Q: What is a free machining brass?    
Typically, free machining brass contains about 58% copper and 39% zinc. Lead is added to improve machinability. It has a machinability rating of 100% compared with say 10% for a 1% C, 1% Cr bearing steel.

Q: What is a suitable material for a security bolt?
There are a number of options:
•    Traditionally these were made from a high tensile steel tube.
•    A better alternative for corrosion resistance and wear is to use a common brass tube to CuZn37

Q: I require a material for use in a mining application that must be “spark resistant”.
The best material for this application is high tensile brass. These have been successfully used for many years and were commonly but incorrectly called “Manganese Bronzes”.
There is a family of high tensile brass with a tensile strength in excess of 700 MPa. See CW705R (CZ116)

Q: I am looking for a suitable material for an air cooler that operates above seawater.
One material to be considered for this application is an aluminium brass, CW702R (CZ110).
It is sometimes employed in plate type heat exchanges.
If seawater was the actual coolant rather than air-born  spray and flow rates are high then titanium plates would  preferred.

Q: What is “Muntz Metal”?  Can it be used for water fittings?
Muntz metal is a 60/40 brass to specification CW509L (CZ109)
Naval brass is preferred for water fittings as Muntz Metal is subject to de-zincification.
The most important de-zincification resistant brass is CW602N (CZ132). This is specified and approved by most Water Regulations Advisory Schemes.

Q: What is PB2?  What is the modern alternative?
This is a cast phosphor bronze. The chemical analysis is available.
The mechanical properties are available.  BS EN 1987 replaced BS1400

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