Easa Module 6 Shaping Metals

Front 1

what are the four basic methods of converting a row material in to the required manufactured shape whilst achieving the desired material structure

Back 1

1- casting

2.- deformation

3 - machining and

4 - fabricating

Front 2

what allows the material to be casted

Back 2

the liquefaction ability of the material

Front 3

what allows a material to be deformed

Back 3

the ability of material to be deformed permanently without damage (plasticity)

Front 4

what are the two basic types of sand castig

Back 4

removable/re=reusable pattern (wood or metal)

disposable pattern (polystyrene pattern which evaporates when the metal is poured)

Front 5

in order to produce good casting using sand-casting, what would be the quality the sand must possess

Back 5

good binding quality, ( to achieve this a clay is added).

good porosity to let the gas escape

Front 6

the strength of the sand is controlled be the amount of.........?..........added to it

Back 6

the amount of bonding agent present

Front 7

the moisture content of the sand should be between?

Back 7

2% - 8%

Front 8

how is the moisture content of the sand is checked

Back 8

by weighting the sand before nd after drying

Front 9

the cope and drag (top and bottom) of the mould must incorporate a positive .............

Back 9

alignment

Front 10

the suitable feed channel the molten metal flows in to the mould is called

Back 10

runners orsprue

Front 11

as the molten metal fills the mould it begins to solidify and shrink, what is the percentage of the shrinkage of steel and that of alluminium

Back 11

3% - 4% steel and

6% - 7% aluminium

Front 12

list some of the advantages of sand-casting

Back 12

cheap, simple, suitable for most metals

Front 13

list some of the did-advantages of sand casting

Back 13

slow, not automated, not accurate, cannot produce thin wall sections

Front 14

list some of the most common defects of sand casting

Back 14

porosity ( caused by hot gas that was anable to scape)

inclusion (caused by sand sticking to the wall of the casted material)

cold shuts caused by areas where the molecules hasn't connected properly due to rapid cooling)

hot tears (cracks caused by excessive tensile stresses due to thermal contraction

Front 15

describe shell moulding

Back 15

the process of which a thin shell is produced, a thermoplastic resin and a sand is mixed together and heated together in a heated pattern.

Front 16

describe a centrifugal moulding

Back 16

the molten metal is poured in to a rotating mould

Front 17

in die casting there are two methods of feeding the molten metal in to the mould, what are they.

Back 17

by gravity and by pressure extrusion.

Front 18

why a is metal casting mould might only be suitable to non ferrous metals, and not steel

Back 18

because the metallic casting mould may not withstand the high melting temperature required by steel.

Front 19

is hollow casting produced in a gravity die or pressure die

Back 19

gravity die.

Front 20

what is the difference between drop-stamping and hot pressing

Back 20

drop stamping may involve a light but multible blows,

hot pressing is one long steady squeezing operation

Front 21

what kind of mould does die casting does use, is this permanent or temporary mould

Back 21

die casting process use a permanent metal mould

Front 22

what is the difference between sand casting and the gravity type of die casting

Back 22

the gravity type uses metal mould while sand casting uses a cast built sand

Front 23

what kind of grain structure is produce by gravity type die casting

Back 23

a fine grain is produced due to the rapid and uniform cooling

Front 24

hollow casting cannot be produced by what type of die casting

Back 24

pressure-extrusion casting

Front 25

what is a forging

Back 25

forging is a squeezing/hammering

Front 26

what is the temperature at which a forging is carried out

Back 26

just above re-crystallization temperature

Front 27

why heating the metal to above the re-crystallisation temperature is important when forging

Back 27

because there will be no residual local stresses

Front 28

forging not only shapes the metal but also reduces the .....?.... size, and produces a directional control of ..........? .... flow

Back 28

grain size, grain

Front 29

hot pressing tends to affect the whole structure of the component while multi but light blows tends to affect only..........?.............

Back 29

material closest to the surface

Front 30

if rolling is done cold, what would be the resulted benefit.

Back 30

increased hardness?strength

better finish

higher accuracy

improved surface quality

Front 31

what is drawing

Back 31

it is a tensile operation, the material is pulled through a shaped die. this is suitable to ductile materials

Front 32

what is deep drawing or deep pressing

Back 32

a process in which the metal pressed to shaped die. then the metal deforms according to the die shape

Front 33

what is a pressing

Back 33

pressing involves the use of a male and a female dies, the material is sandwiched between the formers

Front 34

why is it difficult to form a steel by extrusion

Back 34

because of the excessive pressure required, therefore this process is limited to aluminium and coper alloys

Front 35

a soft malleable metal is placed in a die, the metal is squeezed the squeezed metal has no where to go but to scape and extrude through a predetermined recces (crack) the squeezing former, what is this process called

Back 35

impact-extrusion

Front 36

a metal in powder form is heated 70% - 80% of its melting point. it is poured in to shaped die and then compressed, the molecules fuse together and a completer metal block with shape of the die is produces, what is this process called

Back 36

sintering

Front 37

after sintering the end product is usually 10% - 20% porous, what is the next step in order to produce a component that is self lubricating such as plain bearings, bushes etc.

Back 37

impregnating the material with graphite or (a high melting-point grease)

Front 38

what is isostatic-pressing as opposed to sintering

Back 38

somewhat similar to sintering, but isostatic requires a temperatures an a pressing pressure that is much higher than that of sintering, the result is completely porous free material

Front 39

a piece of a sheet metal formed to shape around a former that is rotating, the former is mounted on a spindle of lathe, the necessary force needed to deform the metal is generated by long tool pivoted suitably, cones, flares, and bowls are produces using this process, what is the process called.

Back 39

spinning

Front 40

after chemical milling, why peening is desirable

Back 40

the process could result a drop in fatigue strength, so peening (beating) restores the fatigue strength

Front 41

the cathode of wire is connected to the machine while the anode is connected to the work piece. a high voltage is released while pressurised electrolysis is released between the tool and the work-piece, the tool is moved towards the work-piece, the tool is eating away the work-piece, a fine components and tools are produced this way, what is this process called?

Back 41

electrochemical machining

Front 42

the tool used for electrochemical machining is conducting and functioning in a salt solution, so what features must the tool have

Back 42

good conductivity, high resistant to corrosion

Front 43

what is an electro-discharge machining

Back 43

a process where a pieces of metal is removed by spark

Front 44

why a fluid such a kerosene is fed under pressure between the electrode and the work piece

Back 44

to produce an adequate uniform resistance

Front 45

what are the advantages of electro-discharge, apart from its suitability on hard to machine materials

Back 45

produces high aspect ratio, very small holes of any cross-sectional in very hard metals

Front 46

list the seven basic techniques of conventional macininig

Back 46

1-drilling/reaming2-turning3-miling4-sawing5-shaping/planning/slotting6-broaching7-abrasive machining (grinding)