Different Metal Tests
1. Various tests can be made in order to determine the type of metal
2. One of them is the appearance test. Their physical features could help determine
what they are..
3. However, there are metals that look similar to each other, which is why the other
tests must also be done to help determine the correct type.
4. The magnet test is another one.
5. Metals can be ferrous and non-ferrous. Ferrous metals contain iron making them
magnetic. Non-ferrous on the other hand are non-magnetic
6. Use a magnet for this test to determine for a ferrous or non-ferrous metal.
7. Fracture test helps to identify a metal by analyzing its broken part.
8. Another common test made is the spark test. Metals have their own spark
characteristics and its checked this by touching the metal to the grinder to
produce spark.
Observe the sparks created and take note of the following: Color: The color of sparks
that these metals would produce varies from each other. For instance, yellow sparks
could be from a wrought iron, titanium could produce white sparks, while nickel
could have dark red sparks
Length: The spark’s length could also help you determine the type of metal. For
example, tungsten carbide has light orange sparks that are usually only around 3
inches, while alloy steel has longer sparks that’s typically around 60 inches.
Sprigs and Forks: These would tell the carbon content of the metal. More forks and
sprigs mean higher carbon content.
Identifying Common Types of Metals
Aluminum. This metal is grey and shiny but it doesn’t sparkle. It has a density of 2.70
g/cm3. When it comes into contact with air, it forms clear oxide. It would melt once it
reaches the temperature of 1217°F or 658°
Gold. This precious metal is soft, heavy and it’s shiny yellow. It doesn’t rust, which is
why it’s mostly used on jewelries.
It’s an electric conductor that means that high electricity could pass through an object
made of it. Its non-ferrous and it could melt when exposed to 1,947.52°F or 1,064.18°C
temperature.
Brass. It’s often confused with gold because they have the same color. However, you
could differentiate them by trying to hit on the object.
If there’s vibration like that of a bell, then it’s brass and not gold. However, it’s also
non-ferrous like gold, although its melting point varies depending on how much brass
was used for an object, but it’s typically between 1652°F to 1724°F or 900°C to 940°C
Bronze. This metal is dark coppery but it could turn greenish after some time. Like the
brass, it also has bell like vibration when hit. Bronze is a combination of tin and
copper, as well as a bit of lead.
Copper. It’s light red and turns greenish with oxidation. It’s often mixed with other
metals to produce another type of metal like bronze and brass. It’s non-ferrous and it
has a density of 8.94 g/cm3.
Lead. This is a heavy metal that’s dull grey in color, although it becomes shiny when
polished. It could melt in lower temperature like 621°F or 327°C.
Iron. Like lead, its color is also dull grey. When it rusts, the color of the rust is
somewhat red. It’s magnetic and it has a density of 7.87 g/cm3. It could melt when
2786°F or 1530°C is reached.
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Composite repair :
1. When performing a composite repair there are certain steps that
should be followed.
2. . The first step in the procedure should be a careful damage
assessment. Impact damage to a fibre can appear as a small dent on
the reinforced composite surface but the underlying damage can be
much more extensive.
3. The decision to repair or scrap is determined by considering the
extent of repair needed to replace the original structural performance
of the composite..
4. The initial assessment will determine the repair type to be performed.
Easy repairs are usually small or do not affect the structural integrity
of the component. These repairs are made by following the simple
guidelines indicated for laminate or sandwich panels.
5. Complex repairs are needed when the damage is extensive and needs
to replace the structural performance of the component. The best
choice of materials would be to use the original fibres, fabrics and
matrix resin.
6. Any alternative would need careful consideration of the service
environment of the repaired composite, i.e. hot, wet and mechanical
performance. The proposed repair scheme should meet all the original
design requirements for the structure.
7. . A temporary repair, usually in the form of a patch, can be fixed to
the component to ensure safety until the component can be repaired
at a later date.
8. For a permanent repair all the approved general guidelines for
laminate and sandwich repairs should be followed
9. Some repairs need the specialist equipment of the workshop and
some form of improvised repair is needed to return the component to
a suitable repair workshop.
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These repair operations should be carried out in controlled workshop areas
to ensure high quality. Operating in a controlled environment and
attention to the detail will ensure success.
Before returning to service the quality check is always required. For
comprehensive inspection of repaired parts a number of Non Destructive
Tests (NDT) can be used. Special attention should be given to the quality of
the repaired area and more specifically to the interface between the original
part and the repaired area. Usual inspection methods include some form of
ultrasonic or X-ray inspection.
thread geometry,
the lubrication and
check for cleanliness of the bolt and the nut, and
check for the surface conditions of the washer or
