Copper cathode is heated to melting point then cast into copper billets in a modern remelt and casting facility. Precise control is maintained over metal composition and billet quality is assured by skilled casthouse and on-site laboratory personnel.
A 3,500 tonne hydraulic extrusion press converts the solid copper billets into long tubular "shells" by forcing the preheated billet through a die and over a piercing mandrel. Crane Copper Tube production and engineering excellence has resulted in innovative extrusion techniques which produce shells of superior dimensional and compositional uniformity enabling subsequent cold drawing to finished dimensions with precise tolerances.
Cold drawing of the shell is carried out on an extensive array of specialised equipment. Specially designed cold drawing machines called "bullblocks" economically produce large quantities of thin-walled tube whilst larger diameter and thick-walled tubes are rapidly produced on multi-die "drawbenches". Close supervision by process operators and staff ensures tube of the desired dimensional and mechanical properties.
The cold-drawn tubing is conveyed to "finishing lines" which manipulate and cut the tube to produce a product of the required form and length. All tube is inspected for defects using on-line eddy current analysis which ensures that only flawless tube is packed and shipped from the mill.
The temper of some tube is modified using annealing ovens which maintain strict control over temperature and furnace atmosphere resulting in product without discolouration and with those mechanical properties desired by the customer.
Copper tube is fed through a specially designed cross-head plastic extruder which applies a plastic coating in plain or castellated form. This provides the customer with a cost effective prelagged copper tube.