In fore forging a material is place between two flat swages to decrease the height by pressing down.
On the swage surface, simple common area is made to make simple shapes of forging. The volume is maintained during the process, so when the height of the material decrease, the length is increased.
However, in the actual work, the material doesn’t transform in uniform shape but barrelling effect takes place. The main reason of barrelling is the moving material between the swage.
Therefore barreling can be minimized by using lubrication. Barrelling occurs during upchatting the hot material in cold swage.
The material on the contact surface quickly cools down but other parts stay hot, the ends of the material gets higher impedance than the center. Thus, the central part transforms easily. Effects of heat in barrelling can be used for heating the swage of for reducing the heat shielding on the contract surface.
Free forging can make simple shaped forging.
Large steam turbine spindles are made by hot forging. This part is changed through every blow on the longitudinally placed swage, and is refined regularly, and the mechanical property is improved. Ring-shaped products can be used for mandrill the same way to reduce the thickness, Most of the free forging are 15-500kg but sometimes weighs over 100ton. Sizes differ from very tiny one to 23n-long propellers used in ships. Cogging or drawing out are free forging methods that reduce the thickness of the material.
Simple pressure can reduce the thickness even for the large-sized material or without a machine.
Impression-die and Closed-die forging
In swage forging, the same material gets forged in 2 forging swages, and the same shapes are formed.
During forging, a part of the material forms a flash by sticking out. Flash plays an important role in liquidizing the material during forging. Flash is thin, so cools down fast, and put high pressure on the common swage surface due to frictional resistance, so that the material can fill in the common swage surface, and gets removed after forging.
General swage forging delivers the long part then to the lower swage.
By using the supporting plate, the side of the cut material becomes more right-angled. Through various forging work stages, the material’s shapes change. Preforming like fullering of edging can spread the material in various areas. In fullering, the material is distributed in specific area, and in edging the material is gathered in specific area. The material used in preforming is blocker-die that uses blocking work, which makes the shape. Last processing is using the finisher swage to make the final forging. Flash is removed by trimming, the inner parts are removed by punching. In order to get the measurements in swage forming is to get the processing error, which is accurately measuring the material and to properly design the swage. Inaccurate measurement will make the material not fill the swage, and excessive material will cause pressure and break the swage and machine.
Forging today is becoming more elaborate to cut the additional finishing due to economical reasons.
Near net-shape refers to the forging that make the material become the wanted product as similar as possible. Precision forging is in a very small amount, and is easily removed by trimming or cutting.
In precision forging, the material is processed in more elaborate forging.
Aluminum or magnesium alloy have lower temperature and forging loads, so is suitable for precision forging. These materials have good durabillity, Steel and other alloy are difficult to forge. For precision forging, special swages are needed, and the volume and shape of the material need to be properly controlled, and the materials needs to be placed correctly in the common surface of the swage. However, the additional cutting process is omitted and the material waste is reduced. Therefore the choice between general forging and precision forging are based on the economical view.
Coining is used for making coins, medals, and ornaments. Materials are transformed in completely closed swage.
To make the final shape, 5-6 times the materials’ intensity is needed. In coining, lubrication is not used. This is because the lubrication is completely sealed between the material and the swage, the swage surface makes more accurate shape. Coining is used for other forging products or to make harder and more accurate shapes. This process is called sizing, and it needs higher pressure for no great changes in shape. Coining-like processing can be used for marking the products with text and numbers.
Heading is basically an upsetting work, and is applied for round line or a stick that has larger ending at one end.
With this method, bolt, screw, rivet, nails, and other connecting parts can be made. Heading work takes place in cold, warm and hot automated machines called header
Heading work is used to produce various products by combining the cold press processing.
When the length of the material is longer than the width during the heading work, buckling can occur. The ratio is limited to 3:1, but it can be larger depending on the swage shape. For example, the ratio can be bigger if the diameter of the common part of the swage is within 1.5 times the material.
Piercing & Hubbing
Perforation is the process making the shape by punching on the sur face without penetrating the material.
In perforation, the material can be bind down in the common swage or directly perforating without using a swage.
After perforation, a hole can be made by punching the opposite surface. Perforation load is determined according to the shape, intensity, and friction. Perforation pressure is 3-5 times the material intensity. Hubbing is clamping off the material with specially formed punch. The common area made can be used for shaping the silverware. Common swage surface is relatively thin, but when making deeper swage, the surface needs to be measured and cut-processed before hubbing.
Roii forging & rolling
Roll forging is a process shaping or decreasing the surface by passing the material between a pair of rollers that have shaped grooves.
This method is used in making tapers, layered spring, and tools. It can be used as the 1st shaping work before other forging. sken rolling is similar to roll forging. Timber is moved between the rollers, and is shaped roughly with the continuous round-shaped rolls.
The materials for the round shaped, round bars are cut and upset between two swages that have hemispherical swages. Flash is formed here, and need to be cut and polished for bearing.
Orbital forging is a process to shape the material around the orbit of the specially made device.
This process is like a large mortar. The products made by this processing are plate-shaped parts and babel gears. Contacts are limited to small spaces of the material, so the loading is light. Noise is not bid, and 10-20 rounds of orbital movement makes a product.
Isothermal forgins is also called hot swage forging, the heated material has the same swage temperature.
During the process, material is kept in high temperature, so the stiffness is low, and ductility is high, the forging load is light, and movement within the common swage is increased. Complex parts that need accurate measurements can use hydraulic press for higher level of processing with single administration. Nickel or molybdenum alloy are used as swage material. Isothermal forging is cheap and has low production rate. However, complex shape of products made with titanium or super heat resistant alloys can be economical when there is high quantity.
Rotation swaging or radial forging is using repeated movements to blow the material within the movement range.
The movement of the swage is usually acquired by the rollers that are placed in roller bearing, The material doesn’t move but the swage set rotates and blows the material 20 times per second.
Die-closing swaging machine gets the swaging movement from the moving wedges. Compared to the rotating swager, the swages opens wider, so the products with lager size shapes can be forged. other type is non-rotating swage with the movement within a radius.
For tubing swaging, the inner walls and thickness of the tube are controlled. There are methods using inner mandling and the one not using it. When the inner mendling is used, the thickness of the wall can be controlled, Mendling with longitudinal shape can be manufactured for the tube with shapes inside. For example, the spiral mendling is used for making gun barrels; swaging the tubes in mendling. When making the tubes with smaller diameter, high tensil lines are used as mendling. Some are sized 35nm when processing gun barrels and other products.
Swaging is used for assembling cables or attaching materials on steels
This processing have sizing process that finally finishes the measurement of the parts and pointing of the round shaped compartments. With swaging, maximum diameter of 150nm can be processed, and minimum of 0.5nm can be processed. Processing error is between 0.05nm to 0.5nm. Swaging has high productivity speed, the complexity of the product has about 50-times the ration per minute; the proper processing. In case of using mendling, the length of the material is limited other length of supporting stick, this processing is highly flexible. The producted manufactured by swaging have improved mechanical propertieys. Lubrication is used for more outstanding surface and increased lifespan. For the materials with less ductility in the room temperature, they can use swaging in high temperature.