thermostress releave

[Shisei6]

Need help urgently.We have 4130 disc OD21"xID13"x.109"THK distortion after heat treatment to approach HRC35-40. It was probably result of thermostress differences between ID and OD areas. How to releave thermostress and provide again smooth hardening?

 

[metengr]

Shisei6;
Can you describe the heat treatment for this disc? What was the quenching medium?

 

[redpicker]

How are you fixturing the part during tempering?

What flatness requiremnts are required?

I've seen similar parts placed between heavy steel platens to force them flat for tempering, mabye that would help.

rp

 

[Shisei6]

Thank you fo responds. Additional info:
1.Quinching medium:
-Heating up to 1480F at 30min. Discs been separated.
-Soaking time- 1h
- Puting to oil at 1055 for 30 min
-Postwash at 160F
-Tempering , not forced air at 300F at 2hour
2. Parts have been hangled in on basket - no clamping
3.Flatness- .01"

 

[redpicker]

I do not understand

- Puting to oil at 1055 for 30 min

is 1055 the temperature of the oil, 1055F? That does not make sense

Is your heating at 1480F in a controlled atmosphere?

Do you have the capability to lay the disks horizontally and place between steel platens for tempering?

rp

 

[Shisei6]

To Redpicker: My mention "Puting to oil at 1055 for 30 min" had mistake - it should be 155F @30 min. Sorry for that.
Approacing the 1480F was unfortunatelly uncontrolled. Your suggestion regarding to use horizontal mounting and putting platen separaters is much appreciated. We will try.
It should be clamped or just under their weight? Should we increase the tempering temperaure?
Returning to heating ramp up to 1480F - If we could have a chance to control the ramp speed, what would be the time and speed for that stage?
Thanks,
S6