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Part -1 to 8 Most commonly asked Mechanical Interview Questions with answer

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CHARPY V NOTCH IMPACT TEST

CHARPY V NOTCH IMPACT TEST Object : To determine the amount of energy absorbed in fracturing a standardized test piece at a specified temperature. Method : A machined, notched specimen is broken by one blow from a pendulum. Because scatter occurs in the results, at least three specimens are used to assess the joint represented. Testing is carried out at a temperature specified in the appropriate application standard. Reporting Results: Location and orientation of the notch.  Testing temperature. Energy absorbed in joules.  Description of fracture appearance. Location of any defects. The Charpy impact test, measured in joules, is an assessment of TOUGHNESS. Transition temperature (curve) in steel.
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'NICK' BREAK (BEND) TEST

'NICK' BREAK (BEND) TEST Object :  As for fillet weld fracture, used on butt welds. Method: The specimen is cut transversely to the weld, and a saw cut is applied along the center of the weld face. The best place for the cut is at a start I stop. The specimen is fractured by bending or by hammer blows. The nick bend test will find internal defects. Reporting Results: Thickness of material.  Width of specimen.  Location of fracture.  Appearance of joint after fracture.
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MACRO SECTION

MACRO SECTION Object: To examine a cross section of a weld for internal defects and soundness. Method:  A transverse section of the weld is cut out. The cross section is then visually inspected. The section is filed down from rough to smooth, then emery or wet/dry papered down to a surface finish of 600 grit. The surface is then etched in NITAL (5% - 10% nitric acid in alcohol), washed off, rinsed and dried. (Possibly a final clean with acetone and mount in Bakelite) The specimen is then inspected at up to 10-x magnification. Reporting Results: Material. Welding process. Specimen identification. Sentencing standard. Thickness. Geometric flaws - type, size and location. Internal flaws - type, size and location. Parent metal flaws - type, size and location. Accept or reject, to standard, for each flaw.    Comparison of macro section and micro section:                             ...
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