MCG 1100 Lecture Notes - Lecture 1: Injection Moulding, Die Casting, Work Hardening

• School: University of Ottawa
• Department: Mechanical Engineering
• Course: MCG 1100
• Professor: William Hallett

Document Summary

Vary in strength and hardness depending on composition and heat treatment. Has coating of zinc since steel corrodes easily. Allow of iron with lots of nickel and chromium. Light (density 2. 6 vs steel 7. 8 and brass 8. 4 g/cm3) Used for wear resistance in gears and bearings. Found in rough cast parts where it looks like steel. Want materials to be hard/strong for design, but want soft for manufacturing. Elastic deformation: material returns to shape and deformation is small. Plastic deformation: permanent changes in shape and deformation is big. 3 methods for making soft metals harder: alloying, cold working. Alloy is mix of pure metals (steel, brass) Alloying makes things stiffer and harder to deform: cold working. Hardening a metal by extensive plastic deformation, causing internal structure to change. Ex: copper rod soft wire easier to deform, hard-drawn rod harder. When copper strip repeatedly bent, it gets harder: heat treatment.