Best Types of Forgings and Operations, Uses, Tools of Smithy Shop 2024

Forgings is one of the oldest methods to produce the required shape from the red hot metal. Generally, hammers are used for shaping the parts of an object. Forgings can be defined as the controlled plastic deformation of a metal at elevated temperature into a predetermined size or shape by using compressive forces. Forgings may be done by

(i) Striking a blow

(ii) Shaping by pressure

The forged parts are often called forgings. Forgings are used in manufacturing parts such as tractors, automobiles, shipbuilding, cycle industries, railroad components, agriculture, etc.

For forgings, metal must be heated to a temperature at which, it will possess high plasticity. The plasticity state of a metal should be maintained throughout the forgings operation. In this chapter, we will study forgings, tools of a smithy shop, forgings operations, etc.

Types of Forgings 

Normally, forgings are of three types such as

(i) Hand forgings

In hand forgings, the job is heated and placed on an anvil, and after that with the help of hand forgings tools, forgings is done. 

(ii) Machine forgings 

In the machine forgings, we use a forgings machine to have forgings on the job.

(iii) Drop forgings 

In this method, forgings are made by squeezing the metal of forgings heat either by impact or pressure. In this operation, the accuracy of the job for forgings depends upon the dye to be used. It is used to make the same shape of jobs in huge quantities. Three types of machines are used for this purpose.

(a) By horizontal forging machine 

(b) By presses for shaping process

(c) By power hammer

Forge

A forge is a type of furnace in which, the job is placed for heating. The forge supplies heat for raising the temperature of the metal to be forged. It comprises a mild layer of steel and angle in which, a tuyer coal tank is made from fire bricks and clay. The air is fed from a blower through a pipe and the forge can be oil-fired, gas-fired, or simply fired by solid fuel.

There are two types of forge such as

(i) Stationary forge 

The stationary forge is fixed in one place. It is built with the help of bricks and clay. It has a chimney, which is fitted on the hood of the forge. The chimney is used to throw out the smoke. The air is passed in this forge with the help of an air blower by the nozzle and to control the air, a valve is fitted with it.

(ii) Portable forge 

It is made up of mild steel. It consists of sand having four legs with a square or round-shaped box of steel placed on it. It is also known as hand forge.

Parts of Forge

In the construction of a forge, various parts are involved, which are given below.

(i) Hearth

The hearth is the main part of the forge, where the heating of the metal takes place. It is prepared with refractory (fire bricks) and clay.

(ii) Tuyers (Nozzle)

The forced air is passed through the tuyers to burn the fuel in the furnace. The tuyer is covered with refractory material to avoid melting and air also passes through a tank. cooling

(iii) Cooling Tank

To keep the tuyer cool continuously, the cooling tank is filled with cold water.

(iv) Air Valve

The air valve is used to regulate the supply of air to the hearth.

(v) Hood and Chimney

Smoke and dust are let out through the hood and chimney. The fumes given off by a coal forge are toxic, therefore, good ventilation is essential.

(vi) Quenching Tank

A quenching tank is provided along with the forge. It is filled with water for cooling the hot tools and workpieces. The tank is also used for hardening and tempering.

(vii) Coal Tank

The coal tank is used to store the fuel for forging. Generally, solid fuels i.e., coal, coke, and charcoal are used. Among these, steam coal with low sulfur is used as the best fuel for the forge, hence, it is known as smith’s fuel.

Forge Ignition

To get proper fire in the furnace, a few steps for ignition of the forge must be followed.

(i) The fire should be ignited in the hearth very carefully.

(ii) There should be no leakage of fuel from pipes and pipe joints.

(iii) All the exhaust gases and smoke should go to the chimney.

(iv) The metal piece should neither be overheated nor underheated.

(v) Do not touch any metal part unless you know that, its temperature is normal. be

(vi) Heavy blows of the hammer should only given by keeping the workpiece in the center of the anvil.

