Skip to main content

What are various forging Operations ?


Forging

A number of operations are used to change the shape of raw material to the finished form. The typical forging operations are : 

1. Upsetting.

Upsetting or heading is the process of increasing the thickness of  a bar at the expense of its length and is brought about by end pressure. The pressure may be obtained by driving the end of the bar against the anvil, by supporting on the anvil and hitting with the hammer, by placing in swage block hole and hitting with the hammer or by clamping in a vice and then hammering

upsetting

2. Drawing Down. 

It is the process of increasing the length of a bar at the expense of its width or thickness or both. 

drawing down

3. Setting Down.

It is localized drawing-down or swaging operation as illustrated.

                                     Setting Down

4. Bending

Bending is an important operation in forging and is one very frequently used. This may be classified as angular or curvilinear. Bending may be done over the edge of the anvil face, over the anvil horn, in special forms such as the swage block edges, or for bar stock, by inserting the end in the pritchel hole and bending the bar with a wrench or tong. 

Bending

When the metal is bent, the layers of metal on the inside are shortened and those on the outside are stretched. This causes a bulging of the sides at the inside, and a radius on the outside of the bend. If a perfect square bend is required, additional metal must be worked to the place where the bend occurs. When this is bent the additional metal will go to make up the corner. Gradual bends may be made by using the beak of the anvil as the former, or the metal may be bent round a bar of the correct radius held in a vice.  

5. Welding.

A forge weld is made by hammering together the ends of two bars which have been formed to the correct shape and heated to a welding temperature in a forge fire. The method of preparing the pieces of metal for the welding is known as scarfing. 


Welding

6. Cutting. 

Cutting - off is a form of chiseling whereby a long piece of stock is cut into several specified lengths, or a forging is separated (cut-off) from its stock. For hot chiseling, steel must be heated in blacksmith's hearth or furnace to a light cherry red heat, i.e, from 850*C to 950C. When cutting with the chisels , the hammer blows are directed on to the chisel head, which must be slightly rounded. 

Cutting

7. Punching 


It is the process of producing holes, generally cylindrical , by using a hot punch over the pritchel hole of the anvil, over a cylindrical die, or over a hole of the correct size in the swage block.  
Punching

8. Fullering 


Fullering or spreading the metal along the length of the job is done by working separate sections. In this case, the axis of the job is positioned perpendicular to the width of the flat die. 

Fullering


All these operations are carried out with the metal in a heated condition, which must be maintained by taking a "fresh" heat when the work shows signs of getting cold. 


Labels:

Comments

Post a Comment

Popular posts from this blog

SIMPLE CARBURETOR - CONSTRUCTION AND WORKING

CONSTRUCTION OF SIMPLE CARBURETOR :  The main Components of Simple Carburetor are : Float Chamber, float, nozzle, venturi, throttle valve, inlet valve, and metering jet . In the float chamber, a constant level of petrol is maintained by the float and a needle valve.  The float chamber is ventilated to atmosphere.  This is used to maintain atmospheric pressure inside the chamber. The float which is normally a metallic hollow cylinder rises and closes the inlet valve as the fuel level in the float chamber increases to certain level. The mixing chamber contains venturi, nozzle and throttle valve. The venturi tube is fitted with the inlet  manifold. This tube has a narrow opening called venturi. A nozzle is provided just below the centre of this venturi. The nozzle keeps the same level of petrol as that of the level in the float chamber. The mixing chamber has two butterfly valves.  One is to allow air into the mixing chamber known as choke valve. The other is to al...
Post a Comment
Read more

MELTING FURNACES FOR FERROUS METALS : CUPOLA AND ITS WORKING

Various types of melting furnaces are used in different foundry shops, depending upon the quantity of metal to be melted at a time, and the nature of work that is carried out in the shop.  The primary objective in cupola is to produce iron of desired composition, temperature and properties at the required rate in the most economical manner. Besides, this furnace has many distinct advantages over the other types, e.g., simplicity of operation, continuity of production, and increased output coupled with a high degree of efficiency.  Description Of a Cupola : The Cupola Furnace consists of a vertical, cylindrical steel sheet, 6 to 12 mm thick, and lined inside with acid refractory bricks or acid tamping clay. The refractory bricks or the tamping clay used consist of  silicon oxide acid (SiO2) and alumina (Al2O3). The lining is generally thicker in the lower where the temperatures encountered are higher than in the upper region. The shell is mounted either on a brick work fo...
Post a Comment
Read more

Advantages And Disadvantages Of Air Refrigeration System :

 Advantages Of  Air Refrigeration : 1. The refrigerant used namely air is cheap and easily available. 2. There is no danger of fire or toxic effects due to leakages. 3. The weight to ton of refrigeration ratio is less as compared to other systems. Disadvantages Of Air Refrigeration : 1. The quantity of  Refrigerant used per ton of refrigeration is high as compared to other systems. 2. The COP of the system is very low. Therefore running cost is high. 3. The danger of frosting at the expander valves is more as the air contains moisture content. 
Post a Comment
Read more