Hot working

About: Hot working is a research topic. Over the lifetime, 4512 publications have been published within this topic receiving 70521 citations.

Iron and its dilute substitutional solid solutions

Abstract: The new results of an extensive study of the effects of alloying elements upon the properties of iron are presented, including lattice parameters, elastic constants, the effect of temperature on strength, solid solution strengthening and softening, work hardening, strain aging, hot working and toughness.

Microstructural mechanisms during hot working of commercial grade Ti–6Al–4V with lamellar starting structure

Abstract: The hot deformation behavior of commercial grade Ti–6Al–4V with a lamellar starting microstructure is studied in the temperature range 750–1100 °C and strain rate range 3×10 −4 –10 s −1 with a view to model the microstructural evolution. On the basis of flow stress data obtained as a function of temperature and strain rate in compression, a processing map for hot working has been developed. In the ranges 800–975 °C and 3×10 −4 –10 −2 s −1 , globularization of lamellae occurs for which an apparent activation energy of 455 kJ mol −1 has been estimated using the kinetic rate equation. Stress-dependent thermal activation analyses proposed by Schock and Cocks et al. have shown that the apparent activation energies are in the range 160–245 kJ mol −1 and the normalized activation volumes are in the range 20–80, which suggest that cross-slip is the rate controlling process during globularization. The variation of primary α grain size with Zener–Hollomon parameter ( Z ) in the globularization region exhibited a linear relationship on a log–log scale. At strain rates slower than 10 −1 s −1 and temperatures below 900 °C, cracking at the prior β grain boundaries/triple junctions occurs, which sets the lower limits for globularization. At strain rates higher than 10 −1 s −1 in the α+β range, the material exhibited flow instabilities manifested as adiabatic shear bands. These bands are intense below 800 °C and above 1 s −1 and caused cracking along the bands. In the β phase field, dynamic recrystallization (DRX) occurs at about 1100 °C and in the strain rate range 10 −3 –10 −1 s −1 . The apparent activation energy for DRX of β is about 172 kJ mol −1 which is close to that for self-diffusion in β phase (153 kJ mol −1 ). The application of these results in the design of bulk metalworking processes for achieving microstructural control is discussed.