Formation of System of Scattered Fatigue Damages and Their Effect on Fracture of Structural Silicon Steel

• Published in: IOP conference series. Materials Science and Engineering 2018-12, Vol.463 (3), p.32005
• Main Authors: Buslaeva, I I, Yakovleva, S P, Makharova, S N
• Format: Article
• Language: English
• Subjects: Damage accumulation; Damage detection; Fatigue failure; Impact damage; Microhardness; Micrometers; Normal distribution; Permafrost; Silicon steels; Structural damage
• ISSN: 1757-8981; 1757-899X; 1757-899X
• DOI: 10.1088/1757-899X/463/3/032005

Forecasting of a residual life of machine elements and structures requires consideration of changes of a metal condition during operation. The aim of this article was to study accumulation of critical fatigue damage in structural silicon steel under operational impacts characteristic of the permafrost region. The metal of various zones of a failed main leaf of a truck spring, which was operated under the subarctic conditions, was investigated. It was revealed that formation of a system of volume scattered microdamages at a level of substructure and mesoscale damages in a form of fine and coarse pores ranging in size from a few micrometers to ≈40 µm preceded fatigue failure of the spring. It is shown that at a stage of material prefracture a deviation of a microhardness distribution from the normal distribution is observed. For the considered operating conditions, a determining role of presence of multiple fine pores in reducing resistance to the fatigue failure as compared to the presence of the coarse pores has been established. Results can be used in development of methods for studying the structural damage of materials and identification of fatigue failure stages.