A335P92 welding!

By - Date 04-17-2005 13:07

Are you sure it's A335-P92? The "A335" series is for your Chromium-Molybdenum steel pipe forms. The "P" deisgnation means it is the pipe form. The nearest thing I know of even close to what you listed is a A335-P91 (9Cr-1Mo and V+Nb+N), which is considered a "modified chrome". If this is what you're meaning, the SMAW filler should be E9018-B9 and the GTAW should be ER90S-B9. I'm just not familiar with the "92" designation.

Chuck

By dragon

Date 04-18-2005 05:39

It's A335P92,used in 1000MW power plant!

By chall

Date 04-18-2005 17:12

From SA335:

P-92 is close to the chemistry of P91 with the biggest exception being Molybdenum. P91 has a range of 0.85 to 1.05, while P92 has a range of 0.3 to 0.6.

Mechanically P92 is slightly higher in tensile value: 90ksi, compared to P91 - 85ksi. Elongation specification is the same.

Charles

By - Date 04-18-2005 17:40

Hi Charles,
Respectfully, there are a few more differences in a P-91 and a P-92. The main thing being Tungsten, which is used for added high temperature properties over the "modified" 9Cr grades (P-91). P-91 contains no tungsten. Although P-92 has an ASTM designation, it is a fairly new material. In view of the difficulty of matching the properties of the cast and PWHT microstructure with those of the parent metal, additional welding consumable research is needed. With that being said, I feel that the filler metal of choice is the same for P-91 and P-92, in spite fo the differences. In my opinion, there's not a lot of other choices.

Chuck

By chall

Date 04-20-2005 13:26

Yes, I missed the reference to W (tungsten). I rushed through that. I find it a bit odd that if it's such a significant part of the chemistry that it is included in the column that contains "other elements".

My oversight. Thanks for pointing it out.

Since you did though, maybe you could explain the addition of Boron as well. It is also include in the other constituent elements and I don't know what property it enhances.

Thanks.

By - Date 04-20-2005 20:04

Charles,
Since this material is used in high heat applications, and is very recognizable for creep strength, I am quite sure the Boron is added as an enhancement for the creep strength at elevated temperatures over a long period of time. The allowable range being 0.001-0.006 tells me that it is useful up to the maximum range, but higher can have detrimental affects, like possible cracking problems over a period of time. Maybe a comparative example might be Bismuth. When added to a flux core composition, Bismuth is allowed for easier slag removal, but just slightly higher, it is prone to contribute to hot cracking. Both would be, in my opinion, what we consider trace elements.

Chuck

By - Date 04-20-2005 21:50

Charles,
Yes it is strange that W (tungsten) is listed as one of the "other elements". The data sheet that I have lists every element, there is no "other elements" listing. NF616, produced by Nippon Steel [A213 T92/A335 P92] gives the complete alloy listing. In this P92, tungsten plays a mojor part in improving creep strength values, so it is odd it is not given more credit. Comparing the P91 to the P92, there are various min/max rangers concerning the carbon, Si, P, Cr, Mo (which yu pointed out), W ( a big difference here), Ni, V, Nb, Al, and B ( which we idscussed). The differences are slight except for the tungsten.

Chuck

By GRoberts (***)

Date 04-19-2005 00:41

Metrode in the UK makes Chromet 92 for SMAW, 9CrWV for GTAW, and Supercore F92 for FCAW welding of P92. Obviously there are no AWS classifications for these alloys, and there are also no European ones listed in the Metrode Catalog.

By dragon

Date 04-21-2005 10:53

we often use Metrode electrode in p91!
also have used OERLIKON!