OCR Text |
Show The Diseases "of Metals. Many metals show symptoms of poisoning, rendering them unlit for use Thus steel can, by means of small quantities of hydrogen and under certain cer-tain circumstances, be very seriously affected. Let us take two steel bars of the same material, both heated to a red heat, one surrounded by air, the other exposed to the Influence of hydro gen or hydrogen gas, chilling both bars In water after heating; We shall find the bar boated In hydrogen to be brittle whereas tho other bar, heated in air' will turn out to bo far superior. The hydrogen has in this instance acted like poison upon the heated steel, and very small quantities of suoh poisonous matter mat-ter will sufllco to produco very violent effects. The disease In question can be radically cured, it only being necessary to anneal the poisoned bar, repeating the process by heating oxnosed to air The poisoned steel, by being allowed to He for a long time, will, without anv further expert treatment. ,Bhow signs of improvement to a certain degree tho poison gradually leaving it. a better treatment still is boiling in water or oil. which process may be compared to using warm compresses In the case of human belncs. Similar symptoms of polsonin-caused-by hydrogen or gases containing hydrogen (as gas for lighting purposes) arc apparent In copper when exposed to red heat. ,Not every kind of copper is susceptible to this poisoning in equal decree. Metals can become diseased from Im- proper treatment, as, for instance cod-per cod-per and steol when exposed a certain cer-tain length of time to tepmeratures exceeding tlxed limits. Tho copper in consoquonc.s loses a great part of its f.'V y nd bendI"tr qualities. i fisel tho disease can become so virulent viru-lent that a steel bar so Infected car. in falling on the ground, break to pieces Tho technical expert calls such disease |