The higher strength requirement of heavy generator retaining rings made of Mn18Cr18N austenitic stainless steel can be obtained by cold deformation strengthening. However, the yield ratio of Mn18Cr18N austenitic stainless steel is close to 1 gradually during the unidirectional tensile deformation, which will limit the unidirectional tensile deformation of cold deformation strengthening. In order to investigate the cold deformation strengthening by complex loading paths of Mn18Cr18N austenitic stainless steel, compression-tensile deformation behavior of Mn18Cr18N austenite stainless steel at room temperature was investigated by compression and tensile consecutive loading deformation experiments with the first compressive reduction range of 0%-40% and the second tensile range to fracture. Microstructure evolution, deformation dislocations, fracture behavior and mechanisms have been analyzed by OM, SEM and TEM. The results indicate that the subsequent tensile yield stress and the maximum tensile stress at the uniform plastic deformation stage, the reduction of cross sectional area and elongation increase at first and then decrease with the increase of compressive deformation. When the compressive deformation increases up to the critical reduction of 25%, the subsequent tensile yield stress and the maximum tensile stress reach up to the maximum values of 1039.97 and 1439.20 MPa respectively, and the reduction of cross sectional area and the elongation also reach up to the maximum values of 68.99% and 73.80% respectively. When the compressive deformation is less than the critical reduction, appearance of fractures shows the cup-cone shaped macroscopic fracture profiles, the dimpled microscopic fracture surfaces and the elongated grains. When the compressive deformation is greater than the critical reduction, fractures morphology is distinguished by the flat macroscopic fracture profiles, the crystalline microscopic fracture surfaces and the equiaxed grains with a lot twin structures. Several dislocation configurations with different density forms by dislocation slip when the compressive reduction is lower. Dislocation pile-up can be observed in the subsequent broken tensile specimen. Cross twins emerge in the specimen compressed up to 35% reduction. Twins with high density dislocation tangles arrange in parallel in the subsequent broken tensile specimen.
