27 real Materials & Corrosion Selection questions from the Process Design bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Carbon steel service limits?
Junior
A.hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
B.mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C
C.1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
D.default MOC for hydrocarbons and non-corrosive service between about −29 °C and 425 °C; below −29 °C impact-tested LTCS grades are required
2. Which term means: "default MOC for hydrocarbons and non-corrosive service between about −29 °C and 425 °C; below −29 °C impact-tested LTCS grades are required"?
A.Carbon steel service limits — hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
B.Carbon steel service limits — clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty
C.Carbon steel service limits — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
D.Carbon steel service limits — default MOC for hydrocarbons and non-corrosive service between about −29 °C and 425 °C; below −29 °C impact-tested LTCS grades are required
5. Which term means: "316 adds 2–3% molybdenum for better pitting and chloride resistance; both are austenitic and unsuitable for hot concentrated chlorides"?
A.SS 304 vs 316 — cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
B.SS 304 vs 316 — 316 adds 2–3% molybdenum for better pitting and chloride resistance; both are austenitic and unsuitable for hot concentrated chlorides
C.SS 304 vs 316 — sour-service standard limiting hardness to 22 HRC for carbon steel and restricting alloys to prevent sulphide stress cracking in H2S environments
D.SS 304 vs 316 — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
A.mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C
B.316 adds 2–3% molybdenum for better pitting and chloride resistance; both are austenitic and unsuitable for hot concentrated chlorides
C.hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
D.operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
8. Which term means: "mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C"?
A.Duplex stainless steel — clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty
B.Duplex stainless steel — 316 adds 2–3% molybdenum for better pitting and chloride resistance; both are austenitic and unsuitable for hot concentrated chlorides
C.Duplex stainless steel — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
D.Duplex stainless steel — mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C
A.operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
B.hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
C.sour-service standard limiting hardness to 22 HRC for carbon steel and restricting alloys to prevent sulphide stress cracking in H2S environments
D.1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
11. Which term means: "sour-service standard limiting hardness to 22 HRC for carbon steel and restricting alloys to prevent sulphide stress cracking in H2S environments"?
A.NACE MR0175 / ISO 15156 — cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
B.NACE MR0175 / ISO 15156 — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
C.NACE MR0175 / ISO 15156 — hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
D.NACE MR0175 / ISO 15156 — sour-service standard limiting hardness to 22 HRC for carbon steel and restricting alloys to prevent sulphide stress cracking in H2S environments
A.hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
B.clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty
C.cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
D.1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
14. Which term means: "hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure"?
A.HIC vs SSC — 316 adds 2–3% molybdenum for better pitting and chloride resistance; both are austenitic and unsuitable for hot concentrated chlorides
B.HIC vs SSC — cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
C.HIC vs SSC — hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
D.HIC vs SSC — mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C
A.hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
B.default MOC for hydrocarbons and non-corrosive service between about −29 °C and 425 °C; below −29 °C impact-tested LTCS grades are required
C.cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
D.1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
17. Which term means: "cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water"?
A.Chloride SCC of austenitic steel — clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty
B.Chloride SCC of austenitic steel — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
C.Chloride SCC of austenitic steel — cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
D.Chloride SCC of austenitic steel — 1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
A.Corrosion allowance selection — 1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
B.Corrosion allowance selection — clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty
C.Corrosion allowance selection — hydrogen-induced cracking is blistering along inclusions in wet H2S without applied stress; sulphide stress cracking needs tensile stress and a hard microstructure
D.Corrosion allowance selection — cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
23. Which term means: "clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty"?
A.Cladding vs lining — 1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
B.Cladding vs lining — mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C
C.Cladding vs lining — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
D.Cladding vs lining — clad plate metallurgically bonds a thin corrosion-resistant alloy to carbon steel backing for pressure parts; loose or rubber lining serves near-atmospheric duty
A.mixed ferrite-austenite grade such as 2205 with about twice the yield strength of 316 and better chloride SCC resistance, limited to about 250–300 °C
B.operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
C.1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
D.default MOC for hydrocarbons and non-corrosive service between about −29 °C and 425 °C; below −29 °C impact-tested LTCS grades are required
26. Which term means: "operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack"?
A.Nelson curves (API 941) — operating limits of temperature and hydrogen partial pressure for carbon and Cr-Mo steels to avoid high-temperature hydrogen attack
B.Nelson curves (API 941) — 1.5 mm for mild, 3 mm for moderate and 6 mm for severe corrosive service in carbon steel; usually zero for stainless steel
C.Nelson curves (API 941) — sour-service standard limiting hardness to 22 HRC for carbon steel and restricting alloys to prevent sulphide stress cracking in H2S environments
D.Nelson curves (API 941) — cracking of 304/316 under stress in chlorides above about 60 °C, which drives the choice of duplex or nickel alloys for hot brine and cooling water
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