Bob:
Isothermal transformation diagrams (ITDs) for D2 and M2 tool steels are on pages 141 and 181 of the vintage book "Metallurgy and Heat Treatment of Tool Steels" by Robert Wilson, McGraw Hill (1975).
For D2 tool steel the start (1%) of the pearlite reaction is at 725C and 600 sec. For D2 tool steel the start of the bainite reaction is at 250C and 5000 sec. The martensite start temperature is 220C.
For M2 tool steel the start of the pearlite reaction is at 750C and
3000 sec. For D2 tool steel the start of the bainite reaction is at 300C and 800 sec. The martensite start temperature is 220C.
Pittsburgh Pete
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