Types of Die & Metal Forming Process
Q. The raw material for the rolling Process is the output of the sheet metal forming Process.
A. True
B. False
.
.Answer: B
Explanation: Process The raw material for the sheet metal forming is basically the output of the rolling Process. IN the sheet metal forming Process, flat rectangular solid sheets of standard sized are used and then the operations like piercing or blanking is performed on the metal sheets to obtain the desired output.
Q. Which of the following methods of manufacturing is used for the production of appliances like the fridge and vacuum cleaner?
A. Forging
B. Deep drawing
C. Sheet metal forming and cutting
D. Rolling
.
.Answer: C
Explanation: Process Sheet metal forming and cutting Processes are widely used for the manufacturing of home appliances like fridge, vacuum cleaner radio, toys, dryers etc. In the sheet metal forming Processes, bending operation is takes place which form the metal and sheet cutting is used for shearing out the metal part from the large metal sheet.
Q. It is not possible to use cutting dies for the metal drawing operations.
A. True
B. False
.
.Answer: A
Explanation: Process Cutting dies are mainly used for cutting the metal. They use shearing action for cutting the metal sheet. Various cutting dies are used such as blanking dies, piercing dies, perforating dies, notching dies, shaving dies and nibbling dies. And it is not possible to use cutting dies for the metal drawing operations.
Q. What should be the appropriate thickness of the metal sheet when it is used as a raw material for the sheet metal operations?
A. 1 cm to 5 cm
B. 5 cm to 10 cm
C. Q.5 mm to 15 mm
D. 0.4 mm to 6 mm
.
..Answer: D
Explanation: Process The sheet metal forming and cutting operations are mainly performed on relatively thin sheets of metal. The thickness of metal sheet should be 0.4 mm to 6 mm to operate efficiently. If the thickness is more than 6 mm, then it is normally called as metal plate. The operations are generally performed as cold working.
Q. Combination die is a die which combines cutting and non-cutting actions in the blanking Process.
A. True
B. False
.
.Answer: A
Explanation: Process In a combination die, the cutting action like blanking or punching is combined with the non-cutting actions like forming which may further include bending, drawing and extrusion Process. More than one operation can be possible in single stroke with the help of combination dies, but the die is more applicable for two operations only.
Q. In the metal forming operations, forming dies are also called as progressive dies.
A. True
B. False
.
.Answer: B
Explanation: Process Forming dies and progressive dies are different from each other. Progressive dies can perform two or more operations in a single stroke in different stages in which mainly cutting operations like blanking and punching are performed. And forming dies are only used for forming operations.
Q. Transfer dies are same as progressive dies in which piercing and blanking operations are performed.
A. True
B. False
.
.Answer: A
Explanation: Process In the metal forming and cutting operations, transfer dies are almost similar to progressive dies, the only difference is that the already cut blanks are fed from the station to station manually or by automation. In the operation, first the blanking is performed which is then followed by the piercing Process.
Q. Which of the following types of force is predominant in the sheet metal forming Processes?
A. Shearing force
B. Compressive force
C. Tensile force
D. Indirect compressive force
.
.Answer: C
Explanation: Process Tensile force is the predominant force in most of the sheet metal forming operations as compared to the bulk forming which basically involves compressive forces. Due to the tensile stresses in the metal sheets, they may experience localized deformation which is further followed by cracking.
Q. Die-punch clearance is mainly provided for inducing strength in the blank obtained by the metal sheet cutting.
A. True
B. False
.
.Answer: B
Explanation: Process In sheet metal forming or cutting operations, die punch clearance is present which basically used to govern the kind of finish obtained on the final part. Die punch clearance is very critical in operations like blanking and punching because it involves very close tolerances which give accurate and precise details on the finished part.
Q. Which of the following materials is used for the manufacturing of dies and punches in the sheet metal forming?
A. Grey cast iron
B. Copper
C. Aluminium
D. Carbide
.
