Use of titanium grade 4 for pressure vessel applications

[ME231]

Use of Titanium Grade 4 (UNS R50700) is not permitted for use in PV applications per ASME VIII-1 as it is not included on Table UNF 23.4
Any idea why? Any code cases available that permit its use at all?
I have looked at a lot of places and just cannot figure out the reason it is excluded and I seek your help.
Thanks!

 

[EdStainless]

It has limited ductility.
If you need strength look at Gr9.

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Plymouth Tube

 

[ME231]

But the specified min elongation requirements for Grade 4 and Grade 9 in Section II-B are the same (15%) [II-B for SB265]

 

[metengr]

There are many reason why material is not permitted for use in Codes and Standards;

forming problems
low ductility
embrittlement
weldability
lack of use or interest

 

[EdStainless]

The diff is that gr4 will just make 15% and gr9 is usually 25%.
Weldability and forming are also issues.

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Plymouth Tube

 

[ME231]

Thanks all for your help.
It seems I will need to look at alternatives to using gr 4.

 

[Fizza453]

ME321,

See also Code Case 2497 that permits some titanium alloys, it may help you in alternatives.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[ME231]

Thanks Fizza453