(vii) Never handle the loose tongs and hammer while working in a forge shop

(viii) Never wear silky cloths in forging while working on a forge

To ignite the substance, we need fuel to burn the size which helps us to ignite the required substance. In case of igniting the furnace, we can use some important fuels, which are as follows.

Fuels

For heating the metal, many fuels are used. The most common fuels are coal, coke, charcoal, oil and fuel gases, etc.

(i) Coal

It gives out volatile matter. It maintains heat for longer periods and has a good calorific value. Anthracite coal containing more quantity of carbon, burns slowly. It is most suitable for forging operations.

(ii) Charcoal

It gives a clean fire and better fuel for the blacksmith hearth but does not maintain the heat for a longer period. It does not produce smoke and is quickly burned and converted into ash. Due to its high cost, it is rarely used for forging.

(iii) Coke

Coke is obtained by distilling bituminous coal in the absence of oxygen. It is mostly used for smelting purposes. It has a higher calorific value. Due to its higher cost, it is not used for forging.

(iv) Oil and Gas

The use of oil and gas is better in forging because the stock can be observed at all times and the heat can be controlled effectively.

Tools Other than Forge

Different types of tools are used with forge, which are as follows.

(i) Blower

For proper combustion of fuel, an efficient and adequate supply of air at proper pressure is required. A fan or blower may be used for this purpose. The blower is used when a small quantity of air is needed.

The fan is used when a large volume of air at a small pressure is needed, and the root blower is more efficient and economical when air has to be delivered at any appreciable pressure. It consists of two impellers housed on a casing. These are mounted on two parallel shafts and rotated by an electric motor through a set of reducing gears.

The shaft revolves in the opposite direction. Air is drawn at the top and released through an outlet pipe. The centrifugal blower is driven by an electric motor. It draws the air from the atmosphere towards the center and then forces it out at high pressure through an outlet pipe.

(ii) Rake

The rake is a rectangular shape flat bent on the front side at 90°, which is used to pull the charged fuel over the job.

(iii) Shovel

It is used to place coal or coke in the furnace. It is also used to set coal pieces in the furnace as well as remove ash from the furnace. Its blade is made up of steel.

(iv) Poker

It is a rod at which one end is pointed and turned. It is used to remove clinkers from the furnace.

(v) Sprinkler

The sprinkler is used to localize the heat. The outer ring of the fire is kept wet so that, the heat is concentrated in the middle of the hearth.

Tools of Smithy Shop

Tools are used to make the work easy and comfortable in different ways. Many tools are used in smithy shops other than forge, which are discussed below.

1. Anvil

The anvil is a heavy block of cast steel, which is used in forging sheets. It acts as a support for the blacksmith’s work during hammering. The body of the anvil is made up of mild steel or wrought iron with a tool steel blade welded on the face of the body, but the beak or horn used for bending curves is not steel-faced.

The round hole in the anvil is called a pritchal hole. It is generally used for bending rods of small diameter and as a die for hot punching operations.

Parts of Anvil

Anvil has many different parts, which are given below.

(i) Tail square beak 

It is opposite to the beak. It is used to bend the work at right angles.

(ii) Face

The face is used for drawing down and cutting off the metals.

(iii) Beak 

This is used for bending and rounding operations.

(iv) Upsetting block 

It is used for upsetting or jumping off metals.

(v) Hardie hole 

This is used for inserting hardies and stakes.

2. Swage Block

It is a square block made up of cast iron or steel. It is mainly used for heading, bending, squaring, sizing, and forming operations on forging jobs. It may be used either flat or edge-wise in its stand.

3. Tongs

Tongs are made up of mild steel or medium carbon steel These are used for keeping the heated metal piece as well as for gripping or turning the workpiece during forging Blacksmith’s tongs consist of two bars joined by a rivet These are made in different shapes according to the nature of work.

Different types of tongs are as follows

(i) Closed Mouth Tong

A closed-mouth tong does not have a gap when its mouth is closed. It catches thin job strongly.

(ii) Open Mouth Tong

Open mouth tong has a gap when its mouth is closed so that, it is used to hold the face job strongly.