..Answer: D
Explanation: Process Carbide is mainly used for the manufacturing of dies and punches in the sheet metal forming operations. Sometimes tool steel is also preferred to maintain the lateral rigidity in the tools. Dies and punches must possess mechanical properties such as hardness, strength, rigidity, toughness, machinability etc.
Q. Forging is a metal forming operation in which the metal is stretched to form the desired shape of a metal part.
A. True
B. False
.
.Answer: B
Explanation: Process Forging is a metal forming operation in which heated metal is beaten by a hammer to give it the desired shape. It is basically a deformation Process in which the material is compressed between dies by using impact load to deform it. Forging can also be used for making complex shapes of metal parts.
Q. Precision forging is a type of forging operation in which the metal stocks and dies are controlled very tightly.
A. True
B. False
.
.Answer: A
Explanation: Process In precision type forging operation, the volume of the metal stock and the dies are controlled very tightly. Such operations are called as precision forging which is a modern technique of forging. Metal parts of better strength, high quality details, and complex shape can be easily produced by the forging operation.
Q. In general, the casted metal part is much stronger and tougher than that produced by the forging operation.
A. True
B. False
.
.Answer: B
Explanation: Process In general, forged parts are much stronger and tougher than the casted parts made from the same metal. The metal components have high strength because the hammering operation maintains its structure that makes proper alignment of grains along the profile of metal components, which leads to an increase in strength.
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Q. The open die forging Process is also known as upsetting or upset forging Process.
A. True
B. False
.
.Answer: A
Explanation: Process In an open die forging Process, the metal billet is heated up to a very high temperature and then compressed between two flat die halves. This method is like a compression test, which is also known as upsetting or upset forging. In the Process, billet is basically deformed by a decrease in its height and increase in its diameter.
Q. Which of the following Processes is mainly used for making the connecting rods?
A. Casting
B. Deep drawing
C. Rolling
D. Forging
.
..Answer: D
Explanation: Process Connecting rods are generally manufactured by the forging operation. In forging, a hammer is used which strikes on the heated metallic part to get into the desired shape. The properties like strength, toughness, etc are greatly enhanced by performing the forging operation. Forging can be open die forging or closed die forging.
Q. In open die forging Process, homogenous deformation of billet has occurred with uniform increase in its diameter.
A. True
B. False
.
.Answer: B
Explanation: Process In open die forging Process, the deformation is not homogenous as bulging occurs due to the presence of friction at the interface of die and billet. This friction opposes the motion of billet; this effect is generally called as barreling effect. Homogenous deformation only occurs when the friction is zero, which is an ideal condition for the forging Process.
Q. In impression die forging Process, extra deformed material is produced which is called a flash.
A. True
B. False
.
.Answer: A
Explanation: Process In impression die forging Process, flash can be produced which is considered as scrap material that is removed from the formed part during the finishing of a metal part. But in flash-less forging, the metal is fully prevented within the die, so no flash is produced during the Process.
Q. Isothermal forging is also known as cold forging operation.
A. True
B. False
.
.Answer: B
Explanation: Process Isothermal forging is a hot forging operation in which the metal part is maintained at some high temperature. The forging dies are also maintained at the same high temperature. In this method, the metal flows readily that reduces the amount of force required. But this Process is expensive than the conventional forging and mainly used for materials like titanium and super-alloys.
Q. The metal forging operation can be performed manually or by automation.
A. True
B. False
.
.Answer: A
Explanation: Process Metal forging is a forming operation that performs hammering to shape the metal component. In forging Process, the metal component is heated sufficiently, and then it is hammered by using a hammer which can be performed manually or by automation, depending on the scale of production and properties required in the forged metal component.
Q. A cone shaped die is used in the orbital forging for the forging of metal parts.
A. True
B. False
.
.Answer: A
Explanation: Process In the orbital forging Process, forming is done to the meat part by using a cone-shaped die that is simultaneously rolled and pressed into the material. The metal part is supported on a lower die, because of inclined axis of cone. In the Process, only a small area of the metal surface is compressed at the stage of forming.
