Question 2
(a) State the purpose of each of the following heat treatment processes:
(i) Tempering; (ii) Normalizing.
(b) (i) What is a ferrous metal? (ii) List two types of steel used in auto body construction.
(c) State two differences between oxygen and acetylene cylinders used in gas welding.
Observation
The Candidates did well on this question number. However, some of the candidates could not satisfactorily answer the questions asked in 2(b)(ii) and (c).
Solution
(b) (ii) Two Types of Steel Used in Auto Body Construction
- Carbon steel;
- Alloy steel;
- Cold-forming steel;
- Free-cutting steel;
- Spring steel;
- Rust-resistant steel;
- Stainless steel.
(c) Two Differences between Oxygen and Acetylene Gas Cylinders
- Oxygen cylinders are painted black or blue while acetylene cylinders are painted maroon or red.
- While the valves of oxygen gas cylinders are right threaded, those acetylene gas cylinders are left threaded.
- Oxygen gas cylinders have smaller diameters.
- Oxygen gas cylinders are longer.
- The hose of oxygen cylinder is painted black, while that of acetylene cylinder is painted red.