Please enable JavaScript.
Coggle requires JavaScript to display documents.
transformation processes of metals - Coggle Diagram
transformation processes of metals
Shaping techniques
To make pieces for sale or for industry, the metal goes through a series of shaping processes, depending on the type of metal and what we want to make
Press forging
Punching
Forging
Bending
Extrusion
Wire drawing
Rolling
CASTING
Molten metal is poured into a container with a hollow space inside, which is the shape of the object we want to make. The mould can be made from sand, steel or cast iron.
The metal is heated in a furnace.
The liquid metal is poured into the mould.
It is left to cool down.
The piece is removed from the mould.
Marking, cutting and finishing techniques
We use hand and power tools for these techniques. We will look at marking, cutting, drilling, shaping and finishing.
MARKING
The centre punch is used to mark lines and the scriber to mark points on sheets of metal.
CUTTING
DRILLING
SHAPING
CLEANING
Scraper: This is a small metal, triangular blade with sharp edges. It's used to shave small fragments
POWER TOOLS FOR CLEANING
Finishing
Finishing involves removing surface imperfections, polishing and protecting metals from water and corrosion.
Grinding. A grinder is used to refine surfaces to precise, accurate dimensions and to remove any imperfections. We can use it on flat pieces or cylinders.
Lapping. A lapping machine has a vertical handle and abrasive discs. This is usually used for finishing openings and conical surfaces, and is very accurate.
Polishing. This technique produces a shine, using a polishing wheel with revolving, abrasive wheels or strips.
Buffing. This technique also produces a shine. A mechanical buffing wheel is used with a steel disc or roll, which can be abrasive.
Coating. This technique is used to protect the metal. The metal is coated in plastic or other metals, e.g. zinc, silver, gold, nickel or chrome. This technique is called galvanisation. Paints, varnishes and enamels can also be used
Joining
When the piece is finished and ready, we can join it to another piece by using permanent or temporary joints.
PERMANENT JOINTS
Welding and soldering is the process of joining metal together, using pressure and heat on the surface. There are several types:
Soft soldering
We use a tin-lead alloy. This is heated with an electric soldering iron, which reaches temperatures of 400°C.Uses: Join tinplate, sheets of metal, brass and electronic and electrical components.
Rivets
This is a metal tube with a head at one end. It is inserted into the openings of the pieces to be joined together and then, with a tool known as a riveter, a head is placed onto the other end, joining the pieces.
TEMPORARY JOINTS
If you use temporary joints, they can be joined and separated again without breaking the joint or damaging the pieces.
Nuts and bolts
The bolt is inserted through the pieces that need to be joined together. Washers are used so that the pieces don't break and to secure the joint.
Keyed joint
With a piece of metal called a key, you can join two objects by putting the key in a groove.