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Correct ANSWER is (c) Cogging

To explain I WOULD say: Among the following processes, cogging is a process which is USED for the manufacturing of processes LIKE blooms and slabs from the cast INGOTS.

The correct choice is (a) Open DIE forging

To elaborate: While the manufacture of products like shafts, discs or rings, the method of CLOSED die forging or IMPACT forging or flashless forging is not ADVISED, but open die forging is used.

Correct answer is (b) Folds

For explanation I WOULD SAY: Folds are found to occur during the plate rolling if the reduction PER mass is very low. And ZIPPER cracks occur when the given rolls get bended.

The correct answer is (b) 2000 PIECES PER MINUTE

Explanation: Thread rolling is considered to be one of the fastest methods of manufacturing threads. The rate of PRODUCTION is as high as 2000 pieces per minute.

The CORRECT choice is (c) BACK tension

The explanation is: When the material is ENTERING the ROLLER, the tension experienced at the entering zone is CALLED as back tension.

The CORRECT option is (c) DRAWING

To explain: Drawing is a metal forming process which is widely used for MAKING the wires from round bars of metal. This process is similar to EXTRUSION process, except that instead of pressure on the metal mass, in drawing, the wire is pulled from one side of the metallic round bar which results into the formation of thin wires. This process is only suitable for ductile materials.

Correct option is (b) Forging

The EXPLANATION: Forging is a deformation process in which the MATERIAL is compressed between the dies by using the IMPACT load or hydraulic load. This process includes large forces that gradually or instantly deformed the material resulting in production of variety of high strength components LIKE connecting rods, GEARS, jet engine turbine parts, aircraft parts etc.

Right option is (d) 30%

The BEST I can explain: In the blanking operation, the material LOSS is approximately 30 % of the metal sheet used in the cutting off OPERATIONS. To reduce the waste or metal loss, the SHAPES to be cut are arranged on the metal sheet properly, this process of reducing metal loss is called as nesting. Nowadays, CAD SOFTWARE is used for this purpose.

Correct choice is (d) BOILING POINT

Explanation: When a ROLLED STACK is made, there is an improvement seen in the physical properties of the material, it does not AFFECT the boiling point of the material.

The correct choice is (b) False

Best explanation: In the stress-strain CURVE of any material exhibits plasticity or strain hardening above the yield point. And below the yield point, the area REPRESENTS the elasticity of the material. Yield point is only present in the stress-strain curve of DUCTILE materials. In brittle materials, yielding does not TAKE place during the application of load; it directly shows the fracture FAILURE.

The correct answer is (b) Drop forging

The BEST I can explain: AMONG the following processes, that is PRESS forging, drop forging, OPEN die forging and closed die forging, drop forging is a process where more amount of noise OCCURS.

The correct option is (a) True

The BEST I can explain: Flow stress is generally defined as the instantaneous value of stress which is REQUIRED to continue the deformation of metal, which means to keep the MATERIAL flowing. It is also defined as the YIELD strength of the material as a function of STRAIN, or the strength that determines the forces required to complete a specific forming operation.

Correct ANSWER is (d) Car bodies

The best explanation: Sheet metal FORMING is a process which uses DUCTILE materials like aluminium or low carbon steel to form lightweight products with versatile features. Car bodies are mainly manufactured by sheet metal forming by PERFORMING operations like shearing, slitting, cutting, or sawing of thin metal plates. This method is also used for making PARTS like beverage cans, metal desks, appliances etc.

Correct option is (a) Difference between STARTING and FINAL THICKNESS

Explanation: DRAFT is CALCULATED as, the difference between the starting thickness of the workpiece and the final thickness of the workpiece.

The correct option is (C) DRAFT

The BEST explanation: During rolling PROCESS, the workpiece gets squeezed, causing the thickness of the workpiece to reduce. This reduced thickness is called a draft.

Correct ANSWER is (a) True

To elaborate: In general, the metal FORMING is a large set of manufacturing PROCESSES in which the metal is deformed plastically to get into the shape of the die geometry. The tools like dies and punches are mostly used in the processes for the deformation of the material. For the plastic deformation, Stresses beyond the yield STRENGTH of the material is required.

The correct CHOICE is (a) Direct EXTRUSION

To elaborate: Direct extrusion is also called as forward HOT extrusion. This method is most widely used and MAXIMUM production is done by this method in extrusion.

Correct ANSWER is (a) True

To elaborate: By keeping the metal at higher temperature, both the strength and STRAIN hardening of the metal decreases. And the ductility is increased at the higher temperature. These changes are very important and ESSENTIAL so that any deforming operation can be easily accomplished by LOWER forces at HIGH temperatures.

Correct option is (c) Cylindrical

Easiest EXPLANATION: The SHAPE of the billet in an EXTRUSION process is designed to be cylindrical only. A cubical or spherical or a PYRAMIDAL billet cannot be designed for a good output.

Right answer is (a) True

The explanation is: Punching is basically a kind of shearing operation in which the required part is the SHEET left out after making a punch hole in the metal sheet. This method is also KNOWN as contour shearing. Die punch clearance is generally very critical for BLANKING as well as for punching operation, as it maintains the kind of finish obtained on the FINAL part.

Correct option is (a) True

The explanation: In the metal forming processes, the EXTENT of plastic deformation of the material is mainly dependent on its GRAIN structure. The deformation of metal also depends on the NATURE of bonding, surrounding temperature and DEFECTS like DISLOCATION which might be present in the material during the metal forming process.

The correct OPTION is (c) Clockwise-anticlockwise- clockwise

For explanation I would say: In THREE high ROLLING mill, the DIRECTION of the rollers in the top and bottom are the same, and the direction of the ROLLER in the middle is opposite to the two.

Right answer is (B) False

The explanation: In the metal forming processes, formability is an essential mechanical PROPERTY which is defined as the ability of sheet metal or any material to undergo shape change without occurring of any FAILURES like tearing or necking in the metal part. This property is vital and MUST be present in the material to be used for the metal forming process.

The correct choice is (a) SQUEEZING dies

To explain: Blanking dies, piercing dies and notching dies are widely USED in the metal cutting OPERATIONS. But the squeezing DIE is a type of forming die which is used for performing metal forming operations. In metal forming, DRAWING dies and bending dies are also used for the forming of metal sheets.

The CORRECT choice is (d) 500-600 tonnes

Explanation: The presses used for such forging processes are manufactured for very HEAVY USE. The presses which are generally used in press forging are of the capacity of 500 to 600 tonnes.

Correct answer is (b) Rolling at HIGH temperatures

Best EXPLANATION: When the MATERIAL to be squeezed is rolled at high temperatures, the strength of the material is FOUND to decrease.

The CORRECT CHOICE is (a) True

Easy explanation: Exiting VELOCITY is has the most magnitude when compared to the other VELOCITIES, and is higher than the ROLL velocity.

Right choice is (c) Stress-strain curve

The best I can explain: The behaviour of MATERIALS during metal forming can be determined by the stress-strain curve. The stress-strain curve for most of the materials is divided into an elastic region and a plastic region. In metal forming, the plastic region is the MAIN consideration because the MATERIAL is plastically DEFORMED during the forming process.

Right OPTION is (a) True

The explanation is: ROLLING is a metal forming PROCESS in which the metal plate is squeezed between the two hard rollers. In the operation, the thickness is decreased and the length is increased as the volume of the metal is conserved. This method is mainly used for the production of THIN metal plates which can be done by PERFORMING hot rolling or cold rolling, depending on the required mechanical properties.

Right choice is (b) Press forging

The explanation is: Among the following METHODS, press forging is one method that is the most widely and commonly used method for the MANUFACTURE of hollow BODIES, wheel discs and PANELS.

Right choice is (a) True

The explanation is: PROGRESSIVE die is also called a follow on die. It can perform two or more operations in a SINGLE stroke of a ram. Normally, the first operation is punching which is then followed by the BLANKING operation. The metal SHEET is transferred to the next place in between the stroke to FORM a complete specimen.

The CORRECT answer is (b) Zipper cracks

The explanation: The FOLLOWING figure DEPICTS in itself the defect, this crack is CALLED as zipper cracks. A defect like zipper crack may occur when the ROLLS which are employed for it, get bended.

Right choice is (a) True

To ELABORATE: It is observed that the INITIAL COST of DIES in case of cold dies forging is comparatively high. Not just that, but this process is also a little complex ONE.

Correct OPTION is (C) EXTERNAL cracking defect

Easy explanation: Among the following DEFECTS in rolled parts, external cracking defect cannot be termed as a defect in rolled parts.

The correct ANSWER is (b) Decrease

Explanation: Radius of the ROLLER is directly related with the draft. Hence, with a decrease in the roller radius, there is a decrease in the draft value and VICE VERSA.

The correct answer is (b) False

To EXPLAIN I would say: The shape and the cross section shape of the billet, which is DESIRED is not OBTAINED in one single pass. One MAY have to USE multiple pass to achieve desired cross section shape.

Right option is (B) Cold forging

To explain: For the manufacturing of products like SCREWS, PINS or nails, the process of HOT forging or IMPACT forging is not recommended. But, for this, cold forging is highly used.