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Basic concepts in Engineering metallurgy | Gate Mechanical Concepts

 Basic concepts in Engineering metallurgy | Gate Mechanical Concepts

1.      Delta iron occurs at temperature between 1400 oC and 1539 oC .
2.      Gamma iron exists at temperature between 910 oC and 1400 °C.
3.      Ferromagnetic alpha iron exists in temperature range below 723 °C.
4.      Para-magnetic alpha iron changes to gamma iron at 910 °C.
5.      Fatigue failure: Fatigue failure occurs when a part is subjected to compressive stress.
6.      Homogeneous: A body having identical properties all over
7.      Elastic behavior: If a material recovers its original dimensions, when load is removed.
8.      A ductile fracture is characterized by appreciable plastic deformation prior to propagation of crack.
9.      Resilience: The ability of a material to absorb energy when deformed elastically

 Basic concepts in Engineering metallurgy | Gate Mechanical Concepts

10.     Machining properties of steel can be improved by adding sulphur, lead, phosphorus.
11.     Eutectoid steel the percentage of carbon is 0.8%.
12.     A cold chisel is made of high carbon steel.
13.     An engineer’s hammer is made of forged steel.
14.     Cyaniding: The process of adding carbon and nitrogen by heat treatment of steel to increase its surface hardness.
15.     Tensile strength of common varieties of cast iron is in the range 840-500 Mpa.
16.     In carbon steel casting the percentage of carbon is less than 1.7%.
17.     Aluminum alloys for pressure die casting must possess considerable fluidity.
18.     Electro forming is specially valuable for thin walled parts requiring a high order of accuracy and internal surface finish.
19.     In power metallurgy the process of heating the cold pressed metal power is called sintering.
20.     The hardness of steel increases if it contains martensite.
21.     The presence of sulphur in pig iron makes the casting unsound.
22.     Compressive strength of grey cast iron in tones per square cm is of the order of 5-7.
23.     The machinability of steel can be increased by phosphorous, lead and sulphur.
24.     Steel with 0.8% carbon and 100% pearlite is known as eutectoid steel
25.     The maximum hardenability of any steel depends on the carbon content.
26.     In 18-4-1 high speed steel the maximum percentage is of iron.
27.     In compression, a prism of brittle material will break by shearing along oblique plan.
28.     Cast-alloy contains nickel and molybdenum.
29.     Trimming is a process associated with forging.
30.     Addition of lead and bishmuth to aluminium results in improving machinability
31.     Foundry crucible is made of graphite.
32.     Age-hardening is related with duralumin.
33.     For heavy loads in aircraft bearings the malarial used with lead to reduce the risk of seizure, is silver.
34.     As compared to steel the tensile strength of wood is generally 1/5.
35.     Compressive strength of wood is generally more along the grains.
36.     Superconducting property exist at temperatures below 10 K.
37.     Weld Decay: The phenomenon of weld decay is associated with stainless steels.
38.     Bloom: Bloom are obtained by passing hot ingots through the rolling mills and are of size 150 mm x 150mm to 350mm x 350mm.
39.     A knoop indenter is a diamond group to a pyramdidal from.
40.     A unit cell that contains nine atoms is known as body centered cubic space lattice.
41.     The process commonly used for thermo-plastic material is injection moulding.
42.     The most important element that controls the physical properties of steel is carbon.
43.     In process annealing process, the hypoeutectoid steel is heated below A1 line with a view to make steel ductile for cold working.
44.     The imperfection in the crystal structure of metal is known as dislocation.
45.     Polyesters belong to the group of thermosetting plastics.
46.     The effect of alloying zinc to copper is to increase strength and ductility (if added up to 10-30 %.)

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