A micromechanistic approach to the warm pre-stressing of ferritic steels

✍ Scribed by D. A. Curry

• Publisher: Springer Netherlands
• Year: 1981
• Tongue: English
• Weight: 581 KB
• Volume: 17
• Category: Article
• ISSN: 1573-2673
• DOI: 10.1007/bf00034507

✦ Synopsis

Warm pre-stressing of a cracked body can result in an apparent elevation of its fracture toughness at lower testing temperatures. This effect has been observed in mild steel pre-loaded at room temperature and tested at -150°C, when the apparent toughness elevation can be as great as a factor of two. This toughness elevation is produced both when the pre-load is maintained during cooling and when the pre-load is completely removed prior to cooling.

Crack tip stress distributions have been estimated for different warm pre-stressing histories by the superposition of the appropriate monotonic loading stress distributions. The Ritchie, Knott and Rice model of cleavage fracture and its associated fracture criterion have been used in conjunction with the crack tip stress distribution to predict the final fracture load after warm pre-stressing. Predictions so made are seen to be in good agreement with the experimental observations.