480 



METALLURGY. 



with bone dust or old leather that has been burned 

 The box is next placed in a brisk fire and allowed 

 to remain about one hour, or until no doubt is 

 left that all parts of the iron are heated to red- 

 ness. The contents of the box are then dumped 

 quickly into water. This operation requires 

 great care, as the air must not strike the iron be- 

 fore it reaches the water. Special apparatus and 

 practice are necessary to give the iron the de- 

 sired blue-gray mottled color, for if the air 

 touches the iron it assumes a black or blue-black 

 streaked hue accordingly as the experiment is 

 more or less imperfect. After the case-hardened 

 iron is cooled it is varnished. 



A new process for enameling iron, introduced 

 bj^M. 0. de Rochefort Lucjay, depends upon a 

 chemical action which can be produced upon 

 iron with the aid of another metal. The opera- 

 tor causes a thin adherent pellicle of another 

 metal to be formed on the iron or casting, and 

 exposes it to a heat of 1000 C. in a current of 

 a gas having oxidizing properties. The oxygen 

 penetrates the pellicle and forms a magnetic 

 oxide. This oxide increases as the exposure to 

 the oxidizing current and the heat is continued, 

 forming deeper within the metal as long as the 

 process is kept up. The pellicle of metal first 

 deposited disappears, forming oxides which com- 

 bine with the magnetic oxide, or being volatilized 

 according to what metal is employed. Bronze 

 lias been found by M. Bertrand to be the best 

 metal for this purpose, and the electric process 

 or the dip bath with sulpho-phenic acid the best 

 method of effecting the deposit. 



An ironmaster of Wolverhampton, England, 

 has patented a process for removing the coat- 

 ings from waste tinned and galvanized iron and 

 considerably increasing the value of the iron, 

 which is usually of good quality and capable of 

 standing a high tensile strain. 



An abstract of five series of tests made at the 

 Massachusetts Arsenal to determine the effect of 

 temperature on iron indicate that the strength 

 of steel is greater at about 500 F. than it is 

 at 79 F. The tests were made with five differ- 

 ent qualities of steel, containing, respectively, 

 0-09, 0-20, 0-31,0-37, and 0-51 percent, of carbon, 

 and the percentage of strength was obtained by 

 dividing the tensile strength of a sample at the 

 given temperature by the strength of the same 

 quality of steel at 70. The specimens were 

 stronger in the neighborhood of zero, Fahren- 

 heit, than at ordinary temperatures all of them 

 showing a minimum of strength at 210 F., or 

 thereabouts, and a maximum of strength at about 

 550 F. 



The new electric process for welding iron, 

 of Mr. Julien, of Brussels, is based upon the fact 

 that if one pole of a source of electricity is 

 plunged into acidulated water, or water having 

 in it a salt solution, and a sufficiently strong 

 electric current is passed through, oxygen is 

 given off at the (lead) anode, and hydrogen at 

 the (iron) cathode. By increasing the current 

 the evolution of gas can be augmented to such a 

 degree that the iron bar, surrounded by hydrogen, 

 is no longer in contact with the solution. As, 

 however, the hydrogen " envelope " offers great 

 resistance to the passage of the current, consider- 

 able heating takes place, whereby the " envelope " 

 and the iron bar are brought to a white heat or 



glowing condition. In this way temperatures up 

 to 4000 F. can, it is said, be attained. 



C. B. Adams, of the Wabash Railroad, has ob- 

 served that after removing some main-line rails 

 and relaying them on another part of the road, 

 many of them gave out immediately, while 

 others manifested no signs of wear. An investi- 

 gation of the matter showed that the road from 

 which the rails had been removed was built in a 

 northwest to southeast direction, and that, in re- 

 laying, a large number of rails had been turned 

 end for end. Those that had not been so placed 

 exhibited no additional loss by attrition, while 

 the turned rails succumbed in from thirty to 

 ninety days. The conclusion was that the metal 

 had been polarized from long use when first 

 laid, and that the fiber was broken up by the 

 traffic in the opposite direction from that in 

 which it had been formed. It was also found 

 that cast-iron wheels generally yielded twice the 

 mileage when the cars were turned at each end 

 of the journey than when they were run back- 

 ward and forward. 



L. J. D. Halter has produced a new kind of 

 steel which is characterized by its specific com- 

 position, and is more especially adapted for the 

 manufacture of springs of all kinds. It is claimed 

 that springs made of this steel are capable of sup- 

 porting, without permanent set, much heavier 

 loads then springs now in use. The following 

 are the component parts of the steel : 



Silicon 1-8 to 2-2 percent. 



Carbon 0'85to<V45 " 



Manganese 0-46toO - 55 " 



The process of manufacture remains practically 

 the same as for ordinary steel, the proportion of 

 the ingredients alone being varied. The metal 

 is tempered at a higher temperature than usual 

 i. e. at from 900 to 1000 C. 



To increase the yield of steel in the Bessemer 

 and Siemens processes, J. Colley and T. Twynam 

 utilize some of the excess of heat and the heat 

 giving metalloids in the pig iron to be converted 

 for the direct reduction of iron oxides, which 

 oxides are thereby converted into steel simul- 

 taneously with the pig iron. 



M. Sergius Kern concludes that the best re- 

 ducing addition for steel castings is silico-spiegel 

 with 10 per cent, of silicon and 12 per cent, of 

 manganese. After casting, the products should 

 contain from 0'25 to 0'30 per cent, of silicon. 

 Mr. J. W. Spencer, of the Newburn Steel Works, 

 made experiments to the same end, almost 

 simultaneously with M. Kern, and arrived at 

 nearly identical results. Aluminium was found 

 to be an excellent reducing agent, decomposing 

 the oxides and giving a metal without blowholes. 

 But in castings of 165 to 250 kilogrammes it 

 yields a crystalline structure which is defective. 

 The presence of this metal increases the resist- 

 ance to breakage. 



In a new method, employed at Birmingham, 

 England, for making weldless cold-drawn steel 

 tubes suitable for bicycle-making, and other 

 machine work where strength, lightness, and 

 accuracy are required, the steel used is of special 

 quality, and is received from the steel works in 

 the form of sheets. Circular flat disks are next 

 cut out of the sheets ; these disks are pressed into 

 the form of shallow cups, which are then passed 

 successively through dies of decreasing diameter, 



