METAL PROPERTIES, CHAR, USES, AND CODES - OD1643 - LESSON 1/TASK 2
(6) Manganese Steel. Manganese steel yields a brilliant stream of
very high temperature. The brilliance is due to the fine chip size
and easy oxidation.
(7) Stainless Steel.
Stainless steel could be confused with
machine steel; however, stainless steel sparks are of less brilliant
color near the wheel and the stream itself is thinner.
(8) Plain Carbon Steel and Stainless Steel. These are two types
of metal whose sparks vary widely, depending upon composition.
Spurts from structural and machine steels cover a large part of the
range between wrought iron and carbon tool steel, being influenced by
their carbon content. Different brands of stainless steels and irons
yield spark streams with a wide divergence of volume and color. The
spark stream shown is from steel that is from a 12 to 14 percent
chromium, low-carbon type.
(9) Tungsten-chromium Die Steel.
Like cast iron, the sparks
emitted by tungsten-chromium die steel are red near the wheel,
turning to a straw color at the end of the stream.
But tungsten-
chromium die steel is noticeably different than the cast irons, as
indicated by blue-white glows at the spurts.
(10) Nitrided Nitralloy.
This metal exhibits one peculiar
characteristic; the sparks near the wheel form whorls and some
actually turn from the main line of travel by as much as 90.
The
same tendency, to a lesser extent, is exhibited by manganese steel.
(11) Stellite and Cemented Carbide. Stellite and cemented carbide,
in contrast to their brilliant performance as tools, provide very
little spark action.
As seen in figure 5 on page 32, the spark of
these two metals is hardly noticeable. Any oxidation that occurs in
the air does not raise the spark temperature appreciably.
The line
of travel is plain and short.
Temperature color from the carbide
material is slightly higher that from the stellite and the stream is
very short. These differences are attributed to grinding sparks from
the more resistant cemented carbide.
(12) Nickel. Nickel yields a spark that at first may be confused
with a stellite spark.
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