Material Selection and Testing
- Mechanical Drive Shaft - A suitable material would be medium carbon steel.
- Electrical Socket - Suitable materials for this would be, brass cable terminals, plastic, and mild steel screws.
- Welded Pressure Vessel - A suitable material would be manganese steel.
- Medium carbon steel - A drive shaft is required to be strong, tough, have high fatigue resistance and a high surface hardness, at least at splines and bearing surfaces. Therefore a medium carbon steel of 0.4% carbon for improved fatigue resistance would be suitable. The steel would be heat treated by normalising to give a fine grain-sized structure throughout and then the areas needing to be of high hardness selectively hardened by flame or induction hardening.
- Brass cable terminals/Plastic/Mild steel - An electrical socket has to be hard and rigid as well as aesthetically pleasing to the eye in a domestic installation.
A thermoset (plastic) will possess suitable properties and a UF resin (urea-formaldehyde) can be made with a light or white colour. The preferred forming process for a thermoset of this type is transfer moulding although compression moulding could also be used. Brass has good thermal and electrical conductivity and is markedly superior in this respect to ferrous alloys, nickel-based alloys and titanium. Therefore its high conductivity combined with its high corrosion resistance makes it ideal for cable terminals. Mild steel screws are ideal for their low cost, reasonable strength and ductility. Due to low levels of carbon they do not respond to heat treatments.
- Manganese metal - There is a natural desire to employ materials of high strength and satisfactory fracture toughness for pressure vessels, this makes manganese metal ideal for this type of use. This type of metal has 1.5% manganese added which...