metals Flashcards
what are six wasting processes of metals?
-Milling
-Turning
-Flamecutting
-Plasma cutting
-Laser cutting
-Punching and stamping
How does milling work?
-work to be machined is clamped onto table of machine
-can be run in XY or Z direction to cut slots, shaped edges, or thread holes
what are four milling types called
-face milling
-end mills
-fly cutter
-slot cutter
What is turning carried out on?
A centre lathe
How does turning work?
A bar can be held in rotating truck and machines to reduce diameter and to face off end, thread and drill
-material is machined by cutting tools held in tool post- can be moved in and out along bar
What is the two types of turning carried out on?
-CNC lathe
-manually
what does turning using CAD allow
-complex and accurate shapes to be repeated quickly and efficiently
How does flamecutting work?
-it uses Oxy acetylene, gas and flame, cutting torch to deliver intense and focused flame above 3500° C
-It has an additional jet of oxygen to intensify the flame
What’s the disadvantage of flamecutting?
It’s difficult to maintain parallel line with high levels of tolerance
what is the excess material created by flamecutting called?
dros material
what is flamecutting used to cut?
low carbon and alloy steel plate
What is plasma in plasma cutting?
-Superheated, ionised gas that is electrically conductive
How does a plasma cutter work?
plasma cutter will use conductive gas to transfer the energy from the power supply to a conductive material such as a steel plate. It’s heated by plasma to 28,000° C which burns and blows the material away. The cut is fast and clean.
what is laser cutting used for?
Used in industry for precision cutting metals
where does lasercutting get its power from?
Laserbeam thats directed through optics
what does a laser head contain on a laser cutter?
A lens that focuses the laser into a fine beam for cutting and engraving, giving a very fine tolerance of less than 1 mm
What are the advantages and disadvantages of laser cutting?
it’s accurate and uses less energy than plasma cutting. However it can’t cut very thick material. It’s typically used to cut flat sheet material
What is punching and stamping
it uses computer controlled machines that stamps out sections of sheet material by using a sharing action on sheet of metal place between upper tool (punch) and lower tool (die)
what is punching and stamping usually used for?
-Small and medium size production
-And processing metals from 0.5 mm to 6 mm thickness
what are seven types of turning?
-Facing
-Drilling
-knurling
-Taper turning
-parallel turning
-parting
what are five metal forming methods?
-Press forming and spinning
-cupping and deep drawing
-Forging and deep forging
-Casting
what is a stock form and products produced in press forming?
SF: sheet
Products: metal sheets, car body panels, and boxes
what are key features of press forming?
-shapes sheet metal into 3-D forms
-often uses robotics for lifting sheets
-Mass/large scale batch production
What is the stock form used for spinning and the products it produces?
SF: sheet
Products : Body of kettle, saucepans, and metal light shades
Key features of spinning
-Product may show parallel lines, where sheet has been forced onto mandrel
-Mass/small batch production
what is the stock form and products produced using cupping and deep drawing?
SF: sheet
Product : tube like shapes, like fire, extinguisher and drinks cans
what are key features of cupping and deep drawing?
-Starts with metal blank
-Metal is stretched into shape
-High initial tooling cost
-Large scale mass/continuous production
what is a stock form and products produced using drop forging?
SF: billet
Product : spanners and pliers
what are key features of drop forging?
-used for products that need to be tough/hard
-Maintains internal grain structure, which retains strength
-Hot metal billet shaped on anvil/die then pressed into shape and cooled
-Suitable for mass production
what is the stock form and product produced using wrought iron forging?
sf: bar
Products : decorative metal work like gate scrolls and fencing
what are key features of wrought iron forging
-uses wrought iron which has a carbon content of 0.08%
-Hand/hydraulic press
-One off/small batch production
bending stock form and products produced?
sf: sheet/plate
Product : seams on metal edges
Key features of bending
-Doesn’t include punching/trimming of metal
-Can be carried out in school workshop
-Large scale batch in industry
stock form and products of rolling?
sf: billet
Product : hot rolling- angle bar, beam railway tracks
Cold rolling -filing cabinets, chairs and drums
what are key features of rolling?
