Recent content by Carburize

Correct concerning the sphere. The non martensitic product will most likely be bainite rather than austenite.

Without a deep freeze option you are always going to have a hardness problem. For a sample of 9310 with a chemistry in the middle of the specification range at a case carbon of 0.8% the martensite transformation will not be even theorotically complete until the case is cooled to below minus 20C...

The "ideal diameter" is a term developed by Grossman in the late 30's to describe the hardenability of an alloy and represents the diameter of an infinitely long bar which will quench to 50% martensite in the center.

If it is a severe erosion problem you might want to consider ceramic sleeves and some kind of locking nut to hold them in place.

There are lots of details in Chapter 5 of "Developments in Pressure Vessel Technology-3" Edited by R W Nichols - Applied Science Publishers - London

At mid range of the analysis for these two alloys the ideal diameter is about 85-mm for 100Cr6 and about 230-mm for 100CrMn6 resulting from higher silicon and manganese. For a 64-mm ball therefore I would expect to see approximately the same hardness profile for both alloys which would be...

Vfigueroa - do you mean pressure tests??

Agree fully with metengr - depending on the size and shape of the vessel and the uniformity of the PWHT fairly severe thermal stresses can be set-up during this "final" operation which have been observed on numerous occasions to cause cracking.

I think you need to go in the other direction and try to find the source of the torsional exitation and eliminate it.

I think you mean galvanic corrosion due to the connection of a more noble (more corrosion resistant) material. Generally the galvanic couple tends to cause the less noble material to corrode more rapidly but the effect is dependent on the surface area of the two materials and a small area of...

RUFUS2K - It has all the hallmarks of a torsional fatigue failure.

RUFUS2K - can you post a side view of one of the fracture and perhaps try one from just a little further back from the fracture face to get a better focus?

Gear repair shops are now beginning to use sophisticated CMM machines to get the required data, eliminating the need for measurements over pins.

Both EN 16T and EN 24T have tensile stengths of: Yield 98560 psi min Ultimate 123200 - 145600 psi. Perhaps someone can suggest a reasonable relationship between this data and shear properties.

The "star shaped" pattern of crack growth is characteristic of torsional fatigue - reference ASM Handbook Vol 10 8th Edition page 379 figure 7