One way to become proficient in spark testing fer-
rous metals is to gather an assortment of samples of
known metals and test them. Make all of the samples
about the same size and shape so their identities are not
revealed simply by the size or shape. Number each
sample and prepare a list of names and corresponding
numbers. Then, without looking at the number of the
sample, spark test one sample at a time, calling out its
name to someone assigned to check it against the names
and numbers on the list. Repeating this process gives
you some of the experience you need to become profi-
cient in identifying individual samples.
from small, broken fragments to a continuous strip. The
chip may have smooth, sharp edges; it maybe coarse-
grained or fine-grained; or it may have sawlike edges.
The size of the chip is important in identifying the metal.
The ease with which the chipping can be accomplished
should also be considered. The information given in
table 1-4 can help you identify various metals by the
The use of a magnet is another method used to aid
in the general identification of metals. Remember that
ferrous metals, being iron-based alloys, normally are
Another simple test used to identify an unknown
piece of metal is the chip test. The chip testis made by
removing a small amount of material from the test piece
with a sharp, cold chisel. The material removed varies
magnetic, and nonferrous metals are nonmagnetic. This
test is not 100-percent accurate because some stainless
steels are nonmagnetic. In this instance, there is no
substitute for experience.