Weld Porosity: A Gas Cavity Is Different from an Unfused Interface

Retain the pore description

TWI describes weld porosity as gas trapped during solidification. A pore is therefore a different morphology from an unjoined fusion interface. Primary reference: TWI technical explanation.

The observation should preserve cavity shape, distribution and location. A photograph or section may identify voids without establishing which gas, contamination source or process event caused them. Keep the hypothesis separate from the recorded geometry.

Classify fictional observations

Imagine an invented section contains several approximately rounded internal cavities. Another shows a planar unjoined boundary following a sidewall. Reporting both simply as holes would discard information useful to the fabrication review.

For the first record, describe the cavity morphology and any independently supported porosity identification. For the second, preserve the interface location. These teaching observations are not diagnostic findings on real specimens and establish no allowable pore count or cavity size.

Make cause evidence a separate field

Prepare a morphology table containing specimen identity, location, observation method and the proposed imperfection category. Add the evidence supporting any gas-source or contamination explanation in another column.

Ask what connects the proposed cause to the actual process history. A classification can guide the next documentation request without certifying the cause or prescribing a remedy. Preserve unresolved explanations rather than selecting one merely because porosity has several familiar possible origins. The appropriate joint acceptance requirement remains separate from this taxonomy.

Customer Questions

Primary References

These references support the technical principles discussed in this guide. The worked examples and review questions are educational.

• Primary reference: TWI technical explanation