AME 3 Q6

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With reference to a ball race bearing, what does the term "brinelling" refer to?

A) Permanent deformation of the raceway surface due to excessive load, resulting in indentations from the rolling elements.

C) Wear of the bearing surfaces due to inadequate lubrication over time.

B) Corrosion of the bearing surfaces caused by exposure to moisture and contaminants.

D) Formation of excessive heat within the bearing assembly due to high-speed operation.

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How can false brinelling be reduced in practice?

A) By using vibration dampeners or isolators to minimize vibrations during storage or transportation.

D) By storing bearings in a vertical position to prevent any contact between rolling elements and raceways.

B) By increasing the operational load on the bearing to prevent false brinelling.

C) By applying excessive lubrication to the bearing to create a thicker film between the rolling elements and raceways.

Correct Answer: A) By using vibration dampeners or isolators to minimize vibrations during storage or transportation.

Explanation: False brinelling occurs due to vibrations that cause small movements of the rolling elements against the raceways when the bearing is stationary. To reduce false brinelling, the most effective method is to minimize or eliminate these vibrations during storage or transportation. Using vibration dampeners or isolators helps absorb and reduce the impact of external vibrations, preventing the small, repeated movements that lead to false brinelling.

Incorrect Options:

B) By increasing the operational load on the bearing to prevent false brinelling.

Explanation: Increasing the operational load might actually cause other types of damage, such as true brinelling, where excessive load leads to permanent indentations. False brinelling occurs when the bearing is not in use, so increasing the load during operation does not address the root cause of false brinelling, which is vibration while the bearing is stationary.

C) By applying excessive lubrication to the bearing to create a thicker film between the rolling elements and raceways.

Explanation: While proper lubrication is important for bearing operation, excessive lubrication does not prevent false brinelling. False brinelling is caused by vibration-induced movements, not by lack of lubrication. In fact, excessive lubrication can lead to other issues, such as increased friction or overheating, without addressing the vibration problem.

D) By storing bearings in a vertical position to prevent any contact between rolling elements and raceways.

Explanation: Storing bearings in a vertical position does not prevent contact between rolling elements and raceways. Bearings are designed to have rolling elements in contact with the raceways. The key issue in false brinelling is not the static contact but the movement caused by vibrations, which would not be resolved by simply changing the storage orientation.

Correct Answer: A) By using vibration dampeners or isolators to minimize vibrations during storage or transportation.

Explanation: False brinelling occurs due to vibrations that cause small movements of the rolling elements against the raceways when the bearing is stationary. To reduce false brinelling, the most effective method is to minimize or eliminate these vibrations during storage or transportation. Using vibration dampeners or isolators helps absorb and reduce the impact of external vibrations, preventing the small, repeated movements that lead to false brinelling.

Incorrect Options:

B) By increasing the operational load on the bearing to prevent false brinelling.

Explanation: Increasing the operational load might actually cause other types of damage, such as true brinelling, where excessive load leads to permanent indentations. False brinelling occurs when the bearing is not in use, so increasing the load during operation does not address the root cause of false brinelling, which is vibration while the bearing is stationary.

C) By applying excessive lubrication to the bearing to create a thicker film between the rolling elements and raceways.

Explanation: While proper lubrication is important for bearing operation, excessive lubrication does not prevent false brinelling. False brinelling is caused by vibration-induced movements, not by lack of lubrication. In fact, excessive lubrication can lead to other issues, such as increased friction or overheating, without addressing the vibration problem.

D) By storing bearings in a vertical position to prevent any contact between rolling elements and raceways.

Explanation: Storing bearings in a vertical position does not prevent contact between rolling elements and raceways. Bearings are designed to have rolling elements in contact with the raceways. The key issue in false brinelling is not the static contact but the movement caused by vibrations, which would not be resolved by simply changing the storage orientation.

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How is a Brinell hardness test carried out?

D) A sharp edge is dragged across the material's surface to create a scratch, and the resistance to scratching is measured to determine hardness.

B) A diamond pyramid indenter is pressed into the material's surface, and the diagonal length of the indentation is measured to calculate hardness.

C) A conical indenter is pressed into the material's surface, and the depth of penetration is measured to determine hardness.

A) A hardened steel or carbide ball is pressed into the material's surface under a specific load, and the diameter of the indentation is measured to calculate hardness.

Correct Answer: A) A hardened steel or carbide ball is pressed into the material's surface under a specific load, and the diameter of the indentation is measured to calculate hardness.

Explanation: The Brinell hardness test involves pressing a hardened steel or carbide ball into the material's surface under a specified load. After the load is applied and then removed, the diameter of the indentation left on the surface is measured. The Brinell hardness number (BHN) is calculated using the applied load and the diameter of the indentation. This method is commonly used for testing materials like metals to determine their hardness, especially when dealing with materials that may have a coarse or uneven grain structure.

