Unmet quality level B per ISO 5817
Invalid assessment group B per ISO 5817 refers to welds that don't meet the highest quality standards. They have too high defect rates or sizes and aren't suitable for highly stressed applications.
Physical-Chemical Mechanism
ISO 5817 defines different acceptance levels for welds, with level B setting the highest quality requirements. An invalid level B means the weld doesn't meet the specified standard and has too many flaws.
Metallurgical Relevance & Welding Risks
Welds in invalid level B are dangerous for highly stressed applications because they're more prone to cracking and failure. This can cause safety issues and shorten the component's life.
Workshop Practice & Instructions
To avoid invalid level B, welds must be done exactly per ISO 5817 requirements. This includes picking the right process, pre-treating the materials properly, and checking carefully during and after welding. If needed, do extra tests like ultrasonic or X-ray inspection.