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SOLUTIONS

Magnet test

Aluminium/magnesium test 1. Clean a small area of the metal. 2. Drip onto it one or two drops of 20% caustic soda (NaOH) solution. 3. Wait 5 minutes and wash with clean water.

2.03

Black: Al + Cu Al + Ni

Al + Zn

Grey/brown: Al + Si (over 2%). White: Pure aluminium. Unchanged: Magnesium (Mg).

Non-magnetic

This indicates an Austenitic stainless steel.

Manganese steel, stainless steel: good weldability, but remember: no pre-heating.

Magnetic

Indicates a Ferritic normal steel. If stainless steel: poor weldability. If unalloyed / low-alloyed steel: good weldability.

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Flame test

Another simple test to find out whether the component is of alumin­ ium, magnesium-alloyed aluminium or magnesium is as follows: Place the component on a piece of paper and file some shavings onto the paper. Hold the paper over a flame and let the filings fall into the flame. If the filings glow the metal is alumin­ ium. If some of the filings spark in the flame the aluminium is alloyed with magnesium (seawater resistant aluminium). If all the filings spark in the flame, the metal is magnesium and must not be welded.