Page 65 - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

1
50 Automobile mechanical and electrical systems

Figure 1.70 Cast iron exhaust manifold

Table 1.22 Comparison of material properties

Material Ease of Strength Resistance Electrical Corrosion Cost Typical motor vehicle
shaping to heat resistance resistance uses

Copper 2 3 2 1 3 4 Wires and electrical parts
Aluminium 2 3 2 1 3 4 Cylinder heads
Steel 3 2 1 1 4 3 Body panels and exhausts
Cast iron 3 2 1 1 4 3 Manifolds and engine
blocks

Platinum 3 1 1 1 2 5 Spark plug tips
Soft 1 5 5 5 1 1 Electrical insulators
plastic
Hard 1 4 4 5 1 1 Interiors and some engine
plastic components
Glass 3 5 2 5 1 2 Screens and windows

Rubber 2 4 5 5 3 2 Tyres and hoses
Ceramics 4 4 1 5 1 4 Spark plug insulators
1 best; 5 worst.

one material with another. Note that this table is just to help you compare
properties; the league table positions are only rough estimates and will vary with
different examples of the same material.

Corrosion is the eating away and eventual destruction of metals and alloys
(mixtures of metals) by chemical action ( Fig. 1.71 ). Most metals corrode
eventually, but the rusting of ordinary iron and steel is the most common form
of corrosion. Rusting of iron or steel takes place in damp air, when the iron