Martensite Start Temperature Calculator — Ms Temperature from Steel Composition

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The martensite start temperature (Ms) is the temperature at which martensite begins to form on cooling of steel from the austenitising temperature. Accurate Ms prediction is essential for designing quenching and tempering heat treatment cycles, predicting as-quenched hardness, and assessing cold-cracking risk in steel welding. This calculator uses three established empirical equations — Andrews (1965), Steven-Haynes (1956), and Barbier (2012) — to give a range of predictions with a recommended value.

Martensite Start Temperature Calculator (Ms)

Ms — Andrews (1965)—
Ms — Steven & Haynes (1956)—
Ms — Barbier (2012)—
Recommended Ms (mean of 3 models)—
Mf estimate (Ms − 215°C, approx.)—
Martensite condition at room temp (25°C)—

Andrews (1965): Ms=539−423C−30.4Mn−17.7Ni−12.1Cr−7.5Mo+10Co−7.5Si
Steven & Haynes (1956): Ms=561−474C−33Mn−17Ni−17Cr−21Mo
Barbier (2012): Ms=565−600(1−e^(−0.96C))−31Mn−13Cr−9Mo−18Ni+10Co+15Al
Mf ≈ Ms − 215°C (approximate rule; dependent on composition)

Annealing Process Types — Temperature Ranges Relative to A1 and A3 0°C 400 700 727 A1 800 912 A3 950+ A1 A3 Stress Relief550–650°C Spheroidise690–720°C Full Anneal30–50°C above A3 Normaliseabove A3, air cool No phase change Spheroidite forms Coarse pearlite Fine pearlite © metallurgyzone.com/
Figure: Steel annealing process types and their temperature ranges relative to A1 (727°C) and A3 (912°C) critical temperatures. © metallurgyzone.com/

References

  • Andrews, K.W. (1965). Empirical formulae for the calculation of some transformation temperatures. JISI, 203, 721–727.
  • Steven, W. and Haynes, A.G. (1956). The temperature of formation of martensite and bainite in low-alloy steels. JISI, 183, 349–359.
  • Barbier, D. (2012). Extension of the martensite transformation temperatures to high-alloyed steels. Advanced Engineering Materials, 14(8).

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