Q. In plastic deformation of metal, the deformation is temporary and can regain its original shape.
A. True
B. False
.
.Answer: B
Explanation: Process Plastic deformation of any material means permanent deformation without the presence of external constraints. The plastic deformation of crystalline materials generally takes place by Processes which are very different from that for the amorphous materials. In plastic deformation, material cannot regain its original shape.
Q. Elastic deformation can disappear completely when the load is removed from the metal.
A. True
B. False
.
.Answer: A
Explanation: Process In general, deformation can be of two types, elastic or plastic. Elastic deformation can disappear completely when the load is removed from the metal, whereas plastic deformation is a permanent deformation which occurs when the elastic range of deformation exceeds. The plastic deformation takes place without any failure and does not disappear after removing the load.
Q. The fluids reveal its flow behaviour when it is subjected to normal compressive stresses.
A. True
B. False
.
.Answer: B
Explanation: Process The fluids reveal their flow behaviour only when it is subjected to shearing stress. A little amount of shear stress can deform the flow and it never regains its original shape even after removing the shearing load. The compressive or tensile stress does not make any changes to the fluid behaviour.
Q. In crystalline materials, the plastic deformation occurs when the group of atoms or molecules slides past each other.
A. True
B. False
.
.Answer: B
Explanation: Process Material always shows a non-recoverable deformation when it is subjected to stresses beyond certain minimum stress. Crystalline materials experience permanent deformation when slipping occurs along the definite crystalline planes. But in amorphous materials, permanent deformation occurs when the group of atoms or molecules slides past each other.
Q. Metal forming operations can only be performed when the material undergoes plastic deformation.
A. True
B. False
.
.Answer: A
Explanation: Process In metal forming Process, plastic deformation of the material is compulsory. It is a Process in which the required shape of metal is achieved by plastic deformation. Stresses are induced in the metal which is greater than its yield strength but less than its fracture strength so that the metal can be deformed into the required shape.
Q. The Process of forming new grains in the material is known as re-crystallization.
A. True
B. False
.
.Answer: A
Explanation: Process The Process of forming new grains in the material is known as re-crystallization. And the temperature at which the re-crystallization occurs is known as re-crystallization temperature. The plastic or permanent deformation at elevated temperature occurs at less stresses as the growing of new grains are much easier at high temperature.
Q. For the plastic deformation, it is not necessary to have higher applied stress than the yield strength of the material.
A. True
B. False
.
.Answer: B
Explanation: Process In plastic deformation of metal, applied stress is the main parameter which must be higher than the yield strength of the material and less than the fracture strength. The plastic deformation increases with the applied stresses when these stresses present in the middle of yield strength and fracture strength.
Q. In plastic deformation of metal, the metal strength decreases as the increase in its temperature.
A. True
B. False
.
.Answer: A
Explanation: Process In plastic deformation of metal, its strength decreases when the temperature is increased. The plasticity of material is better when the deformation temperature is greater than the re-crystallization temperature but should be below the melting point. Re-crystallization temperature is the temperature at which the metal shows enough plasticity for efficient deformation.
Q. The yield point is very important for controlling the various manufacturing Processes.
A. True
B. False
.
.Answer: A
Explanation: Process The yield point of a metal is defined as the point at which a metal starts to deform plastically. Study of yield point is very important for designing of any component as it shows a limit to the load which can be applied to that metal component. The yield point is very important for controlling the various manufacturing Processes like forging, rolling, bending etc.
Q. In the yield criteria of metal, von-mises criteria are also known as distortion energy theory.
A. True
B. False
.
.Answer: A
Explanation: Process In the yield criteria of any metal, von-mises criterion is also known as distortion energy theory. This theory shows that the plastic deformation of metal occurs when the value of shear strain energy per unit volume of the body becomes equals to the strain energy per unit volume at the elastic limit of the metal.
Q. Tensile strength of a material is the ability of a material to resist the lateral load without failure.
A. True
B. False
.
