Welding P91 chrome pipe

[welder123]

I have been for information on welding P91 chrome pipe. Looking for chemical compostions of pipe filler material that is used welding characteristics if anyone has any experience welding this material. Thanks in advance!

 

[bruv]

Try

http://www.metrode.com

You will have to register to view any data sheets. If there is nothing there, call them and talk to them. They are very knowledgable people.

Bruv

 

[MURZ]

Composition is going to depend on process used and manufacture of the wire or rod. In general, if you are going to use the SMAW process a rod with the AWS designation of E90xx-B9 is used. Typical chemical analysis is C=0.09 Cr=9 Mo=1.1 Ni=0.8 V=0.2 Nb=0.05 N=0.05 Mn=0.5 AWS SFA Number A5.5. Ni+Mn should not be greater than 1.5%

For GTAW welding you would also use a B9 weld wire ER90S-B9 AWS SFA Number A5.28.

There is some flux-core wire available from ESAB, Metrode, and Midalloy. Currently Flux-core welding wire has not been designated by AWS.

Preheat for this material is high. It should be between 400 F and 450 F with a maximum interpass temperature of about 600 F. Preheat must be lost during the welding process. If preheat is lost the weldment should be brought to 600-700F for one hour them wrapped and allowed to cool slowly to the preheat temperature or ambient temperature. If brought to ambient temperature, NDE should be performed before resuming welding.

After welding is completed, you can perform one of two options. 1.) wrap the weld and let it cool slowly to below 200 F. Once you are below 200 F Post Weld Heat Treatment (PWHT) can be carried out. 2.) Do not cool the weldment but rater go from preheat temperature to PWHT soak temperature.

The weldment must be Post Weld Heat Treated. The soak temperature should be between 1375 F – 1425F. If PWHT is carried out over 1425F you run the risk of exceeding the Ac1 temperature of the weld metal, which will reform austenite, which will transform to untemperd martensite.

PWHT time should be 2 hours minimum for thickness up to 2 inches. 4 hours for anything above 2inches.