Fracture Toughness Data

Fracture mechanics frequently requires testing under your own selected conditions to build a body of data. If you find anything relavent, it will be a huge coincidence. Your conditions are quite unique, e.i., test temp, frequency of loading, shape of the defect, size of initial defect, etc.

The most likely source of such data would be TWI (The Welding Institute) in England - if your company is a member or you know somebody from a member company!) they will research the information they have available.

We are members of the TWI, but although they are invariably an excellent source of information/advice/expertise, on this particular subject they have quoted us a very high price for carrying out testwork on our behalf. Hence, my original request for any generally available data for these materials.

The closest thing I know about is this WRC bulletin.

403 Metallurgical and Fracture Toughness Studies of A516-70 Steel: (I) Metallurgical Characterization of the HAZ in A516-70 and Evaluation of Fracture Toughness Specimens, by C.F. Lundin, G. Zhou and K.K. Khan and (II) Comparison of the CTOD Fracture Toughness of Simulated and Weldment HAZ Regions in A516 Steel with Deep and Shallow Cracks, by J.A. Smith, R. M. Holcomb and S.T. Rolfe. July 1995 (111 pp) Ä $85.00.

I would tend to agree with plasgears that you introduce a lot of uncertainty into your calculations if you want to use literature values for a calculation on such a safety critical part as a pressure vessel. You would probably want to look at material from your supplier in the condition used in plant, in the thickness/orientation where you are seeking to evaluate the fracture toughness, and over a representative temperature range.

My suggestion would be to find an appropriate test house that will do the work for you (there are several in the UK that do good quality FT testing - I'd be happy to provide suggestions outside of the forum). If you really want to go down the literature route, then the best source of information on steels of various compositions that I know of is shown below. ESDU is a great source of data and engineering methods, but you need a subscription to use it. (I am not associated with it other than as a user.)

Finally, you could possibly reduce the amount of testing by doing a smaller amount of testing and using the ESDU values in combination.


Data Item 83023
Fracture toughness (K[sub]Ic[/sub]) values of some steels.

Shortened Abstract: ESDU 83023 provides more than 1750 plane strain fracture toughness values for 39 UK and US low alloy, nickel, maraging and stainless steels. The data are presented in tabular form, providing details of test temperature, crack orientation with respect to grain flow, proof stress, chemical composition and heat treatment.