-hot rolling results in uniform, mechanical properties, with no deformation or stresses
-surface coated with carbon deposits, which must be removed using acid pickling
-Cold, rolling results in a material that has hire tolerance and better surface finish
What is a stock form and products produced using sandcasting?
sf: molten metal from billet
Products : railway carriage, wheels, vices, and postboxes
what are key features of sandcasting?
-Labour intensive process
-Not a high-quality surface finish
-Suitable for one off/small batch production
stock form and products produced using gravity diecasting
sf: molten metal from billet
products: Alloy wheels, engine components and doorhandles
Key features of gravity diecasting?
-Low melting point, metals like aluminium and zinc based alloys are used
-Relies on gravity to help metal flow into mould
-Used for thicker mould sections
-Large batch/mass production
stock forms and products produced using pressure diecasting
sf: molten metal from billet
products: toy cars, collectible figures and door handles
Key features of pressure diecasting
-Intricate detail designs
-Low, melting point metal such as aluminium and zinc based alloys
-molten metal stored in a chamber, then shot of molten metal is forced into die
-fast process
-Large batch/mass production
what is a key feature Of a pressure diecasting in a cold chamber
-Molten metal labelled into shot chamber, and hydraulically pushed into chamber
what is stock forms and products produced in investment casting
sf: molten metal from billet
Product : cast jewelry, hip replacement joints
Key features of investment casting?
-used for intricate/awkward shapes that would be difficult/ impossible to mould using any other casting process
-High-quality excellent finish
-Wax patterns are cast from master mould
-Repeatable and high-quality
what are the 7 joining methods of metals
-riveting
-brazing
-hard + soft soldering
-oxy-acetylene
-spot welding
-MIG welding
-TIG welding
what does MIG welding stand for
metal inert gas
what does TIG stand for
tungsten inert gas
what’s MIG welding used to weld
-thin gauge metals like aluminium and steel
how does MIG welding work
-wire electrode melts in ark and fills gap between metals
-Welding torch is gently swelled to form a bead of weld
-The electrode wire is stored on a real and is fed
-Inert gas shield the area being joined to prevent oxidisation in the weld
What type of of production is MIG welding used for?
one off
What type of inert gas is used in MIG welding?
CO2 or argon
What does MIG welding use?
a consumable wire electrode
what is MIG welding Used to make?
Bike frames and climbing frames
what is TIG welding Used to weld
-Stainless steel and aluminium and copper alloys
how does TIG welding differ from MIG welding?
it’s an electric arc welding process but electrode made out of tungsten doesn’t melt in the process of filler is added separately
what does TIG welding gas shield use?
-Argon or helium
what does TIG welding give greater control of?
Where the world is going, meaning increased accuracy, so the joint will be stronger
What products does TIG welding used to make?
Stainless steel ladders for boats
what is spot welding used to weld?
Mild steel sheet metals at the point along in length without using a filler
What does spot welding need to access on the metals for it to work?
Both ends of the metal
what is the sheet held between in spot welding?
Two copper electrodes that form a world when charged electrodes make contact with metal
what two things are applied to the area in spot welding
Heat and pressure
What are the advantages of spotwelding? and a disadvantage
it’s fast needs no filler and low skill. However, it only works on a thin gauge
what is oxy-acetylene welding used to weld
Mild steel sheet, tube or plate
what does oxy-acetylene use
a steel filler rod
what does oxy-acetylene welding mix
Two high-pressure gases forming an intense flame, which can then be adjusted by changing gas and oxygen, enabling flamecutting, welding or brazing
what is Oxy acetylene welding Useful for?
Quick repair jobs in remote locations where there’s no electric power supply
what does soft soldering use?
-Uses low melting point metals(solder) to join metals
-a filler material of a lower melting point than the metal being formed typically tin or lead
what does hard soldering use?
