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.

Part -2 Most commonly asked Mechanical Interview Questions

Most commonly asked Mechanical Interview Questions 1. What is the difference between Critical Speed and Whirling Speed? Ans. In Solid mechanics, in the field of rotor dynamics, the critical speed is the theoretical angular velocity which excites the natural frequency of a rotating object, such as a shaft, propeller or gear. As the speed of rotation approaches the objects natural frequency, the object begins to resonate which dramatically increases system vibration. The resulting resonance occurs regardless of orientation.Whirling Speed is due to the unbalanced forces acting on a rotating shaft. 2. How a Diesel Engine Works as Generator? Ans. Diesel engine is a prime mover, for a generator, pump,and for vehicles etc. generator is connected to engine by shaft. mostly in thermal power plat ,there is an engine is used to drive generator to generate power. 3. Explain Second Law of Thermodynamics? Ans. The entropy of the universe increases over tim...

Chemical compositions of steel

Chemical Composition :- The chemical composition of steel is of great importance since it determines the potential mechanical properties of the finished steel product and controls the degree of corrosion resistance and weld- ability of the material For this reason structural steel specifications always provide a table of chemical composition limits within which the steel producer must develop his own particular recipe. The purpose of the specified chemical composition is not to provide the detailed chemical formula necessary to produce a certain type of steel but to provide safeguards. The steel producer is informed that he must keep within the limits which are deemed to be acceptable for the type of steel considered. Within these limits, which may be broad or narrow, the steel producer has complete freedom to use his skill and knowledge to make steel with the required mechanical properties. Each producer selects a combination of quantities of elements, which fall within the r...

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.

Mechanical Engineering

Search This Blog