METALLURGY. (!ROX AND STEEL.) 



nid, which presented problems for solution 

 i .unely, the loss of heat contained in the iron, and 

 i lie slag. The heat lost in 100 tons of pig-iron 

 was equivalent to 4.1^5 tons of coal. Thus in a 

 blast-furnace plant producing 100,000 tons of 

 Cleveland pig yearly, the heat lost in the iron 

 would be equivalent to that given "by 4.125 tons 

 of coal. The total make of the Cleveland district 

 approximated 2.250,000 tons annually, and the 

 heat in that weight of iron would be equivalent 

 to that of 1)2.800 tons of coal. The heat in the 

 slag was a more serious item of waste. A furnace 

 working on Cleveland ironstone produced 30 hun- 

 dredweight of slag per ton of pig, or 150 tons of 

 slag to 100 tons of iron. The heat in loO^tons 

 of slag was equivalent to 10.3 tons of coal. Thus 

 in a blast-furnace plant producing 100,000 tons of 

 Cleveland pig yearly, the heat lost in the slag- 

 would be equivalent to 10,300 tons of coal. The 

 estimates of the author showed that a total of 

 2.<i70,000 tons of slag was produced yearly in 

 the Cleveland district. The heat in that weight 

 of slag was equivalent to 183,340 tons of coal, 

 and ii' we added to that the loss in the iron, the 

 total amounted to 270,140 tons of coal. At 10 

 shillings per ton that was equivalent to 138,- 

 070 as the sum representing the value of the 

 waste heat in the iron and slag of the Cleveland 

 district. It would of course be impossible to re- 

 cover all that waste heat and apply it to some 

 useful purpose, but a large proportion of it should 

 be reclaimed; and here was a problem for metal- 

 lurgists and engineers to solve. Another item of 

 waste was blast-furnace gases, although of late 

 "thrir value for use in gas-engines had been recog- 

 nized and in some instances they had been em- 

 ployed in that way. The president estimated that 

 the* waste from this source going on in the blast- 

 furnaces of the Cleveland district was equivalent 

 to 92,500 horse-power. The utilization of blast- 

 furnace slag was then considered. It had been 

 clearly shown that useful materials could be made 

 from it its application in the making of paving- 

 blocks, bricks, and slag cement, and as a fertilizer 

 being instanced and the problem was to make 

 the manufacture of such materials a success com- 

 mercially, and at the same time to find out some 

 other means of utilization which w^ould consume, 

 if possible, all the slag made. The president spoke 

 approvingly of the attempts being made to ex- 

 tract potassium cyanid from blast-furnace fumes, 

 and the desirability of producing a pure pig-iron 

 equal to the Swedish, as was done in America. 



The Profitable Utilization of Power from Blast- 

 Furnace Gases was the subject of a paper read by 

 Mr. B. H. Thwaites at the Glasgow meeting of 

 the Iron and Steel Institute. The author sug- 

 gested that in Great Britain, at least, the blast- 

 furnace might be made the center of cheap electric 

 power supply areas, and pointed out that its 

 function might under certain conditions become a 

 dual one, with the production of iron occupying a 

 secondary place. Thousands of horse-power were 

 being developed on the Continent at the present 

 time by the direct combustion of blast-furnace 

 gases, and with a thermal expenditure that a few 

 years ago would have been thought unattainable. 

 Numerous directions were suggested in which elec- 

 tric energy might, under suitable conditions, be 

 made available for industrial purposes. 



A dynamic method of cleansing blast-furnace 

 pases from dust, so as to make it possible to use 

 them for gas-engines, was described before the 

 Iron and Steel Institute by Mr. Adolphe Greiner. 

 It is based upon the principle of throwing the 

 dusty gases and a spray of water together by an 

 ordinary centrifugal fan against the periphery of 



the apparatus. The liquid and solid particles are 

 then expelled by an opening in the envelope, and 

 led away therefrom by a pipe in the lower part 

 of the fan casing, while the gases, which have be- 

 come w r ell mixed by the action of the rotating 

 blades, escape the orifice ready for use without 

 further treatment. 



The progress in the use of blast-furnace gases 

 in metallurgical practise has been very rapid, and 

 it is claimed in Nature of Jan. 3, 1901, that all the 

 difficulties in the way were successfully overcome 

 during 1900. A list of more than 33 blast-furnace 

 engines of from 200 to 1,000 horse-power each, in 

 operation in different European .establishments, is 

 given by Prof. Joseph W. Richards in the Journal 

 of the Franklin Institute. This author makes a 

 calculation based upon the figures from a blast- 

 furnace plant in eastern Pennsylvania showing 

 that a very great saving of power is possible by 

 the economical utilization of the blast-furnace 

 system. 



Iron and Steel. In a paper on the Correct 

 Treatment of Steel, in considering the effect that 

 composition and initial treatment have, as com- 

 pared with subsequent treatment, on the ultimate 

 properties of steel, Mr. C. H. Ridsdale said that 

 too much importance is attached to the composi- 

 tion per se, and too little to the right treatment. 

 He observed that every steel has a composition of 

 its own, and that a specimen made by one process 

 might be softer than a similar metal made by 

 another process, so that to condemn the second 

 as bad because it suffers under certain treatment 

 suitable to the first is obviously wrong. Dealing 

 with the effect of work on steel at different tem- 

 peratures, Mr. Ridsdale said that in cooling from 

 the molten condition the iron crystallizes first, 

 but the grains have no cohesion, owing to the soft- 

 ness of the impure mother-mass or cementing por- 

 tion, so that the material will easily break or 

 be red-short. As the cement becomes more plastic, 

 the metal can be readily worked, since the grains 

 can move freely in it, but in cooling, the grains are 

 likely to grow and produce brittleness. At a 

 lower temperature (about 1,000 C., orange or 

 bright red heat for soft steel), the critical point 

 is reached in which the cement and grains are of 

 equal hardness. Work at this stage breaks up 

 the grains and imparts toughness by the interlock- 

 ing of the grains and cement. If the finishing tem- 

 perature of rolling be high, the metal will soften, 

 but may become brittle with slow cooling, while 

 if it is too low, the hardness of rolling is not 

 entirely eliminated, so that the. temperature of 

 finishing should be between these tendencies. The 

 relative plasticity of the two constituents becomes 

 low through the Iow 7 er or red-heat stages until it 

 reaches the minimum stage at blue heat, about 

 316 to 370 C. At this stage the metal does not 

 uniformly receive the force applied to alter its 

 shape, and critical strains are set up, which, ow- 

 ing to the low temperature, have not time to ad- 

 just themselves during further cooling. The re-" 

 sultant metal is liable to rupture with* sudden 

 shock, or may yield to a slowly applied strain. 

 As the temperature gets below straw heat, 250 

 C., and until cold, the steel is more plastic than 

 at a blue heat, but becomes tender again below 

 zero. If a coarse-grain steel is rapidly heated, 

 the grains are broken up more efficiently than if 

 it is slowly heated. 



The results obtained in an investigation by W. 

 N. Hartley and Hugh Ramage of the spectra of 

 flames resulting from operations in the open- 

 hearth and basic Bessemer processes were differ- 

 ent from those which had been previously ob- 

 tained by observing the acid process. The con- 



