Quality level D
Evaluation group D is the lowest quality level per ISO 5817 with wider tolerances for weld flaws. It's used for parts under lower loads where visual and mechanical perfection is not the main thing.
Physical-Chemical Working Mechanism
Evaluation group D defines the largest tolerance for weld flaws per ISO 5817. It allows a higher number and size of flaws compared to higher groups.
Metallurgical Relevance & Risks When Welding
This low quality level is for parts under light stress. Visual and mechanical perfection is not the main concern. But too many flaws can impair the part's function or shorten its life.
Workshop Practice & Operating Instructions
For evaluation group D, less strict inspection of weld quality is allowed. However, you still need to meet the basic safety standards. If needed, pick higher quality levels (like A or B) to make sure the parts do what they're supposed to.