DESTRUCTIVE TESTING

DESTRUCTIVE TESTING

Destructive tests on raw materials, welded joints are usually made as part of the approval of material/ welding procedure or a welder.

Commonly used destructive tests are:

Hardness
Bend
Tensile
Charpy
Fracture tests
Macro section

TYPES OF TEST

Quantitative (For measuring a 'quantity')

Tensile
Charpy
Hardness
C.T.O.T. (crack tip opening test)

Qualitative (For assessing joint 'quality')

Bend test
Nick break
Macro
Fillet fracture

The test pieces are cut from the test weld and their location is often specified in the standard. The
areas for test are shown below.

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

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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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