Welding 316Ti with HC22, Duplex and 904L

[RubenGA]

Hi,

I want to fulfill the pressure rating of a 12" ANSI CL 2500 @ 350ºC made of 316Ti.

I would like to know if it is possible to weld to this flange a tube made of either Duplex, HC22 or 904L in order to reduce the wall thickness.

Is there any standard which address this topic? e.g from AWS?

My feeling is that there should be no problem with 904L, but I am not sure about HC22 or Duplex.

I do appreciate your support.

 

[metengr]

RubenGA;
What are you trying to do here - you have me lost. What does

fulfill the pressure rating of a flange

mean when this flange is or should be an ANSI B16.5 flange, already manufactured of 316 Ti?

Is this on a piping system or pressure vessel piping?
What are the service conditions?

If this is a piping system, you need to go back and evaluate wall thickness for material substitutions using ASME Piping Code or some other design code for piping. Second, you better evaluate feasibility of alternate materials based on service conditions.

 

[RubenGA]

Hi metengr,
I will reframe my question. I want to weld a Flange made of 316Ti to a tube made of Duplex, HC22 or 904L. Am I allow to do this? To weld to different materials from different material groups knowing this components belongs to a pressure vessel system.

 

[metengr]

Yes, it is possible to weld these base materials to 316 Ti. What you will need to do before welding is to evaluate service conditions related to possible corrosion at the weld region and determining the required pipe schedule, based on design pressure and temperature.

 

[RubenGA]

Hi metengr,

Thanks for your answer.

I believe you are referring to a Weld decay situation, that's why I select the 316Ti for my Flange and in order to reduce the Sch. I want to use a "stronger Material", hence, HC22, 904L or Duplex. However, how do I assess the possible corrosion on the HAZ during service conditions, any Guideline or Standard?

What about cryogenic temperatures? Welding 316Ti with 316Ti for a temperature of -350°F with 2900Psi is not an issue, but I am not sure if welding of HC22 with 316Ti will stand that condition due to the welding itself.

I do appreciate your comments and support.

Regards,
Ruben.

 

[metengr]

Ruben

However, how do I assess the possible corrosion on the HAZ during service conditions, any Guideline or Standard?

Check with NACE for literaure for corrosion rates of metals in specific environments;

http://www.nace.org/content.cfm?parentid=1001&currentID=1001&CFID=1202007&CFTOKEN=36789460

For weing 316 Ti to C22, you will be using a nickel-base filler metal that should provide suitable toughness at cryogenic temperatures. However, you will need to qualify a welding procedure for this combination of base metals and impact testing.

 

[MikeMet]

If you are worried about HAZ zone attack why even use 316Ti? Use the same alloy as the piping. However, if you still use the 316Ti, you can always weld a coupon and do a weld decay test. There is a standard ASTM using HCl for weld decay of austenitic staninless steels.

Alloy C22 is good in cryogenic applications as it is a fully austenitic material, as are 316Ti and 904L. However, not so for Alloy 2205.