Fillet weld patches on a vessel are NOT allowed:

Fillet weld patches on a vessel are NOT allowed:

• A. To cross any longitudinal weld
• B. To cross any longitudinal or circumferential weld
• C. On top of another fillet weld patch
• D. On vessels made of low chromes

Answer: (C)

The reasoning behind the selection of the option concerning fillet weld patches on a vessel is based on the principles of weld integrity and the maintenance of structural soundness. When it comes to welding standards, particularly in pressure vessels, applying a new weld on top of an existing fillet weld patch can introduce complications that may compromise the weld’s effectiveness. This is because any imperfections or stress concentrations from the underlying weld can propagate through the new layer, potentially leading to defects such as cracking or reduced load-bearing capacity. Additionally, the heat from the new weld can alter the properties of the original material and weld, which may negatively affect overall vessel performance. Therefore, code provisions generally discourage or prohibit welding additional patches directly on top of existing welds to ensure that the integrity of both the original repair and the vessel itself is not undermined. Maintaining clear and unoverlapped welds in critical areas helps preserve the intended design strength and ensures safety in pressure vessels.

The reasoning behind the selection of the option concerning fillet weld patches on a vessel is based on the principles of weld integrity and the maintenance of structural soundness. When it comes to welding standards, particularly in pressure vessels, applying a new weld on top of an existing fillet weld patch can introduce complications that may compromise the weld’s effectiveness.

This is because any imperfections or stress concentrations from the underlying weld can propagate through the new layer, potentially leading to defects such as cracking or reduced load-bearing capacity. Additionally, the heat from the new weld can alter the properties of the original material and weld, which may negatively affect overall vessel performance.

Therefore, code provisions generally discourage or prohibit welding additional patches directly on top of existing welds to ensure that the integrity of both the original repair and the vessel itself is not undermined. Maintaining clear and unoverlapped welds in critical areas helps preserve the intended design strength and ensures safety in pressure vessels.