Cranes with magnets or hooks convey the long plates to the “goose necks” over the small rollers of which they are pulled to the shears where the powerful steam or hydraulically-operated square-edged knife with ease trims the ends and irregular edges along the chalk lines into the sizes marked. Accuracy is everywhere necessary as ¼″ over or under ordered dimensions or a variation of two hundredths of an inch in thickness may and probably will cause rejection of a plate.
After weighing and recording, the plates are conveyed to the shipping yard, where they are loaded by electro-magnets into cars for shipping.
In the plate mill process above described plates anywhere between 30 and 120 inches in width, say, can be rolled. And as mentioned, the more or less irregular edges on the sides are “sheared” off. This extra allowance, which must be given, of course becomes “scrap.”
For plates which can best be rolled in long narrow lengths a “universal” plate mill is often used. This has vertical rolls just back of the two horizontal rolls, which are adjustable so that the plate can be regulated, not only as to thickness, but also as to width as well. Such mills give plates which have to be trimmed on the ends only, the sides being quite smooth.
Loading Plate from the Shipping Yard
The rolling of plate has been described thus in detail that a slight conception can be obtained of the refinement and the minutia which is a necessary part of modern mill practice. American outputs which have grown to as much as several hundred tons per twelve-hour turn, require that every operation move along with “clock-like” precision. But with this immense tonnage and with all of the handicaps of occasional broken rolls and machine parts, electric crane delays, and illness of important men, the work must be and usually is kept up without serious delay.
Modern metallurgical and rolling mill practice is a marvel.
Sheets
