Effect of Drawing Strain on Development of Martensitic Transformation and Mechanical Properties in AISI 304L Stainless Steel Wire

Abstract

AISI 304L stainless steel wires are cold drawn to different strains for examining the effect of plastic deformation on the mechanical properties change, the microstructural evolution, and martensitic transformation. Microstructures of drawn wires are characterized using optical microscopy, X-ray diffraction and electron backscatter diffraction (EBSD) techniques. It is shown that deformed structure consists of austenite, ά-martensite, and e-martensite. The ultimate strength of wires drawn to strains of 0.56, 1.13, and 1.7 are found to be equal to to 1028, 1492, and 1743 MPa, respectively, from intial value of 735 MPa. These strengths are correspond to the strain induced martensite of 34, 62, and 100%. Also, it is shown that elastic modulus of wires are changed due to the strain induced transformation during cold drawing. For accessing the strain distribution during wire drawing, FEM simulations are carried out according to the experimental investigations. By help of simulation results and applying different criteria, it is shown that regions near the wire surface are suitable area for initiation of strain induced martensite. Moreover, microstructural observations and hardness measurements reveal that the amount of strain-induced martensite is higher just below the surface.[ Ã ] Prof.

Modification of Olson–Cohen model for predicting stress-state dependency of martensitic transformation

“…Therefore, the obtained results contradict the supposition that formation of strain-induced martensite is a merely monotonic function of stress triaxiality. However, the findings in Figure 4 are confirmed by the experimental results of DeMania [13] who reported that less martensite is produced under plane strain tension than under uniaxial tension. DeMania suggested that geometrical constrains in plane strain tension causes less formation of shear band intersections in comparison with uniaxial tension.…”

“…Based on the Stringfellow model, the rate of martensite formation is a monotonic function of the stress triaxiality. However, much experimental data [10,13–17] reveal that transformation rate of martensite is not merely dependent on the stress triaxiality. Lebedev and Kosarchuk [14,15] suggested that phase transformation is controlled by stress triaxiality and Lode parameter.…”

Effect of Warm Deformation on Mechanical Properties and Deformation Mechanism of Nano/Ultrafine‐Grained 304 Stainless Steel

“…Due to the reduction in deformation‐induced martensite, the work‐hardening rate curve at 200 °C has a missing rising segment compared to 25 °C. [ 27 ] The strain hardening rate curve has been gradually decreasing, and the true strain hardening rate in the uniformly deformed region decreases monotonically as strain increases.…”

The Effect of Drawing Deformation Rate Induced Inhomogeneous Local Distortion on Phase Transformation of 304H Stainless Wire

“…However, the complexity of the cold drawing process necessitates more detailed information about the microscale deformation of wires. Pouyan et al [18] reported that there are significant differences between the axis and subsurface of drawn wires. Therefore, a relationship is found between the configuration of the drawing pass deformation rate and the local uneven deformation in the steel wire, while the final martensitic phase variable and magnetic properties need further exploration.…”