Steel Billets for Forging or Other Purposes
From the contract department to the mill clerk come the orders for plate, with detailed list of sizes and thicknesses, and definite specifications of quality in terms of chemical and physical requirements, etc.
Rolling Ingot into Slabs
After studying these, the clerk makes requisition upon the open-hearth furnace for such tonnages of steel of various compositions as he estimates will give him sufficient stock for his purposes. As soon as possible the steel is made and poured into ingots which are transferred to the soaking pits of the slabbing mill there to await disposition as soon as the chemical laboratory has made analysis of the sample taken and has reported by telephone the result to the clerk who ordered the material. If close enough to the composition he ordered, he sends to the slabbing mill his requisition ordering them to roll and cut the four or six ingots of the “heat” into slabs of definite weights, each one designed for a plate on a customer’s order.
The clerk at the slabbing mill determines to what width and thickness each ingot shall be rolled and in what varying lengths it is to be cut to furnish slabs of the definite weights ordered in the requisition.
After rolling the ingot down to proper width and thickness, the “piped” end is cut off and “discarded.” Slabs are cut and piled in regular order on a little flat steel car on which they are pulled, still red-hot, by the shrieking little dummy engine out from the slabbing mill, through the yard and to the plate mill furnaces, into which they are charged in proper order. Here they remain until they are again white-hot and the plate mill roller is ready for them.
Meanwhile record sheets giving the heat number, the number of the ingot and the weights of the slabs in the order in which they were piled come to the plate mill clerk. From these and the results of analysis of the steel he makes out the rolling orders for the plates to be manufactured.
