API-571 Corrosion and Materials Professional Questions and Answers

Vessels constructed after December, 1987 are subject to the requirements of ________ of ASME Section VIII, Division 1.

Which of the following materials is susceptible to carburization?

In pressure containing equipment, SOHIC and SCC damage is most often associated with __________.

Amine units are used in refineries to remove H²S, CO² and _________ from process streams originating in many units including the coker, crude, FCC and hydrogen.

To prevent carburization, select alloys with a strong surface oxide or sulfide film former such as ________.

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 are susceptible to thermal fatigue?

Inspecting for high-cycle fatigue can be difficult since:

_________ is the main concern during start-up, shutdown and/or hydro testing for equipment/piping operating at elevated temperatures. This event can also occur in an auto refrigeration event in units processing light hydrocarbons.

Formation of a metallurgical phase known as sigma phase results in a loss of _________ in some stainless steels as a result of high temperature exposure.

With 885º F embrittlement, increasing amounts of ________ increase susceptibility to damage when operating in the high temperature range of concern.

The best way to prevent failures by atmospheric corrosion is to:

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

Temper embrittlement is a metallurgical change that is not readily apparent and can be confirmed through ________.

A form of mechanical fatigue in which cracks are produced as a result of dynamic loadings is _______.

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.

Which of the following can be affected by 885º F Embrittlement?

Sulfidation of iron-based alloys usually begins at metal temperatures above _____.

____________ 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.

ASME Section VIII had few limitations concerning brittle fracture prior to:

Carbonate SCC can occur at relatively low levels of ________ but usually occurs at welds that have not been stressed relieved.

Carbon dioxide corrosion results when CO² dissolves in water to form _________ acid.

Preventative measures to minimize the potential for brittle fracture in existing equipment are limited to controlling _______ and ________, minimizing pressure at ambient temperatures during start-up and shutdown and periodic inspections at high stress locations.

Thermal fatigue damage is in the form of cracking that may occur anywhere in a metallic component where relative movement is constrained, particularly under repeated __________.

Weld heat affected zone graphitization is most frequently found in the heataffected zone adjacent to welds in a narrow band, corresponding to the low temperature edge of the heat affected zone, In multi-pass welded butt joints, these zones overlap each other covering the entire cross section. Because of its appearance, this type of graphitization is called________.

With chloride stress corrosion cracking, __________ temperatures ________ the susceptibility for cracking.

Which of the following are affected by sulfidation?

When caustic stress corrosion cracking is a concern, steam out of _________ carbon steel piping and equipment should be avoided.

Alloys with nickel content above _________ are highly resistant to Cl SCC. The greatest susceptibility is 8% to 12% nickel.

A vacuum tower operating at 740º F is being entered to inspect. Several sets of Type 410 SS trays are bent at various angles. The trays are removed in order to straighten them. When an attempt is made to straighten them cracks form at the bends. What type of damage mechanism would cause the cracks to form?

Cavitation is best prevented by avoiding conditions that allow the absolute pressure to fall below the ___________ of the liquid or by changing the material properties.

_________ is the result of cyclic stress caused by variations in temperature.

The loss in strength from spheroidization (Softening) is usually accompanied by a(n) _________ in ductility, which allows for deformation at stress concentrations.

Galvanized steel components should not be welded to ________ due to LME.

Sigma phase in welds can be minimized by controlling ferrite in the range of _________ for Type 347 SS.

In HF service, carbon steel operating above ________ should be closely monitored for loss in thickness and may need to be upgraded to Alloy 400.

__________ is a change in the microstructure of certain carbon steels and 0.5 Mo steels after long term operation in the 800º F to 1100º F range.

_________ is a mechanical form of degradation that occurs when a component is exposed to cyclical stresses for an extended period, often resulting in sudden, unexpected failure.

Amine stress corrosion cracking is most often associated with lean amine services. The pure alkanolamine does not cause cracking. Cracking in rich amine services are most often associated with _______ problems.

The creep threshold temperature for carbon steel is ________.

Mechanical fatigue can cause cracks that initiate from the surface and often form a:

All piping and equipment exposed to HF acid at any concentration with hardness levels above ________ are subject to hydrogen stress cracking.

Carburization can be confirmed by a substantial increase in hardness and a _______ in ductility.

The regenerator reboiler and the regenerator are areas where the temperature and __________ of the amine stream are the highest and can cause significant corrosion problems.

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

The removal of a material’s protective scale by impacting materials is called:

Sulfidation of iron-based alloys usually begins at about:

The most common method used for monitoring underground structures is measuring the structure to soil ______ using dedicated reference electrodes near the structure.

Mitigation of CUI is best achieved by _________.

The removal of surface material by impacting materials is called:

__________ is usually found in aqueous environments or services where water is sometimes or always present, especially where stagnant or low-flow conditions allow the growth of microorganisms.

If the BHN is 400-500 it may indicate __________.

What structure is 410 stainless steel?

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

With high temperature sulfide corrosion (Sulfidization), noticeable increases may be found downstream of _________ injection points.

Inspection for wet H2S damage generally focuses on _____ and ______.

300 Series SS can be used for sour water service at temperatures below ____________, where Chloride SCC is not likely.

Hydrogen blisters may form as surface bulges on the ID, the OD on within the wall thickness of a pipe or pressure vessel. Blistering occurs from hydrogen generated by ______, not hydrogen gas from the process stream.

Cracks that are typically straight, non-branching, and devoid of any associated plastic deformation are likely associated with which type of failure?

In HF service, carbon steel forms a protective _________ scale in dry concentrated acid. Loss of the protective scale through high velocities or turbulence will result in greatly accelerated corrosion rates.

Temper embrittlement can be identified by a(n) shift in the ductile-to-brittle transition temperature measured in a Charpy impact test.

The major factors affecting high temperature sulfidation are the temperature, the presence of hydrogen, the H²S concentration and the ________.

Creep and stress rupture is more likely in a _________ grained material than a _______ grained material.

For carbon steel, common velocity limits are generally limited to _________ fps for rich amine and _______ fps for lean amine.

Thermal fatigue cracks usually initiate on the _________ of the component. They are generally wide and filled with oxides due to the elevated temperatures.