NDT ( NON DESTRUCTIVE TESTING )

NDT (NON DESTRUCTIVE TESTING) :-

Non Destructive Testing in great variety are in world wide used to detect variations in structure,minute changes in surface finish, the presence of cracks or other physical discontinuities,measure the thickness of materials and coatings and to determine other characteristics of industrial products.

REASON'S FOR THE USE OF NDT:

"NDT" is used by the manufacturers for the following reasons:

1. To ensure product reliability.

2. To make profit for the user.

a) To ensure customer satisfaction

b) To aid in better product reliability.

c) To control the manufacturing processes.

d) To lower the manufacturing costs.

e) To maintain uniform quality level.

SOME OF THE MOST COMMON NDT METHODS ARE :

1.VISUAL INSPECTION

2.LIQUID PENETRATION TEST

3.MAGNETIC PARTICLE TEST

4.RADIOGRAPHY TEST

5.ULTRASONIC TEST

BEND TESTS

BEND TESTS Object: To determine the soundness of weld metal, heat affected zone and weld zone.These tests may also be used to give some measure of the ductility of the weld zone. It is not usual to use transverse and longitudinal bend tests for the same application. Method: All specimens to be removed and prepared without causing significant distortion or heating. The cap and root are ground flush. The specimen is bent by the movement of a former of prescribed diameter, the relevant side of the specimen to be placed in tension. Angle of bend and diameter of former should be as specified in the appropriate standard. Reporting Results: Thickness of specimen Direction of bend (root or face) Angle of bend Diameter of former Appearance of joint after bending e.g. type and location of flaws

Part - 6 Most commonly asked Mechanical Interview Questions with answer

Most commonly asked Mechanical Interview Questions 1. Why Entropy decreases with increase in temperature? Ans. ds=dQ/T Entropy is inversely proportional to the temperature so, as temp. Increases, entropy decreases. 2. Why different types of sound are produced in different bikes, though they run on SI Engines? Ans. Engine specifications are different in different manufactures like as Bore Diameter (CC), Ignition timing. Also the exhaust passage takes more responsible for sound. 3. How much Watt means 1Hp? Ans. 746.2 Watt 4. Explain Bicycle Rear Wheel Sprocket working? Ans. Rear wheel sprocket works u...

VISUAL INSPECTION OF WELDING

VISUAL INSPECTION OF WELDING INTRODUCTION Inspection starts with examination of the material prior to fabrication, scabs, seams, scale or other harmful surface conditions may be detected in visual inspection. The inspector should check the following : Weld preparation, dimensions and finish. Clearance dimensions of backing strips. Alignment and fit up to the pieces being welded. Verification of cleanliness. Visual Inspection During Welding Visual inspection checks details of the work while welding is in progress. Among the details to be checked are : Welding process. Cleaning. Preheat and inter pass temperature. Joint preparation. Filler metal. Flux or shielding gas. Chipping, grinding, or gouging. Post heating temperature and time. Visual Inspection After Welding Visual inspection is useful for finished-product verification of such items as : Profile irregularities of the weldment....

Mechanical Engineering

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