Accession Number : ADA133428

Title :   A Metallographic Interpretation of the QLT Heat Treatment of Ferritic Cryogenic Steels.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV BERKELEY DEPT OF MATERIALS SCIENCE AND MINERAL ENGINEERING

Personal Author(s) : Kim,J I ; Morris,J W , Jr

PDF Url : ADA133428

Report Date : May 1982

Pagination or Media Count : 11

Abstract : Commercial 5-6Ni steels are toughened for service by a 3-step heat treatment which is sometimes designated the QLT treatment. The present investigation was undertaken to determine why this treatment is necessary and successful. It was concluded that the multi-step heat treatment is necessary because of the low nickel content. The intercritical anneal (L) serves to create regions of high solute contents along the martensite lath boundaries. The intercritical temper (T) then precipitates a dense distribution of high solute, stable austenite within these enriched regions.

Descriptors :   *Structural steel, *Cryogenics, *Heat treatment, *Ductile brittle transition, Nickel steels, Ferrites, Microstructure, Toughness, Quenching, Annealing, Tempering

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE