PIPE-MONEL 400-OXYGEN SERVICE 1

[peter vaf]

We need to purchase pipe-10"-Monel 400 for oxygen service
Any body can help us for selection of PIPE SPECIFICATION (SEAMLESS OR HFW)

Note: Our client will not accept Filler Metal for Welded pipe .

 

Welded pipe may or may not entail filler metal. There are corrosive environments where welded pipe compromises the corrosion resistance.
HFW, a common process for making long seams in a variety of materials, uses no filler metal. Seamless is the most desirable option but is more costly.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[peter vaf]

According to ASTM B725 ,Supplementary S3 ,Welded pipe with more than 3.5 mm thickness should be made with Filler metal.
But our client emphasize to purchase pipe with ERW/HFW seam.However there is no company has approved WPS/PQR for such a size/material & thickness and all has declined!

What we can do now!

 

[EdStainless]

Since oxygen service is non-corrosive most users are very willing to use welded pipe. It is usually easier to get a good ID surface finish on welded pipe compared to seamless. This is especially true in larger sizes where seamless is nearly non-existent.
I don't know if you will find HFERW in this size, you may end up looking at pipe that has been TIG or Plasma welded as they can also be done autogenous.
ASTM B165 is the seamless pipe spec and B725 is the welded pipe spec.
References:
ASTM MNL36, Safe Use of Oxygen and Oxygen Systems: Handbook for Design, Operation, and Maintenance
NASA RP-1113, Design Guide for High Pressure Oxygen Systems
NFPA 53: Recommended Practice on Materials, Equipment, and Systems Used in Oxygen-Enriched Atmospheres

And cleaning is usually one of the hardest parts. The system has to be super clean with zero organic residue. Make sure that the pipe has been pickled, and presume that you will buy it with a cleaning spec attached.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[peter vaf]

We have a PMS for the class Oxygen service / Monel material ,But up to 8"(All pipe should be seamless).
Now they have a modification on pipe size ,which Increased to 10" .
Notes : HFW/ERW has not been allowed,According to ASTM B725 ,Supplementary S3 / TIG or Plasma welded is available ,but will not acceptable by client ,and seamless is very expensive .

 

[EdStainless]

Why would they accept HFW and not TIG? That is backward thinking in terms of weld soundness.
What specs are allowed? B165 only? If that is their stand then tell them the price.
With any welded pipe the real issue is the NDT, but it is also an issue with seamless. Buying any pipe for critical service without at least ECT (UT being preferable) is a fool's errand.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[peter vaf]

What's your Idea about the method:
"10"-pipe monel 400-EFW (According to SA-671) + Filler Metal which also covers ASTM B725 ,Supplementary S3(Additional filler metal)