STRUCTURAL FABRICATION TECHNOLOGY, MATERIALS AND METALLURY

CRAFT CERTIFICATE IN MECHANICAL ENGINEERING
(PRODUCTION OPTION)
MODULE 1
SECTION A: FABRICATION TECHNOLOGY
Answer at least TWO questions from this section
1. (a) State any five precautions to be observed for good housekeeping (5marks)
(b) Identify any three safety colours stating their meaning and use in each case (9 marks)
(c) Explain the purpose of the following tools in the fabrication of standard steel door:
i. Straight edge ;
ii. Swinging blade protractor;
iii. Steel tape. (6 marks)
2. Illustrate :
i. draw filing;
ii. cross filing. (6marks)
b) Explain three circumstances under which power tools are preferred to hand tools (6 marks)
c). i) Differentiate between heming and seaming as applied to sheet metal work
ii) Illustrate three ways of edge treatment in sheet metal work
iii) Sketch and name any three types of seam joints. (6 marks)
3. (a) i) Explain soft soldering. (8 marks)
ii) Differentiate between passive and active fluxes giving an example in each case as
applied to soft soldering. (6 marks)
b) i) list any three methods of joining a steel truss structure .
ii) State any two factors to consider when choosing fasteners (5 marks)
c) Illustrate the three basic oxy –acetylene welding flames (9 marks)
4. (a) Explain the effect of the following in manual metal are welding
(i) Damp electrode coming
(ii) too low welding current
(iii) excessive welding current
(iv) too long an arc . (12 marks)
(b) State two factors to consider when choosing a finishing process (2marks)
(c) Explain the following finishing processes
(i) bluing
(ii) blackening (6marks)
SECTION B: MATERIALS AND METALLURGY
Answer at least two questions from this section

5. (a) Define corrosion and state any four methods of its prevention (6 marks)
(b) State four reasons for heat treatment (4 marks)
(c) Explain the following heat treatment processes
(i) hardening
(ii) normalizing (10marks)
6. (a) Differentiate between physical and mechanical properties of materials (4marks)
(b) Explain the following properties of materials
(i) brittleness
(ii) toughness
(iii) strength
(iv) elasticity (8marks)
(c)Explain any four properties of a bearing material (8marks)
7. (a) Sketch and label the copula furnace (10marks)
(b) (i) List any two types of cast irons other than grey cast iron
(ii) Give four reasons why grey cast iron is widely used in general engineering applications
(10 marks)
8 (a) (i) Differentiate between carbon steel and alloy steel .
(ii) Explain any four improvements in properties that alloy steels process as compared to carbon
Steels (10 marks)

(b) ( i ) differentiate between brass and bronze
(ii) outline four properties that make bronzes better than brasses (6marks)
(c) Identify an engineering application for each of the following types of rubber
(i) soft rubber
(ii) hard rubber
(iii) foam rubber
(iv) sponge rubber (4 marks)



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