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SOLUTIONS Filing test Restance to file

Type of steel

Brinell hardness

No resitance; the file bites into the metal.

Unalloyed and Low alloyed steel

100

Little resistance; the file bites into the metal, but the pressure has to be increased.

Medium-carbon steel

200

Medium resistance. The file does

High-alloy steel

not bite into the metal and the pressure has to be increased.

300

High resistance. The metal can be High-carbon steel filed, but with difficulty.

400

High resistance. The file leaves

Tool steel

marks, but the metal is almost as hard as the file.

500

2.03

Spark test

This test may be carried out in the ship’s workshop and is very useful for identifying the type of steel and determining its approximate carbon content. Hold a sample lightly against the grindstone and note the shape, colour and length of the sparks. Unalloyed and low alloyed steels are difficult to tell apart, but when tested together it is comparatively easy to see the difference. Chisel test Unalloyed steel

The sparks separate at the end into several small sparks (leaf shaped). Some sparks are short.

Manganese steel

The sparks split up, and end in stars.

High speed steel

Weak red sparks, with forked ends.

Unalloyed steel (Cast steel). Long (continuous) shavings are formed when chiselled.

Stainless

Bright yellow sparks, with steel pointed ends.

Cast iron

Weak red sparks, ending in many pronged yellow stars.

Monel

Weak red sparks, quickly extinguished.

Cast iron.

The metal does not give off shavings; material chiselled away is in the form of brittle fragments.

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