| Level | Description | Typical Disposition | |-------|-------------|----------------------| | | Very fine, widely scattered pores – barely detectable under standard viewing conditions. | Always acceptable for most applications. | | Level 2 | Small pores, still scattered but more frequent. | Acceptable for general commercial use. | | Level 3 | Moderate pore size and frequency. The "gray area" – often requires engineering review. | Acceptable only with reduction factors. | | Level 4 | Coarse pores, frequent clustering, measurable loss of section integrity. | Usually rejectable for structural parts. | | Level 5 | Severe porosity – gross discontinuities visible without viewers. | Unacceptable for all but the lowest-grade castings. |
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