Development of grain boundary chromium depletion in type 304 and 316 stainless steels

Journal Article · Tue Jul 01 04:00:00 EDT 1986 · Scr. Metall.; (United States)

DOI:https://doi.org/10.1016/0036-9748(86)90428-X· OSTI ID:5350900

Bruemmer, S M; Charlot, L A

Sensitization of austenitic stainless steels is dependent on the thermodynamics of carbide precipitation and the kinetics of chromium diffusion. Heat treatment in, or slow cooling through, the temperature range from 500 to 800/sup 0/C promote intergranular, chromium-rich precipitation and concomitant depletion of chromium in adjacent regions. These local chromium depleted regions are more electrochemically active than the bulk material and may become susceptible to intergranular corrosion and/or stress corrosion in many environments. The ability to adequately predict sensitization behavior in stainless steels requires a better understanding of the development of chromium-depleted regions. The present study examined the development of chromium depletion during isothermal sensitization in high carbon Type 304 and 316 stainless steels. Chromium minimums and concentration profiles were determined at grain boundaries using the STEM-EDS technique. Chromium depletion measurements are discussed in reference to equilibrium and kinetic aspects of existing models for sensitization development in austenitic stainless steels.

• Research Organization: Pacific Northwest Lab., Richland, WA 99352
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5350900
• Journal Information: Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 20:3; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ANNEALING
CHROMIUM
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
DIFFUSION
DIMENSIONS
ELEMENTS
GRAIN BOUNDARIES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HEAT TREATMENTS
HIGH TEMPERATURE
IRON ALLOYS
IRON BASE ALLOYS
ISOTHERMAL PROCESSES
MATERIALS
METALS
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
QUANTITY RATIO
SEGREGATION
STAINLESS STEEL-304
STAINLESS STEEL-316
STAINLESS STEELS
STEELS
TEMPERATURE EFFECTS
THERMODYNAMICS
TIME DEPENDENCE
TRANSITION ELEMENTS
VERY HIGH TEMPERATURE
WIDTH