20CRMnNi Steel for Gears
20CRMnNi Steel for Gears
(OP)
Have been told this is equal or better than 8620 for gears which have hardness of RC 58-62.
Can anyone comment on this? Chemicals are quite different. The 20CR material shows no Moly and the Ni and Cr are a lot lower than 8620.
Can anyone comment on this? Chemicals are quite different. The 20CR material shows no Moly and the Ni and Cr are a lot lower than 8620.





RE: 20CRMnNi Steel for Gears
RE: 20CRMnNi Steel for Gears
They are saying it is equal or better than 8620 for gears. My concerns are the differences in chemicals and whether or not it can be carburized to RC58-62, depth of .020 to .030 as specified on current gears.
Here is the chemical certification for 20CrMnNi:
.19 C, .27 Si, .89 Mn, .017 P, .004 S, .02 Ni, 1.017 Cr, .029 Cu, and no Mo.
Thanks for the reply.
RE: 20CRMnNi Steel for Gears
More than composition comes into play when you talk about steels that are "equal or better". Amount of wrought processing, grain size, surface condition, etc all are things that figure into whether one LOT of steel might be as good as, or better, than another LOT of steel.
Another comment I have is that your composition doesn't SEEM right. You'd think that a designation of "20CrMnNi" would have some nickel content. Your 0.02 % is a residual amount- i.e., the amount I would expect to find in a steel that does not have any nickel specified.
RE: 20CRMnNi Steel for Gears
RE: 20CRMnNi Steel for Gears
The chemical composition that you provided equates to grade 20CrMn according to the Chinese standard GB 3077. There is no 20CrMnNi designation. As lgearhart and Flesh have pointed out, there are other factors to consider when determining the proper steel grade, such as core hardness/strength, toughness, etc. The equivalent Chinese grade to SAE 8620 is 20CrNiMo according to GB 3077.
RE: 20CRMnNi Steel for Gears
.21 C, .26 Si, .93 Mn, .04 S, .11P, 12.2 Cr, .5 Ni, .15 Cu, .7 Ti. The 12.2 Cr must have a displaced decimal point?
They are saying that 20CrNiMo is available only in large qtys and want to substitute the 20CrMnTi or whaterever it is??
Since 8620 contains Moly and this material does not, wouldn't this affect the gear life if not other characteristics vs. 8620?
RE: 20CRMnNi Steel for Gears