WJEC Vocational Award Engineering Level 1/2

WJEC Vocational Award Engineering Level 1/2 Oxy-acetylene gas welding Filler wire Steel workpiece Steel workpiece Gas valve Gas valve Oxy-acetylene torch Two pieces of steel being permanently joined using the oxy-acetylene gas welding process. Oxy-acetylene gas welding is most commonly used to fabricate (shape/join) steel. It uses a mixture of oxygen and acetylene gases to produce an extremely hot flame (approximately 3,500° Celsius) to melt metals. The flame is so hot the steel turns into molten pools of metal. The hot steel from the filler wire and workpiece mix together and then join to form a single piece. A filler wire is also used to ‘fill’, which is also turned into molten metal. Pop riveting C B A Rivet Mandrel Rivet body Workpieces Mandrel Rivet head A Measure the diameter of the RIVET BODY, drill the correct sized hole in workpieces that need to be joined and insert a RIVET. B Place a RIVET GUN over the mandrel and squeeze the handle as many times as needed to extract the MANDREL from the RIVET BODY. C The workpieces should now be firmly clamped between the RIVET HEAD and the deformed end of the RIVET BODY, and the MANDREL can now be discarded. Shaping materials The following series of processes involves ‘shaping’materials into usable forms. When shaping metals, it is worth noting that after each ‘forming’ process the end product still has to be finished. Forging Forging is a process of joining and/or shaping metals by using force to bond workpieces together and change the form into a desired shape. The most common image people have of forging is a blacksmith using a hammer and anvil to shape heated metal. When metal is heated it becomes more malleable and is easier to shape. If the metal is hot enough it can also be bonded with the use of force (molten metal pools together to create a weld in the welding process). Malleable: pliable, easy to shape without breaking or cracking. Key term Mandrel: a cylindrical rod around which material is forged or shaped. Key term 122