As I recall, the earlier thread didn't locate a TTT diagram for 440C. Anyone?
ASM Handbook Volume 4, Heat Treating, 10th Edn., in the 'Heat Treating of Stainless Steels' chapter, has some possibly useful information. E.g.,
'Table 10 Procedures for hardening and tempering wrought martensitic stainless steels to specific strength and hardness levels' [includes some quenching details]
and
'Fig. 14 Effect of austenitizing and tempering temperatures on typical mechanical properties of type 440C martensitic stainless steel. Austenitized 1 h at 925 °C (1700 °F) and 2 h at 1040 °C (1900 °F); oil quenched to 65 to 95 °C (150 to 200 °F); double stress relieved at 175 °C (350 °F) for 15 min and water quenched; tempered 2 h. (a) Quenched from 925 °C (1700 °F). (b) Quenched from 1040 °C (1900 °F)'
The same info is in Metals Handbook Volume 4, Heat Treating, 9th Edn., with different table & figure numbering.
See also the C-Cr-Fe phase diagrams in ASM Handbook Volume 3, Alloy Phase Diagrams [info from G.V. Raynor and V.G. Rivlin, Phase Equilibria in Iron Ternary Alloys, The Institute of Metals, London, (No. 4), 1988].