Effects of Microstructure, Composition, and Strength on the Nil Ductility Transition (NDT) Temperature of HY-80 Steel

摘要

Steel from 22 heats of low-carbon Ni-Cr-Mo steel, HY-80 (ASTM A543065, and MIL-S-16216G (Ships)) was heat treated to study the effects on the drop weight nil ductility transition (NDT) temperature of (1) commercial variation in composition and inclusion content, (2) variation in microstructure such as prior austenitic grain size and the relative amount of isothermally produced ferrite or bainite in a tempered martensitic matrix, and (3) the observed variation in strength obtained after a one-hour 1150 F temper followed by water quench to prevent embrittlement while cooling from the tempering temperature. (Author)