Metals Flashcards

Question

Duralumin uses

Answer 1

Aircraft parts Vehicle parts

Answer 2

Corrosion resistant Good conductivity Low melting point (930 degrees) Casts well

Answer 3

Boat fittings Door furniture Taps Ornaments

Answer 4

To alter the metals properties via heating and cooling its grain structure

Answer 5

Hardening Tempering Case hardening Annealing Normalising

Answer 6

High and medium carbon steel is heated to a temp above recrystallisation. It is then held here for a given time to create a consistent temp. Then it is rapidly cooled in water, oil, air or salt water.

Answer 7

Increased hardness so products resists wear and fracture on surface Does not change core properties

Answer 8

Typically follows a hardening process. Metal is heated to a temp just below critical temp for a certain time depending on the steel. It is then slowly air cooled. Temperature controls the reduction in hardness (higher the temp, more hardness removed).

Answer 9

Increased machinability Reduces brittleness as well as hardness Increases ductility and toughness

Answer 10

Case hardening hardens the surface of steels. Performed by carburising or quenching.

Answer 11

Case hardening process which changes chemical composition of surface of low carbon steel so it can absorb more carbon, increasing surface hardness. Steel place in ceramic box packed with carbon Heated to 940 degrees Carbon atoms diffuse into materials structure Depth of carbon layer determined by time in box Product is heated to around 760 degrees and quenched.

Answer 12

Only metals with lower melting point like cast iron or steel. Relieves stress from work hardened metal. Heated to high temp where internal stresses are relieved Heated above recrystallisation temperature but below melting point New grains formed and cooling allows them to develop

Answer 13

Easier to work Less brittle More ductile

Answer 14

Ability to be deformed and then return to original shape when force removed

Answer 15

Ability to be permanently deformed and retain deformed shape

Answer 16

Ability to withstand deformation by compression without cracking. It increases with temperature

Answer 17

Ability to be drawn out under tension, reducing the cross-sectional area without cracking (eg stretching a material into a wire)

Answer 18

Ability to resist abrasive wear such as scratching, surface indentation or cutting

Answer 19

ability to absorb impact without fracture

Answer 20

Ability to withstand general wear over a period of time

Answer 21

Ability to naturally decompose by actions of bacteria or other living organisms

Answer 22

Allows flow of electricity Provides little resistance to flow of charge

Answer 23

Does not allow flow of charge

Answer 24

Allows transfer of heat energy through material Better conductors allow heat to transfer faster

Answer 25

Prevents heat energy transfer

Answer 26

Bending Compressive Tensile Shear Torsional

Answer 27

Ability to resist stretching or pulling forces

Answer 28

Ability to resist slinging forces on parallel plane

Answer 29

Ability to resist rotational forces from applied torque of tension

Answer 30

Ability to resist forces that may bend the material

Answer 31

Ability to withstand being crushed or shortened by pushing force

Answer 32

Sand Investment Low/high pressure die casting

Answer 33

The process- 1. A wax pattern is created (can be done in the form of a tree) from a master mould made from steel or aluminium 2. This is then dipped into the refractory clay slurry 3. This is fired in a kiln to bake the clay hard 4. Once final coat has hardened the wax is burned out 5. Molten mould then poured into cavity and solidified 6. Refractory mould then broken including the runner and any connecting channels

Answer 34

Great surface finish Intricate shapes can be made Wax can be reused Strength of products

Answer 35

Time consuming waiting for coast to harden Expensive start up cost Complex machinery Difficult to make parts with hollow centre

Answer 36

Collectible figures Jewellery Construction

Answer 37

The process- 1.Place the mould pattern (wood) (made using CAD) into a steel box called a ‘drag’ 2. Packs and around the pattern and level it 3. Flip the drag over and and a second box called the ‘cope’ is clamped on top 4. Two sprue pins are then placed into the cope to create the runner and the riser 5. Pack sand into the cope around the sprue pins and other half of pattern 6. Separate the cope from the drag and remove the pattern and sprue pins. This should leave a cavity and channels. Cut connecting channels into the sand to connect the channels to the cavity and then connect cope and drag again 7. Pour molten metal through runner until the riser is filling telling us the cavity is full 8. Allow to cool and then remove the sand and cut off the runner and riser using a hacksaw.

Answer 38

Be used for any quantity of products (affordability) Relatively cheap Use high melting point metals unlike die casting Sand can be reused

Answer 39

Rough surface finish due to grainy sand Labour intensive Less accurate than other methods Moulds require constant checking and changing Moulds are one use

Answer 40

Wood working clamps Motor housings Drain covers Post box

Answer 41

1. Die split in half and each side heated to high temperature to prevent metal cooling to quickly. A lubricant is also applied to maintain this temp 2. Two half’s clamped together tightly using high pressure. 3. Molten metal poured in and gravity pulls it down into the entire mould. Metal poured into runner and the riser tells us when it is full 4. It is then left to cool and solidify fur a sufficient tie before removing the mould 5. Ejector pins remove the cast from the machine 6. Gates, runners, sprues and flash are all removed to creat finished product

Answer 42

Non ferrous metals due to lower melting point as most moulds are made from tool steel. If ferrous were used they would deform the mould as melting points are too similar

Answer 43

Tongs and other PPE are used for safety Metal heated until cherry red Dipped into carbon powder Once soaked the process repeats Metal then reheated and quenched in water to rapidly cool

Answer 44

Slow as reliant on gravity Create a low volume as a results of this Very expensive to setup so only really used for mass produced items or large batches

Answer 45

Creates parts with thinner sections than sand casting but thicker than pressure die casting Produces parts with excellent mechanical properties suitable for heat treatment Less machinery than pressure die casting Relatively smooth surface finish Less porosity than pressure as no turbulence

Answer 46

1. Molten metal stored in chamber or crucible. 2. A pneumatic/hydraulic plunger forces a shot of the metal into the mould The high pressure forces the mould to fill allowing fine details to be moulded 3. Once the metal has solidified ejector pins remove the mould from the cavity 4.

Answer 47

Fast process enabling high volumes to be produced Can be automated as no need for runners and risers Fine details can be moulded Can make thin walled parts

Answer 48

Expensive to set up Turbulence from high pressure can cause porosity in components Expensive dies

Answer 49

Tool steel

Answer 50

Alloy wheels Toy cars Door knobs Handles

Answer 51

Uses plaster of Paris instead of sand and can only use non-ferrous metals

Answer 52

Steel placed in ceramic box packed with carbon Heated to 950 degrees Carbon diffuses into steel building up surface content of carbon Depth of layer determined by time (longer exposure means thicker layer) Quenched to cool

Answer 53

Hot metal quenched in water to cool it rapidly and seal hard surface case without affecting inner properties

Metals Flashcards

(79 cards)