Filler - ER90SB3R what is the suffix R?

[doctorjay]

ASME II C, at SFA 5.28 addresses this somewhat but doesn't address the suffix "R". AWS A5.5 address this as low-hydrogen electrodes. From what I see, this is a 2.25CR/1MO used in a cold climate for equipment with high temp and high pressure application. Also that pre-heat and interpass temps are critical and post weld heat treat is required.

what I would like to know is can I substitute this tig wire in other applications and would I need to requalify the PQR for any and all substituted applications?

This is a new plant for me and I found a large supply of this in stock. I am not familiar with this filler.

 

[weldtek]

I don't recall seeing the 'R' designator used on solid filler. As you say it is used for covered electrodes (SFA 5.5), to indicate limited moisture content.
Generally, ER fillers are considered to be a low hydrogen type.
I would agree with your other comments that preheat and interpass temps are critical and that PWHT is typically indicated.
As far as substituting this filler on other WPS' goes, more info is required, but, I think in most cases you'll probably find that you won't be able to do so and stay withing the essential variables. Review QW256.

 

[metengr]

weldtek;
I agree with what you have stated above except for one small point - bare wire does not imply or is considered as having an advantage as low hydrogen. This is something that I have discussed with many welding engineers. You need to specify a diffusible hydrogen designator if you want low hydrogen.

 

[weldtek]

metengr,
Thanks for the correction.

 

[unclesyd]

I think you will find your answer about "R" here.

http://www.lincolnelectric.com/knowledge/articles/content/20faq.asp#1

 

[doctorjay]

thanks everyone.

you have been a lot of help. i guess i'm just stuck with a bunch of rod i probably won't ever use.

 

[metengr]

doctorjay;
All is not lost. This filler metal can be used understanding that it is not low hydrogen. For example, after welding, you should perform a hydrogen bake-out prior to immediate PWHT. If a hydrogen bake-out is performedon welds before PWHT, I see no problems with the use of this filler metal.

 

[GRoberts]

Only SMAW with -15, -16, -18, -28 (and possibly another -2X coating, but I can't remember without looking it up) coatings are "low hydrogen" officially. Otherwise, an electrode/filler/flux can be tested for hydrogen level and be designated with H2, H4, H8, or H16. Although within industry, the term "low hydrogen" is usually talking about a hydrogen level, not an officially defined term except with regards to the afore mentioned coatings. Depending on who you are talking to, a low hydrogen level is either H4 or less, H8 or less or H16 or less. The R designator as it applies to moisture resistance, only applies to SMAW electrodes, so it is not applicable to bare wire.
The processes that use bare wire (without slag) are generally considered to be lower hydrogen than the ones with slag, but poor practice can introduce hydrogen into the weld. This is why bare electrodes are rarely ever tested for hydrogen, because they would almost always meet the lowest levels if welding is performed properly.

There is another possibility as to what the R designator means. In SFA-5.23, the 2 1/4 Cr-1Mo (among others) has the optional R designator if it meets limits on residual elements that lead to embrittlement during high temperature service, such as P, S, Cu, Sn, Sb, and As. (more commonly referred to as X-factor). It is possible that AWS has added this designator to A5.28, but I don't see it in my copy of SFA-5.28, which references A5.28-96.