Question 5
(a) State one reason each why the following heat treatment processes are carried
out on metals.
i. Normalizing
ii. Annealing
iii. Case hardening
iv. Tempering
(b) State the difference between drilling and reaming.
(c) State one suitable surface finishing process each for the following:
(i) aluminum dishes;
(ii) bicycle frames;
(iii) sheet steel litter bin.
Observation
Candidates performed well in this question. However, some candidates could not adequately answer questions 5(c) (i), (ii), (iii).
The solution of those poorly answered questions are as follows.
Stating one suitable surface finishing process for:
i. Aluminium dishes – Anodising, Chromating
ii. Bicycle frames- Nickel plaiting, Chromium plaiting, Zinc coating, Painting
iii. Sheet steel littre bins- painting, plaiting