API-571 Exam Dumps and Practice Questions

API RP 751 (referenced in RP 571) lists materials appropriate for HF acid alkylation service. It specifies:

''Chrome-moly steels such as ASTM A-193 B5 (5% Cr) bolts are preferred for their resistance to HF acid-induced cracking.''

''Standard low alloy steels (e.g., B7) are not considered adequately resistant.''

(Reference: API RP 571 summary & API RP 751, Section 5.6.3 -- Bolting Materials)

Therefore, the correct and industry-approved answer is option A.

API RP 571 describes under Caustic Corrosion:

''One of the significant contributing factors is caustic accumulation in low-flow or stagnant areas, especially in heat-traced lines or around steam injection points.''

''Localized heating can concentrate caustic solutions, promoting corrosion even in carbon or stainless steels.''

Thus, option C (heat-traced equipment) is the correct and technically accurate choice.

API RP 571 states under Chloride Stress Corrosion Cracking (Cl-SCC):

''Nickel contents above approximately 35% provide significant resistance to chloride stress corrosion cracking. Alloys such as Alloy 625 and Alloy 825 exhibit excellent resistance.''

''Austenitic stainless steels with lower nickel contents, such as 304 and 316, are more susceptible to Cl-SCC.''

Hence, option C (35%) is correct.

API RP 571 explains the typical location of dissimilar metal weld (DMW) cracks as follows:

''DMW cracking usually occurs in the heat-affected zone (HAZ) on the ferritic side of the weld.''

''The difference in thermal expansion coefficients, grain structures, and creep rates between the ferritic and austenitic materials contributes to the development of high stress and strain concentrations in the HAZ of the ferritic material.''

(Reference: API RP 571, Section 4.2.1.6 -- Dissimilar Metal Weld Cracking)

Thus, these cracks do not occur in the center of the weld or on the austenitic side, but rather at the ferritic HAZ, making option A correct.

Per API RP 571, susceptibility to hydrogen embrittlement is strongly influenced by:

Material strength level

Microstructure

Heat treatment condition

Heat treatment determines:

Dislocation density

Trap sites for hydrogen

Residual stress state

The modulus of elasticity does not significantly affect hydrogen embrittlement susceptibility, making Option A incorrect.

Referenced Documents (Study Basis):

API RP 571 -- Section on Hydrogen Embrittlement