Heat treatment — TTT diagram

Time-Temperature-Transformation curves + cooling overlay

Pick a steel preset or enter your own C-curve nose coordinates. Overlay a Newtonian cooling curve to see whether you'll get pearlite, bainite, or martensite.

Inputs

Steel preset

Pearlite nose T°C

Pearlite nose times

Bainite nose T°C

Bainite nose times

Ms (martensite start)°C

A₁ (lower critical)°C

Austenitization T°C

Cooling time-constant τs

Newton cooling: T(t) = 25 + (T_aust − 25)·exp(−t/τ). Water quench ≈ 5–20 s. Oil quench ≈ 30–60. Air cool ≈ 600. Furnace anneal ≈ 10000.

classical eutectoid — Bain & Davenport original

Results

TTT — Time-Temperature-Transformation

Pearlite nose @ 650°C / 1s · Bainite nose @ 450°C / 10s · Ms = 220°C · cooling τ=60s → predicted: pearlite (slow cool)

CCT — Continuous Cooling Transformation (Atkins-style approximate)

τ_surface=12s → ferrite + pearlite · τ_core=60s → ferrite + pearlite · Ms=220°C · A₁=723°C

Predicted dominant phasepearlite (slow cool — soft / annealed)

Estimated bulk hardness25HRC

The TTT diagram shows phase transformations at constant temperature; Newton cooling is a continuous-cooling approximation. For full continuous-cooling-transformation behaviour run the CCT module (austenite → ferrite/pearlite transformation kinetics with Avrami).

Download all inputs + calculations + outputs as a single PDF.