Characterization of Hot Deformation behavior for Ultra-High Strength (UHS) Steel containing Tungsten
Keywords:Hot Deformation behavior, Ultra-High Strength (UHS) Steel, Computational flow curve model, Strain hardening and dynamic softening mechanisms, Isothermal flow curves, Dynamic recovery and recrystallization phenomena
The steel alloy of the current study contains 0.3% carbon with different amounts of Cr, and Mo, in addition to W. Single simulation hits were designed as isothermal passes for compressive hot deformation up to 0.5 true strain. Each simulation compressive pass was carried out at temperatures, 1050, 950, 850 and 750 oC, with strain rates 0.1 and 1.0 sec-1. A numerical computational model is used for formulation of the alloy hot flow behavior at the specified conditions. The model considers inseparable strain hardening mechanism and dynamic softening phenomenon. It is noticed that high deformation temperature lowers the flow stress value (σf), while the increase of the strain rate raises it. The flow curves reveal initial high strain hardening phenomena in combination with low dynamic softening features. With the increase of strain, the dynamic softening, becomes dominant, and the flow stress gradually drops until a relatively stable stress level. Predicted flow curves were then constructed and compared with their counterpart experimental flow curves. The predicted flow curves are typically matching the counterpart experimental ones.