Metal Finishing Techniques

Metal Finishing

• The purpose of metal finishing is to clean, polish, and enhance the surface of metals in both functional and visual aspects.
• It is the final touch of the manufacturing process, ensuring environmental protection and heightened aesthetic appeal.
• Popular metal finishing techniques include electroplating, anodizing, powder coating, hot blackening, brushing, sandblasting, and buff polishing.

Ferrous Metals

• Definition: Metals containing iron and exhibiting magnetic properties.
• Characteristics: Prone to rust, requiring protective finishes to prevent corrosion.
• Examples and applications:
  • Cast Iron: brittle if thin, strong compressive strength, good electrical and thermal conductivity. Used for gates, manhole covers, drains, and vices.
  • High Carbon Steel (Tool Steel): hard and brittle, less malleable than mild steel. Good electrical and thermal conductor. Used for tools, screwdrivers, and chisels.
  • Low Carbon Steel or Mild Steel: ductile and tough, easy to shape, braze, and weld. Good conductor of heat and electricity. Popular for nuts and bolts, screws, bicycle frames, and car parts.

Non-Ferrous Metals

• Definition: Metals that do not contain iron and are not magnetic.
• Characteristics: Do not rust.
• Examples and applications:
  • Aluminium: lightweight, malleable, and strong. Good conductor of heat and electricity. Used in drinks cans, cycle frames, and saucepans.
  • Copper: very malleable, excellent conductor of electricity and heat. Used in plumbing and central heating applications.
  • Silver: precious metal used in jewelry. Soft and malleable when hot, highly corrosion-resistant, and a good conductor.

Alloys

• Brass: strong, ductile, and a good conductor of heat. Used for taps, door fittings, hinges, locks, and musical instruments.
• Bronze: hard and corrosion-resistant. Used for bearings, outdoor components, and nautical applications.
• Stainless Steel: shiny silver when polished, hard and tough. Resistant to stains and corrosion. Used in kitchen sinks, cutlery, hospital equipment, architecture, aerospace, and transport.

Properties of Metals

• Hardness: a metal's ability to withstand friction and abrasion.
• Toughness: how well a metal can resist fracturing when force is applied.
• Elasticity: the rate at which a metal distorts in size and shape under stress.
• Conductivity: how well a metal allows electricity or heat to flow through it.
• Ductility: the ability of the metal to be drawn or deformed without fracture.
• Tensile strength: the amount of load a metal can withstand before failure.
• Malleability: the metal's ability to be bent or shaped easily.