Forge

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The inside of a typical smithy in Finland 0 typical smithy in finland.JPG
The inside of a typical smithy in Finland
Wooden smithy built in 1726 in Opole, Upper Silesia, Poland Muzeum Bierkowice-kuznia 1726.JPG
Wooden smithy built in 1726 in Opole, Upper Silesia, Poland
A smithy built around 1880 in Mersrags, Courland, Latvia currently located at The Ethnographic Open-Air Museum of Latvia Lotysske etnograficke muzeum v prirode (17).jpg
A smithy built around 1880 in Mērsrags, Courland, Latvia currently located at The Ethnographic Open-Air Museum of Latvia

A forge is a type of hearth used for heating metals, or the workplace (smithy) where such a hearth is located. The forge is used by the smith to heat a piece of metal to a temperature at which it becomes easier to shape by forging, or to the point at which work hardening no longer occurs. The metal (known as the "workpiece") is transported to and from the forge using tongs, which are also used to hold the workpiece on the smithy's anvil while the smith works it with a hammer. Sometimes, such as when hardening steel or cooling the work so that it may be handled with bare hands, the workpiece is transported to the slack tub, which rapidly cools the workpiece in a large body of water. However, depending on the metal type, it may require an oil quench or a salt brine instead; many metals require more than plain water hardening. The slack tub also provides water to control the fire in the forge.

Contents

Types

Coal/coke/charcoal forge

Bottom blast coal forge Coal-forge-diagram.svg
Bottom blast coal forge

A forge typically uses bituminous coal, industrial coke or charcoal as the fuel to heat metal. The designs of these forges have varied over time, but whether the fuel is coal, coke or charcoal the basic design has remained the same. [1]

A forge of this type is essentially a hearth or fireplace designed to allow a fire to be controlled such that metal introduced to the fire may be brought to a malleable state or to bring about other metallurgical effects (hardening, annealing, and tempering as examples). The forge fire in this type of forge is controlled in three ways:[ citation needed ] amount of air, the volume of fuel, and shape of the fuel/fire.

A forge fire for hot working of metal Schmiedefeuer 2.jpg
A forge fire for hot working of metal

Over thousands of years of forging, these devices have evolved in one form or another as the essential features of this type of forge: [2]

During operation, fuel is placed in or on the hearth and ignited. A source of moving air, such as a fan or bellows, introduces additional air into the fire through the tuyere. With additional air, the fire consumes fuel faster and burns hotter (and cleaner - smoke can be thought of as escaped potential fuel).

A blacksmith balances the fuel and air in the fire to suit particular kinds of work. Often this involves adjusting and maintaining the shape of the fire.

In a typical coal forge, a firepot will be centred in a flat hearth. The tuyere will enter the firepot at the bottom. In operation, the hot core of the fire will be a ball of burning coke in and above the firepot. The heart of the fire will be surrounded by a layer of hot but not burning coke. Around the unburnt coke will be a transitional layer of coal being transformed into coke by the heat of the fire. Surrounding all is a ring or horseshoe-shaped layer of raw coal, usually kept damp and tightly packed to maintain the shape of the fire's heart and to keep the coal from burning directly so that it "cooks" into coke first.

If a larger fire is necessary, the smith increases the air flowing into the fire as well as feeding and deepening the coke heart. The smith can also adjust the length and width of the fire in such a forge to accommodate different shapes of work.

The major variation from the forge and fire just described is a 'backdraft' where there is no fire pot, and the tuyere enters the hearth horizontally from the back wall.

Coke and charcoal may be burned in the same forges that use coal, but since there is no need to convert the raw fuel at the heart of the fire (as with coal), the fire is handled differently.

Individual smiths and specialized applications have fostered the development of a variety of forges of this type, from the coal forge described above to simpler constructions amounting to a hole in the ground with a pipe leading into it.

Gas forge

A gas forge typically uses propane or natural gas as the fuel. One common, efficient design uses a cylindrical forge chamber and a burner tube mounted at a right angle to the body. The chamber is typically lined with refractory materials such as a hard castable refractory ceramic or a soft ceramic thermal blanket (ex: Kaowool). The burner mixes fuel and air which are ignited at the tip, which protrudes a short way into the chamber lining. The air pressure, and therefore heat, can be increased with a mechanical blower or by taking advantage of the Venturi effect.

Gas forges vary in size and construction, from large forges using a big burner with a blower or several atmospheric burners to forges built out of a coffee can utilizing a cheap, simple propane torch. A small forge can even be carved out of a single soft firebrick.

