Customers, of course, have a right to see that their specifications are lived up to. Though years ago the mills perhaps intentionally sold to customers products which did not fulfill his specifications to the letter, it is not generally so to-day. Now the mills’ own inspectors are commonly more severe in their rejections of products than are the representatives which the customers themselves send. Not only does the mill laboratory make careful and accurate analysis of each heat or batch of steel made, but, after its application to orders, pieces of plate, shapes or rails rolled from it are examined, gauged, and test bars of the steel are pulled in the physical testing laboratory.
The mill rightly recognizes that it is for its own interest that the standard of its product be kept high.
A trip through one of the large steel plants with its furnaces, its blooming and slabbing mills, its rail, plate, structural and rod mills is one of the most interesting that can be taken. If the visitor is not afraid of smoke or dust or of what seems to him an uncomfortable heat on a warm day he will discover new worlds. No particular attention is paid to the casual visitor to the plant, but, for those who show real interest, steel men have a warm welcome, from manager to the sample boys.
CHAPTER XVIII
THE ROLLING OF RODS
Steel rods and what we will call large wires are rolled from billets which are long, and approximately square blocks of steel. The size and shape of the billets used vary, depending upon the process and the size of the rod to be rolled. Much of the finished rod is sold as such for various purposes for which round steel is desired and an immense tonnage of one of the smaller sizes is used as the intermediate raw material from which wire is drawn.
Rod mills have a very interesting history, which, by the way, is but one of several histories of the development of the iron and steel processes and products which should make us proud of the genius of man in the way of metallurgical, mechanical and business development.
The Belgian Mill
The first bars and rods were rolled in the old two-high mill, where, after each pass they were pulled back over the top roll and inserted into the next groove by the roller as is usual with the two-high mill. Then along came the three-high mill which probably resulted in greater advantage to rod rolling than to other lines, important, even, as it was to them.
But long, thin bars or rods are quite pliable when at white or rolling heat and the “catcher” soon discovered a way by which he could save time and push up his tonnage. He skillfully caught the forward end of the bar as it came through, and, giving it a quarter twist, he inserted it in the proper return groove without waiting for the whole bar to run through to his side before starting it on its return journey. This, of course, was easily possible with the slow speeds then used.
Naturally the rod coming through from one side and going back to the other formed a loop.