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95 Cards in this Set
- Front
- Back
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How does the addition of MANGANESE change the properties of steel?
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Increases Toughness and Hardness
Used for components subject to wear and abrasion Surface hardens with wear/cold working while core retains it's toughness |
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How does the addition of NICKEL change the properties of steel?
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Increases Toughness and Corrosion Resistance
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How does the addition of CHROMIUM change the properties of steel?
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Increases Hardness and Corrosion Resistance
Chromium oxide forms on the surface, protecting from corrosion 11% chromium or more is classed as stainless steel |
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How does the addition of COBALT change the properties of steel?
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Reduces Hardness
Increases Tensile Strength at high temperatures |
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How does the addition of MOLYBDENUM change the properties of steel?
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Increases Toughness and Hardness
Increases Creep Resistance, especially at high temperatures Increases Corrosion Resistance in stainless steels |
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How does the addition of TUNGSTEN change the properties of steel?
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Increases Hardness, especially at high temperatures
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How does the addition of VANADIUM change the properties of steel?
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Increases Hardness
Increases Creep Resistance, especially at high temperatures Increases Corrosion Resistance |
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Describe Borax
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Fluxes in brazing are based on borax
Also known as Sodium Borate A mineral that converts water (H2O) into hydrogen (H) when heated, preventing oxidization Mixed with ammonium chloride for brazing steel |
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Describe 'Deflection'
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The ability to withstand a load without flexing out of shape permanently
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Describe 'Toughness'
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The ability to withstand the impact of a blow
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Describe 'Hardness'
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The ability to withstand wear, indentation or scratching
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Describe 'Conductivity'
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The ability to pass heat or electricity through it
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Describe 'Dielectric Strength'
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The ability to insulate from electricity
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Describe 'Creep'
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The tendency to deform under stress over time
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Describe 'Metal Fatigue'
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Caused by repeated loading to the materials elastic limits
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Describe 'Tensile Strength'
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The ability to withstand being pulled apart or stretching
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Describe 'Elesticity'
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The ability to return back to it's original shape
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Describe 'Ductility'
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The property that allows material to be drawn into wire or tube
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Describe 'Malleability'
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The ability to be formed or bent into shape without fracture or failure
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Describe 'Brittleness'
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The tendency to fracture without bending or changing shape
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Describe 'Shear Strength'
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The ability to withstand offset loads
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Describe 'Compressive Strength'
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The ability to withstand squashing forces
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What are the main types of MMA electrode flux coatings?
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Class (C) - Cellulosic
Class (B) - Basic Class (R) - Rutile Class (RR) - Heavy Rutile |
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What are added to brazing filler materials and why?
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Silver - Improves fluidity and strength
Silicon - Acts as a de-oxidizer Nickel - Improves strength Manganese - Improves strength |
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What do fluxes contain that are suitable for brazing aluminium?
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Alkaline chlorides
Fluorides |
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What do fluxes contain that are suitable for brazing manganese?
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Alkaline chlorides
Fluorides |
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What do fluxes contain that are suitable for brazing silver?
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Boric acid, potassium borates, fluorides
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What do fluxes contain that are suitable for brazing high temperature ferrous metals?
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Boric acid, alkaline borates
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What do fluxes contain that are suitable for brazing iron and steel?
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Borax, ammonium chloride
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What is the difference between an element, a molecule and a compound?
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Elements are the different types of atoms (copper, hydrogen etc.)
Molecules consist of atoms made from a single chemical element (oxygen O2 etc.) Compounds consist of atoms made from different elements (Water H2O etc.) |
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What is the term for when a length of material expands due to it's temperature being raise by 1º
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Coefficient of linear expansion
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What residue is left after brazing or hard soldering with borax?