The primary advantage of a gas forge is the ease of use, particularly for a novice. A gas forge is simple to operate compared to coal forges, and the fire produced is clean and consistent. They are less versatile, as the fire cannot be reshaped to accommodate large or unusually shaped pieces. It is also difficult to heat a small section of a piece. A common misconception is that gas forges cannot produce enough heat to enable forge-welding, but a well-designed gas forge is hot enough for any task.

Finery forge

A finery forge is a water-powered mill where pig iron is refined into wrought iron.

Forging equipment

Anvil

The structure of an anvil Anvil, labelled en.svg
The structure of an anvil

The anvil serves as a workbench to the blacksmith, where the metal to be forged is worked. Anvils may seem clunky and heavy, but they are a highly refined tool carefully shaped to suit a blacksmith's needs. Anvils are made of cast or wrought iron with a tool steel face welded on or of a single piece of cast or forged tool steel. Some anvils are made of only cast iron and have no tool steel face. These are not real anvils, and will not serve a blacksmith as such because they are too soft. A common term for a cast iron anvil is "ASO" or "Anvil Shaped Object". The purpose of a tool steel face on an anvil is to provide what some call "Rebound" as well as being hard and not denting easily from misplaced hammer blows. The term rebound means it projects some of the force of the blacksmith's hammer blows back into the metal thus moving more metal at once than if there were no rebound. A good anvil can project anywhere from 50 to 99% of the energy back into the workpiece. The flat top, called the "face" is highly polished and usually has two holes (but can have more or less depending on the design). The square hole is called the hardy hole, where the square shank of the hardy tool fits. There are many different kinds of hardy tools. The smaller hole is called the pritchel hole, used as a bolster when punching holes in hot metal, or to hold tools similar to how the hardy tool does, but for tools that require being able to turn a 360-degree angle such as a hold-down tool for when the blacksmith's tongs cannot hold a workpiece as securely as it needs to be. On the front of the anvil, there is sometimes a "horn" that is used for bending, drawing out steel, and many other tasks. Between the horn and the anvil face, there is often a small area called a "step" or a "cutting table" That is used for cutting hot or cold steel with chisels, and hot cut tools without harming the anvil's face. Marks on the face transfer into imperfections in the blacksmith's work.

Hammer

Various traditional blacksmith tools Turaidas muizas kalves darbariki.jpg
Various traditional blacksmith tools

There are many types of hammer used in a blacksmith's workshop but this will name just a few common ones. Hammers can range in shape and weight from half an ounce to nearly 30 pounds depending on the type of work being done with it.

  1. Hand hammer - used by the smith.
  2. Sledge hammer - used by the striker.

Chisel

Chisels are made of high carbon steel. They are hardened and tempered at the cutting edge while the head is left soft so it will not crack when hammered. Chisels are of two types, hot and cold chisels. The cold chisel is used for cutting cold metals while the hot chisel is for hot metals. Usually, hot chisels are thinner and therefore can not be substituted with cold chisels. Also, many smiths shape chisels as to have a simple twisted handle as to resemble a hammer, they can be used at a greater distance away from the hot metals. They are very useful and found throughout the world. [3]

Tongs

Blacksmith using tongs Eddystone, Pennsylvania - Railroad parts. Baldwin Locomotive Works. Blacksmith forging and hammering tools. - NARA - 518729.tif
Blacksmith using tongs

Tongs are used by the blacksmith for holding hot metals securely. The mouths are custom made by the smith in various shapes to suit the gripping of various shapes of metal. It is not uncommon for a blacksmith to own twenty or more pairs of tongs; traditionally, a smith would start building their collection during the apprenticeship. There are various types of tongs available in the market. (1) flat tong (2) rivet or ring tong (3) straight lip fluted tong (4) gad tong

Fuller

Fullers are forming tools of different shapes used in making grooves or hollows. They are often used in pairs, the bottom fuller has a square shank which fits into the hardy hole in the anvil while the top fuller has a handle. The work is placed on the bottom fuller and the top is placed on the work and struck with a hammer. The top fuller is also used for finishing round corners and for stretching or spreading metal.

Hardy

The hardy tool is a tool with a square shank that fits in a hardy hole. There are many different kinds of hardy tools such as the hot cut hardy, used for cutting hot metal on the anvil; the fuller tool, used for drawing out metal and making grooves; bending jigs - and too many others to list.

