What Does Weld Inspection Mean?
After metal pieces are welded, an important and necessary step is to inspect the quality of the weld to ensure satisfactory performance. Various test procedures are followed to perform a weld inspection. An ideal weld inspection procedure is non-destructive testing (NDT), which helps to evaluate the weld without causing any damage. Types of weld inspection procedures include:
- Remote visual inspection (RVI)
- X-ray inspection
- Ultrasound inspection
- Liquid penetration inspection
Corrosionpedia Explains Weld Inspection
Welds are inspected based on the function for which the weld was intended. In addition to NDT testing there are various other ways to inspect the weld's quality:
- Weld distribution - When welding is performed, the weld material is distributed equally between the two joined metal pieces. An equal distribution of weld on both metal pieces indicates a good quality weld.
- Waste - The weld is free of waste materials such as slag. When the weld cools slag is peeled away. If the slag does not get peeled away by itself or after scratching, then the metal pieces were not cleaned properly before welding.
- Porosity - Any pores or holes in the welded structure indicates low quality work and these will contribute to weld weakness. Holes are created during welding when the base material is dirty or has an oxide coating on it.
- Tightness - The weld joint is checked for tightness. If not tight, it is considered to be a welding fault.
- Leak proof - Liquid is spread across the weld to check for seapage. If it occurs, it means the weld has pores that will lead to failure of the welded materials.
More sophisticated NDT inspection methods are used after these visual inspections are performed.