Page 65 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton
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      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
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