STEEL. 



589 



is the manufacture of steel rails, though, strange to 

 say, when granted the patent for this process he was 

 denied the right to manufacture rails. 



Fio. 3. Open hearth Furnace. 



The Uchatius process of making steel is to effect 

 the partial decavburation of pig-iron by fusion in 

 contact with ferric oxide, or some other substance 



Fio. 4. Open-hearth Furnace. 



to offer a large surface of contact for the gases. 

 There are four of these chambers, two communi- 

 cating with one, and two with the other, end of 

 the furnace. The mixture of combustible gases 

 and air reaches the furnace F after having passed 

 through two of the regenerators, A, A, at one end, 

 and passing through the furnace pass out through 

 the two regenerators A, A, at the other end, as shown 

 by the arrows in Fig. 3. The bricks of the regener- 

 ators store up the greater part of the heat of the gases 

 that have left the furnace, and the products of com- 

 bustion pass off by the chimney D. Now, by aid of 

 the valves, the course of the gases is reversed, "and the 

 gases pass into the furnace through the regenerators 

 that have just been heated, and out by the ones that 

 have been famishing heat. In this way the gases, 

 slowly passing through a honey-comb of hot bricks, 

 are intensely heated, and reach the hearth at a tem- 

 perature nearly that of the furnace itself, so that the 

 combustion develops an intense heat. The temper- 

 ature is raised at each reversal of the valve E, the 

 volume of the gases being regulated by the register 

 C, the volume of air being controlled by B, and the 

 draught by the chimney damper D. The gas pro- 

 ducer (Fig. 4) consists of a chamber, A, of fire-brick. 

 D is a hopper to regulate the supply of fuel, and C 

 a pipe for introducing water to the bottom of the 

 furnace. The pipe E conducts the gases to the fur- 

 nace. 



The furnace (Figs. 5 and 6) is reverberatory, with a 

 single door, A, on one side, and on the opposite side 

 a tapping hole, B. The gases from the regenerators, 

 and the air to burn them, arrive and depart at the 

 ends C, C and E, E. A bed of iron, cooled by a 

 current of air from below, holds the lining of sand 

 or gannister. The furnace is heated to a white heat 

 by the hot gas, and receives then a charge of hot cast 

 iron, and when this is properly melted soft iron, 

 heated to a bright red, is introduced. These addi- 

 tions are made about every half-hour, and the whole 

 is then vigorously stirred. When by tests the metal 

 is found to be sufficiently refined, red-hot cast- 

 iron is added. Tests are made, and cast-iron added 

 till the proper carburization is arrived at, and the 

 product is then tapped. The operation takes from 

 nine to eleven hours with 5 to 6-ton charges. From. 

 13 to 14 cwt. of coal is consumed per ton of ingots. 



A modification of this process is seen in the Per- 

 not rotating furnace, which is made with an inclined 

 bed, as shown, and when rotated the molten metal 

 flows from side to side, the bed standing under the 

 arch of the reverberatory furnace, and over the re- 

 generators. From two to four revolutions are made 



capable of yielding oxygen. The pig-iron is granu- , 



lated by running the fused metal into water, and per minute, and as the pieces of the charge are con- 

 mixing the granulated metal with about 

 20 per cent, of roasted spathic ore and 4 

 per cent, of fire-clay. The mixture is 

 then melted in clay crucibles in an ordi- 

 nary cast-steel furnace. 



Another method of obtaining steel is 

 by the fusion of a mixture of cast iron 

 and wrought, the carbon distributing it- 

 self between the two and so forming 

 steel. 



The production in a reverberatory fur- 

 nace of cast-steel, by the solution of 

 malleable scrap in molten pig-iron, has 

 been brought to a high state of perfec- 

 tion by tlie use of the Siemens regenera- 

 tive gas furnace. This is heated by gas 

 produced in the furnace itself. 



The greater part of the heat of the 

 gases coming from the furnaces is stored 



in regenerators, and this heat is used in 

 keeping up the temperature of the furnace. 



The 



regenerators are chambers of refractory brick placed 

 in horizontal layers, with spaces between them 



Fio. 5. Open hearth Furnace. 



tinually changing from exposure to the flame to full 

 immersion the fusion is very rapid, and the bottom, 

 being exposed to the flames at short intervals, ia 



