Lesson Notes By Weeks and Term v4 - SHS 2
WELDING TECHNOLOGY
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WELDING TECHNOLOGY
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Subject: Applied Technology
Class: SHS 2
Term: 1st Term
Week: 13
Grade code: 2.2.2.LI.2
Strand code: 2
Sub-strand code: 2
Content standard code: 2.2.2.CS.1
Indicator code: 2.2.2.LI.2
Theme: METAL TECHNOLOGY
Subtheme: WELDING TECHNOLOGY
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Welcome, learners. Today, we are exploring three fundamental ways we shape metal: Forging, Rolling, and Extrusion. While our sub-strand is Welding Technology, these processes are crucial because they are often how metal parts are made *before* they are joined by welding. Think about the metal gates on our houses, the roofing sheets on our buildings, or the aluminium frames for our windows. None of these start in their final shape. They begin as blocks or slabs of metal and are forced into new shapes without melting them.
These three processes are known as metal forming processes. They work by applying immense force to a piece of metal to cause plastic deformation—changing its shape permanently without breaking it. Most of these processes are done when the metal is hot to make it softer and easier to shape.
A. FORGING
Definition: Forging is the process of shaping metal by heating it and then applying compressive forces, usually with a hammer or a press. Analogy: Think of a local blacksmith heating a piece of metal in a fire until it glows red, then hammering it on an anvil to make a hoe or a cutlass. That is forging.
Principle: When metal is heated, its atoms can move more easily. The force from the hammer or press forces the atoms into a new arrangement, changing the metal's shape. This process also refines the internal grain structure of the metal, making it very strong and tough.