442 



METALLURGY. 



curve was continuous throughout; but when 

 thp cooling wao from about 1,000, a point of 

 recovery was observed, indicating recalescence. 

 The speaker said he had arrived at the same 

 results, working independently. Mr Vickers 

 remarked upon the difficulty of deciding wheth- 

 er the effects noted were due to carbon or 

 chromium, as it seemed impossible to separate 

 the one from the other, the chromium invari- 

 ably disappearing with the carbon. Mr. P. W. 

 We'bb, engineer of the London and Northwest- 

 ern Railway, gave high praise to chromium 

 steel, saying he used it entirely for springs, and 

 also with advantage for tires. He also found it 

 an excellent material for tool steel. 



The high-carbon nickelized-steel armor plate, 

 which has been commended by the United 

 States naval authorities in the highest terms, 

 and has been adopted as the special protection 

 for American ships of war, has endured the 

 tests to which it was subjected by the British 

 Admiralty with great success. The accuracy of 

 the American reports was completely verified by 

 the results of the firing. The most remarkable 

 feature of the trial was the fact that the plate 

 withstood the punishment so well that not a 

 crack was produced. 



Bessemer steel for being drawn into wire 

 should not be too highly charged with carbon, 

 and should contain a sufficiency of manganese. 

 The rods are dipped for a half hour in sulphuric- 

 acid solution, and then kept wet till a dark- 

 green, slimy coating, turning brown, is formed 

 on them. They are then dipped quickly in 

 lime water, after which, the ends being pointed, 

 they are ready to be drawn. Reducing the wire 

 too much before annealing causes crystalliza- 

 tion, and the wire continues brittle and hard 

 after annealing. In the liquor-bright process 

 for making fine wire the rods are dipped twice 

 in sulphuric acid heated to not more than 130 D , 

 and dried between the dippings in the baking 

 oven till a red oxide is formed upon them. 

 Animal fat or grease is employed as a lubricant. 



A new steel-hardening process by G. H. Blake 

 has stood the severest tests at the Washington 

 Navy Yard. Cutting tools made of steel hard- 

 ened by it showed a keenness and tenacity of 

 edge in cutting iron that left nothing to be de- 

 sired. The most important test was made with 

 a low-priced steel which had been rejected as 

 useless, because it would not stand continuous 

 use. Tools of it hardened by Mr. Blake, sub- 

 jected to the same conditions, worked nearly 

 nine hours without grinding. 



Aluminum. By means of the electrolytic 

 methods of preparation, an enormous reduction 

 has been achieved in the cost of producing alu- 

 minum, particularly at the works in Neuhausen, 

 Switzerland, which are run by water power, so 

 that a metal of 99 per cent, guaranteed purity is 

 obtainable there, according to G. L. Addenbrooke, 

 at 2 shillings, or about 50 cents, or even less, per 

 pound. Alfred E. Hunt, of the Pittsburg Re- 

 duction Company, which has made a good many 

 tons of the metal of 99-80 per cent, purity, asserts 

 that by the Hall process it will be possible with- 

 in the next few years to produce aluminum at a 

 cost of between 18 and 20 cents per pound. In 

 this process there is practically no waste. Most 

 of the aluminum now manufactured is made by 



the process of Mr. Hall, of Pittsburg, or by that 

 of M. Heroult, which is employed at Neuhausen. 

 In both cases the reduction is made from the 

 oxide. This is dissolved in a fused flux, consist- 

 ing of fluorides of aluminum and sodium, and is 

 heated in electric furnaces with carbon anodes. 

 Decomposition takes place at a full red heat, 

 the alumina is resolved into its elements, the 

 oxygen partly uniting with the carbon to form 

 carbonic oxide, and partly escaping free, while 

 the aluminum sinks to the bottom and gradually 

 accumulates. The working quality of the metal 

 manufactured has greatly improved within the 

 last ten years by the reduction of the proportions 

 of iron and silicon, the chief impurities contained 

 in it. The pure metal is rather softer than cop- 

 per, and behaves in the same way, showing a 

 tendency to pull and tear and clog the tools ; it 

 does not cast quite so well, and is not so hard and 

 strong as when it contains from 2 to 3 per cent, 

 of silicon, though then its malleability is de- 

 creased, and it has a scratchy, sandy feel. The 

 addition of iron is detrimental. Copper hardens 

 the metal when added up to 5 or 6 per cent., be- 

 yond which brittleness is produced ; but Mr. Ad- 

 denbrooke's experiments in remelting the alloy 

 have not given favorable results. According to 

 Mr. Addenbrooke, zinc hardens aluminum and 

 toughens it when added to the extent of 3 or 4 

 per cent., but the alloy is not clean, is difficult to 

 turn, and does not stand remelting well. Tin, up 

 to 3 or 4 per cent., makes the aluminum short, 

 but improves its turning qualities; if 10 per 

 cent is added, the bar is at first as pliable as the 

 pure metal, and of about the same strength ; but 

 if this metal is once or twice remelted it soon 

 becomes crystalline. Nickel has much the same 

 effect, but when added to copper it produces a 

 closer grain, though still leaving a bad surface 

 under the tool. The chief difficulty in casting 

 aluminum, and many of its alloys, arises from 

 the brittleness it acquires by frequent remelt- 

 ing. An alloy of aluminum (23 per cent.) and 

 gold discovered by Prof. Roberts-Austen has a 

 crystalline structure and a very beautiful rose- 

 pink color, very different from anything that has 

 been observed in metal before. Of alloys of alu- 

 minum in general, it may be said that they de- 

 crease its malleability. The purer the metal the 

 better for rolling or drawing. Sheets of alumi- 

 num cold rolled become very hard and quite 

 springy, with a rigidity greater than that of or- 

 dinary brass sheets, will still stand a fair amount 

 of bending, and can quickly be made soft by 

 annealing. Aluminum lends itself readily to 

 stamping and spinning. It is very little affected 

 by sea water. 



Herr G. Rupp, in his experiments to determine 

 the adaptability of aluminum to the manufac- 

 ture of domestic utensils, used both drawn ves- 

 sels of aluminum and aluminum plate 1 milli- 

 metre in thickness. The vessels, having been 

 carefully cleaned, dried, and weighed, were sup- 

 plied with the aliments experimented upon, and 

 left for periods of from four to twenty-eight 

 days, with daily stirrings and shakings. Then 

 the contents of the vessels were examined for 

 the amount of aluminum that had gone into so- 

 lution, and cleaned, dried, and weighed again. 

 The experiments were conducted with white 

 wine and red wine, beer, cherry-water, cognac, 



