STRESS CORROSION CRACKING OF SINGLE CRYSTALS OF SOME AUSTENITIC STAINLESS STEELS
Crack nucleation site, orientation of the crack plane, fracture time- stress relationship, fracture surface morphology, and corrosion product composition were studied during the stress corrosinn cracking of austenitic stainless-steel single crystals. Fe--20 wt.% Cr--20 wt.% Ni, Fe--26 wt.% Cr-- 12 wt.% Ni, and commercial type 304 stainless-steel single crystals were loaded in tension in boiling 42% MgCl/sub 2/ solution. The commercial type 304 stainless steel cracked or fractured in 4 to 17 hr, the Fe--20 wt.% Cr-12 wt.% Ni in 16 to 62 hr, and the Fe--20 wt.% Cr--20 wt.a Ni in 70 to 170 hr. The crack in all three alloys nucleated from elongated pits formed when portions of slip lines were attacked by the solution. The crack plane of the Fe--20 wt.% Cr--20 wt.% Ni specimens followed the (100) plane with the highest normal stress upon it. Electron diffraction pattern made of the corrosion product from a Fe--20 wt.% Cr-- 20 wt.% Ni crack face showed that it may be a chromium-iron oxide. Colorimetric analysis of the corrosion solution showed an increase in nickel during the test. The general crack plane in type 304 and Fe--20 wt.% Cr-- l2 wt.% Ni specimens was approximately normal to the tensile axis. (auth)
- Research Organization:
- Carnegie Inst. of Tech., Pittsburgh
- DOE Contract Number:
- NONR 760(14)
- NSA Number:
- NSA-15-000565
- OSTI ID:
- 4124331
- Report Number(s):
- NP-9241
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- United States
- Language:
- English
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