.Answer: B
Explanation: Process Tensile strength of any material is defined as the ability of a material to resist axial or centric load without failure, it is mainly determined by performing tensile test. When equal and opposite forces are applied to the material simultaneously that axially pulls the material, which further causes elongation of the material by decrease in its diameter.
Q. The behaviour of the material is generally determined by its mechanical properties.
A. True
B. False
.
.Answer: A
Explanation: Process The behaviour of the material is generally determined by its mechanical properties, when a material is subjected to different loading conditions like tensile load, compressive load etc. then properties like young’s modulus, various strengths, toughness, ductility etc. are determined, which are very important in design and manufacturing.
Q. The necking phenomenon of material can be observed in tensile test as well as in compression test.
A. True
B. False
.
.Answer: B
Explanation: Process When an axial load is applied to the material, the material first elongates, then necking occurs and the fracture is produced. The necking phenomenon is only occurring in the tensile test due to the elongation of material, a neck like structure is formed. Its behaviour generally depends on the material used for the test. Necking does not take place in brittle materials.
Q. The induced stress in the material and the young’s modulus, both are the properties of the material.
A. True
B. False
.
.Answer: B
Explanation: Process When a material is subjected to any load then the stress is induced in the material which is not a material property, it basically depends on the load applied and the cross-sectional area of the material. And young’s modulus is a material property which indicates stiffness of the material and it is different for different materials.
Q. When material subjected to load then elongation becomes more faster beyond the yield point.
A. True
B. False
.
.Answer: A
Explanation: Process Beyond the yield point, as the load increases, elongation of material proceeds at a faster rate than before. This part of stress strain curve is called as hardening region. When the load reaches a maximum value, the engineering stress at this point is called as the tensile strength or ultimate tensile strength of the material.
Q. Necking is a localized elongation through which the load carrying capacity of material increases beyond its tensile strength.
A. True
B. False
.
.Answer: B
Explanation: Process In the stress-strain curve, beyond the tensile strength, the load carrying capacity reduces and the test material goes through a localized elongation called necking. There is no any constant strain in this region and the elongation occurs in one small segment of specimen. The stress measured just before the failure is known as the fracture stress.
Q. The amount of strain that the material sustains before failure is a property which is called as ductility of the material.
A. True
B. False
.
.Answer: A
Explanation: Process When a material is subjected to a load, then the amount of strain that the material sustains before failure is an important property which is called as ductility of the material. This property is very useful in manufacturing of machine products which works more dynamically than statically. The ductility is generally measured in terms of its area reduction.
Q. In the computation of engineering stress, the actual or instantaneous cross-sectional area is used.
A. True
B. False
.
.Answer: B
Explanation: Process The original cross sectional area is used in the computation of engineering stresses. But in computation of true stresses, the instantaneous cross-sectional area is used. Because of the length and cross-sectional area both changes at every instant during loading of material. The instantaneous load divided by instantaneous cross-sectional area is called true stress.
Q. The relationship between the shear stress-strain is similar to the flow curve for plasticity of material.
A. True
B. False
.
.Answer: A
Explanation: Process Shear stress basically involves an application of load parallel to the surface of material in the opposite direction. The relationship between the shear stress-strain is similar to the flow curve for the plasticity of material. The applied load always increases as the increase in its strain hardening; then the material becomes much stronger and harder.
Q. The brittle material directly fractures without yielding when it reaches the ultimate strength material.
A. True
B. False
.
.Answer: A
Explanation: Process The behaviour of the material is completely defined by its stiffness. Such material directly fractures without yielding when it reaches ultimate strength material. These materials are called as brittle materials. Examples of brittle material are ceramics, cast iron, etc. These materials are not suitable for forming operation, where permanent plastic deformation is required to get the final product.
Q. Materials like lead (PB. and tin (Sn) can be hot worked at room temperature.
A. True
B. False
.
.Answer: A
Explanation: Process Hot working or hot forming of materials is normally performed at the temperature above than its re-crystallization temperature, but for materials like lead (PB. and tin (Sn), the hot working can be done at room temperature because these materials possess very low crystallization temperature.
