Stress corrosion cracking of slowly stressed fine-grained structural steels in flowing hot, simulated boiler feedwater
Description
Three fine-grain structural steels of the type 22NiMoCr37 (material no. 1.6751) were analysed in CERT test with strain rates of 10-7 -1 to 10-5 -1 in simulated hot (1000C to 2200C) flowing (35000<Re<70000) boiler feeding water which was brought to a pH value of 8.5 (250C) and a corresponding conductivity of 0.95 mS/cm. The sulphur content was 0.005 or 0.011 or 0.022 weight %. The doping of the feed water with oxygen (5 ppb to 400 ppb) as another parameter causes a stable regulation of the free corrosion potential εR, independent of the material. It was the aim of these investigations to determine and quantify influencing factors of the stress crack corrosion under practice-relevant conditions and to be able to evaluate limit values. Furthermore, it should be possible to make qualitative statements on the mechanism. (orig./IHOE)
Availability note (English)
Available from the library of Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.).Abstract (German)
In CERT-Versuchen mit Dehnraten von 10-7 s-1 bis 10-5 s-1 in simuliertem heissem (1000C bis 2200C) stroemendem (35000<Re<70000) Kesselspeisewasser, das mit NH3 auf einen pH-Wert von 8,5 (250C) und eine damit korrespondierende Leitfaehigkeit von 0,95 μS/cm gebracht worden war, erfolgte die Pruefung dreier Feinkornbaustaehle des Typs 22NiMoCr37 (Werkstoff-Nr. 1.6751). Der Schwefelgehalt betrug 0,005 bzw. 0,011 bzw. 0,022 Gew.%. Die Dotierung des Speisewassers mit Sauerstoff (5 ppb bis 400 ppb) als weiterem Parameter bewirkt eine stabile Einstellung des freien Korrosionspotentials εR unabhaengig vom Werkstoff. Das Ziel der vorliegenden Untersuchungen bestand darin, unter praxisrelevanten Bedingungen Einflussgroessen der Spannungsrisskorrosion (SpRK) zu bestimmen, zu quantifizieren und Grenzwerte abschaetzen zu koennen. Darueber hinaus sollte es moeglich sein, qualitative Aussagen zum Mechanismus zu machen. (orig./IHOE)Additional details
Additional titles
- Original title (German)
- Untersuchungen zur Spannungsrisskorrosion langsam gedehnter Feinkornbaustaehle in stroemendem, heissem, simuliertem Kesselspeisewasser
Publishing Information
- Imprint Pagination
- 89 p.
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 20021813
- Subject category
- S36: MATERIALS SCIENCE;
- Resource subtype / Literary indicator
- Thesis, Non-conventional Literature
- Descriptors DEI
- ACTIVATION ENERGY; BOILERS; CRACK PROPAGATION; CURRENT DENSITY; ELECTRIC POTENTIAL; FEEDWATER; FLOW RATE; HIGH TEMPERATURE; LENGTH; LOW ALLOY STEELS; MANGANESE SULFIDES; MECHANICAL TESTS; MICROSTRUCTURE; OXYGEN ADDITIONS; PRECIPITATION; STEEL-NIMOCR; STRAIN RATE; STRESS CORROSION; SULFUR ADDITIONS; SURFACE TENSION; TEMPERATURE DEPENDENCE
- Descriptors DEC
- ALLOYS; CARBON ADDITIONS; CHALCOGENIDES; CHEMICAL REACTIONS; CHROMIUM ADDITIONS; CORROSION; CRYSTAL STRUCTURE; DIMENSIONS; ENERGY; HEAT RESISTING ALLOYS; HYDROGEN COMPOUNDS; IRON ALLOYS; IRON BASE ALLOYS; MANGANESE COMPOUNDS; MATERIALS TESTING; MOLYBDENUM ADDITIONS; NICKEL ADDITIONS; OXYGEN COMPOUNDS; POLAR SOLVENTS; SEPARATION PROCESSES; SOLVENTS; STEELS; SULFIDES; SULFUR COMPOUNDS; SURFACE PROPERTIES; TESTING; TRANSITION ELEMENT COMPOUNDS; WATER