Normalization of the Cold Shortness of Plate Steel: II. Short-Brittleness Thresholds in Pipe Tests

Resumo

The following serial curves are obtained for a pipe steel of strength class K65 (Kh80): strength and plasticity curves during tension in the temperature range from–80 to +20°C, fracture energy from drop weight tear test (DWTT) diagrams, and impact toughness KCV curves (from–180 to +20°C). The ductile–brittle transition temperature range determined from the DWTT energy is shown to be higher than that determined from a KCV diagram by 80 K. The KCV^–40 criterion is concluded to be more reliable than the DWTT^–20 criterion. KCV and DWTT tests are shown to reproduce the crack starting conditions in a pipe, and the resistance of a high-strength pipe steel to extended fracture should be estimated using other criteria.