Q. Hot working of brittle materials is not possible as they do not show yielding behaviour.
A. True
B. False
.
.Answer: B
Explanation: Process At high temperature, the materials generally have great amount of ductility and so there is no limit or restriction on the amount of hot working that can be performed on a metal. Hence, even the brittle materials can be used for the hot working. In hot working, the grain structure of material is refined which enhances the mechanical properties of material.
Q. In the hot working of materials, porosity may increase in the material rather than decrease.
A. True
B. False
.
.Answer: B
Explanation: Process In the hot working of materials, the porosity always decreases and reaches to negligible amount in the material. The high temperature of the material makes dynamic changes in the material and the gases entrapped in the material loses out and vapourized due to the high temperature of material. This minimizes the amount of porosity in the material.
Q. Hot working does not affect the properties like tensile strength, hardness etc. when the Process is performed properly.
A. True
B. False
.
.Answer: A
Explanation: Process When the hot working Process is properly carried out, then hot work does not affect the mechanical properties like tensile strength, hardness, corrosion resistance, etc. The shear stress is reduced at the higher temperature, so this Process does not require much force to obtain the desired deformation, due to this properties remains same.
Q. In hot working of material, the continuous reformation of grains can be possible in material.
A. True
B. False
.
.Answer: A
Explanation: Process In hot working of materials, it is possible to continuously reform the grains in material. It requires proper controlling of temperature and rate of hot working. In hot working, very favourable grain size can be obtained which further enhances the mechanical properties of material. And no any residual stresses are present in the material during hot working which also gives rise to better mechanical properties.
Q. In cold working, larger deformation can be obtained more rapidly than that obtained by the hot working.
A. True
B. False
.
.Answer: B
Explanation: Process The mechanical properties, elongation and izod values are enhanced in the hot working of materials. In hot working, the other properties like directional properties and fibre are also produced in the material which helps in achieving the larger deformation more rapidly than that obtained by the cold working, as the material is present in the plastic state.
Q. The surface finish obtained by cold working is better than that achieved by the hot working of material.
A. True
B. False
.
.Answer: A
Explanation: Process In the hot working of metals, rapid oxidation or scale formation and surface de-carburization Processes occur on the surface of metal due to the presence of high temperature. This results in a poor surface finish of the metal and the metal loss too. But in cold working, the temperature is kept moderate which maintains the better surface finish of the metal.
Q. In the hot working of steel material, steel metal may lose its strength due to carbon loss.
A. True
B. False
.
.Answer: A
Explanation: Process In the hot working of steel material, the carbon content can be disturbed; means the carbon loss can occur from the surface of steel metal which leads to losing of its strength. This is a major drawback which can also weaken the surface layer that gives rise to fatigue crack which may further result in complete failure of the metal component.
Q. The hot working Process is mainly used for achieving the high dimensional accuracy of the metal.
A. True
B. False
.
.Answer: B
Explanation: Process In the hot working of metal components, the temperature is very high, which is more than the re-crystallization temperature of the metal. This high temperature leads to high thermal expansion of the metal component. This expansion varies the shape and size of the metal, so the dimensional accuracy of the metal component cannot be achieved by hot working.
Q. The cold working of material facilitates its cutting operation due to a decrease in its ductility.
A. True
B. False
.
.Answer: A
Explanation: Process In the cold working of material, the material is deformed plastically which increases the strain hardening. This further increases its strength by losing its ductility; the loss of ductility is useful in machining operation. The breaking of chips becomes much easier due to less ductility, which further facilitates the cutting operation of material.
Q. The main function of the lubricant is to reduce the tensile or compressive stresses required in metal forming.
A. True
B. False
.
.Answer: B
Explanation: Process The main function of the lubricant is to control the frictional force that arises due to sliding contact between the sheet metal and cutting tool material during sheet metal forming operation. Lubricants are also used to prevent galling problems by protecting tool material from direct contact with the sheet material.
