Task 1 i) To makethe point of a centre punch hard angle tough the tool will need to go through twodifferent heat treatment processes.
The first heat treatment called “hardening”uses heat at really high temperatures to increase the material hardness. The secondtreatment called “tempering” is a heat treatment process used to increasetoughness and remove excess hardness given by previous hardening process. Thecomplete process for both treatments is divided in 4 phases:Hardening· 1st phase: The punch isslowly and uniformly heated at first. Then all the heat is concentrated on thetip. This will then gradually become red hot· 2ndphase: After arriving the red-hot stage the punch will be cooled by dippinginto water Colour of the metal per temperatureTempering· 3rd phase: A methylacetylene propidine flame is then used to heat the tip just below the critical point of the material for a certain period.As the heat is concentrated in the tip slowly a blue line of heat will appear nearit. The brazing torch will then be turned off when the blue line reaches thetip · 4thphase: The tempered punch will be allowed to slowly cool in the air temperatures and the associatedcolours required when temperingii) Thehardening of process of a mild-steel clamp jaw is a thermochemical process inwhich alloying metals like carbon or nitrogen are diffused in the surface ofthe clamp jaw and result in a solid solution much harder than the original thatimproves its wear resistance without dropping its toughness. The process isdived in four stages:· 1ststage: the clamp jaw is heated until becomes red hot.
· 2nd stage: Usingblacksmiths the steel is removed from the brazing hearth and plunged into acase hardening compound rich in carbon allowing it to cool. · 3rdstage: stage 1 is repeated but when removed the clamp jaw is plunged into coldwater · 4thstage: Mow the clamp jaw has a hardened outer surface but a flexible and softinterioriii) Otherheat treatment techniques include 2nd stage differential hardening, flame hardening and inductionhardening.· In differential hardening differentareas of a single object receive different heat treatment s. This technique iscommonly used in the production of knives and swords. The process uses layers, usually made ofclay, to cover the area of the material that need to remain soft, instead thoseparts the need hardening is left exposed, allowing during quenching, thehardening of only those parts of the material.· Flame hardening can concur and differfrom differential hardening.
Similarly, in flame hardening only a portion of ametal is hardened. However, unlike differential hardening, whir the entire bodyis heated and then made cold at different rates, only a part is heated beforethe quenching. This is a lot easier to carry out than differential hardening,however, it usually produces brittle zone between the unheated and heatedparts.· Task 2Powder coatingPowdercoating of metal wheels is type of coating that is apply as a free-flowing, dryingpowder by spraying it in the surface of the wheel. This application is used toachieve a hard finish tougher that conventional painting. The full process ofpowder coating includes three stages, the part preparation of equipment, the powderapplication processes and the curing:· Pre-treatment of equipment are used to remove oil, lubrication greases, dirt, metal oxide etc.
from the wheel. Thisachieved through different types of pre-treatments methods but in theautomotive industry chemicals pre-treatments are the more popular. Chemical pre-treatmentimplies the wheel to be submerged in a phosphates solution through differentstages that include degreasing, desmutting, etching, and several rinses. Thiswill lead to the phosphating of the wheel. This pre-treatment process bothimproves bonding of the powder to the wheel and cleans it from all impurities.
Another pre-treatment process includes normalizing which is often used even beforethe chemical pre-treatment. Normalizing is a type of heat treatment used torelieve from stress the post-machined wheel; this will also improve itsductility and toughness. The operation will warm the car wheel just above itsupper critical point (usually 50ºC above). The car wheel is held enough timetime to ley small metal grains to firm and high energy grain to combinethemselves.
