The grain size number, explained
What G actually measures, why bigger G means finer grain, and how the intercept and planimetric procedures arrive at it.
ASTM E112 · ISO 643 · ~6 min readNodularity, measured
ISO 945-1 graphite forms I–VI, what counts as a nodule, and what makes the percentage move between heats.
ISO 945-1 · ASTM A247 · ~6 min readPoint counting, step by step
The systematic manual point count of ASTM E562 — grid, tally, statistics — and when it beats automatic segmentation.
ASTM E562 · ~6 min readMeasuring decarburization depth
Complete vs partial vs total decarb, how to measure each defensibly, and why springs and gears care so much.
Microscopical method · ~6 min readInclusion rating, explained
Types A–D, thin versus heavy series, and how chart-method severity ratings work in practice.
ASTM E45 · ~6 min readMore coming
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