forging

FORGING

Presented by \u2013 Rajatabh Banerjee

HISTORY OF

FORGING

As with the cultural history of man, the history of metals springs from the land between the Tigris and the Euphrates, once called Mesopotamia. The earliest signs of metalworking date back to about 4500 B.C.

The inhabitants of this fertile valley were the Sumerians. These people, a mixture of many ethnic backgrounds, were the true founders of metallurgy as we know it today.

\ue000Forging

as an art form started with the desire to produce decorative objects from precious metals. Today, forging is a major world-wide industry that has significantly contributed to the development of man.

Post Medieval (1600 ) Post Medieval (1600 ) True use of deliberate cast iron does not develop untill the introduction of coal as a smelting fuel in the very late 1500's on the continent and into the early 1600's in England.

By the time of Jamestown Virginia (1610 +) there are starting to be small pots available. These were extremely expensive and limited to the upper class. Think of the 'witches caldron' shape with three legs, maybe holding one or two gallons.

Settlement Era (1700 ) GENERAL use of cast ironCast iron becomes easier to produce and control. It still is expensive, but prices and availability have dropped to the point that many families can afford a SINGLE pot or pan.

Industrial Age (1820 ) EXTENSIVE use of cast ironCast iron cookware will not become both cheap and widespread until the introduction of steam powered technologies. The Victorian period has the largest use of cast iron for all kinds of objects, from personal goods to architectureal.

19th and 20th CENTURY Forging industry saw a new revolution in the world with wide use in many of the metalware industry.

FORGING TERMINOLOGIES

Cold forging: These include bending, cold drawing, cold heading, coining extrusion (forward or backward), punching, thread rolling and others.

Hot forging: plastically deforming an alloy at a temperature above its recrystallization point, i.e., high enough to avoid strain hardening.

Open Die Forgings / Hand Forgings: Made with repeated blows in an open die, The operator manipulates the workpiece in the die. Impression Die Forgings / Precision Forgings: Are further refinements of the blocker forgings. The finished part more closely resembles the die impression.

Anvil serves as a work bench to the blacksmith, where the metal to be beaten is placed. made of cast or wrought iron with a tool steel face welded on The flat top has two holes; the wider is called the hardy hole, where the square shank of the hardy fits. The smaller hole is called the punch hole, used as clearance when punching holes in hot metal

ADVANTAGES AND DISADVANTAGES OF FORGING ADVANTAGE • Uniformity of qualities for parts subject to high stress and loads. • No weight loss. • Close tolerance. • Less machining or no machining in some cases. • Smooth surface. • High speed of production. • Incorporation in welded structures, i.e., what can be welded easily.

DISADVANTAGES • • •

High tool cost. High tool maintenance. Limitation in size and shape.

HOT FORGING – DISADVANTAGES ADVANTAGES • • Undesirable reactions between the Decrease in yield strength, metal and the surrounding therefore it is easier to work atmosphere (scaling, or rapid and takes less energy (force). oxidation, of the work piece). •

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Increase in ductility. Elevated temperatures increase diffusion which can remove or reduce chemical inhomogeneities. Pores may reduce in size or close completely during deformation.

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Less precise tolerances due to thermal contraction and warping from uneven cooling. Grain structure may vary throughout the metal for various reasons. Requires a heating unit of some kind such as a gas or diesel furnace or an induction heater, which can be very expensive.

COLD FORGING – ADVANTAGES •

No heating required.

DISADVANTAGES •

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Better surface finish.

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Better reproducibility and interchangeability. Directional properties can be imparted into the metal.

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Contamination problems are minimized. •

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Higher forces are required. Heavier and more powerful equipment and stronger tooling are required. Metal is less ductile. Metal surfaces must be clean and scalefree. Intermediate anneals may be required to compensate for loss of ductility that accompanies strain hardening. The imparted directional properties may be detrimental.

Undesirable residual stress may be produced.

Forging applications FORGING refers to the production of those parts which must be heated in a closed furnace . The portion of work in which forging is done is termed as the forge and the work is mainly performed by the means of hammers, machines and presses. Forging processes are among the most important manufacturing techniques since its used in small tools ,rail road equipment ,automobile ,aviation sector ,as well as home and other accessories .

Knives

Punching tool

Steel clamps

Forging can be used in home accessories like lamps, kitchenware and screws .

Upset or machine forging Forging of ring and rod types with all kinds of heads such as bolts,nuts ,washers and collars ,gears etc that can be produced conveniently in forging machine .

Another application can be in making gears of various sizes used in machines .