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A hard scale of copper borate
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Describe Dead Mild Steel
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Contains 0.05% - 0.15% carbon
Very ductile |
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Describe Mild Steel
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Contains 0.15 - 0.3% carbon
General purpose steel |
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Describe Medium Steel
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Contains 0.3% - 0.8% carbon
Brittle but capable of being hardened through heat treatment Cannot be cold formed |
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Describe High Carbon Steel
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Contains 0.8% - 1.4% carbon
Very brittle but very hard wearing when heat treated Also called tool steel |
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Describe Wrought Iron
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0.01% - 0.03% Carbon
More workable than cast iron Easily Welded Good corrosion resistance No longer normally produced - replaced by steel |
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Describe Cast Iron
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Contains 2% - 4% carbon
Dampens vibration Easily fractured High compressive strength but low tensile strength |
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Describe Alloy Steel
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Carbon steels that contain additional elements
Example: For bicycle frames alloy contains 10% chromium and 4% molybdenum, increasing tensile strength and stiffness |
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What is at the centre of an atom and what does it consist of?
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Nucleus, which consists of protons and neutrons
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What surrounds a nucleus?
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Electrons
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Describe annealing of aluminium
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Annealing is a softening process
The aluminium is heated to 550ºc then quenched Aluminium with less than 6% copper will remain malleable unless work hardened Aluminium with more than 6% copper will harden after 2 hrs, longer if refrigerated at -20ºc the annealed aluminium can be left to 'natural age hardening' or artificially hardened by heating to 130ºc - 200ºc |
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What simple methods can indicate correct temperature for annealing aluminium?
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soap or wood (e.g. matchstick) draws a black line on the surface, showing the material is ready for quenching
Temperature indicating crayons |
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Describe strain hardening of aluminium
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The material is cold rolled. The metals grain is elongated, reducing malleability and increasing tensile strength.
A letter 'H' and figures indicate hoe much strain hardening from soft, quarter hard, half hard, three quarter hard to hard Also called work hardening or cold working |
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Describe 1000 series Aluminium
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Pure aluminium
Soft Highly workable Good conductivity Good corrosion resistance Cannot be heat treated |
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Describe 2000 series Aluminium
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Contains copper
Used for machine parts Used as a base for more complex alloys Can be heat treated Good strength Lower corrosion resistance than other aluminium alloys |
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Describe 3000 series Aluminium
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Contains manganese
Used for pot, pans and heat exchange equipment
weldable Good ductility |
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Describe 4000 series Aluminium
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Contains silicon
High castability High strength Good corrosion resistance |
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Describe 5000 series Aluminium
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Contains magnesium
Relatively soft but quickly work hardened High tensile strength High corrosion resistance Weldable Can be heat treated Used in automobile and ship building |
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Describe 6000 series Aluminium
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Contains magnesium and silicon
High strength Corrosion resistant Can be work hardened Easily welded Suitable for anodising |
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Describe 7000 series Aluminium
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Contains zinc
Brittle High strength High rigidity Weldable Can be heat treated |
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Describe silver solder
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Tin / zinc / silver alloy
Good fluidity and strength Melting point 620ºc - 855ºc Often supplied in flat strips referred to as 'spelter' |
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How does the addition of phosphorous affect copper brazing rods
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The rod becomes self-fluxing
Essential for hard soldering of refrigeration pipework, where the presence of flux would lead to contamination and corrosion |
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What is the temperature range for borax or fluoroborate fluxes?
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Above 750ºc
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What is the temperature range for fluoride fluxes?
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Below 750ºc
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What is the temperature range for alkali halide fluxes?
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Below 580ºc
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Shielding gas is usually made up from what gases?
