what is the definition of "forging" in manufacturing processes?

Question

what are various forging operations and what is meant by grain flow?

Answer 1

see: http://en.wikipedia.org/wiki/Forging

Answer 2

G'day Sunny Mania,

Thank you for your question.

Forging Forging is the term for shaping metal by plastic deformation. Cold forging is done at low temperatures, while conventional forging is done at high temperatures, which makes metal easier to shape and less likely to fracture.

A basic smithy contains a forge, sometimes called a hearth for heating the metals, commonly iron or steel to a temperature where the metal becomes malleable (typically red hot), or to a temperature where work hardening ceases to accumulate, an anvil to lay the metal pieces on while hammering, and a slack tub to rapidly cool, and thus harden, forged metal pieces in. Tools include tongs to hold the hot metal, and hammers to strike the hot metal.

Once the final shape has been forged, iron and steel in particular often get some type of heat treatment. This can result in various degrees of hardening or softening depending on the details of the treatment.

In modern times, industrial forging is commonly done either with machine presses or with hammers powered by steam or compressed air. These hammers are very large, having reciprocating weights in the thousands of pounds. Smaller power hammers, 500 pounds or less reciprocating weight, and hydraulic presses are common in art smithies as well.

In industry a distinction is made between open- and closed-die forging. In open-die work the metal is free to move except where contacted by the hammer, anvil, or other (often hand-held) tooling. In closed-die work the material is placed in a die resembling a mold, which it is forced to fill by the application of pressure. A great many common objects, like wrenches and crankshafts, are produced by closed-die forging, which is well suited to mass production. Open-die forging lends itself to very short runs and is appropriate for art smithing and custom work.

Closed-die forging is more expensive for mass production than is casting, but produces a much stronger part, and is therefore used for tools, high-strength machine parts and the like. One particular variant, drop forging, is often used to mass produce flat wrenches and other household tools.

The grain flow of the metal changes during the e forging process making it stronger and more ductile than casting or machining. Its directions are aligned so that it flows in the same direction.

I have attached sources for your reference.

Answer 3

it's hammered into shape, not formed by material removal(machining) or by metal being cast into a finished shape, a piece of stock is literally hammered into the desired shape