After this operation the car wheel is air-cooled to normalise its thermalreading to room temperature. Normalizing temperature vary between 810ºC to 930ºC · Powder application processes implies the spaying of the powder onto the wheel usingelectrostatic or corona gun. The gun imparts a positive electric charge to the powder, which is then sprayed towards the wheel throughcompressed air spraying. The wheel is then heated, until the powder melts andproduces a uniform film. It is then cooled to form a hard coating. · Curing; When a thermoset powder reaches hightemperatures, it begins flow out and melt, it will them chemically react toform a higher molecular weightpolymer in a network-like structure (a much stronger structure. To achieve thisthe post-coated wheel will be exposed to temperature between 200 ºC for about 10-15 minutes to reachfull cure and establish the full film properties.Anodizing aluminiumcook pansAluminium cookware is usually anodized to increase its corrosionresistance, adhesion allow dyeing and improve its lubrication.
When exposed toair at room temperature aluminium reacts by forming a layer of amorphous aluminiumoxide 2 to 3 nm thick that provide effective protection toward corrosion. Theanodizing process consist of multiple step process:· Cleaning – This part removes all the fabrication oilsfound in the aluminium pan by soaking it into a H2O-based solution thatcontains mild acids, dispersants and detergents · Pre-treatment is used as decorative process toimprove the surface of the pan prior to anodizing. Common pre-treatmentsmethods include bright dip, which impart a bright, shiny finish and etch, which imparts a satin, mattefinish· Anodizing,which is the main operation that produces the actual coating. The procedure isthe following, a direct current of 15 to 21 V is passed through the pan actingas a positive electrode while the pan is completely submerged in a bath ofwater and sulfuric acid that acts as the electrolyte.
The water will then break down liberating oxygen fromthe surface of the pan this will the combine with the aluminium of the pan andcreate the coating. The coating is a microscopic transparent layer of aluminiumoxide (thickness 0.5 micrometres)· Integral colouring – imparts to the pan a colour of choice (usually brass, bronze and black) as it isbeing formed in the anodizing bath properly modified for that purpose. Exceptimparting colour to the pan, this process will allow also provide a betterresistant coating than normal anodizing· Sealing – in this process the pores on thesurface of the pan will be closed as unsealed pores could lead to poorcorrosion resistance or the assimilation of unwanted stainsMaking of aPan Calphalon Task 3Shaped car panel blanking and formingThe material used in car panel is carbon steel a very strongalloy using a blank machine the shaped needed is cut off into a flat shaped thea stamping press which is a forming machine will that forces the sheet of metalin the desired shape, that was designed for both aerodynamic and strength.Surface protecting treatment include: stampingpress· Rustproofing, in which the car body is protected using s a special chemicalformulation typically phosphate conversion coating. This can prevent or delay therusting of the carbon steel· Colourpainting, although it is used primarily to give the panel a good visual alsogive an extra layer of protection for the carbon steel.
After application the wheelis then heated, until the painting melts and produces a uniform film. It isthen cooled to form a hard coatingMedal blankingMedals manufacturingare divided into 10 stages· Designstage in this stage the medals are design and customized for the purpose needed,it is usually done on sketch or digital platforms · Sculptingstage in this process will provide three-dimensional depth and texture toplaster cast sculpt used in the building of the coining die. · Diesphase in this part of the process two hardened steel will both engrave andstrike the metal material onto the chosen design on top of the medal· Custom medal melt phase, in this phase the metals used for creationof the medallion are melted down, poured into billets and then pressed intolong and soft annealed metal strips· Extruding phase, the metal strips heated in billet ovens at 1000 degrees. After thisprocedure they are then extruded, this makes the billets turn into thin strips andready for the rolling phase· Rolling phase the thin strips are allowed cooling downand each one is trimmed before arriving the trolling phase.
This is the phase thespecific thickness of the metal is calibrated, this happens by letting the stripinto a rolling machine that uses hydraulic power to flatten it into the precisethickness needed· Blanking phase each properly flattened strip is sentto a blank press that punches out metal discs. Each one of them is then preppedand claned before arriving the strike phase· Polish phase Using a solution of soap and watereach blank is polished using ball bearings· StrikeMinting Phase This part of the process uses a minting press that strikes everyblank with the custom-made dies. When the dies strike each blank it leaves adetailed impression on either side the sum of all the strike will give life to theimagery designed.