Development of nickel-free austenitic stainless steels for ambient and cryogenic applications
A series of alloys have been developed as possible replacements for some austenitic stainless steels. These alloys utilized a Mn substitution for Ni and a reduced Cr concentration from the 18% ordinarily found in the AISI 300 series stainless steels to a concentration of 13%. The base system studied was an alloy containing Fe-16%Mn-13%Cr while other elements added included small additions of N, Si and Mo. A range of microstructures was produced from the alloying additions. The base composition had a triplex (fcc, hcp, bcc) structure while the most highly modified compositions were fully austenitic. Mechanical testing included tensile testing and Charpy V-notch testing conducted at various temperatures between -196/sup 0/C to 23/sup 0/C. Excellent combinations of strength and ductility were obtained (40--65 ksi yield strength, 100--125 ksi ultimate strength, 45--75% elongation and 60--80% reduction of area) at room temperature. Upper shelf energies in Charpy V-notch testing were as high as 185 ft-lbs with a ductile-brittle transition temperature (DBTT) of -160/sup 0/C. Analysis of fracture surfaces determined that alloys without interstitials had no transition in the mode of failure between room temperature and liquid nitrogen temperature. Results of an ASTM sensitization corrosion test, where the experimental alloys were compared to 347 stainless steel, indicated that the alloys were not susceptible to intergranular attack.
- Research Organization:
- California Univ., Berkeley (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6807772
- Report Number(s):
- LBL-7397; CONF-7709115-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
AUSTENITIC STEELS
CHARPY TEST
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
IRON ALLOYS
IRON BASE ALLOYS
LOW TEMPERATURE
MANGANESE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLYBDENUM ADDITIONS
MOLYBDENUM ALLOYS
NITROGEN ADDITIONS
PHASE TRANSFORMATIONS
SILICON ADDITIONS
SILICON ALLOYS
STAINLESS STEELS
STEELS
VERY LOW TEMPERATURE