ACHIEVEMENTS OF CHEMICAL INDUSTRY — DUISBERG. 237 



even at 400 to 500° C. They are needed by engineers for the con- 

 struction of steam turbines, for the embossing and spraying of 

 metal objects when heated to redness, a process which has lately 

 found extensive application. Chemists use these lands of steel 

 whenever chemical reactions are carried out at high temperatures 

 and pressure, e. g., for the synthesis of ammonia according to Haber's 

 process. 



The very latest alloy has now been patented and is being manu- 

 factured by Krupp for the construction of safety vaults and safes. 

 This steel can neither be drilled nor exploded, nor can it be cut by 

 the oxyhydrogcn flame. 



Two samples of steel are exhibited, one of ordinary steel m which 

 great holes have been cut in five and one-half mmutcs by usmg an 

 oxyhydrogen flame and in six minutes by an oxyacetylene burner, 

 and a specimen of this new alloy which has remained intact after 

 being treated with the same oxyhydrogen and oxyacetylene flames 

 for one and one-half hours. Let us hope that on this hard and 

 infusible material the scientific safe burglar will exercise liis noble 

 art in vain. 



Manganese steel. — Of the alloys made vnih. manganese the manga- 

 nese steel or hard steel, first produced by Robert Hadfield, because 

 of its great wear is chiefly used for cast-iron parts of disintegrators 

 and rails of electric tramways. On account of its hardness this 

 steel is not malleable, but it can be bent in the cold state, and is 

 thus very safe against breaking. It is therefore of much interest to the 

 chemical industry where, in almost all branches, grinding operations 

 are carried out. 



Silicon steel. — Finally I wish to refer to alloys of iron and sihcon 

 which contain 1^ to 2^ per cent sihcon and a high percentage of 

 carbon. Tliis steel is excellently adapted for tools and springs which 

 must stand high strain. Smce steel alloys contaming much sihcon, 

 although brittle and porous, have proved very stable against acids, 

 they are now being used more and more where such a property is 

 of importance. 



Alloys with about 4 per cent sihcon, but very poor in carbon, are 

 of greater value than the above. Kobert Hadfield first pomted out 

 the importance of tliis alloy, wlulst Krupp, working in connection 

 with Capito and Klein, a firm of fine-plate rollers in the Rhineland, 

 considerably imi)roved it and introduced it for electric purposes. 

 It is employed in lai'ge quantities in the form of sheets of 0.35 milh- 

 meter (yV inch) thickness for the construction of dynamos, alternate- 

 current motors, and transformers. In Germany alone the consump- 

 tion of tliis alloy already amounts to 8,000 tons a year. Tliis material 

 has a resistance to electricity four or five tunes greater than that 

 of ordinary iron and loses only half as many watts, so that the inju- 



