Hardening, tempering, annealing and forging of steel; a treatise on the practical treatment and working of high and low grade steel .. . he gas is out of the interiorcoal, and the outside is well caked, it may be broken up with abar, so that the gas may be burnt out of the outside, and thenthe blast may be stopped and the coke placed ready for use at amoments notice. Good blacksmiths always keep a store of thiscoke for use in making welding heats as well as for hardeningprocesses. . If an article has a very weak part, it is neces-sary to avoid resting that part upon the coal or charcoal of the
Hardening, tempering, annealing and forging of steel; a treatise on the practical treatment and working of high and low grade steel .. . he gas is out of the interiorcoal, and the outside is well caked, it may be broken up with abar, so that the gas may be burnt out of the outside, and thenthe blast may be stopped and the coke placed ready for use at amoments notice. Good blacksmiths always keep a store of thiscoke for use in making welding heats as well as for hardeningprocesses. . If an article has a very weak part, it is neces-sary to avoid resting that part upon the coal or charcoal of thefire; otherwise the weight may bend it, and in heating long slen-der pieces they should bed evenly in the fire or furnace, or, whenred hot, the unsupported parts will sag. In taking such piecesfrom the fire, the object is to lift the edges vertically so that thelifting shall not bend them; and this requires considerable skill,because it must be done quickly, or parts will become cooledand will warp, as well as not harden so much as the hotterparts. Quenching for now come to the cooling or quenching, which requires. FIG. 62.—MILLING CrTTER. THE HARDENING OF STEEL. lOI as much skill as the heating to prevent warping and cracking,and to straighten the article as much as possible during the cool-ing process. The cooling should be performed with the view toprevent the contraction of the metal from warping the weakerparts; and to aid this, in cutters of the type shown in , tooth parts are sometimes made a little hotter than «hemore solid parts of the article, the extra heat requiredto be extracted compensating in some degree for the di-minution of the sectional area from which the heat must beextracted. Water for cooling must be kept clean, and in that ^^^^ SHANK 1 strugftt I TIPW ! RESMER s H^H ^?^Ib^H iSJiil Hiilii M L ^ i f»»»V»»V»T»»»»V7S fV»»»»».»»»».»»»=-- : ^^ r * I C ^j-. S FIG. 63.—STAY BOLT TAP. case becomes better from use. It
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Keywords: ., bookcentury1900, bookdecade1900, bookidhardeningtem, bookyear1903
