Worksheet 202 new

RSNF Technical Institute of Naval Studies AS_001 / AS2 / LP001 – New Wo Item (Identify Item; e.g. word, Definition (Define and/or Example (Id term, phrase, abbreviation) describe Item) Materials Items such as compounds Typical raw m and elements, wood, glass, nickel, titaniu Materials Science Maritime environment metals, ceramics and Extruded plastics, that are used to Microbial attack build, make or create a product The design and discovery A computer c of new materials, materials sc particularly solid materials processed an To live and operate on and The sailor’s m he serves on around ships and associated maritime craft, on and near the seas and oceans Where a material (e.g. a When we sq metal) is forced through a and its shape shaping die in order to make something of a specific shape The process of corrosion of The microbe a material (e.g. metal) by other materia the actions of a microbe over time. Version 2.0 / H016340-AS_001-AS2-LP001-New-Words-and-Terms-Handout.docx

ords and Terms - Handout dentify example use of term) materials used to make steel are manganese, chromium, copper, um, tungsten etc. chip is the result of many years of research and experimentation by cience engineers and scientists; different materials have been nd tested in order to make smaller, faster computer components. maritime environment consists of the dockyard, his ship or boat that n, and the sea that the ship or boat sails on. queeze a toothpaste tube, the toothpaste inside the tube is extruded e is the same as the nozzle of the tube. es present in the sea can have a negative effect on some metals and als, which can lead to them corroding or otherwise becoming unusable Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / Lesson 2 – Activity (Choosing Materia Everything made, must be made from some sort of material. The choice of mate properties of the material. Once these and other questions have been answered Complete the table below, to describe the common engineering metals: Material Colour Composition Properties and Melting Point Copper Low- carbon steel (Mild steel) Medium- carbon Steel Version 2.0 / H016340-AS_001-AS2-LP002-Activity.docx

als) erial is very important. In order to make this choice you need to know the d, you will be able to choose a suitable material. Uses Common Forms Date 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / LP002 – New Wo Item (Identify Item; e.g. word, Definition (Define and/or Example (Id term, phrase, abbreviation) describe Item) Acrylic Made from a type of acid or “The jumpers Alkali a resin (chemically “The artist pr Anneal produced sticky substance) which is used in making Anodized plastic, cloth, and paint. Anvil A substance that has the Caustic soda opposite effect or chemical Salts. behaviour to an acid. Make metal soft by heating Copper, silve and then cooling it slowly. water, unlike In this fashio shaping, stam To cover a metal with a “The rotor pl layer of oxide by using an flat plate disk electric current. A heavy block of iron on Small anvils which heated pieces of be found in i metal are made into a particular shape with a “The blacksm hammer. Version 2.0 / H016340-AS_001-AS2-LP002-New-Words-and-Terms-Handout.docx

ords and Terms - Handout dentify example use of term) s in the shop were all made from a mixture of acrylic and wool”. referred to use acrylic paints for his work”. a, and caustic potash, and Limewater are a few examples of Alkali er and brass can be cooled slowly in air, or quickly by quenching in e ferrous metals, such as steel, which must be cooled slowly to anneal. on, the metal is softened and prepared for further work such as mping, or forming. late was modified - to accept four 25mm diameter anodized, parallel, ks”. are found in a blacksmith’s workshop and much larger versions can industrial foundries. mith hammered out the shape of the horse shoe on the anvil.” Date: 22/01/2020

RSNF Technical Institute of Naval Studies Billet Large blocks or cylinders of “The overhea metal ready for further further proce processing. Brittle Delicate and easily broken. “As you get o Busbar Composite A metallic strip or bar, Busbars are Counterweight typically housed inside outgoing sup Decorative switchboards for local high voltage equip Die current power distribution. Diverse A material made up of Carbon fibre more than one substance “The small fa that is used for building things. A weight that is as heavy Large weigh as something else, so that balance the the two objects can balance. Made to look good. “The clock h A shaped piece or mould Dies are use (hollow container) made of plastic. metal or other hard material, used to shape or put a pattern on metal or plastic Varied or different “There is a d Version 2.0 / H016340-AS_001-AS2-LP002-New-Words-and-Terms-Handout.docx

ad crane lifted the steel billet and moved it to the furnace opening for essing”. older your bones become increasingly brittle”. used in electrical panel boards to connect the incoming supply to the pply in distribution systems. Also used to connect high voltage and low pment together. e, Kevlar, Glass reinforced plastic. ast patrol boat was made from Glass Reinforced Plastic (GRP)”. ht or set of weights, (for example at the base of a crane), used to load being carried. has a decorative enamel face and finely carved legs”. ed to create the pattern of extruded materials such as aluminium and diverse range of opinion on the issue”. Date: 22/01/2020

