Original scientific paper

https://doi.org/10.21278/TOF.462036921

Hot Compression Test and Microstructure Evolution in LZ50 Axle Steel

Qinhong Fan ; School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi Province, China
Hongwei Gao ; School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi Province, China
Zhibing Chu ; School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi Province, China
Yuxin Zhang ; School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi Province, China
Yanan Cui ; School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi Province, China
Wenze Wang ; School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi Province, China

Abstract

True strain-true stress curves of the LZ50 axle steel were obtained after hot compression tests had been performed on a Gleeble-3800 thermal simulator at strain rates of 0.01, 0.1, 1 and 5 s^(-1) and at deformation temperatures from 850 to 1,150 ℃. Following the data processing, the relationship between the flow stress and the deformation temperature of the material under different true strain conditions was analysed. On this basis and according to the influence of deformation factors, the constitutive equation of the Johnson-Cook flow stress model is established, and the model is modified according to the defects of the model, so that the improved model can effectively predict the mechanical behaviour in the range of high strain rates and temperatures. The dynamic material model (DMM) was used to generate the hot working diagram of the material. Through calculation and analysis, the optimum process area in terms of temperature was found to be in the range from 1,050 to 1,150 ℃ and in terms of strain rate in the rage from 1 to 5 s^(-1). Finally, the microstructure evolution of the compressed specimens under different strain rates and temperatures was studied in the metallographic analysis, which provided a theoretical basis and reference value for later damage.

Keywords

LZ50 axle steel; hot compression; constitutive model; hot working diagram

Hrčak ID:

279235

URI

https://hrcak.srce.hr/279235

Publication date:

15.6.2022.

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