E110XX-X pre-bake?

Date 02-21-2009 21:36

The reason that the E100XX-X electrodes and higher are exempt is that the manufacturer of the electrode controls the hydrogen to a lower level since they know it will be used on high strength steel. The E7018 that you buy may not have as strict hydrogen control because the manufacturer doesn't know that you will be using it on high strength steel. so it has to be baked first. If you want good information on welding A514, Arcelor-Mittal has information available since they bought the company that originally brought it to market as "T-1".

By spots

Date 02-23-2009 14:45

Thank you very much, reconditioning ovens are expensive.

By 803056

Date 02-23-2009 15:54 Edited 02-24-2009 04:51

AWS D1.1 does not cover steels having a yield (not tensile) strength greater than 100 ksi unless their use is approved by the engineer and qualified by testing. You'll notice that the filler metals listed in Table 3.1 only go as high as 90 ksi. The clause refers to electrodes with a tensile strength less than 100 ksi (not inclusive), i.e., 90 ksi, 80 ksi, etc.

The bottom line is that any electrode having a tensile strength greater than 70 ksi, but less than 100 ksi has to be baked before use when welding A 514 or A 517 steels.

I would reason that if electrodes less than 100 ksi have to be baked before use, higher strength electrodes would be baked as well. High strength steel, i.e., A 514 or A 517, with a higher Ce is more susceptible to hydrogen cracking than lower strength steel with a lower Ce, so baking is necessary to ensure the covering (flux) is free of moisture.

Best regards - Al

By spots

Date 02-23-2009 23:14 Edited 02-23-2009 23:19

It is logical that all electrodes would have to be baked, but in 5.3.2.5 E110XX is excluded from this requirement.

In addition E110XX-X is listed in table 5.1 (atmospheric exposure limits) so the code does address these low hydrogen electrodes specifically, as long as they have been tested in accordance with section 4.

You mentioned section three which only deals with prequalified WPS's.

"any electrode having a tensile strength greater than 70 ksi, but less than 100 ksi has to be baked before use when welding A 514 or A 517 steels." <-- there are exclusions for E7018M and 70XX-H4R could this also point to an exclusion for 110XX-X

"I would reason that if electrodes less than 100 ksi have to be baked before use, higher strength electrodes would be baked as well."

The above statements are confusing, please clarify if this is an opinion or something you have learned the hard way.

Respectfully,
spots

By 803056

Date 02-24-2009 04:49

If that's your take on the subject, so be it.

I would take any precaution necessary to ensure success.

You're right, Table 3.1 is for prequalified base metals and filler metal combinations. Anything other than what is listed as prequalified (including A514 and A517 using high strength filler metals) has to be qualified by testing and approved by the engineer. I guess you could dip your electrodes in cow dung (I can assure you with some conviction it isn't addressed by D1.1) before using them as long as you qualify your procedures using the same and the engineer approves it.

I guess it is fair to say there is a danger in reading something into the code that isn't there. There are differences between minimum code requirement and good practice. My opinion is that a measure of caution is prudent.

Best regards - Al

By spots

Date 07-20-2009 22:30 Edited 07-21-2009 12:01

Thank you very much jarcher!

I made the call not to bake E110XX electrodes as the code eluded to and the pamphlet you posted explains why on page seven.

http://www.aws.org/cgi-bin/mwf/topic_show.pl?tid=21845

http://factionists.net/Download/Welding%20T-1%20Steel.pdf

By ssbn727 (*****)

Date 07-27-2009 16:33

So let me get this correct in my interpretation of your last post...
"I made the call not to bake E110XX electrodes as the code eluded to and the pamphlet you posted explains why on page seven."

Does this mean that if you use the 110XX electrodes straight out of a previously hermetically sealed container, you will not be required to bake the remaining electrodes that are in the now "OPEN" container either, and the electrodes that you do use will still be safe from excessive hydrogen absorption after lets' say; an exposure time of one hour?

If this is what you mean then, I must wholeheartedly disagree with you because if you look at page eight in the .pdf, you will read that even though the 110XX electrodes do conform to the allowable weld metal diffusible hydrogen to 5ml/100gm or less when they are still in the hermetically sealed container, one must note that upon opening the container, the .pdf recommends that the electrodes be immediately put into a ventilated holding oven at 250 to 300F, and the electrodes that have been removed from the previously sealed container are also subject to being exposed to excessive moisture pick up after a certain amount of time which should be checked by contacting the electrode manufacturer because generally speaking, the electrodes are at risk to excessive moisture absorption after one half of an hour out of an opened container that was previously hermetically sealed as noted in paragraphs marked (1.), (3.), and (4.) respectively.

Here's an article that may interest you:
http://www.thefabricator.com/ArcWelding/ArcWelding_Article.cfm?ID=1636

Respectfully,
Henry

By spots

Date 07-28-2009 20:58

All electrodes were put into rod ovens at or above 250F as soon as their containers were opened. The welders then transferred the hot electrodes to heated rod caddies that were plugged in where they were working.

According to table 5.1 the electrodes had a maximum atmospheric exposure time of 30 minutes, we were using the -H4R flavor so we should have been OK with 4 hours out of the oven provided they were then thrown away or baked for one hour @ 700F+. As they were working out of heated caddies atmospheric exposure was not an issue.

The electrodes were not baked for one hour between 700F and 800F prior to use.

All welds were penetrant checked and VT'd after 48 hours then glycol checked three months later with no relevant indications.

Thank you for posting that article. I ran across it during my research on this topic. It did not directly address my specific question so I did not post it, but it should be of use to others in the future.

By Lawrence (*****)

Date 07-28-2009 22:29

Hey Spots,

What is a "glycol check" ??

I'm not familliar with the term.

Thanks

By spots

Date 07-29-2009 14:16

Glycol testing is the new environmentally friendly incarnation of the diesel test used to detect leaks for years in the tank building industry.

Quick and dirty all you do is spray diesel or in this case a 10% minimum solution of glycol (Prestone LoTox in this case) on one side of a finished weldment and check the other side for leakage.

By Lawrence (*****)

Date 07-29-2009 14:26

Thanks Spots!