Modified 43XX Steels for High Toughness
Abstract
Isothermal transformations were carried out in the vicinity of M sub s temperatures on Si, Al+Si modified AISI 4330, 4340 steels, which had been remelted by electroslag refining (ESR) techniques. The microstructures of the heat-treated variants were characterized by transmission electron microscopy. Mechanical property evaluations (Charpy impact energies, tensile strengths, plane-strain fracture toughness data) of the different microstructures were also carried out. Isothermal transformations in these steels resulted in bainite, bainite + martensite microstructures, containing moderate amounts of retained austenite. The austenite was found to be in the form of thin films around the bainite, martensite laths. The strength-toughness combinations obtained in this investigation for Si-modified AISI 4330 steel appear to be superior to those for unmodified AISI 4340 and 300-M steels, whilst the strength-toughness combinations obtained for Al+Si modified AISI 4340 steel appear to be comparable to those for 18 NiCoMo maraging steel. The merits of ESR-processing these steels are also reflected in the uniform Charpy impact properties obtained for the different orientations investigated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1980
- Accession Number
- ADA086453
Entities
People
- E. R. Parker
- Naresh J. Kar
- V. F. Zackay
Organizations
- University of California, Berkeley