Heat treatment can propagate the existing crack ?

[nmalmasum]

Hi!
Can anyone help me about the followings:
If there is a crack on the engine crank pin and having hardness about 665 HB, Then what would be wise-----machining the crank pin before heat treatment to remove the cracks or perform heat treatment before machining.

If the heat treatment is done first whether the cracks can propagate further since the crankshaft elongate during heat treatment.

I will be grateful if anyone can help me in this regard.

N.M. Al Masum
NEPC Plant
Narayangonj
BD

 

[racookpe1978]

Machine first. Heat treat, re-examine the grooved area to verify the crack did not re-appear.