RSNF Technical Institute of Naval Studies Ductile A ductile metal can be bent Copper, alum Extrusion and stretched easily. The most ductile Malleable opposite of brittle. Molecule Polymer To form something by Extruded alu forcing or pushing it out, Reiterate especially through a small “Squeezing a Tempering opening. nozzle”. A malleable substance is Gold, lead an easily changed into a new shape. An electrically neutral Oxygen (O2) group of two or more Water (H2O) atoms held together by chemical bonds. A large molecule, made up Natural – e.g of many repeated sub- Synthetic – e units. There are two classes of polymer. Natural and synthetic. To say something again, “He reiterate once or several times. A process of heating and “Very hard to cooling metal, which is tempered at used to increase the toughness of iron-based alloys. Version 2.0 / H016340-AS_001-AS2-LP002-New-Words-and-Terms-Handout.docx

minium and steel are ductile to varying degrees, but platinum is the metal. uminium or plastic rods which may be formed into complex shapes. a toothpaste tube causes the toothpaste to be extruded through the nd tin are malleable metals. ) – two atoms of Oxygen. ) – two atoms of Hydrogen and one atom of Oxygen. g. wool, silk, rubber, hemp, amber. e.g. polyethylene, polypropylene, polystyrene, neoprene, nylon. ed that five o’clock was time to finish work for the day”. ools are often tempered at low temperatures, while springs are much higher temperatures”. Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / Lesson 3 - Activity (Material Propertie Everything made, must be made from some sort of material. The c you need to know the properties of the material. Once these and o a suitable material. Think back to your previous lessons to recall th Complete the table below, to describe the common engineering m Material Properties High-carbon Steel Cast iron Stainless Steel Version 2.0 / H016340-AS_001-AS2-LP003-Activity.docx

es) choice of material is very important. In order to make this choice other questions have been answered, you will be able to choose he common forms of supply. metals: Uses Common Forms Date 22/01/2020

RSNF Technical Institute of Naval Studies New Words and Terms - Handout Item (Identify Item; e.g. word, Definition (Define and/or Example (Ide term, phrase, abbreviation) describe Item) Conductivity The degree (or amount) to “Glass and rubb which a particular material conducts electricity (or heat or conductivity w sound) because they h Version 2.0 / H016340-AS_001-AS2-LP003-New-Words-and-Terms-Handout.docx

entify example use of term) ber offer good protection from electric shock because they have poor whereas metals such as copper and gold are used for electrical wiring have very good conductivity properties”. Date: 22/01/2020

RSNF Technical Institute of Naval Studies Corrosion The slow destruction of “The salt water materials due to chemical reaction with its environment Version 2.0 / H016340-AS_001-AS2-LP003-New-Words-and-Terms-Handout.docx

had caused a lot of corrosion to the metal” Date: 22/01/2020

RSNF Technical Institute of Naval Studies Density How compact or concentrated “The steel rod h something is rod, which has a Often materials with a higher “Density can be density will be heavier than less dense materials Version 2.0 / H016340-AS_001-AS2-LP003-New-Words-and-Terms-Handout.docx

had a very high density, which is why it was so much heavier than the plastic a much lower density, making it much lighter”. e calculated using the formula: mass (m) divided by volume (v). Date: 22/01/2020

RSNF Technical Institute of Naval Studies Galvanised The result of the galvanising “The metal mop process on metals, used to protect from rust and corrosion Insulation The ability of a material to “The plastic coa reduce or prevent the transfer of heat or cold between preventing the t objects (sometimes referred to person!” as thermal insulation). There are other forms of insulation such as sound and electrical insulation. Magnetism The action associated with “The effects of m magnets and magnetic fields where particles are either use of magnets attracted or repelled according to whether they are positively of mobile phone or negatively charged in computers”. Version 2.0 / H016340-AS_001-AS2-LP003-New-Words-and-Terms-Handout.docx

p bucket had a galvanised finish to make it last longer” ating on electrical copper wires provides insulation of the copper wires inside, transfer of the electrical current to something less well insulated, such as a magnetism are in use all around us: fridge doors are kept closed through the s; it is used in speakers in the earphones that you use with your music player e and in the speakers in televisions. It is also used in the discs that store data Date: 22/01/2020

RSNF Technical Institute of Naval Studies Polycarbonate A tough and stable clear “The riot policem Polyethylene/Polypropylene plastic, offering high levels of light transmission, incredible but very strong strength and incredibly light in crowd”. weight Type of plastic material. Polyethylene is Polyethylene is also known as polythene Polypropylene cars, ropes etc. Version 2.0 / H016340-AS_001-AS2-LP003-New-Words-and-Terms-Handout.docx

man’s riot shield was made of polycarbonate, which gave him a lightweight means of self-protection from rocks and other missiles being thrown by the s typically used to make packaging, bags and plastic films (e.g. cling film) etc. e tends to be more rigid and is typically used to make bottles, hinges, parts for . Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / LP004 – New Wo Item (Identify Item; e.g. word, Definition (Define and/or Example (Ide term, phrase, abbreviation) describe Item) Dissolving To cause a substance (such “When he add as salt, or sugar) to break that it could no Oxidise/Oxidised up into smaller particles so Electrolysis that they seem to have disappeared when the substance is mixed with another substance (such as water) The chemical reaction of a “The old car h substance (such as metal) bodywork was with oxygen A process where (a DC) “The manufac electrical energy is used to produce a chemical change in a substance Version 2.0 / H016340-AS_001-AS2-LP004-New-Words-and-Terms-Handout.docx

ords and Terms - Handout entify example use of term) ded sugar to his tea and stirred it with a spoon, the sugar dissolved so o longer be seen, but it could be tasted in the tea”. had been left standing out in all weathers for so long that much of the s covered with rust, where it had oxidised”. cturing plant used electrolysis to obtain pure aluminium metal” Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / Lesson 5 - Activity (Material Properties Working in your groups and in the areas as defined by your Instructor, locate and note their location and what they are used for. Colour Appearance Copper Mild steel Aluminium Cast Iron Ceramic Lead Stainless steel Version 2.0 / H016340-AS_001-AS2-LP005-Activity.docx

s and their identification) identify the metals listed in the table. Examine their material properties and Texture Location Use Date 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / LP005 – New Wo Item (Identify Item; e.g. word, Definition (Define and/or Example (Ide term, phrase, abbreviation) describe Item) Anisotropic A material’s properties vary For example, w with orientation; a physical property that has a different value when measured in different directions Thermoplastics Thermoplastics can be cooled Thermoplastics and heated several times component that without any change in their chemistry or mechanical properties. When thermoplastics are heated to their melting point, they melt to a liquid. Version 2.0 / H016340-AS_001-AS2-LP005-New-Words-and-Terms-Handout.docx

ords and Terms - Handout entify example use of term) wood is stronger along the grain than across it. s can be heated and then injected into a specially shaped mould to create a t is exactly the right shape. Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / LP006 – New Item (Identify Item; e.g. word, Definition (Define Exam term, phrase, abbreviation) and/or describe Item) Abrasion A scraped spot or area The w Brittle Easily damaged or Instea destroyed Coarse Rough or harsh in The b texture Denser Component parts In ge compacted together Equivalent Equal in value A tex Lattice A structure of crossed The a metal strips usually arranged to form a diagonal pattern with open spaces between the strips Quench To cool suddenly by The h plunging into liquid Residue Something that remains There after a part is removed Version 2.0 / H016340-AS_001-AS2-LP006-New-Words-and-Terms-Handout.docx

Words and Terms - Handout mple (Identify example use of term) wound was clean, but the abrasion looked painful ad of being strong, bones can become weak and brittle beach had rough coarse sand eneral metals are denser than non-metals xt message is the modern day equivalent of a telegram apple pie had a lattice top to it. hot metal rod was quenched in the water e was a sticky residue left on his skin after the plaster was removed Date: 22/01/2020

RSNF Technical Institute of Naval Studies Structure The arrangement A gro Susceptible between parts of The p elements Affected by a particular thing Version 2.0 / H016340-AS_001-AS2-LP006-New-Words-and-Terms-Handout.docx

owth in the body can affect the size and structure of other body parts patient with liver disease was susceptible to infection Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 /AS2 / Consolidation1-Activity-A (Word Search) DCE L AS T I C I T YGL T T B L QNA AS Y YOV U OX B H X S I HMKN F N K K I P S T T X R FWMQX U C P Q N EM I D D E DGS Y OD GR Y T I L I B A E L L AMO R E L B E M U X T DOS T GE VRVRUAGTP BMN NRG VER U S S K I I I MZ HQMSCGUC E SHOMU T C I E U Y VWM T G X C R T N J L X N I J S V M T ON Z X A I GNEWE Z P I T O E GP T QB V I NDG K Z N T T V E OX Y T C S Q F CWY QA L R R E A E P C C P B B U I L S I MWO U V T R I E A S R O K EWU Z QR L E S A T X L S B P K T SHT DCO FQADB TEMC L T YON F RH Y I SG F J J D P E G NMRH Y G X P U Z WA L Z S RM L XG Z S J I OO I X D F M L R V R Z S Y T RS S EN F F I T SNC J V E R NF X CKW Z ACE QQHC T Z E AYUGNV P SA Z PRH UN F L E X I B L E BOUB J I L S BUQ T L J X T A K N U T L P I Z C P V N U YWMB B C J X F Q QN F K M A L A I T I E C G L WWK X Z J V K P F I WK O I K OX VOMEWC I T F D D R S AQ Z I OU T I HCHUGHRDCM KDN F N F H Y C J P Y E I F L N UPQMR X U Y U H R J H OWC X T I P N Q X P S R F VWC N I G K L DM Z AV J VDQRYA T LNAU J S V PPK REP ABSORBENT FLEXIBLE BRITTLENESS HARDNESS COLOUR MACHINABILITY CONDUCTIVITY MALLEABILITY CORRISIONRESISTANT MELTINGPOINT CREEP PLASTICITY DENSITY STIFFNESS DUCTILITY STRENGTH ELASTICITY TOUGHNESS Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-A.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / Consolidation 1 – Activity-B (Consolidation Cards Part 1) Consolidation Cards – Common Materials used in Engineering How to use them The consolidation cards have been developed to help you to summarise some of the main points of knowledge and understanding after covering the theory for each unit. The cards can be used prior to the sample question papers or after the papers to refresh your memory prior to summative (final) tests. The cards are also helpful as you progress with the qualification to help maintain the knowledge. Remember if you do not understand the main points, you need to learn more in-depth knowledge. The consolidation cards only cover some of the main points and you are advised to refer to worksheets, handouts and activity assignments, and your own notes for more information as well as using textbooks. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Metals The majority of metals are extracted (this means removed or taken out) from metal- ores. An ore can be any kind of rock or mineral from which metal can be extracted. Metals are not usually used in their pure form; they are normally mixed with other metals to improve their properties. This type of mixing is called ‘alloying’ Ferrous Metals – contain iron Non Ferrous Metals – Do not contain Examples iron Examples Steels Aluminium Stainless Steels Copper Carbon Steels Brass Cast Irons Titanium Iron Mild Steel All ferrous metals are magnetic. Stainless Steels Stainless steels are highly resistant to corrosion and used where contact with water is expected. They are expensive compared to ‘plain’ steels. Examples are tools like screwdrivers, razor blades, galley and kitchen equipment Cast Iron It is tough and absorbs impact very well; however it is also brittle and has low ductility. This means it cannot be stretched or bent far before it will break, usually with a loud rupture, and once broken it is very difficult (or impossible) to repair. Examples are manhole covers, vice bodies, motors, valves. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Aluminium Pure Aluminium is soft, ductile (can be stretched easily), highly corrosion resistant (except to seawater) and is highly conductive of heat and electricity (but not as good as copper). Pure aluminium metal is much too soft for most uses. Examples are engine components, drink cans, aircraft parts, boats. Copper Copper is soft, malleable (easily worked), ductile (easily stretched) and has a very high thermal conductivity and high electrical conductivity. Copper does not react with water, but does slowly react with oxygen. Aside from gold and silver, it has the highest electrical conductivity. Examples are water pipes, electrical wires, heat sinks and thermal conductors. Plastics The term plastic covers a wide range of materials with a wide range of properties mainly with the pre-fix Poly, for example: Polyethylene (PE), Polyvinylchloride (PVC), Polypropylene (PP), Polystyrene (PS), Nylon. Generally they are light, malleable and can be extruded and moulded into intricate shapes. Plastic can be used for Toys, windows, PVC electrical conduit, nylon ropes, adhesives, modular bathroom units for ships. Composites Composites include reinforced plastics, such as fibre-reinforced polymers, fibreglass, Kevlar, GRP, carbon fibre UK English (or carbon fiber – USA English). Examples are Kevlar, armour, small marine craft, cables Rubbers Natural, Vulcanized, Synthetic Examples are Latex gloves, tyres, rubbers hoses, erasers. