Effect of Strip Defect on Cleavage Fracture Toughness of Steel 16MnR

Abstract:

A research on the effect of strip defect in the notched specimen of low alloy hot rolled steel 16MnR at -196°C is carried out in this paper. 4-point positive and negative bending experiments of notched specimen with different preloads are carried out to introduce strip defects of different dimensions in the front of notch. And then the residual stress and work hardening is eliminated through high temperature tempering. Bending fracture experiment is carried out at -196°C. Through microscopic observation and the measurement and analysis of mechanical parameters, it is discovered that: when the preload ratio P0/Pgy0.861, the Pf /Pgy rapidly decreases as the P0/Pgy increases. That’s because the increase of local high stress-strain region caused by the strip defect at the front notch end makes the distribution of crack-shaped nucleus active region of cleavage fracture increase, causes the cleavage initiation and leads to discrete numeric values of material notch toughness Pf and W.

• Periodical: Advanced Materials Research (Volumes 490-495)
• Pages: 3089-3093
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.490-495.3089
• Online since: March 2012
• Authors: Yan Guo Liu, Jin Ma, Xian Ming Sun
• Keywords: 16MnR Steel, Cleavage Fracture, Notched Specimen, Strip Defect

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