(iii) Pick-up Tong

It’s both bits shape such as zig-zag and used to hold small jobs. e.g., rivets and small-sized round rods, etc.

(iv) Hollow Round Tong

Its bits are in round shape and used to hold the job by its bits. e.g., Cylindrical, hexagon, and octagon, etc.

(v) Hollow Square Tong

Its bits are in a V shape. It is used to hold the job e.g., circular, square, etc.

(vi) Hammer Tong

The front part of bits of hammer tong is folded at 90° so that, it holds the job very tightly.

(vii) Angle Iron Tong

It is a bit shape such as the alphabet of the English letter V and the second bit is flat. It is used to hold the angle iron.

4. Hammer

A hammer is a tool that is used to strike, crush, and hammer the job. The weight of the hammer used by blacksmiths is 0.5 to 1.8 kg.

According to the different shapes of hammers, they are classified into three types, which are as follows

(i) Hand Hammer

The weight of this hammer is from 1 to 2 kg and is fitted with a short wooden handle.

(a) Ball peen hammer 

It is used to spread metal in all directions. This hammer’s peen is hemi spherical.

(b) Cross peen hammer 

It is used to spread metal only in one direction. This hammer’s peen is a wedge type.

(c) Straight peen hammer 

It is used to spread metal in one direction but it is at the right angle to the live striking.

(ii) Sledge Hammer

The sledge hammers are used by the smith’s helper or striker. The mass of the sledge hammer varies from 3 to 9 kg for ordinary work and 8 to 10 kg for heavy work.

The shaft is about one meter long and it is mostly made up of wood. The three types of sledge hammers.

(a) Double face sledge hammer 

It provides an extra powerful slam. It is constructed of high-quality materials for durability and dependability. Its handle length is 36 inches and its head weight is 16 pounds.

(b) Straight peen sledge hammer 

It is used for striking the jobs on the anvil. It is similar in design to a standard sledge hammer but with a vertical peen. Its overall length is 755 mm. Its handle does not have a wedge.

(c) Cross peen sledge hammer 

It is used for forging or riveting metalwork. Its head is made up of hardened steel for durability and strength. It is also known as a machinist’s hammer.

(iii) Power Hammer

It is a mechanical forging hammer that is a non-muscular power source to raise the hammer preparatory to striking and accelerate, it depends on the work being hammered. It is also known as an open-die power forging hammer.

5. Chisels

Chisels are made up of high-carbon steel. It is a metal tool with a sharp beveled edge, used for cutting and shaping wood and metal.

There are different types of chisels and each has a particular use, which is as follows.

(i) Cold Chisel

The cold chisel is made up of steel and has a cutting angle of about 60°, and its edge is hardened and tempered. The name cold chisel comes from, its use by blacksmiths to cut metal, while it was cold as compared to other tools they used to cut hot metal.

The edge of a chisel should not be quite straight but slightly rounded. It is used to remove waste metal when a very smooth finish is not required.

(ii) Hot Chisel

The hot chisel is made up of low-carbon steel and has a cutting angle of 30°. This type of chisel is fitted with wooden shafts. It is used for cutting the metal that has been heated in a forge to soften the metal.

(iii) Gauge Chisel

It has some curvely cutting edges not straight. It is used for cutting curved profiles.

These chisels are generally used in pairs. The top chisel which is held by the smith may be a hot or cold chisel. The bottom chisel (often called hardie), has a square shank and fits in the square hardie hole in the anvil face.

6. Swage

Swage is used for forging work, which has to be reduced or finished to a round, square, or hexagonal form. It is made with half grooves of dimensions to suit the work being reduced. It has two parts and a bottom part Its bottom part has a flat flat-shaped shank, which is fitted in hardie hole of the anvil. Then, the top part is kept on it and struck by a hammer so that, the job length is increased and the surface flat.

It is clear that the top part of the swage (neck) is wrapped by wire and it is used as a handle i.e., spring swage, in which both parts (top and bottom) are joined by spring, so that work is easy. Swage is always made up of steel and made hard by heat transfer.