Press forging Press forging is done in presses rather than with hammers .the action is relatively slow squeezing instead of delivering heavy blows and penetrates deeply because it gives metal time to flow .

Towel holders. A hook is there so that the towel can be hung

Drop forging Drop forging is a metal shaping process in which a heated workpiece is formed by rapid closing of a punch and die forcing the workpiece to conform to a die cavity. A workpiece may be forged by a series of punch and die operations (or by several cavities in the same die) to gradually change its shape. Drop forging is also called impression die or closed die forging, or rot forging.

Press Forging Press Forging is a process whereby slow pressure is continuously applied to the area to be shaped. The pressure extends through the material which can be either hot or cold. Cold press forging is primarily used on thin materials, while hot press forging is preferred for larger work such as parts for trains and heavy machinery

The pressure necessary to form to steel at forging temperature varies from about 3000psi(pounds per square inch) 27,000psi (20 to 190MPa). These pressure are based on the cross-section area of the forging when measured across the surface of the die at the parting line Press capacity is expressed as P= F/A 2000 P= Pressure required,psi F= Pressure capacity, tons A= Area of the forging at the parting line

Process

Press forging is done in presses rather than with hammers .The action is relatively slow squeezing of delivering heavy blows and penetrates deeply because it gives the metal time to flow .Dies may have less drafts, and the forging comes nearer to the desired sizes . Pressed forgings are shaped at each impression with a single smooth stroke and they stick to the die impression more rigidly . Unless some provision is ,therefore , made the escape of air and excess die lubricant may be difficult .Thus press forging dies require a mechanical means for ejecting the forging are venting for escape of air and lubricant.

Hydraulic press

Hydraulic press for closed die forging has the same principle as that of a press for smith or flat die forging except the construction of the dies Moreover , they form an integral part of the frame to maintain accurate alignment of the dies

Mechanical forging press

Mechanical forging presses of the cranks type have found wide application in forging practice The operative units of the press are powered from motor mounted on the press frame. By means of the v-belt drive, power is transmitted from pulley to flywheel mounted on the auxiliary shaft . The is stopped by the auxiliary brake which is automatically engaged when the motor is switched off. Used for the production of rivets, screws ,and nuts where a high operating speed is desired .

Material Used

Iron, Copper, Aluminium Carbon steels, Alloy steels, Stainless steel Cast aluminum alloys, Wrought aluminum alloys Cast copper alloys, Wrought copper alloys Titanium alloys, Magnesium alloys Polyamides, Polycarbonates

ADVANTAGES

Press forging can be used to perform all types of forging, including open-die and impression-die forging. Impression-die press forging usually requires less draft than drop forging and has better dimensional accuracy. Also, press forgings can often be done in one closing of the dies, allowing for easy automation

Press Forging Beryllium Copper Billet

Press, Puching Press. Forging

Upset Forging

What is Upset Forging? Performed on bar stock, upset forging decreases the length of the stock and increases its cross-section. High pressures deform the metal and force material into a designated area of the bar. The material is shaped into tools such as bolts, pinions,drill rods, and other objects where high strength is a necessity. Upset forging refines the mechanical properties by reorienting the grain flow to the shape of the tool. The result is a component which is inherently stronger than that which has been cast, welded, or machined.

Upset forging is a metal shaping process in which a heated workpiece of uniform thickness is gripped between split female dies while a heading die is forced against the workpiece, deforming and enlarging the need of the workpiece. A sequence of die cavities may be used to control the workpiece geometry gradually until it achieves its final shape. This is a rapid "cold forming" process.

Process Characteristics Increases the diameter of the end of the central portion of a workpiece by compressing its length. Complex parts are usually formed gradually in a sequence of separate die cavities. May produce diameters up to three times the original diameter. Impressions may be in the punch die, gripping die, or both. Usually requires no trimming May be performed cold on ductile materials.

Materials Used for Upset Forging

Philadelphia Forgings supplies a wide variety of forgings. Our forgings are produced from materials such as aluminum alloy, carbon steel, stainless steel, nickel alloys, Inconel, titanium alloy, superalloys, and many more. To see the complete listing of materials or to learn more about their metallurgical properties, please visit our forging forging section. materials se ction.

Benefits of Upset Forgings

The act of upset forging breaks up the cast structure of the material, aligns the grain flow, and eliminates weaknesses in the material, such as microshrinkage, gas porosity, and areas of low density. Rods, pinions, bolts, and other components created through upset forging exhibit better levels of strength and soundness. Upset forged components resist deformation and breakage during use. These characteristics make them ideal for applications where high performance is a must.

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