EFFECT OF TITANIUM ON THE TENDENCY OF STAINLESS STEEL CONTAINING 18% Cr AND 9% Ni to UNDERGO INTER-CRYSTALLITE CORROSION

Journal Article · Sun Jan 01 04:00:00 EST 1956 · Huntnicke listy

OSTI ID:4323875

Vladimir, C; Rudolf, P

Investigation of the effect of maintaining stainless steels of the 18-8 type, stabilized with Ti, in the range of 550 to 700 after cooling down from excessively high temperatures has revealed that at high temperatures TiC begins to dissolve. At 650 deg separation takes place from the oversaturated solid solution of a chromium carbide of the type (CrFe)/sub 23/C/sub 6/ and the steel shows a tendency to intercrystallite corrosion (IC). If Ti content exceeds the theoretical umount required to bind the C, the amount of ferrite increases in such steels, and at temperatures somewhat below 800 deg the ferrite uadergoes transformation into the G-phase. Rate of reversed separation of the thermodynamically more stable TiC is regulated by the slower rate of diffusion of Ti as compared with that of Cr. This takes place at more elevated temperatures. The greater the ratio of Ti to C, in the steel, and the less the steel is overheated at high temperatures, the less TiC is dissolved in the solid solutiona and accordingly, the chromium carbide particles formed within the dangerous temperature range do not form a continuous network at the boundaries of the grains. Steel having the composition (in%): C, 0.08; Mn. 1.18; Si. 0.88; Cr. 18.24; Ni, 9.25; Mo. 0.21; Ti. 0.80; and N. 0.003. hardened at 1350 deg and held at 550 deg shows theresfter a tendency to IC, which is associated with separation of carbides of chromium at grain boundaries. Stabilizing annealing at 850 to 950 deg , resulting in separation of fine particles of TiC, precludes the tendency of steel to undergo IC. (auth)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-12-008460
• OSTI ID: 4323875
• Journal Information: Huntnicke listy, Journal Name: Huntnicke listy Vol. Vol: 11, No. 5
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CHROMIUM ALLOYS
CHROMIUM CARBIDES
COOLING
CORROSION
DIFFUSION
FERRITES
GRAIN BOUNDARIES
HEATING
HIGH TEMPERATURE
INTERMETALLIC COMPOUNDS
IRON CARBIDES
MINERALOGY, METALLURGY, AND CERAMICS
NICKEL ALLOYS
PARTICLES
QUANTITY RATIO
SEPARATION PROCESSES
SOLID SOLUTIONS
SOLUBILITY
STAINLESS STEELS
TEMPERING
TITANIUM
TITANIUM CARBIDES