Acta Metall Sin  2020, Vol. 56 Issue (7): 960-968    DOI: 10.11900/0412.1961.2019.00403
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Effect of Al and Ni on Hot Deformation Behavior of 1Cr9Al(1~3)Ni(1~7)WVNbB Steel
ZHAO Manman1, QIN Sen1, FENG Jie1, DAI Yongjuan1, GUO Dong1,2()
1. College of Materials Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050000, China
2. College of Mechanical Engineering, Tianjin Vocational and Technical Normal University, Tianjin 300222, China
Abstract

The addition of Al and Ni to ferritic heat resistant steel can improve its high temperature strength and high temperature oxidation resistance. Al and Ni in steel have some effects on the thermal deformation behavior of steel. But there is less research on it. In this work, a new type of 1Cr9Al(1~3)Ni(1~ 7)WVNbB high aluminum ferrite heat-resistant steel was prepared by adding Al element to T92 steel and adjusting Ni content properly. Gleeble-3800 thermal simulation test machine was used to conduct isothermal and constant speed thermal compression experiment with 60% deformation at 950~1150 ℃ and 0.1~10 s-1 strain rates, respectively. The effects of Al and Ni additions on the hot deformation behavior, peak stress and activation energy of hot deformation of the steel were studied. The rheological stress expression containing Zener-Hollomon parameters were obtained by fitting, and the constitutive equation of the test steel was established. The results show that the addition of Al and the increase of Al content significantly reduces rheological stress and peak stress under thermal compression, which greatly reduces the difficulty of test steel processing. Compared with T92 steel, the thermal deformation activation energies of four sample groups increase by 38.136%, 19.188%, 28.003%, and 11.915%, respectively. The peak stress calculated by the constitutive equation is in good agreement with the experimental data. The results show that the constitutive equation has high accuracy. The relationship between peak flow stress, deformation temperature and strain rate can be expressed well.

 ZTFLH: TG142.33
Fund: National Natural Science Foundation of China(51774108);National Natural Science Foundation of China(51874116)
Corresponding Authors:  GUO Dong     E-mail:  guodongbill@126.com
 Table 1  Chemical compositions of T92 steel[9] and 1Cr9Al(1~3)Ni(1~7)WVNbB steel Fig.1  Schematic of isothermal compression test ($ε˙$—strain rate; T—deformation temperature; ε—engineering strain) Fig.2  True stress-ture strain curves of alloy steel under ideal conditions (σp—peak flow stress; εp—strain under peak stress; I—work hardening stage; Ⅱ—dynamic recovery stage; Ⅲ—the dynamic recrystallization stage; Ⅳ—stable stage) Fig.3  True stress-true strain curves of 1Cr9Al(1~3)Ni(1~7)WVNbB steel and T92 steel[9] at 950 ℃ (a) and 1150 ℃ (b) with strain rate of 1 s-1 Fig.4  True stress-true strain curves of sample No.4 at strain rates of 0.1 s-1 (a), 1 s-1 (b), 10 s-1 (c) and 950 ℃ (d), 1000 ℃ (e), 1050 ℃ (f), 1100 ℃ (g), 1150 ℃ (h) Fig.5  Three-dimensional peak flow stress diagrams at different deformation temperatures and strain rates of samples No.1 (a), No.2 (b), No.3 (c), No.4 (d) and T92 steel[9] (e) Fig.6  Relationship curves of sample No.4 with respect to lnσp-$lnε˙$ (a), σp-$lnε˙$ (b), ln[sinh(ασp)]-$lnε˙$ (c) and ln[sinh(ασp)]-1000/T (d) (α—stress level parameter) Fig.7  Relationship curve of lnZ-ln[sinh(ασp)] of sample No.4 (Z—Zener-Hollmon parameter) Table 2  Parameters of the constitutive equation of 1Cr9Al-(1~3)Ni(1~7)WVNbB high aluminum steel under peak stress Fig.8  Comparisons between experimental and theoretical calculated values of samples No.1 (a), No.2 (b), No.3 (c) and No.4 (d) at 950~1150 ℃ and 0.1~10 s-1 strain rates