Influence of tensile stresses on the structurally deformed state and defect formation in the near-surface layer of pipe steel

Keywords

pipe steel, structurally deformed state, mechanical characteristics, tensile stress, defects.

Cite as

Dmytrakh І. M., Syrotyuk А. М., and Leshchak R. L. Influence of tensile stresses on the structurally deformed state and defect formation in the near-surface layer of pipe steel. Physicochemical Mechanics of Materials. 2026. 62(4), 64-70.

Abstract

It is established that the applying of mechanical tensile stresses to specimens of pipe L450M ferritic-pearlite steel leads to the following structural changes and the formation of defects in its near-surface layer. In particular, the local weakening of ferrite grain boundaries as­sociated with pearlite colonies is observed; single crack-like defects of the order of ~ 10 mm appear; the chains of small microcracks are formed along the boundaries of ferrite grains weakened by pearlite; defects in the form of voids with a size of 10 mm, and more appear; surface cavities with a size of 10–70 mm are formed. An empirical dependence for assessing the minimum thickness of the defective near-surface layer in steel is proposed, which can be used to predict the level of applied tensile stress in order to obtain a defective near-surface layer of steel of an assigned thickness.