# Study on Dynamic Mechanical Behavior of 34CrNi3MoA Alloy Steel Considering the Coupling Effect of Temperature and Strain Rate

## TL;DR

This study examines how temperature and strain rate together affect the mechanical behavior of 34CrNi3MoA steel and introduces a new model to better predict its properties.

## Contribution

A novel constitutive model integrating the coupling effect of temperature and strain rate for 34CrNi3MoA steel is developed.

## Key findings

- Mechanical properties of 34CrNi3MoA steel are significantly influenced by both temperature and strain rate.
- True stress shows a temperature-softening effect between 25 °C and 600 °C.
- The new model outperforms the Johnson–Cook model in accuracy.

## Abstract

Temperature and strain rate play a crucial role in determining the mechanical properties of metals. These critical parameters are typically assessed using the split Hopkinson pressure bar (SHPB) test. However, previous studies have seldom considered the coupled influence of temperature and strain rate on dynamic mechanical behavior, thereby reducing the accuracy of constitutive models. To accurately characterize the dynamic mechanical behavior of 34CrNi3MoA low-alloy steel, a new constitutive model combining temperature and strain rate was developed. Firstly, SHPB experiments under varying temperatures and strain rates were designed to obtain actual stress–strain curves. The results indicate that the mechanical properties of 34CrNi3MoA low-alloy steel are significantly influenced by both temperature and strain rate. True stress has a significant temperature-softening effect within the temperature range of 25 °C to 600 °C, while the flow stress in the yield stage increases with rising strain rate. Secondly, a novel constitutive model was established by integrating a correction function. The model comprises three components: a strain rate-strengthening function influenced by temperature, a temperature-softening function influenced by strain rate, and a strain-hardening correction function accounting for the coupling of temperature and strain rate. Comparing the mean relative error, the new model significantly improves accuracy compared to the original Johnson–Cook (J-C) model.