Compression temperature to activate kinking in pearlitic steel

The preferable condition for kinking in the compression of pearlitic steel is reported in this study. Spring steel (0.53 wt%C-1.48%Si-0.70%Mn-0.76%Cr-Fe) with a pearlitic structure was compressed at different temperatures ranging from ambient to 600 degrees C. The deformation microstructure clarified that the kinking occurred more oftenwhen the compression temperature was less than 400 degrees C. Three-dimensional reconstruction of the scanning electron microscopy images with focused-ion-beam serial sectioning revealed that the kinked structure comprised a band-like sheared area surrounded by the bent structures. The shear strain in the kinked structure is greater than the macroscopic strain applied by compression. A series of measurements of compressive flow stress (strain rate: 0.001/sec to 1/sec) elucidated negative strain rate sensitivity (m-value < 0) at similar to 300 degrees C. Strain localization by kinking occurs preferentially at relatively lower temperature because a smaller strain rate sensitivity can promote local plastic instability. The preferable condition for kinking in the compression of pearlitic steel is reported in this study. Spring steel (0.53 wt%C-1.48%Si-0.70%Mn-0.76%Cr-Fe) with a pearlitic structure was compressed at different temperatures ranging from ambient to 600 degrees C. The deformation microstructure clarified that the kinking occurred more oftenwhen the compression temperature was less than 400 degrees C. Three-dimensional reconstruction of the scanning electron microscopy images with focused-ion-beam serial sectioning revealed that the kinked structure comprised a band-like sheared area surrounded by the bent structures. The shear strain in the kinked structure is greater than the macroscopic strain applied by compression. A series of measurements of compressive flow stress (strain rate: 0.001/sec to 1/sec) elucidated negative strain rate sensitivity (m-value < 0) at similar to 300 degrees C. Strain localization by kinking occurs preferentially at relatively lower temperature because a smaller strain rate sensitivity can promote local plastic instability.

Automated summary

This study reports the preferable condition for kinking in the compression of pearlitic steel. The deformation microstructure and three-dimensional reconstruction analysis reveal the mechanisms involved in the kinking process.