The members of the American Gun Foundry Board visited these works in 1883, and give the following in their report: The most important steel works in France are situated at Le Creusot, and bear the name of the location in which they are situated. These works have advanced year by year in importance and in magnitude since their purchase by Mr. Eugene Schneider.
This gentleman's death, in 1875, was a source of mourning to the whole town, the inhabitants of which looked up to him as a father. The grateful people have erected to his memory a monument in the market square.
Under the administration of his son, Mr. Henry Schneider, the fame of the products of the works has been enhanced, and the proportions of the establishment have been much increased. The whole number of workmen now employed here and at other points amounts to 15,000; and it is the great center of industry of the adjoining region. At no other place in the world is steel handled in such masses.
It would be foreign to the purpose of this report to dwell on the many objects of commerce which are supplied from these works, but it is safe to say that no proposed work can be of such magnitude as to exceed the resources of the establishment.
For the preparation of metal for cannon and armor-plates Le Creusot is thoroughly equipped. The iron is produced on the premises from the purest imported ores, and the manufacture of the steel is carried on by the most approved application of the open-hearth system with the Siemens furnace; the chemical and mechanical tests are such as to satisfy the most exacting demands of careful government officials; and the executive ability apparent in all the departments and the evident condition of discipline that pervades the whole establishment inspire confidence in the productions of the labor.
The capacity for casting steel is represented by seven open-hearth furnaces of 18 tons each, equal to 126 tons; and the process of casting large ingots is a model of order and security. Ladles capable of holding the contents of one furnace, mounted upon platform cars, are successively filled at a previously determined interval of time and run on railways to a convenient position over the mould; before the first ladle is exhausted the supply from the succeeding one has commenced to run, and so on to the completion of the casting, the supply to the mould being uninterrupted during the entire process. The precision with which the several ladles are brought into position in succession makes it entirely unnecessary to provide a common reservoir into which all the furnaces may discharge. By this process the casting of a 45 ton ingot, which was witnessed by the Board, was effected in 23 minutes.
The process of tempering the gun-tubes was also witnessed by the Board. The excavation of the pit is, as at St. Chamond, 15 meters deep, with the furnace at one end and the oil tank (100 tons) at the other. One side of the upright furnace is constructed in the form of a door, which, by a convenient arrangement for swinging, is made to turn on its hinges. Thus, when the tube is raised to the right temperature, it is seized by the traveling crane, the door of the furnace swung open, and the tube at once advanced to the tank in which it is immersed.
All tubes are immersed in oil the second time, but at a temperature much below that to which they are raised at the first immersion. This process constitutes the annealing after tempering.
The manufacture of steel-armor plates is a specialty of Le Creusot, which is engaged in an active competition with the manufacturers of compound armor. Plates up to 60 centimeters in thickness and 3 meters wide are forged here; they are tempered after forging, but what subsequent treatment they receive was not explained.
The tempering pit for the plates consists of an excavation of convenient size, in the center of which is placed a tank containing 180 tons of oil. At the four corners of the pit are furnaces in which the plates are raised to a proper temperature. When sufficiently heated, a plate is seized by a walking crane and immersed in the oil.
Hoops for cannon are manufactured here in large quantities. They are cut from solid ingots, and those for guns up to 24 centimeters are rolled like railway tires; those for larger calibers are forged on a mandrel. Jackets of large size are also manufactured; these are made from solid ingots, which, after being forged, are bored out.
At Le Creusot a remarkable test of hoops was witnessed, which exemplifies not only the excellence of the manufacture of the steel but also the exacting character of the French requirements. The hoops for naval guns are made with the interior surface slightly conical. When forged, turned, and brought under a hammer, a standard mandrel of steel, conically shaped to suit the form of the cone in the hoop, but of a slightly increased diameter, is introduced, the smaller end of the mandrel being able to enter the larger end of the hoop. The mandrel is then forced in by the hammer until its lower edge has passed through the hoop. The blows are then made to operate on the upper edge, detaching it from the mandrel. Careful measurements are taken of the diameter of the hoop before and after this test, and it is required that the measurement subsequent to the operation shall show that the hoop has partially, but not entirely, returned to the diameter that it had before the entrance of the mandrel. This would show that there is left to the metal a small margin within its elastic limit.
A system of manufacture which can comply with such a refinement of exactitude must be very precise.
Perhaps the most striking feature at Le Creusot is the forge, where is assembled an array of steam hammers not equaled in the world, viz.:
One 100 ton hammer with a fall of 5 meters.
One 40 ton hammer with a fall of 3 meters.
One 15 ton hammer with a fall of 3 meters.
Two 10 ton hammers with a fall of 2½ meters.
One 8 ton hammer with a fall of 2½ meters.
As the 100 ton hammer at these works is the largest in the world, some particulars concerning it will be appropriate.
The foundations are composed of a mass of masonry laid in cement resting on bed rock, which occurs at a depth of 11 meters, an anvil block of cast iron, and a filling-in of oak timber designed to diminish by its elasticity the vibrations resulting from the blows of the hammer. The masonry foundation presents a cube of 600 meters. Its upper surface is covered with a layer of oak about one meter in thickness, placed horizontally, on which rests the anvil block.
At the Perm foundry in Russia the anvil block for the 50 ton hammer is made in one piece, moulded and cast on the spot it was intended to occupy. Its weight is 622 tons. At Le Creusot, however, this idea was not approved, and it was determined to construct the block in six horizontal courses, each bedded upon plane surfaces. Each course is formed of two castings, except the upper one, a single block, which weighs 120 tons and supports the anvil. Thus formed in 11 pieces, it is 5.6 meters high, 33 square meters at the base, and 7 square meters at the top. Its entire weight is 720 tons.
The space between the block and the sides of the masonry in which it rests is filled in solidly with oak. The block is thus independent of the frame of the superstructure.
The legs of the frame, inclining toward each other in the form of an A, are secured at their bases to a foundation plate embedded in the masonry. They are hollow, of cast iron, and of rectangular cross section, each leg in two pieces joined midway of their length by flanges and bolts. The legs are also bound together by four plates of wrought iron, which, at the same time, holds the guides. The height of the legs is 10.25 meters, and their weight, with the guides, 250 tons. The binding plates weigh together about 25 tons, and the foundation plates 90 tons.
The entablature of the frame work weighs 30 tons; on it is placed the steam cylinder, single acting, made in two pieces, each 3 meters long united by flanges and bolts. The diameter of the cylinder is 1.9 meters, giving a surface of 27,345 square centimeters (deducting the section of the rod, which is 36 centimeters in diameter); which, for 5 atmospheres, gives a pressure under the piston of about 140 tons. As the weight of the hammer is 100 tons, it is evident that it can be raised with great velocity.
The stroke of the piston in the cylinder is 5 meters. This height of fall, multiplied by the 100,000 kilogrammes of the mass, gives a working force of 500,000 kilogrammeters, or about 1,640 foot tons. The width between the legs is 7.5 meters, and the free height under the cross ties 3 meters, thus providing ample space for maneuvering large masses of metal.
The entire height of this colossal structure from the base of the masonry foundation to the upper part of the steam cylinder is 31 meters (102 feet), but notwithstanding this unfavorable condition for stability and the enormous effect resulting from a shock of 500,000 kilogrammeters, everything is so well proportioned that there is but slight vibration.
The workman who maneuvers the hammer is placed on a platform on one of the legs, about 3 meters above the floor. He is here protected from the heat reflected from the mass of metal during the operation of forging.