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.
Conformity to drawing requirements.
Acceptability of welds with regard to appearance (eg: surface roughness).
The presence of unfilled undercut, overlaps and cracks.
Evidence of mishandling from center punch or other inspection markings or excessive grinding.

FILLET WELD FRACTURE TEST

FILLET WELD FRACTURE TEST Object : To break the joint through the weld to permit examination of the fracture surfaces for flaws and to check root penetration and fusion. Method: The specimen is cut to length and a saw cut, normally 2 mm deep, is made along the center of the weld face. The specimen is fractured by bending or hammer blows. Reporting Results: Thickness of parent material. Throat thickness and leg length. Location of fracture. Appearance of joint after fracture. Depth of penetration / lack of penetration or fusion.

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.

Part -5 Most commonly asked Mechanical Interview Questions

Most commonly asked Mechanical Interview Questions with answer 1. Why the Centrifugal Pump is called High Discharge pump? Ans. Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal action of the impeller accelerates the liquid to a high velocity, transferring mechanical (rotational) energy to the liquid. So it discharges the liquid in high rate. It is given in the following formulae: Centrifugal force F= (M*V2)/R. Where, M-Mass V-Velocity R-Radius 2. How Cavitation can be eliminated by Pump? Ans. Cavitation means bubbles are forming in the liquid. To avoid Cavitation, we have to increase the Pump size to One or Two Inch To increase the pressure of the Suction Head Decrease the Pump Speed. 3. Why Cavitation will occur in Centrifugal Pump and not in Displacement Pump? Ans. The form...

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