Welding Visual Inspection and Tools

Why weld visual inspection?
When designing an inspection plan, we need to establish the most appropriate areas to apply our inspection. We need to consider the possibility of preventing welding related problems, rather than finding problems which may have already occurred.

Non- destructive testing (NDT),which is typically used for the inspection of completed welds, is usually designed and conducted to find welding problems after the fact,

SOME BEST WELD VISUAL EXAMPLES
Conclusion
A good pre-weld inspection plan may provide us with an excellent opportunity to prevent welding problems before they start, through the detection and correction of situations that may cause welding problems or welding discontinuities.

Inspection conducted during the welding operation can often detect problems before they escalate and also helps to provide confidence in the final welded product.

Post-weld inspection can often provide an economical method of determining a weld's acceptability with regard to many surface discontinuities.

Post-Weld Inspection
Surface discontinuities,

The most common welding discontinuities found during visual inspection are conditions such as undersized welds, undercut, overlap, surface cracking, surface porosity, under fill, incomplete root penetration, excessive root penetration, burn through, and excessive reinforcement.

2. Inspection During Welding
This inspection includes such items as interpass cleaning methods, interpass temperature control, welding current settings, welding travel speed, shielding gas type, gas flow rate, and welding sequence, if applicable.

Also, any environmental conditions that may affect the quality of the weld such as, rain, wind, and extreme temperatures.

1. Pre-Weld Inspection
This inspection is conducted prior to the start of the welding operation.
This type of inspection is typically associated with checking the, preparation of the welding joint and verification of parameters that would be difficult or impossible to confirm during or after welding.
Groove weld bevel angles, if too small, may cause lack of fusion, and if too large, can result in distortion of the weld joint from overheating and excessive shrinkage stress.
Joint alignment (misalignment of the weld joint) can result in difficulty in producing a sound weld and stress concentration at its location, resulting in a reduction of fatigue life.
Plate surface condition and cleanliness, pre-cleaning prior to welding, can often be of extreme importance.
Other pre-weld inspections may include preheat verification, temperature and heating method, presence and location of heat treatment monitoring devices, and type and efficacy of gas purging, if applicable.
Pre-weld inspection may also include evaluation and verification of documentation, material certification, filler alloy certification, welder performance qualification, welding procedure qualification, and welder and weld identification, for traceability, if applicable.

Welding inspection
The welding inspection function is often divided into three areas:

First, and often the least utilized, is pre-weld inspection. This type of inspection can often provide us the opportunity to detect and correct unacceptable conditions before they develop into actual welding problems.
Second, inspection during the welding operation can often prevent problems in the completed weld through verification of the welding conditions and procedural requirements.
Third, post-weld visual inspection is a relatively easy method of conducting completed weld quality evaluation.

PREPARED BY
MAULIK PRAJAPATI
WELDING ENGINEER
WORK EXPERIENCE - TEMA INDIA LTD. , L&T – HEIC , WELSPUN CORP LTD. ,
ME & BE – METALLURGY AND MATERIALS ENGINEER (ME IN WELDING TECHNOLOGY )
INSPECTION TOOLS
INSPECTION TOOLS
WELDING VISUAL INSPECTION AND TOOLS
INSPECTION TOOLS
Common Weld Faults
Incomplete Penetration
Lack of Fusion
Undercutting
Porosity

Visual Weld Equipment
Fillet Weld Gauge
Fillet Weld Gauge is an essential weld quality testing tool. It is used to check fillet leg size, checking fillet throat size
Weld hand held fillet gauge: measures -
- flatness of the weld
- convexity (how the weld is welded outward)
- concavity (how the weld is rounded inward)
Protective lenses with pocket viewer and shade lens for use when observing the welding process
Magnifying glass per the code in your area
Flashlight
Tape measure
Calipers
For pipelines and oil and gas plants, the variety of parameters demands personal attention

Modern science has developed many techniques and equipment to inspect welds after they are completed, like radiography, ultra sound, liquid penetration, and magnetic practical tests. But, visual inspection during welding operation is still the most effective way to obtain good quality welds.
A qualified welding inspector has a responsibility to be personally present where the welding operation is conducted .His duty is to ensure the welding operation achieves good quality welds, specifically by monitoring the following items:

Welders' certificates;
Weld joint preparation;
Condition of electrodes;
Welding technique;
Weather condition;
Welding current;
Welding machines and tools;
Slag cleaning;
Incomplete welds;
Selection of welds for radiography.

inspections of pipeline welds are done according to API 1104 and plant inspections are done through ASME Sec. IX.
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Welding Visual Inspection and Tools

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