Machining properties of steel are improved by adding___________________?
(A) sulphur, lead, phosphorous
(B) silicon, aluminium, titanium
(C) vanadium, aluminium
(D) chromium, nickel
(D) lubricants
Depth of hardness of steel is increased by addition of_________________?
(A) nickel
(B) chromium
(C) tungsten
(D) vanadium
(D) ell of the above
In which of the following cases, consideration of creep is important_________________?
(A) flywheel of steam engine
(B) cast iron pipes”
(C) cycle chains
(D) gas turbine blades
(D) piston I.
Maximum percentage of carbon in austenite is______________?
(A) 0.025%
(B) 0.26%
(C) 0.8%
(D) 1.25%
(D) 1.7%.
Hardness of steel depends on_________________?
(A) amount of carbon it contains
(B) the shape and distribution of the car-bides in iron
(C) method of fabrication
(D) contents of alloying elements
(D) the quality of ore from which it is made
Which of the following is the binding material in cemented carbides___________________?
(A) cobalt
(B) nickel
(C) vanadium
(D) iron
(D) carbon
Which is false statement about tempering. Tempering is done to_______________?
(A) improve machinability
(B) improve ductility
(C) improve toughness
(D) release stresses
(D) reduce hardness and brittleness
Vanadium in high speed steels__________________?
(A) promotes decarburisation
(B) provides high hot hardness
(C) forms very hard carbides and thus in-creases wear resistance
(D) promotes retention of austenite
(D) increases toughness
Hardness of lower bainite (tempered martensite) is about________________?
(A) RC 65
(B) RC 48
(C) RC 57
(D) RC 80
(D) RC 32
Which is false statement about annealing. Annealing is done to________________?
(A) relieve stresses
(B) harden steel slightly
(C) improve machining characteristic
(D) soften material
(D) permit further cold working