Edge Check for high Ni grades

[MagBen]

when the hot rolling temeprature is too low, there will have edge check issues. what could be the reason(s) of edge check when the hot rolling temperature is too high? (starting tem about 2400F, reducing atmosphere furnaces). How to prevent edge checks during hot/cold rolling?

 

[EdStainless]

If you are too hot the edges may be failing and rupturing because they are too weak.
Original edge condition is critical to minimize checking.
For some low ductility alloys the edges are trimmed multiple times during the cold rolling process (many passes).

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Plymouth Tube

 

[MagBen]

thanks Ed. any other possible causes? 2400F is still lower than the alloy's incipient melting, and this temperature works at other facility from an outside source.
Maybe severe oxidation, since hot rolling occurred in air? the machine doesnot have enough power to roll at 2200-2300F.

 

[metengr]

I would send a section containing the edge cracking out for met analysis.

 

[remetaper]

Evaluations of Ed and suggestion of Metengr are right. But, do you think it wouild useful to know which kind of Ni-alloy ( or ASS ) are you reffering ?
General speaking ,temperature of 2400 F for most kind of Ni-alloy is exagerated and close to melting (2550-2600 ). At first plastic deformation at/ or high strain rate , de-coesion will happen due to oveheating: not only slivers at corners but also burst in centre of billet.
In case of ASS, temperature 2300 F is still enough high. Slivers may depend on Ferrite% or low melting elements( as Pb,Sb,Sn and so on )
Therefore, which grade is involved ?

 

[EdStainless]

reme, you had to go and use the "S" word didn't you? Slivers are the bane of our existence in the strip business.
They make edge checking look like child's play.

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Plymouth Tube

 

[MagBen]

It is Fe-80Ni permally with a melting point of 2650F. 2100-2200F for Fe50Ni works pretty well. Gleeble test indicates good ductility at lower temperature, but we worry about the strength that seems to be too high for the machine with limited power.