HARRIS DIFFUSION MODEL

Carburize Time

depth = K·√t, solved for time. K interpolated across temperature on an Arrhenius fit to published total-case constants.

Target case depth

Depth basis

Furnace temperature (°F) Temper temperature (°F) Material grade

Grade shifts time ±10–15% at most — a trim, not the main dial. Temperature moves it far more.

SOAK TIME AT TEMPERATURE

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SURFACE (tempered)

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HRC

CORE (typical)

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HRC

Surface is carbon-driven and grade-independent; core is each grade's published range, not section-resolved. A ½″ and a 3″ part of the same grade land at different cores — treat core as a band, confirm on the part.

Published constants, not Bennett-calibrated. Diffusion time only — excludes heat-up, boost/diffuse split, and quench. Verify against your own run data before releasing to production.