Spark Testing - Spark Characteristics

Spark Characteristics

Wrought iron

Wrought iron sparks flow out in straight lines. The tails of the sparks widen out near the end, similar to a leaf.

Mild steel

Mild steel sparks are similar to wrought iron's, except they will have tiny forks and their lengths will vary more. The sparks will be white in color.

Medium-carbon steel

This steel has more forking than mild steel and a wide variety of spark lengths, with more near the grinding wheel.

High-carbon steel

High-carbon steel has a bushy spark pattern (lots of forking) that starts at the grinding wheel. The sparks are not as bright as the medium-carbon steel ones.

Manganese steel

Manganese steel has medium length sparks that fork twice before ending.

High-speed steel

High-speed steel has a faint red spark that sparks at the tip.

300-series stainless steel

These sparks are not so dense as the carbon steel sparks, do not fork, and are orange to straw in color.

310-series stainless steel

These sparks are much shorter and thinner than the 300-series sparks. They are red to orange in color and do not fork.

400-series stainless steel

400-series sparks are similar to 300-series sparks, but are slightly longer and have forks at the ends of the sparks.

Cast iron

Cast iron has very short sparks that begin at the grinding wheel.

Nickel and cobalt high-temperature alloys

These sparks are thin and very short, they are dark-red in color, and do not fork.

Cemented carbide

Cemented carbide has sparks under 3 inches, which are dark-red in color and do not fork.

Titanium

Although titanium is a non-ferrous metal, it gives off a great deal of sparks. These sparks are easily distinguishable from ferrous metals, as they are a very brilliant, blinding, white color.