Use of WB 36 pipes for boiler application

[tamal1475]

We want to use WB 36 (Werkstuff no. 1.6368) material for power boiler economizer header and piping. The maximum temperature could be upto 370 deg C. There is some apprehension regarding Copper precipitation in long term service and consequent embrittlement. We are also aware that this steel is popular in Europe. Where can we get more information?

 

[EdStainless]

Is the alloy listed in the pressure code for direct fired service?

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Plymouth Tube

 

[metengr]

You will not be able to use this material for ASME Power Boiler Construction for headers or piping.

 

[metgist]

metengr, it seems that WB36 is listed as a code case in ASME Section I (code case 2353) since 2001 and Section VIII (Div. I & II) is in progress (according to V&M). Then does it not qualify for use as headers or piping?

 

[metengr]

metgist;
Since I am on BPV I standards committee, I will verify this. I don't recall this particular code case. Also, code cases have very specific use requirements.

 

[metengr]

metgist;
I checked my C&S connect and indeed found this code case. Thanks for this information. I reviewed all submitted background information associated with this code case including background code committee correspondence. There was some apprehension regarding use of this material, identified as;
Mannesmann WB36 (DIN 15NiCuMoCb5) VdTUV 377/2 Microalloyed Carbon Steel.

The reason for the code case was to permit use of this microalloyed material based on limited service experience in Germany. This code case has not incorporated into Section I.

I will caution you that code cases are not necessarily approved for use by various Jurisdictions or regulatory bodies. Second, clients may not permit code case materials for boiler construction. As far as your original question, there has been nothing brought forward at code committee meetings regarding concerns for copper precipitation, and adverse effects on long term properties.
I would verify service experience with the original material supplier (Mannesmann) because they were the ones bringing forward the code case submittal over 10 years ago.

 

[metgist]

Another concern is corrosion fatigue (CF). ASME B31.1 (code case 182) issues a cautionary note regarding CF of WB36, and lists factors like temperature, dissolved oxygen content, likely strain rates, etc. to be considered before deciding on the use of this material in headers and pipes.