Brittle at a red or forging heat.
Many of the patent bronzes are by slight variations in the proportions of the constituents made suitable for casting, for forging, and for rolling into sheets.
17), a presbyter in Asia, who out of honour to Paul wrote the Acts, forging at the same time 3 Corinthians.
The divine smith naturally became a "culture-god"; in Crete the invention of forging in iron was attributed to him, and he was honoured by all metal-workers.
Iron founding and forging, which have their chief centre at Pamiers, are principal industries.
A dishonest means of satisfying the craving for relics was that of forging them, and how common this became can be gathered from the many complaints about spurious relics (Sulp. Sev.
However this may be, very soon after man began to practise hot-forging he would inevitably learn that sudden cooling, by quenching in water, made a large proportion of his metal, his steel, extremely hard and brittle, because he would certainly try by this very quenching to avoid the inconvenience of having the hot metal about.
By forging or rolling.
The shaping processes include the mechanical ones, such as rolling, forging and wire-drawing, and the remelting ones such as the crucible process of melting wrought iron or steel in crucibles and casting it in ingots for the manufacture of the best kinds of tool steel.
But deepseated blowholes like those at B are relatively harmless in lowcarbon easily welding steel, because the subsequent operation of forging or rolling usually obliterates them by welding their sides firmly together.
Though the former certainly seems the simpler way, yet its technical difficulties are so great that it is in fact much the more expensive, and therefore it is in general used only in making objects of a shape hard to give by forging or rolling.
In forging, whether under a hammer or under a press, the action is evidently a squeeze, however skilfully guided.
It is also very much cheaper than forging, in large part because it works so quickly.
The piece travels through the rolls very rapidly, so that the reduction takes place over its whole length in a very few seconds, whereas in forging, whether under hammer or press, after one part of the piece has been compressed the piece must next be raised, moved forward, and placed so that the hammer or press may compress the next part of its length.
The fact that rolling is so much cheaper than forging has led engineers to design their pieces so that they can be made by rolling, i.e.
When we come to pieces of very irregular shape, such as crank-shafts, anchors, trunnions, &c., we must resort to forging, except for purposes for which unforged castings are good enough.
Nutand bolt-making machinery, both for forging and screw cutting, operates automatically, and drilling machinery is highly specialized.
This axis is a hollow forging of nickel steel, of which the accurately turned pivots rest on bearings attached to cast-iron uprights bolted upon a massive cast-iron base plate.
The close of the 19th century witnessed the forging of the final links in the great geodetic triangulation of India, so far as the peninsula is concerned.
On one occasion an infantry division of 8000 men repaired 102 miles of railway and built 182 bridges in 40 days, forging their own tools and using local resources.
In order to economize power in these operations, the metal should in general be as soft and hence as hot as is consistent with its reachingalow temperature before the rolling or forging is finished, because, as explained in § 32, undisturbed cooling from a high temperature injures the metal.
Rolling, Forging, and Drawing.
Because of these facts the great hammers have given place to enormous forging presses, the 125-ton Bethlehem hammer, for instance, to a 14,000-ton hydraulic press, moved by water under a pressure of FIG.
But in all the great modern manufacturing processes it is true that metals and alloys, though of the same name, have a different composition according as they are intended for casting on the one hand, or for forging, rolling and drawing on the other.
It has a well-equipped drawing room, carpenter shop, forging room, foundry, science laboratories and machinery department, in which expert instruction is given.
Thus it comes about that rolling is so very much cheaper than either forging or drawing that these latter processes are used only when rolling is impracticable.
Forging proceeds by beating or squeezing the piece under treatment from its initial into its final shape, as for instance by hammering a square ingot or bloom first on one corner and then on another until it is reduced to a cylindrical shape as shown at A in fig.
When the first Europeans visited the Malay Archipelago the Malays had already acquired the art of manufacturing gunpowder and forging canon.