continuous casting of 17-4 PH 1

[alloy33]

Hi all!
do anybody has suggestions to cast succesfully the steel grade 17-4 PH?
currently I am facing problems of centre porosity/centre cracks and internal cracks....(the secondary cooling is already very low).
somebody can help me?
thanks a lot for any help from this forum.

kind regards!

 

[rd400guy]

First off, I'm imagining you're using a horizontal caster, not curved, right? What is the size and shape of the billet you're casting? Are the cracks in the as cast billet or are they noticed in a subsequent wrought form? Are the defects dead center or are they mid-radius? Are you sure they are just cracks, or are there non-metallic inclusions associated with the cracks?

17-4PH is notorious for entrapped flux. Get some micros to see if there are non-metallics serving as crack initiation sites. 17-4PH also has a very large mushy zone, mainly due to the copper. Are you using magnetic stirring? I work in ingot casting and 17-4PH is a problem for everyone I know who makes it. Get back to me with some more info, and I'll try to help more.