192 



BELL SYSTEM TECHNICAL JOURNAL 



The coils are automatically unloaded from the coilers onto a con- 

 veyer, which carries them through cooling water in a tank underneath 

 the floor. An appreciable amount of copper oxide scale is carried off 





o 



♦» » ♦• Billet 



Fig. 4 — Rod mill reductions — 4 in. by 4 in. billet to \i in. rod 



with the cooling water, and deposited in a reservoir from which it is 

 later salvaged. Eighty-two seconds after entering the roughing mill 

 the bar is a coil of % in. rod ready to proceed on its way to the 

 pickling tanks. The mill has a capacity of 70,000,000 pounds annu- 

 ally on a 48 hour per week basis. 



While the diagram and photograph of the intermediate and finishing 

 mills indicate for simplicity that the rod follows only a single path, 

 in actual operation sufficient material is kept in the mill to practically 



H.P. 

 900 

 800 

 700 

 600 



500 



400 

 300 

 200 



too 



10 20 50 4-0 



Five P»3S 



ROUGHINS Ui LL 



Friction Load 



10 20 30 40 50 60 

 Time in Seconds 

 Four Pass 



iNTEnMEDIATE Ml LL , 



J 10 20 )0 40 50 60 



^ ji V y 



J 



Friction Load 



Fi 



FiNl 



KE Pass 

 iHiNS Mill 



Friction Load 



10 20 }0 40 10 20 30 40 50 60 10 20 30 40 50 60 



Time in Seconds 



Fig. 5 



maintain at least two rods in the finishing mill. This is illustrated 

 graphically by that part of Fig. 5 which covers the finishing mill. Re- 

 ferring to line {A- A'), 11 reductions are being made in this mill at the 



