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...cast shape...The powder forging process in diagram outline: 1. Pre-alloyed powders (180–325 µm) are accurately metered into die cavity (±2g) and compacted into preform shape to 80–85% density. [Diagrams to demonstrate 'Powder forging/Hot pressing' - see article ] 2. Preforms are heated to forging temperature in a controlled atmosphere (N2/10%H2) either in...

...sand, sand just like … MARCUS BADGER: … some sort. So, what are they? ANNE JAY: We’re going to go on a journey of discovery, digging out the geology of the world around us. And, whilst we do that, we are going to find out some amazing things about the Earth. MARCUS BADGER: Everything around us that hasn’t been grown either relies on or contains material that had...

...cast synthetic resins, zinc-based alloys or reinforced concrete. At low pressures, a light lubricating oil is applied to the block by brush or spray. At high pressures, HP grease is smeared on the tool. Stretch-wrapping consists of first stretching the sheet beyond its yield point while it is still straight, and then wrapping it around a form block. In one type of...

...cast iron cylinder liners. Cladding There are two methods of cladding (welding) a metal to a substrate; powder fusion (pre-placed or blown) and vapour deposition. Cladding rates depend on laser power and thickness. Uniform layers of cladding are produced by overlapping single clad tracks. Cladding rates can be increased by 50% by using a hemispherical reflector to recycle...

...sand? What’s it made from, and how does it get from where it’s made to the beaches and sand dunes that surround many of our shores? On this album, Dr Dave McGarvie of The Open University takes us on a visit to Cornwall to follow grains of sand on their journey from the high moorland to the sea shore. Back in the lab, he demonstrates some techniques for looking in...

...aluminium alloys copper alloys titanium alloys nickel-based alloys With hot rolling it is easier to deform difficult-to-work metals than with cold rolling. Cast ingot structures, at heavy deformations and at temperatures where recrystallisation occurs, promote recrystallisation. Control of the sheet temperature can produce fine-grained structures. Design: Shaped rolling...

...Cast irons are welded with nickel-rich or monel electrodes (Ni - Cu). Most non-ferrous metals and alloys are welded with electrodes of a composition similar to the metal being welded. Aluminium alloy electrodes are coated with fluxes consisting of mixtures of fluorides and chlorides to dissolve the aluminium oxide Al2O3 surface layer. The precipitation hardening Al-Mg-Si...

...Cast irons can be phosphated (if surface is clean). Aluminium, magnesium, zinc and cadmium can be chromate conversion coated: 100,000 tons per year of aluminium is chromate treated as an intermediate coating and on painted or lacquered strip. Spray-applied PTFE coatings (XYLAN XL™) have good marine corrosion protection and low coefficients of friction. Design: Phosphate...