Vessel ASME VIII 304H material

[dedosan71]

I have to design a 10” diameter ASME VIII div.1 vessel containing hydrogen, with design temp. of 500°C and design press. of 20 barg. I should use 304H stainless steel but it’s hard to find this material on the market. A supplier propose 304/304L as an alternative material. Can be this solution correct? Which material can I use for this application? Is the 321 stainless steel suitable for this application?

 

[NickE]

304/304L is not suitable for replacement of 304H.

One of the pressure vessel guys will be along to provide more info.

Nick
I love materials science!

 

[jte]

dedosan-

You'd reach a better audience in forum794.

At your temperatures, there is no difference in the basic allowable stress in tension for Div. 1 whether you are using SA240 304 or 304H (or SA213 304 or 304H). So unless there is a material engineering issue with hydrogen diffusion into the steel with the differrent grades, there should be no difference. Be sure you read and understand the notes in II-D for these materials and choose your allowable stress accordingly.

jt

 

[ApC2Kp]

dedosan71,

The 304H grade material is necesary for the 500 deg C service temperature. The 304L low carbon material would be limited to less than 425 deg C service, due to de-rated strength.

The straight 304 grade material with a minimum 0.04% carbon would handle the 500 deg C service, as well as would the 304H grade material.

 

[metengr]

Agree with jte. Please review the allowable stress values and temperature limitations in Section II, Part D of the ASME B&PV Code. If you are going to design this vessel, you need to be familiar with Section II, Part D (but you already new this, right?)

 

[metengr]

One added note, austenitic stainless steel is considered impervious to hydrogen in comparison to steel or low alloy steel.

 

[unclesyd]

What is the specific components you are having trouble finding, plate, pipe, fittings, etc?

 

[0707]

ApC2kp is right

luis

 

[dedosan71]

i've troble finding fitting and pipe.
i understand that i've to ask to my suppliers 304 with minimum of 0.04% of carbon. someone told me that now fitting are supplied with a 304/304L certificate.
thank you very much!

 

[ApC2Kp]

deosan71,

There is increasing proportion of dual certified 304/304L material supplied on the markets. Strength of the dual certified material is increased by additions of nitrogen and other elements to meet the ambient temperature strength test requirements for straight 304 SS.

The 500 deg C application requires the strength imparted to the material by the minimum 0.04% carbon content, unlees there is evidence that the particular dual certified 304/304L material would have adequate strength at 500 deg C.

Better to find another supplier for SS fittings. Your application is not the common food service or pharma grade piping design. What fittings do you need with the 10 inch vessel?

 

[unclesyd]

Here are two suppliers that I've used for this alloy.

http://www.gpss.com/products.php

http://www.rolledalloys.com/trc/hrheatalloys.aspx

 

[jte]

ApC2Kp-

Though it may be good practice to require 0.04% C at 500°C (932°F), this is not a Code requirement until the temperature reaches 1000°F per note G12 in II-D. No changes here for the 2007 Edition.

jt