Accession Number : AD0807420

Title :   THERMOMECHANICAL TREATMENTS APPLIED TO ULTRAHIGH STRENGTH STEELS.

Descriptive Note : Final rept.,

Corporate Author : MANLABS INC CAMBRIDGE MA

Personal Author(s) : Kalish, D. ; Kulin, S. A.

Report Date : NOV 1966

Pagination or Media Count : 98

Abstract : The strengthening response of 9 per cent nickel - 4 per cent cobalt (with 0.25 and 0.45 per cent carbon) steels to thermomechanical treatments was evaluated with particular emphasis on fracture toughness. The mechanical properties of both strain tempered and ausformed martensites were compared with the properties of the conventionally heat treated steels. The variables of interest in strain tempering were the pretempering temperature, amount of deformation, retempering temperature and carbon content. Ausforming was studied with respect to deformation temperature and time, amount of deformation, tempering temperature and alloy chemistry. In addition, a combination thermomechanical treatment was employed which involved ausforming followed by strain tempering. Extensive microstructural studies were performed on strain tempered specimens in order to help develop an understanding of the strengthening mechanisms involved in this thermomechanical treatment. The microstructural studies and yield strength behavior led to the development of a dislocation trapping model for the mechanism of strengthening by strain tempering. (Author)

Descriptors :   *HOT WORKING), (*STEEL, (*MARTENSITE, HOT WORKING), FRACTURE(MECHANICS), TOUGHNESS, COBALT ALLOYS, TEMPERING, AUSTENITE, STRAIN HARDENING, BAINITE, TENSILE PROPERTIES, ROLLING(METALLURGY), MICROSTRUCTURE, NICKEL ALLOYS, CARBON ALLOYS, DEFORMATION.

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE