Effect of Microcracks on the Brittle Fracture of Mild Steel,
Abstract
Iron (C 0.044, Mn 0.04, Cr 0.09, O 0.076, and N 0.013 wt. per cent) was subjected to various plastic deformations. Microscopic observations showed that the distribution of microcracks as well as the structure of the metal depended on the history of plastic deformation. Upsetting caused the formation of a much larger amt. of horizontal microcracks (perpendicular to the axis) which caused a loss of strength. It is probable that a metal subjected to plastic deformation and thereafter loaded to brittle fracture had 2 opposing effects acting on it: (1) a hardening effect and (2) the effect of microcracks and intrinsic stresses. The 1st effect depends only on the deformation degree, and does not depend on the form of plastic deformation. However, the 2nd effect depends on deformation degree, form of deformation, as well as on the kind of load applied during the deformation. The macro- and microscopic observations showed that on brittle fracture, the principal factors which affect the resistance of soft steel are the amt. and form of the microcracks and other defects, as well as the orientation of the microcracks and intrinsic stresses. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 04, 1970
- Accession Number
- AD0719832
Entities
People
- T. Sobepanek
Organizations
- National Air and Space Intelligence Center