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The CORRECT answer is (a) True

To explain I would SAY: 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.

The correct CHOICE is (b) False

To elaborate: 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.

The correct answer is (B) False

For explanation: 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.

Correct choice is (b) False

The explanation is: 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.

The correct OPTION is (a) True

Easiest explanation: 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.

Correct choice is (d) Carbide

Easiest explanation: 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.

The CORRECT choice is (a) True

Easiest explanation: 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.

Right option is (b) False

The best explanation: 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.

Correct option is (d) 0.4 mm to 6 mm

The best EXPLANATION: 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.

The correct choice is (b) False

For explanation: 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.

The correct option is (a) True

To EXPLAIN: 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.

The correct OPTION is (a) True

Explanation: 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.

Correct choice is (b) False

For explanation I would SAY: 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.

Right choice is (a) True

The explanation: 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.

Correct option is (d) Forging

Explanation: 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.