7. Fuller

Fullers are made up of high-carbon steel having different types of shapes. It is used for grooving and drawing down the thin portions of a forging against the shoulder. It has two parts. The bottom part is mounted on the anvil and the top part is held in hand from a handle and hammering is done on the top portion.

8. Flatter

It is made up of high-carbon steel and is available in various sizes from 50 to 75 mm. It is similar to the hammer, and its down parts are flat and wide. It is used to make the surface of metal flat. It is placed on the surface of jobs and struck by a hammer to shape them.

9. Set Hammer

A set hammer is used to make sharp corners or to make flat corners. It is found with a square and flat face. It is made up of 0.8% carbon steel. Its shape is different.

10. Beak Iron

Beak iron generally is used in a forging shop. It is also known as a small anvil made up of forged steel and die steel. Its upper front end consists of a horn and the upper back end comprises of flat tail. Its taper shank is inserted into the hardie hole of the anvil. It is commonly used as an anvil for small forge work.

11. Punch

A punch is a hard metal rod with a shaped tip at one end and a butt end at the other, which is usually struck by a hammer. Punches are used to make holes of any shape and size (round, square, oval, or rectangular) on hot and cold metal. It is made up of 0.8% carbon steel.

 12. Drift

Drifts are made up of steel tool, which is hardened and tempered. It is used for finishing the size of the punched holes. They are made taper and bulging in the center

13. Leg Vice

A leg vice is a holding device, generally used in a forge shop for bending or forging work. It is made up of mild steel to avoid breakage while hammering. In the leg vice, the bottom parts are fixed on the earth’s surface and the other side is a movable jaw, which is tight by a screw with the table. It can hold up to 12 cm wide job and movable jaw moves through a screw.

Forgings Operations

Forging may be defined as changing the shape of a piece of metal by heating or hammering. All the various operations that a blacksmith performs in forging iron may be classified into a surprisingly small number of fundamental processes.

For forging, steel must lose its tensile strength and elasticity but increase its plasticity and malleability. When you heat the steel, then its color will vary at different temperatures. At 500°C, it will be dull brown, and at 1300°C it will be white, as given in the table.

Value of Temperatures for Different Colours

The temperature of steel is different for various processes, which are as follows.

Temperature of Steel for Different Processes

With the help of these different types of smithy shop tools and heating effect, we can change the shape of a substance according to the requirements of the forging operation, which are as discussed below.

1. Drawing Out

Drawing out is used to reduce the thickness of a bar and increase its length. It may be carried out by working the metal over the horn. 

Drawing out is done through a number of intermediate steps (thick to thinner section). A fuller and sledgehammer are used for drawing out.

2. Upsetting

Upsetting is a forging operation by which the length of a piece of metal is reduced and its cross-sectional area is increased. This is the most widely used for forging processes.

A few examples of common parts produced using the upsetting forging process are an engine, valve couplings, bolts, screws, and other fasteners. The portion of the bar, which is to be upset is heated. Then, strike by hammer on the heated part, so that it will increase the width and thickness. If the job is too long, then you must stock by hammer carefully otherwise it may bend. So you must keep the job straight and then strike in its center where you upsetting.

Three types of upsetting are applied in forging such as

(i) End Upsetting

Upsetting the end of a piece of stock is called end upsetting.

(ii) Centre Upsetting

Upsetting the central section of a piece of stock is known as center upsetting.

(iii) Jumping

The full upsetting of a piece of stock is known as jumping.

3. Bending

Bending is a method by which steel may be bent to form various shapes without damage to its structure. The method of bending involves the use of an anvil edge, a block of metal held in the hardie hole or in a vice. When a piece of metal is bent, it may be done to a curve or an angle.

Methods of Bending

(i) It can be held up with an anvil hardie hole, then bent up.

(ii) To keep on anvil horn and then hammering.

(iii) To tight rod or plate with vice and then hammering.

Bending Tools

The tools which are used for bending the tools are called bending tools. The various types of bending tools are given as follows.