Q. In lubrication, the boundary layer formed consists of long chain hydrocarbons with a polar head.
A. True
B. False
.
.Answer: A
Explanation: Process In lubrication, the performance of boundary layers and its formation basically depends on its physical and chemical adsorption. The boundary layers formed by a mechanism mainly consist of clusters and long chain hydrocarbons with a polar head. Then this polar group adheres to the surface and forms high viscosity hydrocarbon layers.
Q. In the case of un-reactive contacting surfaces, the fatty acids adheres by chemical reaction during lubrication.
A. True
B. False
.
.Answer: B
Explanation: Process In lubrication, the hydrocarbon layers are meant to reduce the friction and wear under loading conditions. In the case of un-reactive contacting surfaces, the fatty acids only adhere by physical adsorption. For the reactive metal surfaces, the mechanism of chemical adsorption is likely to occur, which combines both the physical and chemical adsorption.
Q. Boundary layers formed by chemical adsorption using additives are also called as friction modifiers.
A. True
B. False
.
.Answer: A
Explanation: Process In the lubrication of metal surfaces, the additives are used to form boundary layers by a mechanism of chemical adsorption. These boundary layers are also known as friction modifiers. In general, the additives used can be fatty acids, ester, or fatty amides. The boundary layer is highly resistant to contact temperature and therefore it can be used for wear and friction reduction.
Q. Temperature cannot affect the friction and lubrication present during the metal forming.
A. True
B. False
.
.Answer: B
Explanation: Process Friction and lubrication in metal forming are greatly influenced by parameters such as temperature, mechanical properties, surface finish, sliding velocity, pressure etc. In general, the viscosity of lubricant decreases with the increase in temperature and vice-versa. And friction becomes more vigorous when the temperature is very high during the metal forming operation.
Q. Strip drawing test is a method which is mainly used for evaluating the characteristics of lubricants.
A. True
B. False
.
.Answer: A
Explanation: Process In strip drawing test method, a strip is used which drawn between two opposite plane dies that are wider than the strip. The amount of stretching strip can change the coefficient of friction. And the test is usually performed with different speeds and different radius of the die. This test is widely used for evaluating the characteristics of lubricants which used during the Process of metal forming.
Q. The flow of material in die cavity solely depends on the flow-ability of material.
A. True
B. False
.
.Answer: B
Explanation: Process The flow of material in die cavity not only depends on the flow-ability of material, it also depends on the frictional conditions at the die and material interface. Therefore, a proper study of parameters that affect the friction is required for selecting suitable lubricants for the operation and producing better quality of metal parts.
Q. The lubrication is not required when the formability of material is sufficiently large in metal forming.
A. True
B. False
.
.Answer: A
Explanation: Process A dry condition (no lubricant) is mainly used when the material formability is sufficiently large to form desired metal part with simple geometry. In this case, the friction is very high as no any lubricant is used during the operation, but this friction does not significantly affect the metal part quality. A dry condition is usually suitable for hot rolling forming Processes.
Q. Semi-synthetic fluid is a type of lubricant which is generally insoluble in water.
A. True
B. False
.
.Answer: B
Explanation: Process Lubricant is a material that is mainly used for reducing friction and for cooling purposes. For example, oils, soluble oils, synthetic and semi-synthetic fluids are widely used in metal forming Processes. Semi-synthetic fluid is a kind of lubricant which easily mixed with water to form a fine lubricant because it includes small quantity of mineral oil, usually less than 30% of the total concentrate volume.
Q. Additives can be added in a lubricant to enhance its performance during metal forming operations.
A. True
B. False
.
.Answer: A
Explanation: Process In metal forming Process, several types of additives are mixed with lubricant to enhance the performance of the lubricant. The extreme pressure (EP) additives are generally used in heavy work metal operations. The temperature dependent EP additives, such as chlorine, phosphorus, and sulphur are mainly used to create chemical films that prevent metal to metal contact during forming operations.
Q. In electromagnetic forming, highly intense magnetic field is used for the forming Process.
A. True
B. False
.
