crack

[Puneet Bobel]

Hi,

we have used C45 steel. we make 120 parts from different diameter but same chemical composition (C-0.45-0.50, Si-0.35 max, S-0.030 max., P- 0.030 max., Cr-0.17-0.20), but when we make a flange having dia 180 (after forging) , in which 3 dia generate 90, 110, 180. [highlight #D3D7CF]mostly on 110 dia have crack like "~" this shape.[/highlight] forging temperature is 1180 - 1200 degree celcius

 

[Dhurjati Sen]

Dear Puneet,

Seems like an internal crack. Design of the dies could be an issue.

DHURJATI SEN

 

[metengr]

You should send one of the cracked parts to a competent metallurgical lab. You need to determine what caused the crack at this diameter. There could be several possibilities for what caused the crack, and there is little information to provide a meaningful response.

 

[EdStainless]

If you see them in the forgings before heat treatment then I suspect internal (sub surface) rupture related to die design.
Get a good lab to help you out.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube