40CR for shaft. Are you familiar with this material?

[fastline12]

A vendor for us is wanting to use this material for a small oil pump shaft. The shaft has very low torsion so that is not much of a concern at all. However, we specify a surface hardness of HRC58-65 due to an oil seal that rides on the shaft. These were previously done by carborizing 8620. We are trying to keep costs down and vendor is recommending this material at I assume it's full hardness of HRC58.

Shaft is also subject to constant vibration so if all the toughness is gone, vibration could be an issue. The diam of shaft is 3/8" but end with pump gear is only 1/4" threaded.

 

[TVP]

This is equivalent to SAE/ASTM grade 5140. It can be induction hardened (water + polymer quench) to 53 to 60 HRC. Low temperature tempering reduces this by 1-2 HRC points. This may be adequate for your end use, but it is not the same as case carburizing 8620. The threads should not be induction hardened. Thread rolling the base 5140 should produce a hardness of ~ 22-28 HRC.

 

[fastline12]

TVP, can you recommend a "bible" to have on hand that would include most all materials including plastics, and heat treatments and such? I work mostly with Aluminum so some of the steels are foreign to me. However, I did compare composition of 5140 to the 40CR and I fail to see how those two directly compare. I don't have to specs in front of me but but I believe 5140 had about 2 elements that 40cr did not. Maybe that is a very rough equivalent?