METALLURGY. (PROCESSES.) 



359 



dium, 61 tons tenacity and 14 per cent, elongation, 

 and when annealed 45 tons tenacity and 20 per 

 cent, elongation. These alloys, although very soft 

 when annealed, become very hard by tempering. 

 It is represented that a large supply of vanadium 

 would admit of its use in the manufacture of steel 

 furnace plates, forgings for ordnance and naval 

 machinery, projectiles, tools, rolls, etc., and various 

 bronzes. 



The causes of hot boxes in railway service and 

 the methods of preventing them have been investi- 

 gated and reported upon by Mr. Robert Job. Be- 

 sides the other usual means of studying the sub- 

 ject, the author was greatly aided by micro- 

 scopic examination of the material of which the 

 defective bearings were made. A wide variation 

 was found in the composition of the bearings. 

 Among the materials employed were the old cop- 

 per-tin alloy of 7 to 1 ; copper-zinc bearings run- 

 ning as high as 35 per cent, of zinc; phosphor 

 bronzes in moderate amount; and most numerous 

 of all, the copper-tin-lead compositions, varying 

 considerably in their proportions, but averaging 

 from 10 to 15 per cent, of tin, with from 15 to 

 5 per cent, of lead and copper. In the majority 

 of cases, however, the mere general composition 

 Avas found to have caused but a small part of the 

 difficulty. The main causes of friction and heating 

 are described by the author as segregation of the 

 metals, coarse crystalline structure, dross or ox- 

 idation products, and an excessive amount of 

 inclosed gas in the metal. Only a veiy small per- 

 centage of the bearings examined seemed to have 

 been discarded solely on account of defect from 

 lack of proper lubrication. Segregation was found 

 to be due in many cases to attempts to alloy the 

 metals in improper proportions. It is also fre- 

 quently caused by high heating, combined with 

 rapid pouring. It may be prevented to a certain 

 extent, even in a wrongly proportioned alloy, by 

 rapid chilling of the metal immediately after pour- 

 ing, but such practice is at the expense of the 

 ductility of the metal, and causes increased brittle- 

 ness with consequent rapid wear in service. The 

 effect of segregation is explained by the fact that 

 instead of an alloy of uniform hardness and heat- 

 ing capacity, a mixture is formed, some portions 

 of which are relatively very hard and others very 

 soft. The difference combined with that occasioned 

 by the varying heating capacity of the different 

 parts localizes friction. In a homogeneous alloy 

 no such conditions exist. The coarsely crystalline 

 structure observed in certain bearings was in some 

 cases found to be due to the composition of the 

 alloy, especially if antimony was present, and in 

 some others was traced to the foundry practice. 

 It was often due to rapid pouring at high tem- 

 perature and sometimes to an excess of materials 

 originally added as deoxidizing agents. Its effects 

 were increased local friction and material diminu- 

 tion of the ductility and tensile strength of the 

 metal. By the presence of dross or oxidized metal 

 mechanically inclosed hard cutting surfaces were 

 presented to the journal. The presence of occluded 

 gas in excess had the effect of reducing the actual 

 hearing surface of the brass, and thus of materially 

 increasing the pressure. In both of these cases 

 increased friction and consequent heating were the 

 sure result. 



In a paper read before the Mining Society of 

 Nova Scotia, Mr. A. C. Ross said that tungsten 

 was generally found associated with tin in wol- 

 framite. Its special value as an alloy of steel was 

 on accotmt of its hardening, toughening, and self- 

 tempering qualities. With an alloy of 9 per cent, 

 of tungsten a self -tempered tool steel of great dura- 

 bility is obtained. " Mushet " steel, manufactured 



at Sheffield, contains this percentage, and sells for 

 seven times as much as the highest priced ordinary 

 tool steel. Tungsten steel possesses strong mag- 

 netic properties, some specimens of it having the 

 high magnetic moment of 62 units, as against 37 

 units for " diamond " steel, 5 units for " Martin " 

 steel, and 3 units for " Bessemer " steel. The pro- 

 duction of the metal to-day in the world does not 

 exceed 1,000 tons. The demand is greatly in ex- 

 cess of the supply, even with the existing high 

 prices. Ore of tungsten had been discovered dur- 

 ing the past year in Nova Scotia of unascertained 

 extent, showing on analysis a composition of tung- 

 sten oxide 66.32, silica 4.26, manganese 12.02, iron 

 0.12. In the real wolfram the percentage of iron 

 is much higher, and this tungsten must be called 

 a hibrenite a mineral supposed to be rarer than 

 wolfram. Tungsten is a difficult metal to mine 

 owing to bunches in the vein, which itself twists 

 about in an extraordinary manner. Besides the, 

 present discovery, tungsten deposits are worked 

 in Germany and Bohemia and Texas, and the ore 

 has recently been found in Nevada. Tungsten also 

 occurs in the Cornish tin mines. 



In a paper read before the American Institute 

 of Mining Engineers, Mr. E. S. Sperry pointed 

 out that the occurrence of cracks during the roll- 

 ing of brass is due, at least in some cases, to the 

 presence of impurities in the copper. In a brass 

 composed of 60 per cent, of copper and 40 per cent, 

 of zinc the author found by adding different quan- 

 tities of antimony that when the amount of that 

 substance reached 0.02 per cent, its presence was 

 indicated by fracture in the rolled metal. 



Motor-car builders in France are using largely 

 in the construction of their vehicles an alloy of 

 aluminum and tungsten which they call " partini- 

 um." It is much cheaper than aluminum, is nearly 

 as light, and possesses greater resisting qualities. 

 The relative percentages of the constituent metals 

 are varied according to the qualities that are de- 

 sired in the alloy. Cast partinium has a specific 

 gravity of 2.890. In the rolled form the specific 

 gravity is 3. The elongation varies from 6 to 8 

 per cent., and the resistance is given as from 32 

 to 37 kilogrammes per square millimetre. 



Experiments on the alloys of gold and copper 

 made by Sir W. C. Roberts- Austen and T. Kirk 

 Rose show that the gold-copper series of alloys 

 present many points of similarity with the silver- 

 copper series, and that the main difference is only 

 one of degree, copper being apparently more solu- 

 ble in gold in the solid state than in silver. 



Processes. A new combustion process, de- 

 scribed by Mr. Paul J. Schlicht before the Frank- 

 lin Institute, is based upon the fact, which the 

 inventor has discovered, that if a current of air 

 is properly introduced into a chimney or flue 

 through which hot products of combustion are 

 escaping the air current will flow in a direction 

 contrary thereto, and becoming heated in contact 

 therewith will reach the sphere of combustion in 

 a condition highly favorable to the union of its 

 oxygen with all the combustible elements of the 

 fuel. By this system there is no solid and vary- 

 ing resistance to the air supply as in the old 

 process, due to accumulations of ashes and vary- 

 ing thickness of fuel, but there is a constant 

 supply of heated air that flows in contact with 

 the combustion products, and which is regulated 

 by the quantity of combustion products pass- 

 ing through the flue or chimney. The air for 

 combustion may be admitted at the top of the 

 chimney or through a flue leading to the same, 

 the place for admission being determined by the 

 conditions. The author finds that by the use of 

 his process he can, in both domestic and manu- 