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Forms of Materials Bar and Rod Hot or cold-rolled. Flat, Round, square, hexagonal. Most ferrous and non-ferrous metals in bar or rod form. Plastics, rubbers, metals supplied via extrusion to achieve correct shape and size. Plastics not normally cold-extruded as it leaves them too brittle. Bars or rods used for components. Plates and Sheets Coiled strip passed through rollers to flatten. Many shapes and sizes and can be corrugated. Most ferrous and non-ferrous metals can be supplied in plates and sheets. Plastics, rubbers, metals. Materials supplied in this form via a rolling method. Pipes and Tubes Small bore pipes and tubes can be made from most materials. Used to supply a wide range of metals, alloys and plastics. Plastic pipes and tubes can be supplied self-coloured. Flexible pipes and tubes, usually called hoses, are made from polymers. Castings Made from most metals or alloys and made from plastics. Castings can be made in a wide range of sizes. Can be cast into complex shapes. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Forgings An item is made by heating metal in a fire or furnace and hammering it. Metals commonly forged: Carbon steel, alloyed steel, stainless steel, titanium, aluminium and copper. Plastics are not ‘forged’ in the same way, but can be heated and shaped. Extrusions Metals, plastics and rubbers supplied in this form. Hot extrusion is where the base material is heated up then drawn through shaped dies until the correct shape and size are achieved. Cold extrusion is where the base material is not heated up. It is drawn through shaped dies until the correct shape and size are achieved. Plastics are not normally cold-extruded as it leaves them too brittle. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 / AS2 / Consolidation 1 – Activity-B (Consolidation Cards Part 2) Properties of Materials Density Compares the amount of matter of an object to its volume. Density = mass divided by volume List of materials in order of density: Low density materials Platinum Low density polyethylene Gold Nylon Lead Acrylic Copper Polycarbonate Brass PVC Steel / iron / stainless steel Carbon fibre Cast iron Aluminium If all the material was in 1kg blocks, Platinum would be the smallest and the low density Polyethylene block would be the largest in size appearance. Colour Material can be recognised by its colour. Cast Iron - Dark grey Steel – Stainless Steel - Silver grey Copper - Reddish brown Brass and Bronze - Reddish yellow Aluminium - Light grey Plastics and Composites - Self coloured (can be supplied in any colour) Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Properties of Materials Electrical Conductivity The ability to allow electricity to move through the material. Good conductors: Gold, Lead, Mercury, Tin, Silver, Copper, Iron, Aluminium, Titanium Materials that do not conduct electricity are called insulators: Glass, Plastics, Rubber, Air, Wood and some composites. Heat Conductivity The ability to allow heat to flow through the material. Metals have good heat conductivity: Copper, Aluminium, Brass, Steel and Bronze. Materials that do not have good heat conductivity are called heat insulators: Woods, Plastics, Rubbers and some composites. Insulation Thermal insulation is the reduction of heat transfer. Electrical insulation is reducing objects with high resistance to prevent electricity from going where it isn’t wanted. Used for coating wires or supports used to attach electric power supply lines to utility poles for example. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Properties of Materials Magnetism Invisible force or field caused by certain materials. Electrons normally spin in random different directions. In magnets electrons spin in the same direction. Any pure material can be magnetised. Enough ferrite added to an object can make it magnetised – even glass If a magnet is used to pick up small metal objects these become magnetised – this is called ‘Induced Magnetism’ Most metals are magnetic. Aluminium, Copper, Lead, Tin, Titanium, Zinc, Brass and Bronze are not magnetic. Plastics, rubbers and most composites are not magnetic. Corrosion Resistance Ability of material to resist chemicals, especially water and oxygen (rusting). Any material with a galvanised or zinc coated is resistant (galvanised steel) Plastics, rubbers and composites are all resistant to corrosion. Metals and alloys not containing iron do not rust (Gold, aluminium, copper, brass and bronze). Stainless steel – highly resistant but rusts slowly. Iron, low and mild carbon steel and cast iron all have a low resistance to corrosion. Seawater is highly corrosive. Surprisingly aluminium corrodes more quickly in seawater. