sinks or protect bench tops where a large amount of acid
is used. Lead-lined pipes are used in systems that carry
This is an alloy of copper and zinc. Additional
corrosive chemicals. Frequently, lead is used in alloyed
elements, such as aluminum, lead, tin, iron, manganese,
form to increase its low-tensile strength. Alloyed with
or phosphorus, are added to give the alloy specific
tin, lead produces a soft solder. When added to metal
properties. Naval rolled brass (Tobin bronze) contains
alloys, lead improves their machinability.
about 60% copper, 39% zinc, and 0.75% tin. This brass
is highly corrosion-resistant and is practically impurity
Brass sheets and strips are available in several
grades: soft, 1/4 hard, 1/2 hard, full hard, and spring
When working with lead, you must take
grades. Hardness is created by the process of cold roll-
proper precautions because the dust, fumes, or
ing. All grades of brass can be softened by annealing at
vapors from it are highly poisonous.
a temperature of 550°F to 600°F then allowing it to cool
by itself without quenching. Overheating can destroy
the zinc in the alloy.
Bronze is a combination of 84% copper and 16% tin
and was the best metal available before steel-making
techniques were developed. Many complex bronze al-
loys, containing such elements as zinc, lead, iron, alu-
minum, silicon, and phosphorus, are now available.
Today, the name bronze is applied to any copper-based
alloy that looks like bronze. In many cases, there is no
real distinction between the composition of bronze and
that of brass.
Nickel is used in these alloys to make them strong,
tough, and resistant to wear and corrosion. Because of
their high resistance to corrosion, copper nickel alloys,
containing 70% copper and 30% nickel or 90% copper
and 10% nickel, are used for saltwater piping systems.
Small storage tanks and hot-water reservoirs are con-
You often see zinc used on iron or steel in the form
of a protective coating called galvanizing. Zinc is also
used in soldering fluxes, die castings, and as an alloy in
making brass and bronze.
Tin has many important uses as an alloy. It can be
alloyed with lead to produce softer solders and with
copper to produce bronze. Tin-based alloys have a high
resistance to corrosion, low-fatigue strength, and a com-
pressive strength that accommodates light or medium
loads. Tin, like lead, has a good resistance to corrosion
and has the added advantage of not being poisonous;
however, when subjected to extremely low tempera-
tures, it has a tendency to decompose.
strutted of a copper-nickel alloy that is available in sheet
This metal is easy to work with and has a good
form. Copper-nickel alloys should be joined by metal-
appearance. Aluminum is light in weight and has a high
arc welding or by brazing.
strength per unit weight. A disadvantage is that the
tensile strength is only one third of that of iron and one
fifth of that of annealed mild steel.
A heavy metal that weighs about 710 pounds per
cubic foot. In spite of its weight, lead is soft and malle-
able and is available in pig and sheet form. In sheet form,
it is rolled upon a rod so the user can unroll it and cut
off the desired amount. The surface of lead is grayish in
color; however, after scratching or scraping it, you can
see that the actual color of the metal is white. Because
it is soft, lead is used as backing material when punching
holes with a hollow punch or when forming shapes by
hammering copper sheets. Sheet lead is also used to line
Aluminum alloys usually contain at least 90% alu-
minum. The addition of silicon, magnesium, copper,
nickel, or manganese can raise the strength of the alloy
to that of mild steel. Aluminum, in its pure state, is soft
and has a strong affinity for gases. The use of alloying
elements is used to overcome these disadvantages; how-
ever, the alloys, unlike the pure aluminum, corrodes
unless given a protective coating. Threaded parts made
of aluminum alloy should be coated with an antiseize
compound to prevent sticking caused by corrosion.