Bolting For High Temps

[BigAndyH]

Hi,

I am looking at a pilot plant with a design temp of 750C (around 1400F). Although pressure is low because of the high temp I am looking at using class 600 B16.5 flanges in 310H. However the only bolting materials listed to these temps (in B31.3) are classed as low strength in B16.5 and therefore are limited to use with class 150 and 300 flanges.

So if there anyone on the forum operating at these temps - if so what materials do you use, or how do you get around these issues ?

Thnaks for your help

 

[metengr]

Look at ASME B&PV Code, Section II, Part D, Table 3. There are nonferrous bolting materials that can be used at 1400 deg F.

 

[gr2vessels]

ASME SA 193 gr. B8, B8M ferrous bolting is listed in Table 3 up to 1500 F (obviously, not much strength let in it at 1500 F).

 

[heatexguy]

gr2vessels...SA-193 Gr B8 and B8M carry note G5 (greater than 0.04% carbon content on heat analysis). This is not guaranteed, since these grades specify a maximum carbon content, not minimum. My preference would be SA-193 Gr B8P.

 

[BigAndyH]

Thanks for everyone's comments so far.

I saw SA193 B8/B8M, but it is listed as low strength in B16.5 and therefore limited to class 150 and 300 joints (see note 4 of table 1B and para 5.3.3, ASME B16.5 1996).

As far as I can see B8P is not listed in B16.5; is it a grade that is commonly available?

 

[gr2vessels]

I subscribe the B8P is a better option than B8M (but as far the carbon content concerns, the SA 193 is specifying C = 0.08% +/- 0.01, hence G5 is not an issue).
BigAndyH, the selection of B8P falls under general Note (b) below the Table 1B of ASME B16.5 edition 2009.
Cheers,
gr2vessels

 

[BigAndyH]

gr2vessels,

Thanks for your help. I only have the 1996 edition of B16.5 - I assume you are referring to the note "ASME Boiler and Pressure Vessel Code, Section II materials which also meet the requirements of the listed ASTM specifications may also be used" ?

Could you confirm for me that B8P is not listed in Table 1B of the 2009 edition ?

If so then my interpretation is I can use B8P material, using the section II values, with my class 600 flanges. Although its allowable stresses are the same as B8, the fact it is not listed in B16.5 as low strength means I do not have to worry about that restriction.

 

[jamesl]

I don't think you can use B8P in this case. B8P has the same allowable stress values as B8 per Section II part D. It is also low strength bolting material.

It does not comply with Note(b) of Table 1B. You have to have at least equivalent or higher strength than one of the high strength or intermediate strength materials to be used on 600# flange.