-Higher temperatures to join precious metals
what must be applied to the metal in hard soldering
A flux must be applied to prevent metals oxidising. It also allows solder to flow.
what is brazing?
it used a lower temperature than welding, so suitable to join in gauge mild steel tubes or bars
-used to join dissimilar metals
What does brazing use?
-a brazing rod that melts around 850° C so isn’t strong
-Uses Oxy acetylene, gas or compressed air brazing hearth
what production is brazing used for
one off / small batch
what is riveting
-semi permanent joint, used to join a sheet or plate
-rivets are metal fasteners that have a head at one end and a shaft or tail at the other
-It uses two pieces are overlapped and drilled, and the end of the shaft is hammered over to join
What is pop riveting?
A quick and easier joint to use, but not as strong
-Uses a pop rivet gun
what is pop riveting good for?
Where the underside of a joint is inaccessible
what is pop riveting used in?
Used in aircraft production to join sheet aluminium to structural parts
what are three temporary joining methods
Self tapping screws
Machine screws
Nuts and bolts
how do you self tapping screws work?
They cut their own thread as they are screwed into sheet metal and some plastics, but a pilot hole is drilled first
what are machine screws?
used to join thicker metals, such as inspection covers on motor or gear housing
-Define thread goes the whole length of the shaft
what needs to be drilled in order for machine screws to work
for the top part to be joined a large clearance so will have to be drilled longer than the bolt thread. The bolt goes through this and is screwed into a threaded hole in the second piece and is often tightened with a spanner.
how does a nut and bolt work?
Goes all the way through both pieces, and then the nut is tightened to hold both pieces in place
what are five types of nut and bolt?
-cheese head
-Counter sink
-Round head
-Hex head bolt
-Socket head
what are the five stock forms of metal?
-Sheet
-Plate
-Bar
-Tube form
-structural angular
what is coppers ore
chalcopyrite
what is aluminium ore
bauxite
what’s tins ore
cassiterite
what’s zincs ore
zinc blende
what is a ferrous metal?
A metal containing mainly iron and carbon
what’s a non-ferrous metal
Metal that doesn’t contain any iron
what is an alloy?
A metal made from two or more metals or one metal and one non-metal
What are seven non-ferrous metals
-aluminium
-Copper
-Zinc
-Gold
-Silver
-Titanium
-Tin
what are the properties and characteristics of aluminium?
Lightweight
Ductile
Malleable
Corrosion resistant
Electrical/thermal conductor
Can be MIG/TIG welded
what is the uses of aluminium?
Drinks cans
Aircraft bodies
Window frames
Bike frames
What are the properties/characteristics of copper?
ductile
Malleable
Tough
Corrosion resistant
Good electrical/thermal conductor
Can be soldered/brazed
what are the uses of copper?
Electrical wiring
Printed electrical circuits
Water pipes
Central heating pipes
what are the properties/characteristics of zinc?
Low melting point
Good corrosion resistance
What are the uses of zinc?
buckets
Farm gates
what are the properties/characteristics of gold?
Malleable
Ductile
Corrosion resistance
Can be soldered
What is gold uses?
jewellery
Electronic components
Connectors
what are the properties/characteristics of titanium?
Hard
Similar strength to steel but more lightweight
High corrosion resistance
what is titanium uses?
Hip replacements
Joint replacements
Golf clubs
what are the properties/characteristics of tin?
Ductile
Malleable
Low melting point
Corrosion resistance
what are the uses of tin?
Soft solder
Coatings for food cans
Rarely used in pure form
What is silver properties/characteristics?
malleable
Ductile
Corrosion resistant
Can be soldered
what is silver used for?
Jewellery
Cutlery
Platings of other metals
what are six ferrous metals
-Low carbon steel
-Medium carbon steel
-Cast iron
-Stainless steel
-High-speed steel
-die steel
what are the properties/characteristics of low carbon steel?
