Etude du comportement mecanique de l'acier au carbone A516-70 fragilise au bleu (French text).

摘要

A locking mechanism occurs between dislocations and intersitial atoms (Carbon and/or nitrogen) when some low carbon steels are plastically deformed in the range of temperatures where dynamic strain aging occurs. This mechanism is responsible for the unusual increase in strength, the unexpected loss of ductility and the appearance of serrated yielding.; The goal of the present study is to evaluate the mechanical properties at 20°C of a low carbon steel A516-70 prestrained in the range of temperatures where dynamic strain aging occurs. The properties are the ductility, the strength, the yield stress, the toughness, the fatigue crack propagation behavior.; The required specimens to evaluate the properties are machined from the reduced section of long specimens. The thickness of the latter specimen is 20,6 mm, the width and the length of the reduced section are respectively 52,6 mm and 317 mm. Four long specimens are pulled in tension to a strain of 13,09% at 260C at a rate of 2,9 x 10-3/s. Four other long specimens are also pulled in tension at the same level of strain and rate but at 20C. (Abstract shortened by UMI.)