Slack tub

A slack tub is usually a large container full of water used by a blacksmith to quench hot metal. The slack tub is principally used to cool parts of the work during forging (to protect them, or keep the metal in one area from "spreading" for example, nearby hammer blows); to harden the steel; to tend a coal or charcoal forge; and simply to cool the work quickly for easy inspection. In bladesmithing and tool-making the term will usually be changed to a "quench tank" because oil or brine is used to cool the metal. The term slack is believed to derive from the word "slake", as in slaking the heat.

Types of forging

Drop forging

Drop forging is a process used to shape metal into complex shapes by dropping a heavy hammer with a die on its face onto the workpiece. [4]

Process

The workpiece is placed into the forge. Then the impact of a hammer causes the heated material, which is very malleable, to conform to the shape of the die and die cavities. Typically only one die is needed to completely form the part. Extra space between the die faces causes some of the material to be pressed out of the sides, forming flash. This acts as a relief valve for the extreme pressure produced by the closing of the die halves and is later trimmed off of the finished part.

Equipment

The equipment used in the drop forming process is commonly known as a power or drop hammer. These may be powered by air, hydraulics, or mechanics. Depending on how the machine is powered, the mass of the ram, and the drop height, the striking force can be anywhere from 11,000 to 425,000 pounds. The tools that are used, dies and punches, come in many different shapes and sizes, as well as materials. Examples of these shapes are flat and v-shaped which are used for open-die forging, and single or multiple-impression dies used for closed die forging. The designs for the dies have many aspects to them that must be considered. They all must be properly aligned, they must be designed so the metal and the flash will flow properly and fill all the grooves, and special considerations must be made for supporting webs and ribs and the parting line location. The materials must also be selected carefully. Some factors that go into the material selection are cost, their ability to harden, their ability to withstand high pressures, hot abrasion, heat cracking, and other such things. The most common materials used for the tools are carbon steel and, in some cases, nickel-based alloys.

Workpiece materials

The materials that are used most commonly in drop forging are aluminium, copper, nickel, mild steel, stainless steel, and magnesium. Mild steel is the best choice, and magnesium generally performs poorly as a drop forging material.

Mythology

Various gods and goddesses are associated with the forge in a number of mythologies, such as the Irish Brigid, West African Ogun, Greek Hephaestus and Roman Vulcan. [5] [6] [7]

See also

Related Research Articles

<span class="mw-page-title-main">Wrought iron</span> Iron alloy with a very low carbon content

Wrought iron is an iron alloy with a very low carbon content in contrast to that of cast iron. It is a semi-fused mass of iron with fibrous slag inclusions, which give it a wood-like "grain" that is visible when it is etched, rusted, or bent to failure. Wrought iron is tough, malleable, ductile, corrosion resistant, and easily forge welded, but is more difficult to weld electrically.

<span class="mw-page-title-main">Chisel</span> Tool for cutting and carving

A chisel is a tool with a characteristically shaped cutting edge of blade on its end; for carving or cutting a hard material such as wood, stone, or metal by hand, struck with a mallet, or mechanical power. The handle and blade of some types of chisel are made of metal or wood with a sharp edge in it.

<span class="mw-page-title-main">Blacksmith</span> Person who creates wrought iron or steel products by forging, hammering, bending, and cutting

A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from other metals, by forging the metal, using tools to hammer, bend, and cut. Blacksmiths produce objects such as gates, grilles, railings, light fixtures, furniture, sculpture, tools, agricultural implements, decorative and religious items, cooking utensils, and weapons. There was an historical distinction between the heavy work of the blacksmith and the more delicate operation of a whitesmith, who usually worked in gold, silver, pewter, or the finishing steps of fine steel. The place where a blacksmith works is called variously a smithy, a forge or a blacksmith's shop.

<span class="mw-page-title-main">Forging</span> Metalworking process

Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer or a die. Forging is often classified according to the temperature at which it is performed: cold forging, warm forging, or hot forging. For the latter two, the metal is heated, usually in a forge. Forged parts can range in weight from less than a kilogram to hundreds of metric tons. Forging has been done by smiths for millennia; the traditional products were kitchenware, hardware, hand tools, edged weapons, cymbals, and jewellery.

<span class="mw-page-title-main">Metalworking</span> Process of making items from metal

Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges down to precise engine parts and delicate jewelry.

<span class="mw-page-title-main">Anvil</span> Metalworking tool

An anvil is a metalworking tool consisting of a large block of metal, with a flattened top surface, upon which another object is struck.