.Answer: A
Explanation: Process In electromagnetic forming, many components like capacitor bank, forming coil, field shaper, conductive material etc. are used to create intense magnetic fields. This magnetic is generally produced by the discharge of capacitors into a coil, which lasts only for a few microseconds. Then further Processing is done to perform the metal forming.
Q. The magnetic field interacts with metal to generate heat in the metal which causes forming Process.
A. True
B. False
.
.Answer: B
Explanation: Process In the electromagnetic forming Process, eddy currents are induced in a conductive material that is placed near to the coil. Then it interacts with a magnetic field to cause mutual repulsion between the metal and the forming coil. This force of repulsion is mainly responsible for inducing stresses in the metal beyond its yield strength which results in plastic deformation of metal.
Q. Metal used for electroforming Process absorbs energy from the magnetic field to get deform.
A. True
B. False
.
.Answer: A
Explanation: Process In the electromagnetic forming Process, the conductivity of the metal and the eddy currents which makes contact with magnetic field creates a net pressure on the surface of the metal. Then the metal surface moves inward due to the effect of this pressure, this mainly occurs due to the transfer of energy from the magnetic field to the metal.
Q. In the electromagnetic forming Process, the forming pulse is kept longer to optimize the use of energy.
A. True
B. False
.
.Answer: B
Explanation: Process In the electromagnetic forming Process, the metal absorbs energy from the magnetic field to get deformed. To utilize most of this energy to forming operation, and to reduce the energy loss due to resistance heating, the forming pulse is kept short for better optimization of energy produced by the magnetic field. In general, pulse has duration of between 10 and 100 second.
Q. Which of the following methods of forming is not the part of electromagnetic forming?
A. Compression
B. Expansion
C. Shearing
D. Counter forming
.
.Answer: C
Explanation: Process In the electromagnetic forming Process, electromagnetic formation mainly used for three forming methods which can be compression, expansion, and counter forming. For compression, a tubular metal is compressed by a coil, usually against a grooved tube. And shearing is a different Process which is not a part of electromagnetic forming.
Q. Electromagnetic forming cannot be used for materials of poor electrical conductivity.
A. True
B. False
.
.Answer: B
Explanation: Process The electromagnetic forming method uses a high intense magnetic field to deform the material. This Process is primarily used for the forming of good conducting materials like copper, aluminum, silver etc. This method can also be used for materials of poor electrical conductivity such as stainless steel.
Q. The efficiency of electromagnetic forming mainly depends on the resistivity of material being formed.
A. True
B. False
.
.Answer: A
Explanation: Process The electromagnetic forming method uses a capacitor and forming coil to create intense magnetic field. The efficiency of the magnetic pulse mainly depends on the resistivity of the material being formed. For better output, the resistivity of the material must be less than 15 micro-ohm-centimeters.
Q. The Process of electromagnetic forming does not require any kind of lubrication.
A. True
B. False
.
.Answer: A
Explanation: Process In most of the forming Processes, tool contacts with the specimen to get the desired output. But in the case of electromagnetic forming, the magnetic field is used to apply the pressure on the surface of a metal, which normally does not require any kind of lubrication. And it leaves no any tool marks on the metal surface.
Q. Which of the following is the main advantage of using the electromagnetic forming Process?
A. High speed
B. Low maintenance
C. Applicable to all materials
D. No spring-back
.
..Answer: D
Explanation: Process In the electromagnetic forming Process, the metal is loaded and achieve plastic region, which results in plastic or permanent deformation, so that the spring-back associated with the mechanical forming Process is completely eliminated because no any mechanical contact is present during the Process of metal forming.
Q. The joints made by an electromagnetic forming Process are much stronger than the parent material.
A. True
B. False
.
.Answer: A
Explanation: Process In the electromagnetic forming Process, the joints made are much stronger than the parent material. This Process also allows increased ductility for several alloys because of the lack of stresses and friction which normally encountered with the Process. This method is widely used for a high rate of production.
