Laminations in SS vs CS
Laminations in SS vs CS
(OP)
Ingot casting was prone to produce laminations, however with continuous casting and the advancements in refining there is significant improvement of steel quality.
My question is, are Laminations more commonly expected in carbon steel (A516-70) v/s stainless steel (304SS) ? We have practice of UT testing CS plates for laminations, however SS material is exempt. I am not sure, why we would have that. Most of commercial quality SS have similar sulfur restrictions as CS and due to volume it is more likely that 304 SS may produced by ingot casting than cont.casting. Please share your expertise. Thank you.
My question is, are Laminations more commonly expected in carbon steel (A516-70) v/s stainless steel (304SS) ? We have practice of UT testing CS plates for laminations, however SS material is exempt. I am not sure, why we would have that. Most of commercial quality SS have similar sulfur restrictions as CS and due to volume it is more likely that 304 SS may produced by ingot casting than cont.casting. Please share your expertise. Thank you.





RE: Laminations in SS vs CS
In stabalized grades (321, 347, 439 and so on) there is a risk for either laminations or clusters of inclusions that are oxidized Ti, Nb, or Zr.
We can find these when we UT 439 tubing (welded from strip).
That said I would UT any plate from ingot cast, and any stabalized grade (especially ferritic).
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P.E. Metallurgy, Plymouth Tube
RE: Laminations in SS vs CS
Seems like a stainless alloy would be more likely to separate and form these type of lamination flaws than a very low percent alloy like plain carbon steel. (Once poured and cooling, obviously, the lamiantions would be be caused by the physical processes of grain growth and layering, etc.)
RE: Laminations in SS vs CS
They pour 100T of stainless in less than 30 min, not enough time for it to separate much.
I have seen samples off of each of 10 slabs out of the caster and you cant tell them apart.
In con-cast the ladle is bottom pour, and the tundish is fairly large, so there is very little turbulence and the metal stays very clean.
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P.E. Metallurgy, Plymouth Tube
RE: Laminations in SS vs CS