MCQ
641. Copper when alloyed with zinc is known as--
Brass
Babbits
Bronze
All of the above
642. Which of the following material has maximum ductility?
Mild steel
Nickel
Copper
Aluminum
643. The cutting tools are made from--
nickel steel
silicon steel
chrome steel
high speed steel
644. The percentage of carbon in grey iron castings usually varies between-
0.5 to 1%
2.5 to 4.5%
1 to 2%
5 to 7%
645. The toughness of a material --when it is heated.
increases
remain same
decrease
none
646. The percentage of carbon in pig iron varies from--
0.1 to 12%
2.5 to 4.5%
1.5 to 2.5%
4 to 4.5%
647. Lead is poured into the joint between two pipes. These pipes may be made of--
cast iron
asbestos cement
vitrified clay
concrete
648. Pearlite is a combination of--
ferrite and cementite
cementite and gamma iron
ferrite and austenite
ferrite and iron graphite
649. Brass contains--
70% copper and 30% zinc
90% copper and 10% tin
85-92% copper and rest tin with little lead and nickel
70-75% copper and rest tin
650. Surveying tapes are made of a material having low coefficient of expansion and enough strength. The alloy used is—
silver metal
duralumin
Hastelloy
Invar
651. Which of the following iron exists between Type equation here.910°C and 1403°C?
∝-iron
δ -iron
β-iron
γ-iron
652. Which of the following element results in presence of free graphite in CI--
carbon
silicon
sulphur
manganese
653. Tensile strength of steel can be safely increased by--
adding carbon up to 2.8%
adding carbon up to 6.3%
adding carbon up to 0.83%
adding small quantities of copper
654. The most effective inhibitor of grain growth. when added in small quantities is--
carbon
manganese
vanadium
Cobalt
655. Discontinous chips are formed during machining of--
brittle metal
hard metal
ductile metal
soft metal
656. The lower critical point for all steels is—
600°C
700°C
723°C
913°C
657. In which forging is possible without any problem?
alloy steel
low carbon
high carbon
cast
658. Recrystallisation temperature can belowered by--
purification of metal
grain refinement
working at lower temperature
all of the above
659. Vanadium in high speed steels--
promotes decarburisation
provides high hot hardness
forms very hard carbides and thus increases wear resistance
promotes retention of austenite
660. The machinability of steel is increased by--
silicon and sulphur
phosphorous, lead and sulphur
sulphur, graphite and aluminium
phosphorous and aluminium