508 



METALLURGY. (!RON, STEEL.) 



An invention for the ma .ufacture of continu- 

 ous sheets of malleable iron and steel direct 

 from fluid metal was described by Sir Henry 

 Bessemer at the annual meeting of the Iron and 

 Steel Institute. The author's first experiments 

 were made in 1856, and resulted in his being 

 able to produce a thin sheet some 3 or 4 feet in 

 length. The sheet had a clear surface, was 

 nearly free from oxidation, and absolutely five 

 from scale. It was as tough as any rolled-iron 

 plate he had ever seen, and it left no doubt in 

 his mind of the entire success of this system of 

 rolling thin sheets direct from molten metal. 

 The invention was patented, but did not find 

 favor with manufacturers. Since then the au- 

 thor had made improvements by which he pro- 

 posed to remedy its defects, and it now became 

 a question which was the least costly mode of 

 dealing with a ladleful of fluid steel forming it 

 into massive ingots in molds or making it into 

 thin sheets in the manner proposed ? 



In a paper at the Iron and Steel Institute on 

 " Illustrations of Progress in Materials for Ship- 

 building and Engineering at the Royal Naval 

 Exhibition," Mr. W. H. White referred specially 

 to the specimens of bending, stamping, flanging, 

 and welding as showing the relative behavior of 

 rnild steel and iron under the shock of powerful 

 explosives, and as serving also as a useful re- 

 minder of the enormous advantages and great 

 economies which had resulted from the substi- 

 tution of mild steel for iron in structures made 

 up of plates and stiffening bars. Allusion was 

 made to the increased sizes of plates now supplied 

 in steel, and it was said that the difficulties ex- 

 perienced in welding mild steel have practi- 

 cally disappeared. The exhibits of forged steel 

 and cast steel were described, and the ram-stem 

 castings in war ships were especially referred to. 

 When these were made in forged iron, the rab- 

 bets to receive the armor plating, shell plating, 

 etc., the special forms required for the spur, and 

 the arrangements for attaching decks, breast- 

 hooks, etc., all had to be obtained by costly ma- 

 chine work, often involving months of almost 

 continuous labor, after the forging had come out 

 of the shop completed as far as the hammer 

 could do the work. Under these conditions it 

 was not unusual to see the central portions of 

 war ships far advanced, while work at the bow 

 and stern were untouched because of the want of 

 stems and stern posts. Now, thanks to the use 

 of steel castings, no such delay was necessary. 



A new method of testing the hardness of iron 

 and steel during manufacture has been devised 

 by A. C. Caspersson, of Forsbacka Iron Works, 

 Margretshill, Sweden, who conducts a current of 

 electricity through a test piece of iron or steel 

 allowing the current to melt the metal ; upon 

 which the strength of the current required in 

 the operation is compared with the strength of 

 current required for the fusion of a standard 

 piece of metal of determined degree of hardness. 



Part of Sir Frederick Abel's address at the 

 opening meeting of the Iron and Steel Institute 

 was de-voted to the self-destruction, if that term 

 may beNjsed, of steel projectiles by the develop- 

 ment of cracks. Steel projectiles may be received 

 from the manufacturer to all appearance sound," 

 yet after a time cracks will develop themselves. 

 In extreme cases the occurrence has been so sud- 



den that a violent rupture, attended by a sharp 

 report, has taken place. The cause doubtless is 

 the surface treatment to which the shot is sub- 

 jected in order to get the requisite hardness, 

 which leads to internal strains being set up. In 

 one case mentioned, the head of the projectile 

 had been thrown to a distance of many feet by 

 the violent spontaneous rupture of the metal. 

 The importance of rest in bringing about a 

 diminution, if not a disappearance, of internal 

 strains in masses of metal is illustrated by the 

 behavior of chrome-steel projectiles which had 

 to be stored for several months before their 

 transportation to a distance could be ventured 

 upon. The tendency to the development of 

 cracks in tempered steel dies was discussed in a 

 letter written to the speaker by Thomas Graham, 

 when master of the mint, who said it was con- 

 sidered that if such dies were kept in store for a 

 year or two, they became less apt to crack when 

 in use, and coined more pieces than dies newly 

 tempered. The same phenomena had to be con- 

 sidered in the manufacture of steel ordnance, a 

 fact which enforces the objections of those who 

 are opposed to oil-hardening the parts of a steel 

 gun, the development by which of minute fissures 

 or cracks in the metal was also referred to by 

 the speaker. 



Describing a new automatic hydraulic forging 

 press that had been erected in Manchester, Mr. 

 W. D. Allen, in the Iron and Steel Institute, 

 said that it was essential in the production of 

 heavy forgings from cast ingots of mild steel, 

 thnt the mass of metal should be operated on as 

 nearly as possible throughout its entire thick- 

 ness. When employing a steel hammer for this 

 purpose, it had been found that the external sur- 

 face of the ingot absorbed a large proportion of 

 the sudden impact of the blow, and that a com- 

 paratively small effect only was produced on the 

 central portion of the ingot, because of the re- 

 sistance offered by the vis inertia of the mass to 

 the rapid motion of the falling hammer a dis- 

 advantage that was entirely overcome by the 

 slow, though powerful, compression of th'e hy- 

 draulic forging press, which seemed destined to 

 supersede the steam hammer for the production 

 of massive steel forgings. 



In the process invented by Capt. G. Fcodos- 

 sieff, of St. Petersburg, for tempering steel, glyc- 

 erin is employed for hardening, tempering, or 

 annealing steels, cast steel, or cast iron. The 

 specific gravity of the glycerin is graduated, ac 

 cording to the composition of the steel and the 

 effect desired, by adding water. The quantity of 

 glycerin is from one to six times greater in 

 weight than the pieces to be plunged into it, and 

 its temperature is varied, according to the hard- 

 ness of the metal, from 15 to 200 C., a higher 

 temperature being employed for tempering the 

 hardened steels, while a lower temperature is 

 used for tempering the milder steels. 



The investigations by M. H. Le Chatelier of 

 the influence of hardening on the electrical re- 

 sistance of steel have been extended to a new 

 series of metals and alloys. These metals, which 

 show no molecular changes before fusing, have 

 electrical resistances that vary directly with the 

 temperature, plus a constant. Copper, silver, 

 and their alloys have almost an identical coeffi- 

 cient for temperature, while the coefficient for 



