimen geometry. The degree of deformation of the test specimens was measured by the use of low angle grain boundary (LAGB) density calculations and it showed no barrelling effect before 500 OP-cycles. Fig. 5. EBSD mapping (reduced amount of zero solution) of the area for the LAGB calculations, a) Sanicro 25 OP- TMF, Δε mech = 0.4%, Fix N = 500, b) Esshete 1250 OP- TMF, Δε mech = 0.3%, Fix N = 500, c) Sanicro 31HT OP-TMF, Δε mech = 0.4%, Fix N = 500, d) Sanicro 31HT OP-TMF, Δε mech = 0.4%, N = 1608, middle area “1”, e) Sanic ro 31HT OP- TMF, Δε mech = 0.4%, N = 1608, waist area “2”.

Acknowledgements

The present study was financially supported by AB Sandvik Materials Technology in Sweden and the Swedish Energy Agency through the Research Consortium of Materials Technology for Thermal Energy Processes, Grant No. KME-701.

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