Q242
The machinability of aluminium increases when _________ is added to aluminium.
A.
Copper
B.
Magnesium
C.
Silicon
D.
Lead and bismuth
AnswerAnswer: Option D
Solution
Answer: Option D
Solution:
The low-melting-point metals such as bismuth, lead, tin, and cadmium are added to aluminum to make free-machining alloys. lead is added at about the 0.5% level with the same amount as bismuth in some alloys to improve machinability.