Question

Gun metal which is used in Journal bearing contains
1. 88% Cu, 10% Sn, 2% Zn
2. 80% Cu, 10% Zn, 10% Al
3. 85% Cu, 5% Mg, 10% Al
4. 85% Cu, 5% Sn, 10% Pb

Answer 1

Correct Answer - Option 1 : 88% Cu, 10% Sn, 2% Zn

Explanation:

Gunmetal:

• Gunmetal is typically composed of 88% copper, 10% tin, and 2% zinc.
• It was used mainly for making guns and bullets. Also used in the Journal Bearing.
• Gunmetal is used extensively for making heavy machinery parts as it can withstand high pressure and is corrosion resistant.
• Zinc is added to cleanse the metal and increase its fluidity.
• It is used extensively for casting boiler fittings, bushes, glands, etc

Rolled gold:

• Rolled gold is an alloy of Copper and Aluminium.
• It is used for making cheap ornaments.
• An alloy is a mixture of two or more metals.

Bell metal:

• Bell metal is an alloy of copper (Cu) and Tin (Sn).
• It is a type of bronze alloy which contains higher tin content.
• Generally, the ratio of Cu to Sn is 4 : 1, which typically means it contains 78% copper and 22% tin by mass.
• It is used mainly in the making of bells, valve bodies, piston rings, and bearings, etc.

Duralumin:

• It is an alloy made up of 93% Aluminum, 3% Copper, 2% Magnesium and 2% manganese.
• It is workable, ductile, and relatable in the normal state and can be drawn and rolled into a variety of shapes.