Alloy steel
Alloy steel
(OP)
Hello All!
I have a Steel sample of a fractured pinion, and I wish to know what kind of Steel is, I have reviewed some standards but it doesn't match for any I have checked. Also, we have made a metallographic examination and the microstucture observed, doesn't correspond to the carbón content detected on the sample by spectroscopy.
The composition is: C 0.22, Si 0.29, Mn 0.93, P 0.019, S 0.036, Cr 1.05, Ni 0.97, Mo 0.0064, Al 0.030, Cu 0.028,
I hope you can help me to know which alloy correspond to this composition, and why the microstructure shows a pearlite content so high in comparison of the carbón content.
Thanks in advance for all your inputs
Regards
D. Nava
I have a Steel sample of a fractured pinion, and I wish to know what kind of Steel is, I have reviewed some standards but it doesn't match for any I have checked. Also, we have made a metallographic examination and the microstucture observed, doesn't correspond to the carbón content detected on the sample by spectroscopy.
The composition is: C 0.22, Si 0.29, Mn 0.93, P 0.019, S 0.036, Cr 1.05, Ni 0.97, Mo 0.0064, Al 0.030, Cu 0.028,
I hope you can help me to know which alloy correspond to this composition, and why the microstructure shows a pearlite content so high in comparison of the carbón content.
Thanks in advance for all your inputs
Regards
D. Nava





RE: Alloy steel
How much pearlite is present? What about martensite, bainite and ferrite?
The alloy looks similar to 16NiCrS4 according to EN 10084 Case hardening steels, although that standard has a carbon range of 0.13 to 0.19 percent by mass. Perhaps your part is carburized and you were not in the core of the part, so the core is between 0.13 and 0.19 but the measurement site is elevated to 0.22 (and the case could be ~ 1.0).
RE: Alloy steel
RE: Alloy steel
Maui
RE: Alloy steel
No, I could not say if the part is carburized or nitrided, and the analysis was taken at the center of the sample, (it is a coupon 3/4" dia, 1/2" h), so I don't think we are checking at the carburized, or nitrided Surface. The verified hardness was 255 HB.
Attached you will find a picture of the microstructure observed.
Again, thanks for all your help
D Nava
RE: Alloy steel
Often, a manufacturer will use a proprietary grade for their specialty products, usually by modifying an existing grade to enhance a specific property. Such as increasing the carbon range to increase the core hardness for large sections.
rp
RE: Alloy steel
I have no idea of the size of the pinion, because the customer only sent a coupon of the failed part. We supply to them heat treatment services, and they asked for help in the analysis of that part.
regards!
RE: Alloy steel
RE: Alloy steel
RE: Alloy steel
Maui
RE: Alloy steel
My best regards!
Daniel