Hot Deformation Behavior of 17-7 PH Stainless Steel

Document Type: Research Paper

Authors

1 Maleke Ashtar University of Technology

2 Amirkabir University of Technology

3 Shiraz University

4 Maleke Ashtar University of Tech.

Abstract

To investigate the hot deformation behavior of 17-7 PH stainless steel, hot compression tests were carried out at the temperatures of 950, 1050 and 1150 oC and strain rates of 0.001 s-1 to 0.1 s-1. Accordingly, the hot working behavior was studied by the analyses of flow stress curves, work hardening rate versus stress curves, exponent- type constitutive equations and deformed microstructures. Meanwhile, the average normalized critical stress for initiation of dynamic recrystallization (DRX) was determined using a 3rd order polynomial curve fitting. The results show that the flow stress depends strongly on the deformation temperature and the strain rate, and it increases with the deformation temperature decreasing and the strain rate increasing. Furthermore, it was found out that the co- existence of δ- ferrite lowers the softening rate at high Z (Zener- Holloman parameter) conditions. The experimental results were then used to determine the constants of constitutive equations. There is a good agreement between the measured and predicted results indicating a high accuracy of exponent- type constitutive equations.

Keywords


[1] H. Mirzadeh, M. H. Parsa and D. Ohadi, Hot deformation behavior of austenitic stainless steel for a wide range of initial grain size, Mater. Sci. Eng., A, 569 (2013) 54-60.
[2] L. L. Wang, R. B. Li, Y. G. Liao and M. Jin, Study on characterization of hot deformation of 403 steel, Mater. Sci. Eng., A, 567 (2013) 84-88.
[3] M. A. Mostafaei and M. Kazeminezhad, Hot deformation behavior of hot extruded Al–6Mg alloy, Mater. Sci. Eng., A, 535 (2012) 216-221.
[4] H. Mirzadeh, J. M. Cabrera and A. Najafizadeh, Constitutive relationships for hot deformation of austenite, Acta Mater., 59 (2011) 6441-6448.
[5] E. Shafiei and K. Dehghani, Prediction of single-peak flow stress curves at high temperatures using a new logarithmic-power function, J. Mater. Eng. Perform., 25(2016)4024-4035.
[6] M. Marchattivar, A. Sarkar, J. K. Chakravarty and B. P. Kashyap, Dynamic recrystallization during hot deformation of 304 austenitic stainless steel, J. Mater. Eng. Per., 22 (2013) 2168-2175.
[7] C. M. Cepeda- Jimenez, O. A. Ruano, M. Carsi and F. Cerreno, Study of hot deformation of an Al–Cu–Mg alloy using processing maps and microstructural characterization, Mater. Sci. Eng., A, 552 (2012) 530-539.
[8] A. Najafizadeh and J. J. Jonas, Predicting the critical stress for initiation of dynamic recrystallization, ISIJ Int., 46 (2006) 1679-1684.
[9] E. Shafiei and R. Ebrahimi, A modified model to estimate single peak flow stress curves of Ti-IF Steel, ISIJ Int., 52 (2012) 569-573.
[10] Y. Han, G. Liu, D. Zou, R. Liu and G. Qiao, Deformation behavior and microstructural evolution of as-cast 904L austenitic stainless steel during hot compression, Mater. Sci. Eng., A, 565 (2013) 342-350.
[11] A. Dehghan- Manshadi and P. D. Hadgson, Effect of δ-ferrite co-existence on hot deformation. and recrystallization of austenite, J. Mater. Sci., 43 (2003) 6272-6277.
[12] H. J. McQueen and N. D. Ryan, Constitutive analysis in hot working, Mater. Sci. Eng., A, 322 (2002) 43-47.
[13] E. Shafiei and R. Ebrahimi, A new constitutive equation to predict single peak flow stress curves, J. Eng. Mater. Tech., 135 (2013) 011006- 4.
[14] H. Mirzadeh and A. Najafizadeh, The rate of dynamic recrystallization in 17-4 PH stainless steel, Mater. Des.,31 (2010) 4577- 4583.
[15] E. I. Poliak and J. J. Jonas, Critical strain for dynamic recrystallization in variable strain rate, ISIJ Int., 43 (2003) 692- 700.
[16] H. Mirzadeh and A. Najafizadeh, Prediction of the critical conditions for initiation of dynamic recrystallization, Mater. Des.,31 (2010) 1174- 1179.
[17] A. Etaadi and K. Dehghani, Mater. Chem. Phy., A study on hot deformation behavior of Ni-42.5 Ti-7.5 Cu alloy, 140 (2013) 208- 215.
[18] H. Y. Wu, J. C. Yang, F. J. Zhu and C. T. Wu, Hot compressive flow stress modeling of homogenized AZ61 Mg alloy using strain-dependent constitutive equation, Mater. Sci. Eng., A,574 (2013)1724- 1726.