is a certain titanium flange adapted to my requirements? EN 1591-1 standard applicable? 2

[swiss037]

Hi,

Correct me if I'm wrong, but I think that titanium flanges are not really standardized, are they? However, they seem not too uncommon:

http://www.hartbv.nl/net-book.php?op=cms&pageid=31&pageid_up=91

http://www.hwn-titan.de/en/pro_rohrzubehoer.html

http://www.nisomet.ch/produkteformen/rohrefittinge.html

In Europe or elsewhere, do they usually have the same dimensions as standard steel, or aluminium flanges?

For my application (40 bar at 250°C), if the flange was steel, I would refer to EN 1092-1 and pick a PN 63, DN 150 (Type 11 welding neck).
Unfortunately, EN 1092-1 to EN 1092-4 standards are for steel, cast iron, copper (and composite materials...) and aluminium alloys and that's it.

I have never used the EN 1591-1 standard and don't have access to it yet, but would it indicate me if a titanium flange, with dimensions according to EN 1092-1, is suited to my requirements?
FYI, EN 1591-1 is the EN standard for
Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation.

I've read that the
ASME Boiler and Pressure Vessel Code SECTION VIII (Rules for Construction of Pressure Vessels), Division 1, Appendix 2: RULES FOR BOLTED FLANGE CONNECTIONS
WITH RING TYPE GASKETS
could be useful in this context, but "unfortunately this would result in gasket dependent ratings". Sounds reasonable, right?

Would that be the preferred route for a European engineer, though?
This work has certainly been done numerous times in the last few decades, am I missing something?

Thanks for reading!

 

[XL83NL]

The preferred route might be to use EN standards, as (at least what I read from your post) you're EU-based, so this will most likely assume the highest conformance to EU directives and such.
Most EU-based NoBo's and clients however nowadays will accept ASME standards more easily, so applying VIII-1 app 2 would be OK, I think.
In the context of the PED 97/23/EC I'm sure you're on the good page if you need to qualify such a 'custom'-engineered Ti-flange for a category application.

Now here coems the fun part. EN 1591-1 calculations are very though, from what I understand, and far less easy than VIII-1 app 2 (allthough it took us quite some hours to standardize an excel calc. sheet for an VIII-1 app 2 flange, its still way less than what EN 1591-1 would require - I believe it cant even be done through excel).

As an alternative, for EN 1591-1 flanges, you might want to look into purchase TEMES fl.cal.
It's a piece of software designed by AMTEC, which is run by (amongst others) Manferd Schaaf. I met him at last years ASME PVP, and he's a great guy when it comes to knowledge on flanges joints. let alone one of the experts worldwide in this field.
Furthermore Manfred is in the committee for EN 1591 standards, he should be able to answer most of your questions, so I think AMTEC should be able to give you great support.
PS: never, ever, do any automated software calculations without knowing the technical background of these calculations. Check EN 1591 first to have a rough understanding of it's rules. Doing the complete and exact calc yourself however is I think too time consuming.

How all this happened in the past is a big question to me too. It would be great if any experienced engineers could shed some light on that.
Maybe the former DIN standards covered Ti-flanges.

On a side note; a few months ago I had to use EN 1092 flanges in Alloy C-276, or at least flanges with a bolt pitch circle diameter that could be attached to EN-flanges.
They did not 'exist' (in the books), although I could easily get them. We bought them with ASTM material requirements.
The way we qualified them for the pipe spec was to do an VIII-1 app. 2 calc on the flanges, assuming a minimum external load (force and moment), to calculate if it would be strong enough, and if it would leak or not.

 

[swiss037]

thank you very much! that was long ago but I thought just "staring" your post would do, since I didn't have much to add.

so for anyone facing a similar situation, here's what I'm concluding:
- start with a geometry (e.g. EN 1092-1 PN 63, DN 150, Type 11, Form B)
- get your material's properties in ASME BPVC Section II, Part D (the only known for Ti)
- then:
[ul]
[li]either follow ASME BPVC Section VIII, Division 1, Appendix 2[/li]
[li]or follow EN 1591-1 (which isn't "light")[/li]
[/ul]
this can be done with the help of software such as TEMES fl.cal (costs at least EUR 3000 and for Ti you need to enter allowable stress values manually) or others*.
- continue with choice of gasket, bolts (actually you should have a rough idea about that before doing the previous work)

*: does anyone know FlangeValid, for instance? the company's website flangevalid.com has awesome ressources on flange joints, especially in German. they also mention the following software: TÜV DIMy, PV-Elite, Compress and Probad

here's a bit of context: this work is for my studies (almost no supervision), but the client and his needs are real. as a result:
[ul]
[li]I have to refrain from going too far (buying software, spending too much time unefficiently, ...)[/li]
[li]I'm motivated and I wouldn't be surprised if the work suddenly became a true contract[/li]
[/ul]

PS: I don't think any DIN standard ever covered Ti-flanges.

 

[moltenmetal]

The reason titanium isn't a B16.5 standard flange material is that it's a waste of material to make a whole flange from this stuff.

Yes, you can buy small 150# blinds, and there are a few occasions when you have a flange wetted on the outside etc. (then the big question is, what do you use for flange bolting?). Unlike with Hastelloy, there's little to no advantage to having the same material through thickness: unalloyed titanium has a high strength to weight ratio but is weaker, particularly at temperature, than much cheaper but less corrosion resistant materials. Most of the time, you'd be better off with a lap joint stub end and a backing flange made out of something cheaper than using a solid titanium flange. If it's a true blind, all you need is full face gasket. If you're drilling and tapping a blind, you're stuck doing an ASME Appendix 2 calculation using the properties of the plate or forging the flange was made from.

 

[SnTMan]

As an aside, you can buy B16.5 pattern flanges made of PVC, but they are NOT B16.5 flanges.

Regards,

Mike

 

[XL83NL]

As an aside, you can buy B16.5 pattern flanges made of PVC, but they are NOT B16.5 flanges.

Same for Ti-gr.2

 

[MJCronin]

I agree with moltenmetal... Virtually no one specifies solid TI bolted flanges

Recently, I was involved with a series of Ti-GR2 vessels with flanged nozzles.

I received bids from all major US & Canadian fabricators. I asked about pressure/temperature ratings for the Class 150 flanged nozzles.

They told me:

- The titanium equivalent to the ASME B16.5 pressure-temperature ratings do not exist

- All flanged nozzles on TI based equipment are lap joint type with carbon steel backing rings.

- If I were to provide operating temperatures/pressures and nozzle loads, they would be happy to provide an FEA analysis (for an additional fee)



MJCronin
Sr. Process Engineer
Venture Engineering & Construction

http://www.VentureEngr.com