Experimental Investigation on GCr15 Steel for Marine Vessels Treated by Ultrasonic Assisted Equal Channel Angular Extrusion

Wang, X. and Yu, Y., 2018. Experimental investigation on GCr15 Steel for marine vessels treated by ultrasonic assisted equal channel angular extrusion. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 548–551. Coconut Creek (Florida), ISSN 0749-0208.ECAE deformation refines grain via large shear deformation. Ultrasonic assisted plastic deformation can reduce flow stress of the material and reduce the friction coefficient, etc. In this paper, ultrasonic is applied to the ECAE deformation process, and impact of ultrasonic assisted ECAE forming process on microstructure and mechanical properties of GCr15 steel for marine vessels is studied. The results show that: With ultrasonic assisted ECAE process, ultrafine-grained material can be obtained, compared with the case without ultrasonic vibration extrusion, for GCr15 steel for marine vessels microstructure, average grain size of cementite is 10μm; the sample underwent ECAE one-pass extrusion, with extrusion force at 11098 N, one-pass extrusion force of UV-ECAE was 10090 N, with extrusion force reduced by 9% compared to before; microhardness without ECAE was 365 HV, but significantly increased to 580 HV after ECAE and significantly increased to 620 HV after ultrasonic assisted ECAE, up by 70% compared with that before extrusion.