Measurement of the Temperature Profile During Shear Band Formation in Steels Deforming at High Strain Rates

摘要

A torsional Kolsky bar (split-Hopkinson bar) was used to deform tubular specimens of AISI 1018 cold rolled steel and AISI 1020 hot rolled steel at a nominal strain of 10 to the 3th power per s. Shear bands were observed to form in both steels and the temperature of the material in the bands was measured by determining the infrared radiation emitted at the metal surface. For this purpose, a linear array of ten indium-antimonide detectors was used to determine temperature history at ten neighboring points lying across the projected path of the shear band. Results showed that shear bands in these low carbon steels are relatively wide, that the maximum temperature rise in the band is about 450 C and that the temperature distribution across the band is consistent with results based on an analysis performed by Shawki and Clifton. The two steels have very different work hardening rates and the strain at which localization is first observed is very different for the two steels: in the cold-rolled steel it occurs at about 15% strain, while in the hot-rolled the strain is nearer 100%. This result also is consistent with predictions based on the analysis. Keywords: Temperature Measurements, High strain rates, Stress-Strain behavior, Steels.