What is root concavity

Excessively high welding speeds make the formation of root concavity more likely.

A general review of the causes and acceptance of shape imperfections - Part 2

It has been updated so the web page no longer reflects exactly the printed version. A 10mm leg length fillet with a root gap of 3mm gives an effective leg of 7mm a throat of 4.

what is root concavity

If welder technique is the problem then retraining is required. The following discontinuities are unique to the TIG welding process. Cluster porosity is caused when flux coated electrodes are contaminated with moisture. The consequence of this imperfection is a significant increase in weld volume.

what is root concavity

Therefore, it is normally assumed that fillet welds will be at least of the size specified. For more information please email: These globs of metal are referred to as icicles.

what is root concavity

Provide Feedback. The idealised design requirement of a 'mitre' fillet weld is often difficult to achieve, particularly with manual welding processes. A shallow groove that may occur in the root of a butt weld. It is very easy to determine by radiograph if the weld has inadequate reinforcement, because the image density in the area of suspected inadequacy will be higher darker than the image density of the surrounding base material.

how much root concavity allowed

A general review of the causes and acceptance of shape imperfections - Part 2. Login Login. It is one of the most objectionable weld discontinuities. That is if we can be sure there is good penetration the smaller fillet may be acceptable, however, this should be discussed with the designer of the fabrication.

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All of these steps make use of the radiographer's visual acuity. Appearance on radiograph: A major problem with fillet welds is ensuring the gap between the components is within defined limits. Adhere to the specified welding procedure and parameters and do not add to the specified weld size. Radiograph Interpretation - Welds In addition to producing high quality radiographs, the radiographer must also be skilled in radiographic interpretation.

Cracks can sometimes appear as "tails" on inclusions or porosity. Acceptance Therefore, it is normally assumed that fillet welds will be at least of the size specified.

what is root concavity

On a radiograph it looks similar to a lack of penetration but the line has irregular edges and it is often quite wide in the center of the weld image.

BS 2633 Class 1 arc welding gives specific limits for smaller diameters pipes, eg for pipe size 25-50mm the maximum allowed bore penetration is 2. Lack of penetration allows a natural stress riser from which a crack may propagate.