Secondary hardening in steels arises out of the (A) Precipitation of fine alloy carbides at high temperatures (B) Refinement of ferrite grain size by working (C) Decomposition of retained austenite upon heat treatment (D) Precipitation of complex inter-metallic upon heat treatment

Secondary hardening in steels arises out of the
(A) Precipitation of fine alloy carbides at high temperatures
(B) Refinement of ferrite grain size by working
(C) Decomposition of retained austenite upon heat treatment
(D) Precipitation of complex inter-metallic upon heat treatment
by

1 Answer

Answer :

Option C
by

Related questions

Maraging steels derive their strength from the following mechanism: (A) A fine, highly dislocated and strong martensite (B) Fine dispersions of inter-metallic of Fe, Ni, Ti etc (C) Fine dispersions of alloy carbides in a ferrite matrix (D) Fine dispersions of Fe3 C nucleated on dislocations in austenite

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Last Answer : Option A

Sub zero treatment of steel is done to (A) Suppress martensite transformation (B) Enhance its working performance in sub zero atmosphere (C) Reduce the retained austenite in hardened steel (D) Induce temper brittleness after its hardening

Description : Sub zero treatment of steel is done to (A) Suppress martensite transformation (B) Enhance its working performance in sub zero atmosphere (C) Reduce the retained austenite in hardened steel (D) Induce temper brittleness after its hardening

Last Answer : Option C

Heating the Hypo-eutectoid steels to 30°C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called (A) Tempering (B) Hardening (C) Annealing (D) Normalising

Description : Heating the Hypo-eutectoid steels to 30°C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called (A) Tempering (B) Hardening (C) Annealing (D) Normalising

Last Answer : Option C

Pick out the wrong statement (A) Hardening makes the steel more brittle (B) High alloy steels contain more than 50% alloying element (C) 18/8 stainless steel is a magnetic steel (D) Both (B) and (C)

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Cold cracking in the heat affected zone of a high strength steel weld can take place because of the (A) Retained austenite (B) Martensite formation (C) Relatively high sulphur content in the base metal (D) Sufficient hydrogen present in the welding arc

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Last Answer : (B) Martensite formation

Steels with high carbon equivalent have poor Weldability, because in these steels during welding (A) Carbon and other alloying elements get oxidised from the weld pool (B) Excessive ferrite forms in the heat affected zone leading to poor toughness of the weld (C) Martensite forms in the heat affected zone leading to poor toughness/ductility of the weld (D) Segregation of carbon and other element occurs in the weld pool leading to poor properties of the weld

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Which of the following statements regarding evacuated tube collectors (ETC) are true? i) ETC is used for high temperatures upto 150oC ii) because of use of vacuum between two concentric glass tube, higher amount of heat is retained in ETC iii) heat loss due to conduction back to atmosphere from ETC is high iv) performance of evacuated tube is highly dependent upon the ambient temperature i & iii b) ii & iii c) i & iv d) i & ii

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