(i) Vice or Anvil Edge

An angle bend may be made by hammering in a vice or over the edge of an anvil.

(ii) Bending Block

Bending blocks with levers and pegs are very convenient to use in a smithy. These are massive blocks pierced with holes in which pegs can be inserted. The work to be bent is placed between a series of pegs, already inserted in the holes and the work is bent with a lever.

(iii) Bending Link

A bending link with top fullers is used for small radius, pipe clips, etc.

(iv) Fork Tool

A fork is used for bending round steel bars.

(v) Twisting

Twisting is done to give additional strength and to change the position of the piece so that, it can be fastened at the ends. Mild steel flat is 6 mm or less in thickness and 40 mm or less in width and can be twisted cold.

Square rods of mild steel up to 12 mm can be twisted without heating. To twist larger sizes of stock, the metal should be heated to a dull red color

4. Punching

This process is used for making holes in metal plate, which is placed over the following cylindrical die. By pressing the punch over the plate, the hole is done. 

5. Drifting

Drifting is the process, which is used for finishing the size of the punched hole with the help of drifts. Drifts are made in various shapes and sizes such as punched and are made up of steel tools, hardened and tempered.

6. Forge Welding

The process of joining two metal pieces by heating and hammering is known as forge welding.

The metal pieces to be welded are cleaned and heated in a furnace up to 1300°C. Then, its color becomes white. Workpieces are placed on each other and hammering is struck on it so that, both pieces get welded. During forge welding, you must consider the following factors.

(i) Metal pieces should be clean and free from any scale.

(ii) Pieces should be heated up to the proper temperature. There are four types of joints made by welding

(i) Butt Joint

When the two ends of the workpiece are joined to each other in the same plane or straight, then it is called a butt joint.

(ii) Lap Joint

when the two ends of the workpiece are overlapped and joined by Strock hammering after heating then is called a lap joint.

(iii) V-Joint

It is a very strong joint. It is made, where the workpiece thickness is more. In this system, one edge of a rod is tapered, and the second edge is opened as a divider because, in thickness, it has a V shape. It is also called fork weld.

(iv) T-Joint

T-joint is shaped such as the English alphabet of the letter T. Both workpieces are joined with each other at an angle of 90°.

7. Cutting

Cutting is a main forging operation to cut out a metal rod or plate into pieces with the help of a chisel and hammer when the metal is in red hot condition. A hot or cold cut (chisel) is used for cutting heated metal bars in a smithy shop.

The hot set does not require hardening and tempering. Its cutting edge is keener than that of a cold set. Hot sets are manufactured from a tough variety of steel in order that they may cut through relatively soft red hot metal with ease.

While cutting, it is best to cut half through the workpiece to turn it over and cut through the other end. Hot cutting is easy as compared to cold cutting, so the reasons of hot cutting are as follows

(i) Cold cutting takes more time and labor.

(ii) Cold cutting easily damages the chisel sharp.

(iii) Do not cut alloy steel with a cold chisel.

Advantages and Disadvantages of Forgings

Advantages and Disadvantages forgings are given below

Advantages

(i)Forged parts possess high ductility and offer great resistance to impact and fatigue loads.

(ii) Forging refines the structure of the metal.

(iii) It results in considerable savings in time, labor, and material as compared to the production of similar items by cutting from a solid stock and then shaping it.

(iv) Forging distorts the previously created unidirectional fiber as created by rolling and increases the strength by setting the direction of grains.

(v) Because of intense work, flaws are rarely found, so have good reliability.

(vi) A reasonable degree of accuracy may be obtained in forging operation.

(vii) The forged parts can be easily welded.

Disadvantages

(i) Rapid oxidation in the forging of a metal surface at high-temperature results in scaling, which wears the dies.

(ii) The close tolerances in forging operations are difficult to maintain.

(iii) Forging has limitations for simple shapes, undercuts parts, etc.

(iv) Some materials do not properly work by forging.

(v) The initial and maintenance costs of forging dies are very high.

(vi) Below the specified temperature limit the metal gets cracked or distorted.