Ductile
High tensile strength
Tough
Malleable
poor corrosion resistance
what are the uses of low carbon steel?
nuts
bolts
washers
screws
car bodies
what are the properties/characteristics of medium carbon steel?
Harder than low carbon steel
Less ductile
Malleable
Tough
What is the carbon content in medium carbon steel?
0.3 to 0.7%
what are the uses of of medium carbon steel?
Springs
Gardening tools, like trowels and forks
what are the properties/characteristics of cast iron?
Hard outer skin, but brittle core
good Under pressure
what is a carbon content in cast iron?
3.5%
what are the uses of cast iron?
Disc brakes
Machine parts
Engine blocks
what are the uses of stainless steel?
Sinks
Kitchenware
Cutlery
what are the properties/characteristics of stainless steel?
Tough
Hard
Corrosion resistance
what is the composition of stainless steel?
18% chrome
8% nickel
what are the properties/characteristics of high-speed steel?
Hard
Tough
High level of resistance to frictional heat
what is the composition of high-speed steel?
18% tungsten
4% chromium
1% vanadium
0.5-0.8% carbon
what are the properties/characteristics of die steel
hard
tough
what are the uses of die steel
-blanking punches/dies
-extruder dies
-fine press tools
what are the properties/characteristics of bronze
tough
corrosion resistant
can be cast
what is the metal composition of bronze
-90% copper
-10% tin
what are the uses of bronze
statues
coins
bearings
what are the properties/characteristics of brass
corrosion resistant
Good electrical/thermal conductors
Low melting point
Casts well
what is the metal composition of brass?
65% copper, 35% zinc
What are the uses of brass?
boat fitting
Door furniture
Cast valves and taps
Ornaments
what are the properties/characteristics of duralium
equivalent strength to mild steel, but more lightweight
Ductile
Becomes harder as its worked
what is a composition of duralium
aluminium with 4%, copper, 1% magnesium and manganese
uses of duralium
aircraft parts
vehicle parts
what are the properties/characteristics of pewter
malleable
Low melting point
Casts well
What is the metal composition of pewter?
85 to 99% tin and the rest is copper and antimony
what are the uses of pewter?
Flasks
Goblets
Photo frames
Sport trophies
What are mechanical properties?
Characteristics a material displays when subjected to an external force
five examples of mechanical properties
-Hardness
-Toughness
-Malleability
-Elasticity
-Tensile strength
What are physical properties?
measurable characteristics a material displays
seven examples of physical characteristics
Density
Melting point
Thermal conductivity
Electrical conductivity
Resistance to corrosion
Ability to take finishes
Ability to be alloyed and joined with heat
what are five different types of metal strength?
Compressive
Tensile
Bending
torsional
Shear
what is case hardening
Used to harden outer layer of steel while maintaining a soft core
-Used for steel with a low-carbon content
What is normalising metals?
form of annealing for Ferris metals, which has a faster according
what is annealing
Application of heat to relieve internal stresses, making the metal more malleable and easier to work with
What is hardening metals?
heating, medium or high carbon steels to a given temperature
-Then rapidly called via quenching and then heating a set temperature to remove excess hardness
what is tempering metals?
Used to reduce brittleness and increase toughness after metal has been hardened
temperature judged by colour of oxide layer
-colour is reached the piece of metal is air cooled
What are three hardness tests for metals
Rockwell
Brinell
vickers
How is it a Rockwell test carried out?
-preload is applied to material sample, using a diamond indenter which breaks through the surface of material
-Additional loaders applied to test material and held for predetermined length of time
-Load is released
-Distance between preload and applied load is measured
why is diamond used in rockwell test
Diamond is used as it won’t deform under load
how does a brinell test work?
-Harden standard size steel ball is forced into material surface using a preset load
-Diameter of indent in surface is measured
how is the Vickers pyramid test carried out?
-Uses a diamond square based pyramid to indent surface of material
-Microscope used to measure the size of indent
-Used for very hard materials
