The Monticellonian., 1902-10-16
CAST IRON IS mALLEABLE.
Modern Progress In Iron Working Has Produced Metal That Is
 Very UsefuI.

Once upon time malleable iron and east iron were two different things. They did not contain quite the same proportion of carbon, and were unlike in their qualities. The former could be worked on an anvil into any desir- able form. Malleable iron was the same as wrought iron. That was the stuff out of which the blacksmith made horseshoes, for instance. Cast iron was produced by pouring molten pig into a mold, and the casting was hard but brittle. The idea of changing the shape by subsequent heating and bend ing was not to be considered. Grinding off the surface or some particular projection was the most that was at tempted. Of late years, however, there has been a good deal of talk about malleable cast iron. This is an article which has been cast in mold, but pos sesses the toughness of the old-fash- toned wrought iron. A great deal of the machinery used on farm to-day is composed of this material. In the American Machinist Joseph V. Wood worth tells how it is made.
 When the metal is first cast in molds it comes out as brittle as glass. 1t must be handled with great care. But after it has been subjected to an an healing process it behaves in a differ ent manner, The castings are placed in iron boxes 24 inches long, 12 inches wide and t2 inches high, to be annealed. They are embedded loosely in mix ture of common sand, steel turnings and scale from steel rolling mills m ois- tened with ammonia. The ammonia keeps the scale and turnings from sticking to the castings. The boxes or pots go to brick ovens, which, at one factory described by Mir. Woodwork. have sides that are three feet thick and tops and bottoms four feet thick Flues run alongside of the chambers and heat the latter. A crude oil blast does the business.
 IT. each annealiHg oven pots contain. ing % tons of castings are packed a close together as possible, after which the vents and doors are sealed up an6 the ovens are heated. It requires q hours of steady blast to get the ovens anu NhStliSS tp q " liltN hCcb' iAAN v hiN then kept at that temperature for five days and five nights after which the blasts are turned off and the vents at the tops of the ovens opened. After the vents have been open for five hours the door is pulled down. and five hours later the nearest pots are removed, ano in the course of a few hours the others are taken out and allowed to cool They are then dumped and the castings are sorted. All that have cracked or blistered or are warped excessively are thrown out. The good castings are then sent 10 the straightening depart ment to be straightened and reformed so as to fit the figs and fixtures which are used for machining those which are required to be machined and to make the others interchangea ble. The straiehtenine and reforming of the castings are accomplished by dies ir powerful presses.
 These operations look costly. but they are conducted on such large scale that expense is trifiing for any individual casting. Were the objects thu- produced made in the old-fash. ioHed way by forcing. they would not ne nearly so cheap as they are now.