METALLURGY. 



479 





METALLURGY. Iron and Steel. Ex- 



pt-rimi'iits nf H. S. Dyer on the production of 

 pure iron in t lie basic furnace were made with 

 (lu> object of nhtaining such an iron in order to 

 determine the value of alloys. By working on 

 the lines that, he followed, the author hopes that 

 pun- iron and steel may be produced at reason- 

 able cost. In the first experiments the furnace 

 was charged in the ordinary manner with pig 

 and scrap of fairly good quality, and the charge 

 was worked slowly, care being taken, by liberal 

 additions of limestone, to keep the slag well 

 saturated with lime. The phosphorus was re- 

 duced during the process, but the result left 

 much to be desired in other respects. Charges 

 composed of from one half to four fifths of good 

 scrap, and one half to one fifth of good Swedish 

 pig, were then worked very quickly, and a re- 

 markably pure iron was obtained. The next 

 stage of Col. Dyer's experiments had for their 

 object the utilization of ordinary scrap steel and 

 the production, in the basic furnace, of steel 

 high in carbon and low in phosphorus, and at 

 the same time to decrease the wear and tear of 

 the furnace. The principle of the process con- 

 sists in melting scrap with carbonaceous mate- 

 rial. The results of the experiments showed 

 that when a pure carbonaceous material and 

 ferro-manganese free from phosphorus can be 

 obtained, there will be no difficulty in produc- 

 ing a pure carbide of iron containing only suf- 

 ficient manganese for forging. 



As the result of a wide series of experiments, 

 the Valentine Iron Company, Bellefonte, Pa., has 

 determined as the range within which the pig 

 iron should run, varying somewhat for light or 

 heavy work : Silicon, 2'50 to 3-75 ; graphite car- 

 bon, 2-75 to 3-25 ; combined carbon, 0-25 to 0'75 ; 

 manganese, 0'30 to 0'70 ; phosphorus, 0'40 to 

 0-80; sulphur, not more than 0-06 per cent. 

 Some of the finest machine borings the com- 

 pany has ever seen, obtained from a sewing-ma- 

 chine company, showed the analysis of the cast- 

 ing to be: Silicon, 2'82; graphite carbon, 3'36; 

 combined carbon, 0-16; manganese, 0-67; phos- 

 phorus, 0'60; sulphur, 0'05 per cent. 



Metallurgical experts, searching for methods 

 for the removal of sulphur from iron, have tried 

 many processes, but abandoned most of them. 

 All are based on the use, in one way or another, 

 of alkaline or basic materials. In the method 

 described by Mr. Stead and Mr. Sainter before 

 the Iron and Steel Institute, calcium chloride is 

 the purifying material in admixture with iron, 

 and the process is adapted either for purifying 

 fluid iron or pig iron direct from the blast fur- 

 nace. The fluid metal is run into a ladle hav- 

 ing a layer of the purifying materials at the bot- 

 tom, and afterward running the metal into pigs 

 or plate metal for subsequent use in the puddling 

 process; or the crude sulphury pig may be treat- 

 ed in the basic Siemens furnace or Bessemer con- 

 verter with the desulphurizing mixture. About 

 70 per cent, of sulphur can be removed from the 

 charge of metal in an open-hearth furnace by 

 this process, which is in practical working at 

 Wigan. 



To the numerous ferro-compounds, in which 

 the qualities of iron are modified by mixture of 

 such substances as silicon, chromium, aluminium, 

 etc., H. N. Warren has contributed a research on 



boroneisen, or boron iron. Prepared by mixing 

 solutions of borax and ferrous chloride and re- 

 ducing with carbon, a boron iron having from 

 4 to 5 percent, of boron breaks with the fracture 

 of metallic manganese, is hard enough to scratch 

 glass readily, is soluble with difficulty in acids, 

 and has a melting point approaching that of cast 

 iron. A more economical method of preparation 

 is by reducing ferric carbonate or oxide in ad- 

 mixture with boron oxide and charcoal. The 

 most peculiar property of the compound thus 

 obtained is its great predominancy when in ad- 

 mixture with large quantities of iron. One 

 ounce of the boride thus melted with about two 

 pounds of iron causes the whole to break with 

 almost an analogous fracture to that of the 4>o- 

 ron compound itself, while it contains only the 

 fraction of a percentage of boron. The boron 

 iron thus produced casts more soundly, expands 

 slightly, and is free from blowholes. 



Trials have been made during the past two or 

 three years, with the most satisfactory results, 

 of armor plates and projectiles hardened or 

 snpercarburized by the Harvey process. This 

 invention of H. A. Harvey, of Orange, N. J., is 

 essentially a cementation process, in which the 

 steel is treated under special conditions. The 

 armor plate is made either from a steel compara- 

 tively low in carbon, or a high-carbon nickel 

 steel, and is laid flat upon a bed of finely pow- 

 dered dry clay, deposited upon the bottom of a 

 fire-brick compartment erected within the heat- 

 ing chamber of a furnace. The treating com- 

 partment is then partially filled up with granular 

 carbonaceous material, which, having been 

 rammed down upon the plate, is covered with a 

 stratum of sand, upon which is laid a covering 

 of fire bricks. The furnace is then raised to an 

 intense heat, which is kept up for such time as 

 may be required for the absorption by the metal 

 adjoining the upper surface of the plate of the 

 quantity of carbon, in addition to that originally 

 present, which may be necessary to enable the 

 metal to acquire the capacity of hardening to 

 the desired degree. After the carburizing treat- 

 ment the plate is taken from the furnace, and 

 without removal of the carbonaceous material 

 from its surface is allowed to cool down to the 

 proper temperature for chilling. During the 

 cooling operation the carbonaceous material pro- 

 tects the hot supercarburized surface from the 

 air. and thus prevents the formation of scale, 

 which, if present, would interfere with the sub- 

 sequent hardening of the metal. When the su- 

 percarburized surface is so far cooled down as to 

 nave a dull cherry-red color, the carbonaceous 

 material is quickly removed, and the plate is 

 then chilled by being sprayed with cold fluid, or 

 by being submerged and kept in motion until 

 cold in a large body of cooling fluid. Certain 

 difficulties in the practical operation of this pro- 

 cess, arising out of the disposition of powdered 

 charcoal to fly off in dust, are obviated by a modi- 

 fication introduced by Mr. Harvey, in which the 

 carbonaceous treating bed is formed partly of 

 finely powdered wood charcoal and partly of 

 animal charcoal. 



In a process for mottling iron, recently intro- 

 duced, the iron particles to be case hardened, 

 having been cleansed, are brightly polished and 

 then placed in an iron box and covered either 



