Effect of nitrogen on sensitization and stress corrosion cracking of AISI 304 stainless steels

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5350393

Mozhi, T A

Sensitization in the heat affected zones of AISI 304 stainless steel (SS) welded piping of boiling water reactors (BWR) has caused intergranular stress corrosion cracking (IGSCC) failures. New grades with reduced carbon levels, to prevent IGSCC, and nitrogen-additions to improve strength, have been proposed as alternative materials, although no systematic study of the effect of nitrogen on SCC of these SS in BWR environments has yet been conducted. This investigations involved both theoretical modeling and experimental studies. Results of the sensitization studies show that nitrogen up to 0.16 wt% increases the chromium concentration at the grain boundary (X/sub Cr//sup i/) and decreases the width of the chromium-depleted zone adjacent to the grain boundary, thereby lowering the degree of sensitization (DOS). However, carbon additions increase the DOS. The results of the SCC studies show that (1) nitrogen up to 0.16 wt% increases the IGSCC resistance, but nitrogen of 0.25 wt% causes TGSCC, (2) nitrogen up to 0.16 wt% increases the critical potential (E/sub scc/) for SCC, while carbon additions decrease it, (3) the potential ranges at which IGSCC and simultaneous IGSCC, TGSCC and pitting occurred correspond to the passive range and the potentials above the breakdown of passivity on the polarization curves, respectively.

• Research Organization: Ohio State Univ., Columbus (USA)
• OSTI ID: 5350393
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
200100 -- Fossil-Fueled Power Plants-- Power Plants & Power Generation
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
BWR TYPE REACTORS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION
CORROSION RESISTANT ALLOYS
CRACKS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
MATERIALS
NICKEL ALLOYS
NITROGEN ADDITIONS
PASSIVITY
PIPES
REACTORS
STAINLESS STEEL-304
STAINLESS STEELS
STEELS
STRESS CORROSION
WATER COOLED REACTORS
WATER MODERATED REACTORS
WELDED JOINTS