EN 19 VS EN 24 GEAR MATERIAL

En24 is a tougher and more ductile material than En19 due to the Ni and Chrome alloying additions. Ultimately, it may not be hardened to quite such a high tensile lod (hardness) condition as En19, but in a driveshaft application which is likely to have alternating 'spike' loadings I imagine, the toughness of En24 is undoubtedly the better material.

You mention that the existing shaft ws HT to 10HRC - this suggests that the part was machined from annealed bar and not really Hardened and tempered at all! Not good for your application!!

If you care to send details (drawing / photo ./ data-sheet), I shall be happy to advise further.

We had been using 16MnCr5 DIN (German Standard) for splined shafts.It was case hardened and we used to get hardness of 56hrc. I f you dont get this steel then En24 is definately better than En19. Only diffenrence is En24 is full hardening steel where 16MnCr5 is case hardening steel which means it can take care of shock loads as core is soft but does not wear out as skin is hard.

Suresh Sharma

Which gear material would be better for High torque applications ? this is for a splined shaft connecting to the motor on one end and the other to a hydraulic drive application is for driving the dredger cuter.Previously used material used material was EN 19 with 10 hrc the shaft has sheared , please advise of any alternative material to be used.

EN 24 is definetly a better material for this application because of its Moly. content. Moly. provides the fatigue resistance which is a big requirement in case of reversal or shock load.

Thanks

Thanks Boothville,Suresh Sharma and Guest for your valuable comments.Which Heat treatment process for EN24 would be better Hardening and then annealing or only toughing ? Please advice.Boothville i shall post the picture of the broken shaft shortly. Thanks

Ok, look forward to seeing failure mode in due course.

Ref HT - unfortunately you are seriously mixing-up treatments in your latest post. Annealing after hardening will TOTALLY undo any good from the hardening process. you MUST TEMPER immediately after hardening.

I need to understand the dimensions / scale / general design characteristics before advising further, but providing the loading is not TOO excessive, then I would think EN24 should be a good choice, probably treated to about 'V' condition. If there is really severe cyclic loading, with resultant fatigue-failure characteristics, it might be sensible to consider an aerospace type of material that has been specially melted and processed to minimise non-metallic inclusions and other deleterious effects, and for the shaft to be finally shot-peened - but I guess this will be difficult for you to source and also of course it is relatively expensive.

i dont know