Heat Treat 1045 Flame Cut Ring
Heat Treat 1045 Flame Cut Ring
(OP)
I am having problems holding Rc 25-32, heat treating 1045 flame cut rings. We currently heat treat 1045 forgings with no problems. Our process is 7.875 OD x 4.5 ID x .75 thick rough:
rough machine, leaving .015 for finish machine
heat treat 1575F
draw 900-980F depending on results from HT
Do we need to normalize or stress relieve. I have tried stress relieve with no better results.
rough machine, leaving .015 for finish machine
heat treat 1575F
draw 900-980F depending on results from HT
Do we need to normalize or stress relieve. I have tried stress relieve with no better results.





RE: Heat Treat 1045 Flame Cut Ring
There is an implied hold time at the temperature and a cooling method/rate from the temperature, but you don't mention what those are. That could be where your problem lies.
rp
RE: Heat Treat 1045 Flame Cut Ring
RE: Heat Treat 1045 Flame Cut Ring
It sounds as if your problem is a spotty hardenss. Some areas harden fine, while others do not. As I mentioned, a well agitated quench is necessary. If some areas see poor circulation, those areas may be soft.
Another factor is surface scale. You mention a controlled atmosphere. Does the steel plate you are using have a mill scale on the surface? Reactions between the scale and the furnace atmosphere and change the mill scale so it becomes loose and insulates the underlying steel during quenching, resulting in a low hardness. Are your forgings free of scale? Often a forge shop will shot blast their forgings to remove all scale, so you may be seeing the difference between a scale free forging and a flame-cut plate that has a mill scale on the surface. If so, you could have a few of the rings from plate shot blast to clean metal, and see if they respond to the heat treatment better.
rp
RE: Heat Treat 1045 Flame Cut Ring
RE: Heat Treat 1045 Flame Cut Ring
The parts are staked 6 high in the furnace, maybe this has something to do with the high/low RC. We check Rc on this surface. From the furnace they are placed on a waffle plate for quench. The quench press ocillates up and down in the oil for 40 seconds. Our oil is also ocillated and goes thru a cooler to maintain the 165 degree temp.
RE: Heat Treat 1045 Flame Cut Ring
I would break up your stack with some type of rack to separate the parts in the austenitizing step. Your quenching setup looks fine.
One question is the furnace door being left open during the quenching step?
RE: Heat Treat 1045 Flame Cut Ring
6pcs X .75" = 4.5" equivilent section size (if not broken up as uncle suggests) means 4.5 hours at temp if using the 1hr per inch thickness rule of thumb.
I would expect to find a different hardness on the side against the waffle plate vs the side freely exposed to the quench oil. Also I would expect to find a difference in hardness where the part is in intimate contact with the waffle plate vs where the part on that same side is not in contact with the waffle plate. You might try quenching by hanging the ring from a J-hook which would give more uniform quenchant contact and less distortion.
RE: Heat Treat 1045 Flame Cut Ring