SS 420 Vs Monel

[helpyou]

Hi,

Can someone tell me the difference between SS 420 and Monel, in terms of strength and corrosion. This is for butterfly valve shaft.

Thank you

 

Depends on what you need from it.
Any reputable valve maker should have sales engineers who can explain all the pros and cons of the various trim levels they offer.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

While I can see both used for a valve shaft their corrosion resistance is so different that they almost cannot be compared.
I presume that the 420 is Q&T, and that the Monel is K-500 in the aged condition.
If that is true then their strength will be similar.

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P.E. Metallurgy, Plymouth Tube

 

[weldstan]

What is the disk material and the body material? That should give you advice on shaft material. As Ed indicated, mechanical properties can be similar but corrosion resistance is not depending on environment.

 

[helpyou]

Hi all,

Thank you for your replies.

Hi weldstan,

Body material proposed is uctile iron with EPDM internal liner

Disk material proposed is ebonite coated ductile iron.

Thank you

 

[weldstan]

Your lining systems are indicative of a corrosive service. Presumably at least some part of the shaft could be exposed.to the corrosive service. You must determine whether the 420 SS has sufficient corrosion resistance to be used. The 420 will be the cheaper of the two, at least initially.