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Argon
Carbon Dioxide - CO2 Helium Oxygen |
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Describe Cartridge Brass
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70% Copper, 30% Zinc
Can be formed and drawn |
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Describe Admiralty Brass
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70% Copper, 29% Zinc, 1% Tin
Can be formed and drawn Has improved salt water resistance |
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Describe Free Cutting Brass
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58% Copper, 39% Zinc, 3% Lead
Not suitable for cold working Machinable Used for thread cutting |
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Describe Bronze
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Copper with 2%, 10% Tin
Suitable for casting |
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Describe Gun Metal
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88% Copper, 10% Tin, 2% Zinc
Bronze alloy Also called free cutting bronze Good for machining |
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Describe Phosphor Bronze
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89% Copper, 10% Tin, 0.25% Phosphorous
Improved fluidity when cast Used for machine bearings and marine fittings |
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Describe Martensitic Stainless Steel
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Contains 86% Iron, 12-18% Chromium, up to 1.2% Carbon, 0.5% Nickel
Can be hardened Unsuitable for welding Used for chef's knives, hard wearing shafts and spindles |
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Describe Ferritic Stainless Steel
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Contains 76% Iron, 12-30% Chromium, 0.1% Carbon, 1% Nickel
Tough and ductile Cannot be heat treated Unsuitable for welding Good corrosion resistance at high temperatures Used for furnace parts |
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Describe Austenitic Stainless Steel
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Contains around 86% Iron, 18% Chromium, 8% Nickel, up to 0.15% Carbon
Comes in a range of alloys with different properties Most commonly used Malleable Non magnetic Weldable |
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Describe Duplex Stainless Steel
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Contains around 61% Iron, 21% Chromium, 9% Nickel, 2% Magnesium, 3.5% Molybdenum
High Strength High Corrosion Resistance Called Duplex because structure consists of 50% ferrite and 50% austenite |
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What is the melting point of soft solder?
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180ºc - 250ºc
Depending on the ratio of tin to lead |
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What is an elastomer?
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An elastic polymer, such as rubber
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Describe natural rubber
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Highly elastic
Excellent vibration absorption Good creep resistance ideal for tyres |
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Describe Ethylene-propylene
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Synthetic rubber
Known as EPM Chemically inert Good electrical insulation Resistant to cracking from age Ideal for insulating power leads |
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How much carbon does steel need to contain for it to be heat treatable?
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0.3% or more
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How does heat treatment change the crystalline structure of metal?
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Structure changes from body centre cubic (ferrite) to face centre cubic (austenite)
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What are the three main groups of adhesives?
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Solvent based - air drying, natural and synthetic
Thermoplastic - temperature setting, liquifies on warming, solidifies when cooled Chemical setting - relies on chemical reaction for curing, very strong, used for structural applications |
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What was the first synthetic resin adhesive developed?
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Phenol formaldehyde
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Fluxes suitable for soldering carbon steel, brass, copper or tin contain what?
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Zinc chloride
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Fluxes suitable for tinning the soldering bit contain what?
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Ammonium chloride (sal ammoniac)
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Fluxes suitable for soldering zinc or galvanised steel contain what?
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Hydrochloric acid
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Fluxes suitable for soldering copper plated stainless steel contain what?
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Phosphoric acid
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What are the corrosive fluxes used in soldering?
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Zinc chloride - used for carbon steel, brass, copper and tin plate
Ammonium chloride - used for cleaning the bit before tinning Hydrochloric acid - used for zinc an galvanised steel Phosphoric acid - used for copper plated stainless steel |
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What are the non-crrosive fluxes used in soldering?
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Natural resin - used for electrical components
Tallow - used for lead sheet and pipes |
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What materials are spanners made from?
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High carbon steel
Alloy steel containing chromium and vanadium Beryllium bronze (non-sparking) |
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What qualities make a good filler alloy for brazing?
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Achieve good bonding
Capable of good capillary action Melts at the right temperature Good resistance to corrosion Sufficient strength for the joint Compatible with the parent material |
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What does LPG stand for?
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Liquid petroleum gas
Also called propane or butane, which make up LPG in varying ratios |
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Describe thermoplastics
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Also known as thermo-softening plastic
Softens when heated then re-hardens upon cooling |
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Describe thermosetting plastic
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Irreversibly cures through heating or chemical reaction (e.g. two part epoxy).
Once hardened they cannot return to a liquid or softened state |
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All carbon steels contain what additional elements?
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Silicon
Sulphur Manganese Phosphorous |
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What is Cementite?
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A compound of iron and carbon
Also called Iron Carbide |
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What is Pearlite?
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Alternate layers of ferrite and cementite
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How much Chromium does steel have to be classed as Stainless Steel?
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Approximately 10-12% or more
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What is this?
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Universal Beam
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What is this?
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Universal Column
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What is this?
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Parallel Flange Channel
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What is this?
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Rolled Steel Joist
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What is the formula for calculating drill speeds?
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RPM = 30,000 / 3 x drill diameter
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