Question

The Non-Destructive Inspection (NDI) technique employed during inspection for castings of tubes and pipes to check the overall strength of a casting in resistance to bursting under hydraulic pressure is:

• A. Radiographic inspection
• B. Magnetic particle inspection
• C. Fluorescent penetrant
• D. Pressure testing

Hint:

Think about what "checking the overall strength ... in resistance to bursting under hydraulic pressure" directly implies. It suggests a test that applies pressure to see if it bursts.

Answer 1

The Correct Option is D

Step 1: Understand the objective of the inspection.
The goal is to check the overall strength of castings of tubes and pipes in resistance to bursting under hydraulic pressure. This means we need to directly assess the ability of the component to withstand a certain level of internal pressure without failure. Step 2: Evaluate each Non-Destructive Inspection (NDI) technique in relation to this objective.
Radiographic inspection: This technique uses X-rays or gamma rays to penetrate the material and create an image on a film or digital detector. It is primarily used to detect internal discontinuities such as voids, inclusions, and cracks. While these defects can affect the strength under pressure, radiography does not directly test the resistance to bursting. Magnetic particle inspection: This method is used to detect surface and near-surface discontinuities in ferromagnetic materials. It involves magnetizing the part and applying fine magnetic particles to the surface. Discontinuities disrupt the magnetic field, causing the particles to concentrate at the defect location. This technique is good for finding cracks and flaws that could lead to failure under pressure, but it doesn't directly measure the bursting strength. Fluorescent penetrant testing: This technique is used to detect surface-breaking defects in non-porous materials. A liquid penetrant is applied to the surface, allowed to dwell, and then excess penetrant is removed. A developer is applied, which draws the penetrant out of defects, making them visible under ultraviolet light if a fluorescent penetrant is used. Like magnetic particle inspection, this method identifies potential weaknesses but doesn't directly assess the bursting strength. Pressure testing: This method involves subjecting the component (tube or pipe casting) to a specific internal pressure for a predetermined period. The component is then inspected for any signs of leakage, deformation, or failure. This directly assesses the ability of the casting to withstand hydraulic pressure and its resistance to bursting. Step 3: Identify the NDI technique that directly tests the resistance to bursting under hydraulic pressure.
Pressure testing is the only technique among the options that directly evaluates the component's ability to withstand hydraulic pressure without bursting. The other methods detect flaws that could lead to failure but do not directly measure the bursting strength. Step 4: Select the correct answer.
Pressure testing is the NDI technique employed to check the overall strength of a casting in resistance to bursting under hydraulic pressure.