Hot deformation behavior and constitutive relationship of Q420qE steel

Abstract

Isothermal compression tests at temperatures from 1 273 to 1 423 K and strain rates from 0.1 to 10 s⁻¹ were carried out to investigate the flow behaviors of Q420qE steel. Stress-strain data collected from the tests were employed to establish the constitutive equation, in which the influence of strain was incorporated by considering the effect of strain on material constants Q, n, a, and lnA. The results show that the flow stress curves are dependent on the strain, strain rate and deformation temperature. They display typical dynamic recrystallization behavior and consist of three stages, i.e., hardening stage, softening stage and steady stage. The flow stress decreases with increasing the deformation temperature and decreasing the strain rate. In addition, the flow stress data predicted by the proposed constitutive model agree well with the corresponding experimental results, and the correlation coefficient and the average absolute relative error between them are 0.990 3 and 3.686%, respectively.

Keywords

Q420qE / bridge steel / hot compression / flow stress / strain dependent constitutive equation

References

[1] AbbasiS. M., ShokuhfarA.. Prediction of hot deformation behaviour of 10Cr-10Ni-5Mo-2Cu steel [J]. Materials Letters, 2007, 61(11/12): 2523-2526

[2] SerajzadehS.. A mathematical model for evolution of flow stress during hot deformation [J]. Materials Letters, 2005, 59(26): 3319-3324

[3] LiaoS.-l., ZhangL.-w., YueC.-x., PeiJ.-b., GaoH.-ju.. Hot deformation behaviors and flow stress model of GCr15 bearing steel [J]. Journal of Central South University of Technology, 2008, 15(5): 575-580

[4] WangJ., ChenJ., ZhaoZ., RuanX.-yu.. Hot deformation behavior and flow stress model of F40MnV steel [J]. Journal of Central South University of Technology, 2007, 14(1): 19-23

[5] CingaraA., McQueenH. J.. New method for determining sinh constitutive constants for high temperature deformation of 300 austenitic steels [J]. Journal of Materials Processing Technology, 1992, 36(1): 17-30

[6] McQueenH. J., RyanN. D.. Constitutive analysis in hot working [J]. Materials Science and Engineering A, 2002, 322(1/2): 43-63

[7] SlooffF. A., ZhouJ., DuszczykJ., KatgermanL.. Constitutive analysis of wrought magnesium alloy Mg-Al4-Zn1 [J]. Scripta Materialia, 2007, 57(8): 759-762

[8] ZhanM. Y., ChenZ. H., ZhangH., XiaW. J.. Flow stress behavior of porous FVS0812 aluminum alloy during hot-compression [J]. Mechanics Research Communications, 2006, 33(4): 508-514

[9] LinY. C., ChenM. S., ZhangJ.. Constitutive modeling for elevated temperature flow behavior of 42CrMo steel [J]. Computational Materials Science, 2008, 42(3): 470-477

[10] MandalS., RakeshV., SivaprasadP. V., VenugopalS., KasiviswanathanK. V.. Constitutive equations to predict high temperature flow stress in a Ti-modified austenitic stainless steel [J]. Materials Science and Engineering A, 2009, 500(1/2): 114-121

[11] WangL., GaoC.-r., WangY.-f., DuL.-x., ZhaoD.-w., LiuX.-hua.. Development of Bridge Steels in China [J]. Materials for Mechanical Engineering, 2008, 32(5): 1-3

[12] QuZ.-y., MaJ.-p., XuKe.. Fracture resistance of Q420 steel and its welding joint [J]. Journal of Mechanical Strength, 2008, 30(4): 668-672

[13] YueC.-x., ZhangL.-w., LiaoS.-l., PeiJ.-b., GaoH.-j., JiaY.-w., LianX.-jie.. Research on the dynamic recrystallization behavior of GCr15 steel [J]. Materials Science and Engineering A, 2009, 499(1/2): 177-181

[14] EbrahimiR., ZahiriS. H., NajafizadehA.. Mathematical modelling of the stress-strain curves of Ti-IF steel at high temperature [J]. Journal of Materials Processing Technology, 2006, 171(2): 301-305

[15] SellarsC. M., TegartW. J. M.. Hot workability [J]. International Metallurgical Reviews, 1972, 17(1): 1-24

[16] WangZ.-x., LiuX.-f., XieJ.-xin.. Constitutive relationship of hot deformation of AZ91 magnesium alloy [J]. Acta Metallurgica Sinica, 2008, 44(11): 1378-1383