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Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.
Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.
Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.
- a)Both A and R are true and R is the correct explanation of A
- b)Both A and R arc true but R is NOT the correct explanation of A
- c)A is true hut R is false
- d)A is false but R is true
Correct answer is option 'D'. Can you explain this answer?
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Assertion (A): In case of hot working of metals, the temperature at wh...
Should be above the recrystallisation temperature
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Assertion (A): In case of hot working of metals, the temperature at wh...
D
becoz hot working of metals takes place always above recrystllisation temp.
or agr process ko recrystllisation ke upr stop krte hai to to usme minor sa changes to hoga hi...
becoz hot working of metals takes place always above recrystllisation temp.
or agr process ko recrystllisation ke upr stop krte hai to to usme minor sa changes to hoga hi...
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Assertion (A): In case of hot working of metals, the temperature at wh...
A. In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.
Hot working is a metalworking process that involves shaping or forming metals at elevated temperatures. It is typically performed above the recrystallisation temperature of the metal, which is the temperature at which the grains of the metal transform into a new set of grains with a lower dislocation density.
When hot working is performed, the metal undergoes plastic deformation due to the application of external forces. This causes the grains to break down and rearrange, reducing the dislocation density and improving the mechanical properties of the metal. However, if the process is stopped above the recrystallisation temperature, it can lead to undesirable grain growth.
R. If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.
When a metal is heated above its recrystallisation temperature, the new grains that form have a higher energy state and tend to grow in size over time. This is known as grain growth. If the process of hot working is stopped above the recrystallisation temperature, the newly formed grains will continue to grow, resulting in a coarse-grained structure.
Coarse-grained structures have several disadvantages compared to fine-grained structures. They have reduced strength, ductility, and toughness, which can significantly affect the mechanical properties of the metal. Additionally, coarse grains can lead to anisotropy, where the material exhibits different properties in different directions. This can result in uneven deformation and failure under load.
Explanation:
Both Assertion (A) and Reason (R) are true. The recrystallisation temperature is an important parameter in hot working because it determines the optimal temperature range for deformation without significant grain growth. If the process is stopped above the recrystallisation temperature, grain growth will occur, leading to a coarse-grained structure and adversely affecting the mechanical properties of the metal.
However, Reason (R) is not the correct explanation of Assertion (A). The reason behind not stopping the hot working process above the recrystallisation temperature is to avoid grain growth, which is a well-known phenomenon in metallurgy. The assertion is a statement of fact, while the reason provides an explanation for why it is important to stop the process below the recrystallisation temperature.
Therefore, the correct answer is option D - Assertion (A) is false, but Reason (R) is true.
Hot working is a metalworking process that involves shaping or forming metals at elevated temperatures. It is typically performed above the recrystallisation temperature of the metal, which is the temperature at which the grains of the metal transform into a new set of grains with a lower dislocation density.
When hot working is performed, the metal undergoes plastic deformation due to the application of external forces. This causes the grains to break down and rearrange, reducing the dislocation density and improving the mechanical properties of the metal. However, if the process is stopped above the recrystallisation temperature, it can lead to undesirable grain growth.
R. If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.
When a metal is heated above its recrystallisation temperature, the new grains that form have a higher energy state and tend to grow in size over time. This is known as grain growth. If the process of hot working is stopped above the recrystallisation temperature, the newly formed grains will continue to grow, resulting in a coarse-grained structure.
Coarse-grained structures have several disadvantages compared to fine-grained structures. They have reduced strength, ductility, and toughness, which can significantly affect the mechanical properties of the metal. Additionally, coarse grains can lead to anisotropy, where the material exhibits different properties in different directions. This can result in uneven deformation and failure under load.
Explanation:
Both Assertion (A) and Reason (R) are true. The recrystallisation temperature is an important parameter in hot working because it determines the optimal temperature range for deformation without significant grain growth. If the process is stopped above the recrystallisation temperature, grain growth will occur, leading to a coarse-grained structure and adversely affecting the mechanical properties of the metal.
However, Reason (R) is not the correct explanation of Assertion (A). The reason behind not stopping the hot working process above the recrystallisation temperature is to avoid grain growth, which is a well-known phenomenon in metallurgy. The assertion is a statement of fact, while the reason provides an explanation for why it is important to stop the process below the recrystallisation temperature.
Therefore, the correct answer is option D - Assertion (A) is false, but Reason (R) is true.
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Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer?
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Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer?.
Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer?.
Solutions for Assertion (A): In case of hot working of metals, the temperature at which the process is finally stopped should not be above the recrystallisation temperature.Reason (R): If the process is stopped above the recrystallisation temperature, grain growth will take place again and spoil the attained structure.a)Both A and R are true and R is the correct explanation of Ab)Both A and R arc true but R is NOT the correct explanation of Ac)A is true hut R is falsed)A is false but R is trueCorrect answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
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