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Physical Properties of Materials Melting Point The point a material changes from a solid to a liquid. Metals have a higher melting points than rubbers or plastics and composites. Stainless Steel - 1510°C Brass - 900°C Wrought Iron - 1482°C Aluminium - 660°C Carbon Steel - 1424°C Polycarbonate - 275°C Iron and Steel - 1149°C Rubber - 260°C Cast Iron - 1127°C Polyethylene - 150°C Copper - 1084°C Heat Treatments Annealing Soften steels that have already been hardened. Heated then cooled in the furnace or by burying it in ashes or lime. Makes the metal very soft and ductile. Prepares metal for flow-forming such as sheet metal pressing and drawing (as in wire or tube) Normalising Heated then cooled down in free air. Slow cooling process, not as slow as annealing. Metal is less soft and ductile. Prepares metal for machining. Quench hardening Heated then cooled down very rapidly in cold water or cold oil. Cooling process is rapid so metal is made very hard. Only used on medium-carbon and high-carbon steels. Tempering Quench hardened steels are brittle as well as hard. Reheating to a set temperature between 200 and 300°C and re-quenching makes the metal slightly less hard but very much tougher. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Physical Properties of Materials Environmental Considerations – Common Effects Metals corrode quicker in sea water due to salt. Rubbers, plastics and wood not as badly affected. Makes them a good choice for fittings on marine craft due to ability to withstand elements. Water makes iron oxidise (rust) faster. Combination of moisture, oxygen and salt damages metal more than just rusting. It eats away at the metal. Salt water corrodes metal five times faster than fresh water. Marine 316 grade stainless alloys usually contain a substance used in strengthening and hardening steel. This serves to resist the corrosive effects of seawater. Electrochemical Corrosion Salt water is a very good conductor of electricity, so electrolysis takes place which corrodes metal quicker. If iron was in contact aluminium and both were in contact with salt water you get a battery which drives very fast corrosion processes. Effect reversed by using ‘sacrificial anodes’. These are made of a metal (like zinc) which causes the current to be reversed and so the zinc corrodes rapidly instead of the iron. Bacteria Bacteria in ocean water eat iron and their excretions turn to rust. Biofouling begins with a thin film made of bacteria or micro-organisms. The film forms a slime which provides a base for seaweed and larger marine organisms. Slime leads to marine organisms (algae, shells and barnacles will colonise it). This leads to roughness below the waterline giving a braking effect on the ship and reducing fuel consumption. Special coatings prevent this growth along with regular cleaning. Copper and nickel alloys have the highest natural resistance of all the metals. Steel, titanium and aluminium (especially with heat exchangers) foul quickly. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Mechanical Properties of Materials Toughness How much a material can withstand an impact load. A tough material can also be soft. A nail is very tough but can bend quite easily. Aluminium is tough but soft. The opposite of tough is brittle (such as glasses and porcelain). Steel is used for car bodies as it absorbs the energy from an impact because it is touch and strong. Hardness Hardness is how well a material can resist an exterior force or abrasion, such as being scratched. If you rub two materials together, the harder material will mark the softer material. The opposite of hard is soft. The order of hardness of materials is: Diamond Carbides Steels / Stainless steel Cast irons Copper Acrylic Brass Aluminium Copper Lead. Most hard materials are brittle. Diamond is one of the hardest materials and can be used to cut metal, however it is brittle. Some soft materials would include: Most plastics Rubbers Wood Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Mechanical Properties of Materials Elasticity The ability of a material to change shape under load and then return to its original size and shape when the load is removed. All materials have elasticity. Materials like cast iron will stretch very little before it ruptures. The opposite of elasticity is rigidity. When the elastic limit is reached a material enters the plastic region. This means it will not return to its original size or shape once the force is removed. If it carries on it will go beyond its plastic ability and reach its failure point where it will snap. Ductility When a material