Incorrect Options:

B) A diamond pyramid indenter is pressed into the material's surface, and the diagonal length of the indentation is measured to calculate hardness.

Explanation: This describes the Vickers hardness test, not the Brinell hardness test. The Vickers test uses a diamond pyramid indenter, and the hardness is calculated based on the diagonal length of the indentation. While it also measures hardness, the method and the indenter used differ from those in the Brinell test.

C) A conical indenter is pressed into the material's surface, and the depth of penetration is measured to determine hardness.

Explanation: This describes the Rockwell hardness test, not the Brinell hardness test. The Rockwell test uses a conical indenter (often a diamond cone) and measures the depth of penetration under a specific load to determine hardness. This method differs in both the indenter used and the measurement technique from the Brinell test.

D) A sharp edge is dragged across the material's surface to create a scratch, and the resistance to scratching is measured to determine hardness.

Explanation: This describes the scratch hardness test (such as the Mohs hardness test), not the Brinell hardness test. The scratch test measures the resistance of a material to being scratched by a sharp edge, which is a different way of assessing hardness compared to the indentation methods used in the Brinell, Vickers, and Rockwell tests.

Correct Answer: A) A hardened steel or carbide ball is pressed into the material's surface under a specific load, and the diameter of the indentation is measured to calculate hardness.

Explanation: The Brinell hardness test involves pressing a hardened steel or carbide ball into the material's surface under a specified load. After the load is applied and then removed, the diameter of the indentation left on the surface is measured. The Brinell hardness number (BHN) is calculated using the applied load and the diameter of the indentation. This method is commonly used for testing materials like metals to determine their hardness, especially when dealing with materials that may have a coarse or uneven grain structure.

Incorrect Options:

B) A diamond pyramid indenter is pressed into the material's surface, and the diagonal length of the indentation is measured to calculate hardness.

Explanation: This describes the Vickers hardness test, not the Brinell hardness test. The Vickers test uses a diamond pyramid indenter, and the hardness is calculated based on the diagonal length of the indentation. While it also measures hardness, the method and the indenter used differ from those in the Brinell test.

C) A conical indenter is pressed into the material's surface, and the depth of penetration is measured to determine hardness.

Explanation: This describes the Rockwell hardness test, not the Brinell hardness test. The Rockwell test uses a conical indenter (often a diamond cone) and measures the depth of penetration under a specific load to determine hardness. This method differs in both the indenter used and the measurement technique from the Brinell test.

D) A sharp edge is dragged across the material's surface to create a scratch, and the resistance to scratching is measured to determine hardness.

Explanation: This describes the scratch hardness test (such as the Mohs hardness test), not the Brinell hardness test. The scratch test measures the resistance of a material to being scratched by a sharp edge, which is a different way of assessing hardness compared to the indentation methods used in the Brinell, Vickers, and Rockwell tests.

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With reference to a ball race bearing, what does the term "false brinelling" refer to?

B) Corrosion of the bearing surfaces due to exposure to moisture and contaminants.

C) Permanent deformation of the raceway surface due to excessive load, resulting in indentations from the rolling elements.

D) Formation of excessive heat within the bearing assembly due to high-speed operation.

A) Surface wear on the raceway caused by vibration and relative motion between stationary rolling elements and raceways when the bearing is not rotating.

Your score is

Correct Answer: A) Permanent deformation of the raceway surface due to excessive load, resulting in indentations from the rolling elements.

Incorrect Options:

Correct Answer: A) Permanent deformation of the raceway surface due to excessive load, resulting in indentations from the rolling elements.

Incorrect Options:

Correct Answer: A) By using vibration dampeners or isolators to minimize vibrations during storage or transportation.

Incorrect Options:

Correct Answer: A) By using vibration dampeners or isolators to minimize vibrations during storage or transportation.

Incorrect Options:

Correct Answer: A) A hardened steel or carbide ball is pressed into the material's surface under a specific load, and the diameter of the indentation is measured to calculate hardness.

Incorrect Options:

Correct Answer: A) A hardened steel or carbide ball is pressed into the material's surface under a specific load, and the diameter of the indentation is measured to calculate hardness.

Incorrect Options:

Correct Answer: A) Surface wear on the raceway caused by vibration and relative motion between stationary rolling elements and raceways when the bearing is not rotating.

Incorrect Options:

Correct Answer: A) Surface wear on the raceway caused by vibration and relative motion between stationary rolling elements and raceways when the bearing is not rotating.

Incorrect Options: