Accession Number : AD0756240

Title :   Effect of Cyclic Transformation Treatments on the Structure and Mechanical Properties of Steels.

Descriptive Note : Technical rept.,

Corporate Author : MANLABS INC CAMBRIDGE MASS

Personal Author(s) : Kulin,S. A. ; Kreder,K. ; Kaufman,L.

Report Date : OCT 1972

Pagination or Media Count : 56

Abstract : Cyclic transformation of 4340 steel was employed to evaluate the structural changes and strengthening efficiency of this method of heat treatment. Section sizes up to one-half inch thick were evaluated. The results show a direct relation of austenite grain size and martensite lath size into the micron range. Composite structures with hard surfaces and soft cores can be obtained in one-half inch sections. Conversely, fully hardened structures can be obtained in one-half inch sections by controlling the cycling temperature. The efficiency of the cyclic strengthening treatment is determined by the grain size established as a result of the melting practice. Grain size or subgrain size is a more sensitive indicator of strength than imperfection structure. Yield strengths up to 350,000 psi were achieved in a 4340 steel by a ten percent rolling reduction of a cyclically produces martensite structure. (Author)

Descriptors :   (*STEEL, *HEAT TREATMENT), TRANSFORMATIONS, TENSILE PROPERTIES, GRAIN SIZE, FRACTURE(MECHANICS), MICROSTRUCTURE, HARDNESS, PHASE STUDIES

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE