Fracture Toughness Source
Fracture Toughness Source
(OP)
Does anyone know of a good resource for fracture toughness data for induction hardened material (in particular 52100 and 4140H)? All of the research I have conducted thus far had fracture toughness data for quench and temper material only.
Thank you!
Thank you!





RE: Fracture Toughness Source
RE: Fracture Toughness Source
I understand what induction hardening is and that the fracture toughness is dependent on the microstructure. My issue is that I haven't been finding fracture toughness data for the high surface hardness that our parts are specified to have (55 HRC). I'm not so concerned with the toughness at the core.
RE: Fracture Toughness Source
I've been told that the best source for fracture toughness and fatigue crack growth rate data is a series of papers by Michael Hudson, published by the Int'l Journal of Fracture:
Vol. 14, 1978, pp. R151 – R184.
Vol. 20, 1982, pp. R59 – R117.
Vol. 39, 1989, pp. R43 – R63.
I myself have also had trouble finding values for plain strain fx toughness (K_1c) to use in design work. Textbooks that I find useful are:
Dieter – Mechanical Metallurgy
Hertzberg – Deformation and Fx Mechanics
Nat'l Materials Advisory Board (NMAB), Report 328 (free on google books) Figure 1 shows ranges of K1c for various alloys in a lab environment (ambient temp, no corrosives).
To state the obvious in case you cannot find published values, a mechanical testing lab can run ASTM E399 for you. Valid plain strain results should be easy with such a high hardness.
As you probably know, for typical alloy steels
55 HRC = UTS apprx 300 ksi = pretty crappy K_1c
With hardness vs fx toughness it's a case of not being able to have cake and eat it too, unless you go with a more expensive material, e.g. AF1410 or maraging steel.