OCR Text |
Show IB New Way of Toughening, j la a novol method of toughing lately brought out, the raotal treated Is jf placed In a closed rotort with a small l ; quuntlty of mercury, the rotort Is sub. & Jeeted to pressure, and as It Is heated M to a point below melting temperature iJ a current of electrlcty is passed ' through the metal. Besides increased f 1 tougbscss, greater reslstncco is given la Ut effWlon by ses, 'water and other T bhU. Tka hardening Is especially l.t adapted for lroa and steel, but Is ii ol&laMd to be uscfdl, for other metals. |