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Flashcards in engineering Deck (17)
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1
Q

forgings tend to be stronger and tougher than similarly shaped castings due to…?

A

grain flow and fibres gives forgings improved strength through preferential arrangement of the materials structure

2
Q

a brinell indentor is what shape ?

A

A brinell indentor is a ball of hardened steel or tungsten carbide

3
Q

impact tests measure a materials ?

A

impact tests measure shock resistance. Test such as izod and charpy are used.

4
Q

the izod test measures what?

A

izod is an impact test

5
Q

as the amount of cold work increases the recrystallisation temperture ?

A

the recrystallisation temperture decreases as the amount of cold working increases

6
Q

select the process involving deformation

a-rolling, forging,extrusion

b-forging,casting,extrusion

c-grinding spinninng welding

d-machining,drawing,powder metallurgy

A

a-is the only answer combination where all three processes involve deformation

7
Q

identify two methods of controlling a motors speed externally and internally

A

externally- gearing and pulley control

internally- varying voltages or changing connections to various windings

8
Q

what is normalising ?

A

normalising is a heat process for ferrous alloys involving heating the material above the upper critical temperature then cooling in still air, the objective being to enhance toughness by refining grain structure

9
Q

what is forging ?

A

compressive forces causing plastic deformation resulting in improved strength due to preferential grain flow or fibre

10
Q

what is pascals principle

A

stated as follows: pressure applied anywhere on a confined fluid is transmitted undiminished in every direction

11
Q

what is extrusion ?

A

a forming technique whereby a material is forced by compression through a die orifice

12
Q

what is hardness ?

A

hardness is the measure of a materials resistance to deformation by surface indentation or abrasion

13
Q

what is casting ?

A

A term referring to a liquid (molten metal) is poured into a shaped mould cavity where it solidifies; this method is used to produce complex components with properties difficult to achieve otherwise

14
Q

outline the steps involved in production of powder metallurgy parts

A

1-perparation and blending of powders

2-pressing of powders in prepared dies

3-sintering of compacted material below its melting points

15
Q

given a machanical advantage of 6 for a simple machine the velocity ratio will always be ?

A

greater or equal to 6 dependent on the efficiency

16
Q

what is a semiconductor ?

A

a substance whoses electrical conductivity is intermediate between that of a metal and insulator

17
Q
A