stretches plastically under tension past its elastic limit. In other words it stays in the same shape. A ball and a rock were dropped from a great height, the rock would break whereas the ball would bounce. Metals are highly ductile for example this how they can be drawn out into very thin wire such as copper. The opposite of ductile is brittle. In order of ductility: Gold, Silver, Aluminium, Copper, Steel. Tensile Strength A measure of the ability of a material to withstand a stretching load without breaking. Materials with a high tensile strength have a low elasticity: Steels, Copper and its alloys, Aluminium, Glass, Kevlar, Cast iron. Materials with a low tensile strength have high elasticity such as rubber and most plastics. Malleability Ability of a material to be worked / deform in a plastic manner without breaking when compressed or the ability for a material to be hit hard without shattering. Malleable material may be flattened into thin sheets by hammering or rolling. Most metals are malleable. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Modifying Properties of Materials Cold Working Most metals in their solid state are crystalline. Metals are denser than non-metals due to the tightly packed crystal lattice pattern of the metallic structure. Cold working is plastic deformation of metal carried out at a temperature below the recrystallization temperature. Recrystallization is a process where deformed grains of the metals crystal structure are replaced by a new set of stress-free grains that grow until all original grains have been consumed. The smaller the individual crystal grains, the harder the metal becomes. In most cases cold forming is done at room temperature. Examples of steel being cold rolled are: Squeezing; Cold Working; Completed Rolled Steel. Hardening Brass is harder than copper as it has zinc added. To make a metal harder another metal is added, usually carbon. To make aluminium harder we add copper. Metal can also be hardened by heating until cherry red then quickly quenching the metal in water. This is a rapid way to cool the metal to room temperature after heat treatment and prevents the metals micro-structure from changing which would happen if it cooled slowly. A hardened material will not wear over time, but it is more brittle and has more chance of breaking during use. Tempering Carried out after the hardening process to reduce some of the excess hardness. Done by heating the metal to a temperature below the critical point. Held at this temperature for a fixed time depending on the metal, then allowed to cool slowly in the air. The exact temperature determines the amount of hardness removed. Very hard machining tools are tempered at low temperature whereas springs are tempered to much higher temperatures. This gives greater toughness and ductility by decreasing the hardness, but also increases the brittleness. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies Modifying Properties of Materials Annealing A metal is heated then allowed to cool slowly to remove internal stresses, toughen it and increase ductility. Forms new grains in a cold-worked metal. New grains are joined together better than those in the cold worked metal. Change returns the metal to its pre-cold worked state with lower strength and increased ductility. Final grain depends on the annealing temperature and annealing time. Metal with large grains has lower strength but is more ductile than metal of the same alloy with smaller grains. Normalising The metal is heated to a temperature roughly equivalent to its hardening temperature. Starts the formation of lots of austenitic grain boundaries. Material is then cooled forming ferrite grains. This gives the metal properties that can be predicted, such as its physical properties, how it corrodes and how the properties will act when used for machining. Normalising permits the refinement of a metals grain size and improves the metals mechanical properties. Normalising gives steel more uniform and finer grained structure. The normalised structure is finer than if the material was annealed. Version 2.0 / H016340-AS_001-AS2-Consolidation1-Activity-B.docx Date: 22/01/2020

RSNF Technical Institute of Naval Studies AS_001 /AS2 / Consolidation1 (Activity-C) Activity-C – Material Properties Table On the results table cadets are given the names of common properties of engineering materials. Cadets must give a suitable definition of each property. The first property has been completed for you as an example. Cadets should work alone on this activity This activity should take 30 mins. Property Title Definition of Property Strength Ability to support heavy loads Brittleness Dielectric Strength (Insulation) Conductivity Hardness Ductility Malleability Elasticity Toughness Plasticity Version 2.0 / H016340-AS_001-AS2-Consolidation-Activity-C.docx Date: 22/01/2020