I just wanted to let everyone following this thread know. The shafts that we normalized did not make any difference. They distorted the same as the ones that were not normalized. The problem was isolated to the one heat of material.
I would like to thank everyone for their contribution to this problem and answer the questions. Irstuff, after hardening, the shaft has an excessive bow in it, app .500” run out, the shafts are straightened to .090” after hardening. We are heating with induction, we start with a low heat level...
Swall
We are rotating the shaft during hardening. We have tried different rotation speeds, the slower speeds distort less, but the shafts still have excessive distortion.
To answer a few of the questions, the material has a core hardness of 18-20 Rc. It seems to be fairly consistant. We to have seen the picture frame in their material but it is not visible in this material. We are using 12% Ucon Quenchant A for this part. We have tried different quench rings...
Bklauba
Unfortunately, the spec is Rc40 @ .400.
Carburize
The material is hot rolled material with no pretreatment. I agree that there seems to be a lot of residual stress in the parts. I suspect that that it has something to do with the way the material is cast, in that it has a bend as they...
We are attempting to induction harden shafts in a vertical scanning operation, and we are getting so much distortion that the shafts cannot be straightened, (without breaking) after hardening. The shafts are 1.875” diameter, 1547 continues cast material, (Mac Steel, formerly North Star, Monroe)...
Thanks for the help everyone. We have a customer who insisted that four exchanges per hour was not enough. I think I have enough information to change his mind.
Can anyone tell me what the recommended atmosphere exchanges per hour should be during a carburizing cycle. We are using endothermic and enriching with methane. Thanks in advance.
Thanks for the help Swall. The rust is not visible until after the tempering operation. The tempering furnaces use shop air that is high in humidity, probably the source of moisture needed to produce the rust. Anyone have a system to prevent the staining?
We operate a captive induction hardening operation where we harden shafts for the automotive industry. We use Lakos separators to remove the scale from our systems, but have not found an effective means of removing tramp oils. Our parts come out stained and seem to rust quickly after tempering...
