Chapter 1 Materials

Question 1

What is the content of carbon in Steel?

Answer 1

Between 0-2%

Question 2

Describe the carbon percentage of steel and the various uses.

Answer 2

Low Carbon Steel – Composition of 0.05%-0.25% carbon and up to 0.4% manganese. Also known as mild steel, it is a low-cost material that is easy to shape. While not as hard as higher-carbon steels, carburizing can increase its surface hardness.
Medium Carbon Steel – Composition of 0.29%-0.54% carbon, with 0.60%-1.65% manganese. Medium carbon steel is ductile and strong, with long-wearing properties.
High Carbon Steel – Composition of 0.55%-0.95% carbon, with 0.30%-0.90% manganese. It is very strong and holds shape memory well, making it ideal for springs and wire.
Very High Carbon Steel - Composition of 0.96%-2.1% carbon. Its high carbon content makes it an extremely strong material. Due to its brittleness, this grade requires special handling.

Question 3

Elements that raise the transition temperature?

Answer 3

Carbon, silicon, phosphorus and sulphur

Question 4

Elements that lower the transition temperature

Answer 4

Nickel and manganese

Question 5

Elements that also effect the transition temperature

Answer 5

Grain size- smaller the grain size the lower the transition temperature

Work hardening -increases transition temperature

Notches- weld defect/machine marks etc. Increase tendency to brittle fracture