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Will commercial grades of copper become hard (like steel) if they are cooled rapidly after heating?

No. Copper is not susceptible to precipitation hardening.
With respect to the MOD Defence Standard 02-879 Part 2 Forgings, what do the terms Class 1, Class 2, Class 3 and Class 4 mean?
  • Class 1 is a forging whose failure would lead to uncontrollable flooding, the total immobilisation of the vessel or serious harm to personnel.(e.g. First Level systems in submarines).
  • Class 2 is a forging whose failure would lead to severe but controllable flooding, the serious disruption of weapon systems, main propulsion machinery, or its attendant auxillaries, including generators
  • Class 3 is a forging whose failure does not constitute an immediate, significant hazard.
  • Class 4 is a forging which is used for forging stock only.
What kind of cleaning do copper alloy cages require?

On average, copper alloy cages must be cleaned approximately once or twice a year, which is significantly fewer than traditional cages, over a service life.
Are small diameter tubes necessary for increasing the energy efficiency of air conditioners?

No. The system energy efficiency can also be achieved with conventional tubes (such as 3/8 inch diameter tubes) simply by using more tubes and thereby increasing the surface area available for heat transfer. Nevertheless, a penalty is paid in terms of the increased weight of tube material and fin material as well as increased refrigerant volume. In general, if larger diameter tubes are used then a larger coil size is necessary to achieve the same performance and energy efficiency that could be achieved in a more compact system with smaller diameter tubes.
Are the 1, 2 and 5 Cent Euro coins pure copper?

No, they are made from steel coated with a thin layer of copper.
Are weld repairs permissible on Class1 and Class 2 Forgings produced to Def Stan 02-879 Part 2?

The rectification of defects by welding is not permitted on Class 1 and Class 2 forgings.
Can chrome plated copper tube be formed into a bend?

Yes, with care and the correct procedure.
Can copper alloys be used for architecture?

Yes, brass and bronze alloys are available.
Can leaded solders be used on drinking water installations?

No.
Can patination of the copper be prevented?

Applying a lacquer is not recommended, particularly when large areas are considered. Lacquers will require regular maintenance over the life of the roof.
Does copper harden when stored for long periods of time?

Copper will not harden during storage; it does not have a shelf life.
Has copper been tested in clinical trials?

Yes. Copper surfaces have been proven to have over 90% less contamination than conventional touch surfaces in hospital trials around the world.  Trials have taken place, or are under way, in China, France, Germany, Greece, Japan, Spain, South Africa, Chile and the US.

Furthermore, in a multi-centre US trial, funded by the Department of Defense, copper surfaces were shown to reduce a patient’s risk of acquiring a healthcare-associated infection by 58%.