Wohler /SN curve for 42CrMo4 steel
Wohler /SN curve for 42CrMo4 steel
(OP)
Hi,
I want to do some fatigue calculations on a structure. Does anyone know where I can find a Wohler or SN curve for the material 42CrMo4 in the Q+T condition? I have done some google searches but nothing comes up. Any help would be appreciated.
I want to do some fatigue calculations on a structure. Does anyone know where I can find a Wohler or SN curve for the material 42CrMo4 in the Q+T condition? I have done some google searches but nothing comes up. Any help would be appreciated.





RE: Wohler /SN curve for 42CrMo4 steel
You can conduct a search of this site - many requests have been made for S-N curves for various materials. Check the printed publications mentioned in these threads.
For a large collection of materials information, including fatigue, look at ASM International:
http://ww
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Wohler /SN curve for 42CrMo4 steel
dyna3d
RE: Wohler /SN curve for 42CrMo4 steel
Actually, I was able to find the fatigue values for this material in a paper on the internet at:
http://fac
I didn't check if their test was specifically for quenched and tempered, but this is the normal treatment for this material when used in driveshafts or whatever.
dyna3d
RE: Wohler /SN curve for 42CrMo4 steel
For 42CrMo4,
sigma f' =1154 MPa
b1 = -.061
To plot the S/N curve:
plot cycle counts versus calcuated stress amplitude, where:
stress amplitude (MPa) = 1154*((2*cycle count)^(-0.061))
Using this equation:
Life (cycles) Stress Amplitude (MPa)
---------------------------------------------
1000 725.8435
10000 630.7293
20000 604.6167
50000 571.7495
200000 525.388
300000 512.5528
800000 482.7858
8000000 419.5218
80000000 364.5478
1.0e+08 359.6193
2.0e+08 344.7308 <- typical cutoff for infinite life
2.0e+09 344.7308
Plot this data on a semi-log plot with the y-axis begin logarithmic.
dyna3d
RE: Wohler /SN curve for 42CrMo4 steel
I was going to try to convert this data into a 'rolling contact SN curve' for use in a brg application. Some people believe this can be done reliably, others say it can't.
Can I ask you for your opinions ?
RE: Wohler /SN curve for 42CrMo4 steel
RE: Wohler /SN curve for 42CrMo4 steel
There are other approaches required to calculate an effective stress range for rolling contact fatigue. Here is a paper that was published on rolling contact fatigue of railway wheels as an example of the complexity of the analysis;
www.s