Improvements in strength and toughness of experimental Fe--Cr--C steels
Efforts to improve Fe-Cr-C steel by modification of heat treatment and alloying additions are described. An important result of this work is in the evaluation of toughness with austenitizing temperature. The resistance to fracture of the conventionally (870/sup 0/C) austenitized structure is greatest ahead of a rounded notch (i.e., in Charpy and K/sub A/ tests), whereas it is least ahead of a sharp crack (i.e., in K/sub Ic/ test). Therefore, the advantages of increased fracture touchness, K/sub Ic/, with increased austenitizing temperature, must be weighed against the deterioration of ductility and Charpy impact energy. However, an optimum austenitizing temperature can be chosen (in the range 1000 to 1100/sup 0/C), where a 30 to 50 percent increase occurs in fracture toughness, K/sub Ic/, with no loss of strength and little reduction in impact energy and ductility. Moreover, low alloy additions of Mn and Ni can further increase the toughness of the alloy without reduction in strength. This was possible because the strengthening in these quaternary alloys was achieved primarily through solid solution hardening and not from substructural twinning in martensite. The toughness properties obtained for Fe-4Cr-2Mn-0.26C steel are superior to conventional 4340 and 300-M steels at the 200 ksi yield strength level, and yet would be cheaper to produce in large quantities.
- Research Organization:
- California Univ., Berkeley (USA). Lawrence Berkeley Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7273938
- Report Number(s):
- LBL-5111; CONF-760804-1
- Resource Relation:
- Conference: 4. international conference on strength of metals and alloys, Nancy, France, 30 Aug 1976
- Country of Publication:
- United States
- Language:
- English
Similar Records
Further considerations on the inconsistency in toughness evaluation of AISI 4340 steel austenitized at increasing temperatures. [Stainless steel 4340 and 300-M]
Effect of austenitizing temperature upon the microstructure and mechanical properties of experimental Fe/Cr/C and Fe/Cr/C/Ti steels
Related Subjects
CHROMIUM STEELS
FRACTURE PROPERTIES
TENSILE PROPERTIES
AUSTENITE
BENDING
CHARPY TEST
CHEMICAL COMPOSITION
ELECTRON MICROSCOPY
HEAT TREATMENTS
MANGANESE ADDITIONS
NICKEL ADDITIONS
VERY HIGH TEMPERATURE
ALLOYS
CARBON ADDITIONS
CHROMIUM ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MECHANICAL PROPERTIES
MICROSCOPY
NICKEL ALLOYS
STEELS
360103* - Metals & Alloys- Mechanical Properties