4:60 



METALLURGY. 



A slight difference is noticed with 0'20 per cent., 

 chiefly in an inferiority in bending properties in 

 pieces cut from the plates of acid open-hearth steel 

 across the direction of rolling after they have been 

 tempered. With 1 per cent, of arsenic the tenacity 

 is increased and the elongation slightly reduced, 

 while the bending properties are fairly good. The 

 changes are more evident when about 1| per cent, 

 of arsenic is present ; contraction of area is reduced, 

 and the bending properties are poor. With 4 per 

 cent, the tenacity is increased and the contraction 

 is reduced to zero. The trials with higher percent- 

 ages of arsenic were, however, not considered fully 

 satisfactory, on account of the small size of the 

 ingots used. An alloy containing 4 per cent, of 

 arsenic will stand about as much heat without 

 burning as a steel containing 1 per cent, of carbon. 

 When heated below the burning point, the material 

 can be hammered and rolled, and appears to be as 

 soft in that state as steel containing about 0'5 per 

 cent, of carbon. Hence the author infers that 

 arsenic has no tendency to produce red-shortness. 

 The effect of quenching steel containing arsenic in 

 large quantity after heating to a red heat was to 

 improve its bending property. Arsenical steel was 

 found not more liable to corrosion than similar 

 material without the arsenic ; in fact, oxidation 

 appeared to be retarded by the presence of small 

 quantities of arsenic. Arsenic appears to be most 

 injurious in steel that is to be welded ; and in such 

 steel even small quantities should be avoided. 



Summarizing the existing knowledge of the 

 molecular structure of hardened steel, M. Osmond 

 represents that in highly carbonized steels, contain- 

 ing more than T3 per cent, of carbon, quenched at 

 temperatures above 1,000' J C., there are two constitu- 

 ents, A and B, which differ widely in their proper- 

 ties. The constituent A is the ordinary hard, 

 strongly magnetic substance of which hardened 

 steel containing 1 per cent, of carbon is almost ex- 

 clusively composed. Its hardness is greater than 

 that of orthoclase. B, on the other hand, is only 

 about as hard as fluorspar, and, so far as can be 

 judged by a study of its properties while mixed 

 with A, is nonmagnetic. The author, however, has 

 not hitherto been able to prepare B free from A, 

 although by quenching steel containing T6 per cent. 

 of carbon at a temperature of from 1,000 C C. to 1,100 

 C. in ice-cold water, he has obtained a mixture of A 

 and B in about equal proportions. This mixture is 

 comparatively very feebly magnetic. The constitu- 

 ents both contain carbon, and exist side by side in 

 separate polyhedra. The author concludes that B 

 is the allotropic form of iron (denoted 7), which is 

 especially stable above 860 C., and is present to the 

 exclusion of the other forms of iron in steels con- 

 taining 25 per cent, of nickel, or from 12 to 13 per 

 cent, of manganese, which steels are nonmagnetic. 

 The hard constituent, A, would then be the allotropic 

 form B. 



The cause of " mysterious " fractures in steel used 

 by marine engineers has been investigated by A. E. 

 Seaton and J. 0. Arnold. Specimens were exam- 

 ined of a shaft of Siemens steel made by a well- 

 known firm of qualities duly certified to. which suf- 

 fered a "sudden and unexpected total failure" 

 after having been in continuous service for twelve 

 years and often tested. A quadrant of the trans- 

 verse section of the shaft was examined chemically 

 and microscopically by Prof. Arnold. The result 

 of the chemical examination indicated that the 

 ingot from which the shaft was forged must have 

 been cast very hot. In round numbers the carbon 

 in the center of the shaft was 50 per cent, higher 

 than that near the circumference. The manganese 

 had liquated with the carbon to some extent. The 

 phosphorus and sulphur of the core were each three 



times greater in quantity than at the circumference. 

 The composition of the steel proved highly unsatis- 

 factory as regarded purity, and the metal was also 

 too hard for the purpose intended. From this and 

 the microscopical examinations, Prof. Arnold con- 

 cludes that the core of the shaft had suffered from 

 bad chemical composition aggravated by liquation, 

 from pipe, and from unfavorable structural ar- 

 rangement of the constituents of the steel. The 

 center of the shaft, weakened by pipe, carbon, and 

 phosphorous hardness and brittle structure, and rid- 

 dled with sulphide of iron, was little tougher than 

 good gray pig iron. It is almost certain that a 

 number of sulphide flaws in the interior gradually 

 worked outward along -the crystalline junctions of 

 the fairly tough metal outside, until under a vibra- 

 tory shock of unusual force the whole mass rup- 

 tured. To this finding, Mr. Seaton adds some 

 observations on the superiority of microscopic to 

 chemical analysis for determining the qualities cf 

 steel, and the deduction that Prof. Arnold's results 

 tend to show the liability of all steel shafts to begin 

 disintegration from the center, whence the fractures 

 and fissures, when started, no doubt gradually spread 

 until they reach the surface. Also that such degra- 

 dation proceeds without visible indication, and total 

 rupture occurs without warning and apparently 

 mysteriously. There is every reason to believe that 

 as many fractures occur with wrought iron as with 

 steel ; but, owing to the laminated nature of wrought 

 iron, the fractures have been small and localized, 

 and seldom of so large and important a character 

 as with steel. 



The advantages of using small cast-steel ingots for 

 certain purposes are set forth in a paper by Richard 

 Smith Casson, of Birmingham, England. A system 

 of casting such ingots, patented by Mr. Thomas 

 Turner and Mr. Casson, is specially contrived for 

 the ingots to be run from the bottom. Its chief 

 features are the grouping of several molds in one 

 ingot-mold casting, the combination therewith of 

 the piling of the molds one upon the other in the 

 casting pit. and the insertion of a small fire-clay fer- 

 rule or division brick in a hole in the top of each 

 mold. In this way the steel rises from the lower 

 row of molds into the second row, and from the sec- 

 ond row into the third, and so on, till as many as 

 120 ingots, containing from 10 to 15 tons of steel, 

 have frequently been successfully cast through one 

 runner pipe. The ingots are virtually joined to- 

 gether without a runner at their adjacent tops and 

 bottoms ; but, notwithstanding this joining, they 

 practically fall away from one another during the 

 stripping, from the effect of contraction and of the 

 presence of the fire-clay division ferrule, which 

 maintains heat, and therefore softens in the neck 

 during the shrinkage of the remainder of the ingot. 



A discussion of the merits of the Walrand process 

 of manufacturing steel in the meeting of the British 

 Iron and Steel Institute at Bilbao. Spain, was intro- 

 duced by a paper by Mr. G. J. Snelus, who named six 

 important industrial centers where that process is 

 used. The process is a modification of the Besse- 

 mer process, adapted to the requirements of small 

 steel foundries, etc. The only modification that had 

 been made in the method since a paper was read 

 upon it two and one half years ago was the adjust- 

 ment of a detail whereby the metal was not so high- 

 ly oxidized, and a superior material was obtained. 

 The process was commended as being very econom- 

 ical ; as lending itself specially well to the manu- 

 facture of alloys ; and as probably capable of being 

 applied to larger operations of the Bessemer process. 

 It was shown to afford a remarkable facility for 

 using up scrap iron or steel ; the inventor, it was 

 said, had melted as much as 75 per cent, of scrap 

 by special means, and had made good castings with 