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<span class="mw-page-title-main">Ball-peen hammer</span> Type of hammer used in metalworking

A ball-peen or ball peinhammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. It is distinguished from a cross-peen hammer, diagonal-peen hammer, point-peen hammer, or chisel-peen hammer by having a hemispherical peen.

<span class="mw-page-title-main">Swaging</span> Metalworking process

Swaging is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.

<span class="mw-page-title-main">Hardy tool</span> Tools used with an anvil

Hardy tools, also known as anvil tools or bottom tools, are metalworking tools used in anvils. A hardy has a square shank, which prevents it from rotating when placed in the anvil's hardy hole. The term "hardy", used alone, refers to a cutting chisel used in the square hole of the anvil. Other bottom tools are identified by function. Typical hardy tools include chisels and bending drifts. They are generally used with a matching top tool.

Sword making, historically, has been the work of specialized smiths or metalworkers called bladesmiths or swordsmiths. Swords have been made of different materials over the centuries, with a variety of tools and techniques. While there are many criteria for evaluating a sword, generally the four key criteria are hardness, strength, flexibility and balance. Early swords were made of copper, which bends easily. Bronze swords were stronger; by varying the amount of tin in the alloy, a smith could make various parts of the sword harder or tougher to suit the demands of combat service. The Roman gladius was an early example of swords forged from blooms of steel.

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This article is a list of terms commonly used in the practice of metalworking – the science, art, industry, and craft of shaping metal.

<span class="mw-page-title-main">Rolling (metalworking)</span> Metal forming process

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<span class="mw-page-title-main">Bladesmith</span> Person who uses an anvil and forge to make various types of blades

Bladesmithing is the art of making knives, swords, daggers and other blades using a forge, hammer, anvil, and other smithing tools. Bladesmiths employ a variety of metalworking techniques similar to those used by blacksmiths, as well as woodworking for knife and sword handles, and often leatherworking for sheaths. Bladesmithing is an art that is thousands of years old and found in cultures as diverse as China, Japan, India, Germany, Korea, the Middle East, Spain and the British Isles. As with any art shrouded in history, there are myths and misconceptions about the process. While traditionally bladesmithing referred to the manufacture of any blade by any means, the majority of contemporary craftsmen referred to as bladesmiths are those who primarily manufacture blades by means of using a forge to shape the blade as opposed to knifemakers who form blades by use of the stock removal method, although there is some overlap between both crafts.

<span class="mw-page-title-main">Walloon forge</span>

A Walloon forge is a type of finery forge that decarbonizes pig iron into wrought iron.

<span class="mw-page-title-main">Cupola furnace</span> Small blast furnace for melting scrap iron without reduction reactions

A cupola or cupola furnace is a melting device used in foundries that can be used to melt cast iron, Ni-resist iron and some bronzes. The cupola can be made almost any practical size. The size of a cupola is expressed in diameters and can range from 1.5 to 13 feet. The overall shape is cylindrical and the equipment is arranged vertically, usually supported by four legs. The overall look is similar to a large smokestack.

Makera Assada is among the areas that form the town of Sokoto state of Nigeria. The area is part of Magajin Gari Ward in the southern part of Sokoto North local government area of Sokoto state, bordered Gidan Haki in the east, Digyar Agyare in the west, Mafara in the north and Helele in the south.

<span class="mw-page-title-main">Lancashire hearth</span> Wrought iron production method

The Lancashire hearth was used to fine pig iron, removing carbon to produce wrought iron.

Rule based DFM analysis for forging is the controlled deformation of metal into a specific shape by compressive forces. The forging process goes back to 8000 B.C. and evolved from the manual art of simple blacksmithing. Then as now, a series of compressive hammer blows performs the shaping or forging of the part. Modern forging uses machine driven impact hammers or presses that deforms the work-piece by controlled pressure.

References

  1. "The Blacksmith Forge Part 1 the Pit Forge : Anvilfire.com article". Archived from the original on 2016-10-07. Retrieved 2016-07-31.
  2. Light, John D. (July 1987). "Blacksmithing Technology and Forge Construction". Technology and Culture. 28 (3): 658–665. doi:10.2307/3104997. JSTOR   3104997. S2CID   112819098.
  3. Peat Oberon's School of Blacksmithing: The cold chisel you will make on our 'Make your own tools' course Archived 2008-08-28 at the Wayback Machine
  4. Manufacturing Processes Reference Guide; Todd, Allen, Alting
  5. Brigid: Triple Goddess of the Flame (Health, Hearth, & Forge)
  6. Ogun = God of Iron
  7. Hephaestus in Greek Mythology - The God of Fire and Forges