Exam 1: Corrosion and Materials

___________ is the result of cyclic stresses caused by variations in temperature.

Carbonate SCC may easily be mistaken for SSC or SOHIC; however, the carbonate cracks are usually ________ the toe of the weld and have multiple parallel cracks.

Which of the following materials are affected by mechanical fatigue cracking?

Carbon dioxide (CO₂) corrosion results when CO₂ dissolves in water to form ________.

Areas of vulnerability in sulfuric acid Alkylation units include reactor effluent lines, reboilers, deisobutanizer, overhead systems and the _________ treating system.

A loss in ductility of high strength steels due to the penetration of atomic hydrogen can lead to brittle cracking called hydrogen embrittlement. Which of the following materials is susceptible to HE.

The graphitization rate ____________ with increasing temperature

Graphitization can be prevented by using chromium containing low alloys steels for long-term exposure above ________.

Fatigue cracks usually initiate on the surface at notches or __________ under cyclic loading.

A form of thermal cracking, __________, can occur when high and nonuniform thermal stresses develop over a relatively short period of time in a piece of equipment due to differential expansion and contraction.

Fatigue will not occur in carbon steel if stresses are below the:

Caustic is sometimes added to process streams for ________ or as a reactant.

______ is most likely found in hard welds and heat affected zones and in high strength components.

Heat treatment can have a significant effect on the toughness and hence fatigue resistance of a metal. In general, ________ grained microstructures tend to perform better than _________ grained.

The most important factors affecting graphitization are the chemistry, stress, temperature and _______.

____________ is the reduction in toughness due to a metallurgical change that can occur in some low alloy steels as a result of long-term exposure in the temperature range of about 650º F to 1100º F.

SSC is a form of hydrogen stress cracking resulting from the absorption of atomic hydrogen that is produced by the ______ corrosion process on the metal surface.

Which of the following is not a prime candidate for thermal fatigue?

A 6", A106 Gr B, flanged line carrying caustic wash water at 200º F has signs of atmospheric corrosion. Which of the following may have help accelerate the corrosion?

A quick test for embrittlement from _________ is a bend test or crush test. Unaffected material will be crushed in a ductile fashion while embrittled components will crack with no signs of ductility.