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.
These are techniques used to change the shape of the piece of metal by applying an external force. It can be done when the metal is hot or at room temperature.
The unprocessed metal is passed through a series of rollers that compress it, reduce its thickness and increase its length. It's usually done when the metal is hot.
Uses: Sheets, plates, bars ...
The heated metal is pushed through a hole by a piston, using compression.
Uses: Bars, tubes and other shapes.
The metal piece is shaped by repeated and continuous compression forces using hammers, tongs and anvils.
Manual forging has been replaced by industrial or mechanical forging. The piece is placed on a platform that acts as an anvil. Using a pneumatic or hydraulic machine, the hammer rises and falls onto the piece again and again. Forging is usually carried out when the piece is hot.
Uses: Railings, bed headboards, horseshoes, keys, tools, nails, screws, rivets, engine pieces ...
The heated metal is placed between two dies, one fixed and the other mobile. The dies are the shape of the object we want to make. They are pressed together so that the piece takes the shape of the die.
Uses: Car body parts, radiators ...
This is a cold forging process: a sheet of metal is hit with a punch to make the required shape in a mould.
Uses: Hollow pieces, such as bearings, from flat pieces.
Bending
A metal sheet is subjected to force to make a curved shape with a specific curve radius.
Uses: Curved pieces or with angles.
A wire is pulled through a hole that has the required dimensions. A rotating drum is used to pull it through the hole to increase its length while reducing its diameter.
Uses: Metal strings and wires.
Shaping processes produce pieces for sale and for industry.
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.
Uses: Engine blocks, fire hydrants, small parts and alloys with low melting points, ornaments, jewellery, sculptures and dental implants.
Activity 19
Why do metal pieces sold for construction have so many different shapes (round, square, I-shaped, H-shaped)?
Activity 20
Look for information about the era when this picture was painted. What metal are they forging? What tools did they have back then?
Activity 21
Of all the shaping techniques you have read about, which one do you think is used to make drinks cans?
Activity 22
Which shaping techniques are used to make these objects?
