The Influence of Loading Paths on Mechanical Behavior and Microstructure of Mn18Cr18N Austenitic Stainless Steel
- PDF / 1,854,944 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 9 Downloads / 224 Views
JMEPEG (2020) 29:4708–4715 https://doi.org/10.1007/s11665-020-04922-7
The Influence of Loading Paths on Mechanical Behavior and Microstructure of Mn18Cr18N Austenitic Stainless Steel Wenwu He, Fei Li, Huayu Zhang, and Huiqin Chen (Submitted February 20, 2020; in revised form May 10, 2020; published online July 8, 2020) The mechanical behavior of Mn18Cr18N steel along different loading paths was investigated at room temperature. In compression–tensile loading paths, the strain hardening behavior depends on subsequent tensile loading directions. When the subsequent loading axis coincides with the previous loading axis, the strain hardening path coincides with the strain hardening path in previous strain stage. When the subsequent loading axis changed, the subsequent strain hardening rate is remarkable greater than that in the previous strain hardening stage. The tensile ductility is different along different loading paths. In consecutive compression–tensile loading paths, the tensile ductility increased first and then decreased. Dislocation rearrangement caused good ductility during the tensile loading. In non-consecutive compression– tensile loading paths, the tensile ductility decreased gradually. Dislocation multiplication occurred rapidly during the subsequent tensile loading. Stress hardening is remarkable during compression–tensile consecutive cyclic loading when the strain amplitude is greater than 0.01. The maximum tensile stress can be reached up to 1549.6 MPa at 3 cycles with 0.15 strain amplitude, which is an increase of 395.4 MPa compared to the simple tensile loading. During complex loading paths, dislocation configurations and the substructures not only depend on the accumulated strains but also on the loading paths. Keywords
Mn18Cr18N steel, loading behavior, microstructure
paths,
mechanical
1. Introduction Retaining rings are used for tightening coils around electric generator rotors (Ref 1-4). It is one of the key parts in large generators. In order to ensure the safe operation of generators in harsh service environment, the retaining rings should have sufficient high strength and good plasticity, toughness and low yield ratio. For retaining rings over 300 MW, yield strength should be greater than 1000 MPa (Ref 5). Due to its distinctive advantages such as high strength and toughness, non-magnetic property and excellent stress corrosion resistance, Mn18Cr18N austenitic stainless steel is widely used to manufacture retaining rings of generators (Ref 6-8). Because Mn18Cr18N is a steel without phase transformation during cooling, strain hardening is the only way to strengthen this steel (Ref 9, 10). Hence, many studies on mechanical behavior and microstructure of Mn18Cr18N steel have investigated effect cold deformation under both uniaxial and nonuniaxial deformation (Ref 11-15). Shin et al. (Ref 11) have studied the effects of twin intersection on the tensile behavior
Wenwu He, Fei Li, and Huiqin Chen, School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyu
Data Loading...
