SMAW rods for boiler construction

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: cbrew, Harold_V

jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

SMAW rods for boiler construction

Post by jlakes85 »

Is there any reason that a rod like 7010 couldn't be used for all passes on a welded boiler joint? My only guess would be the heating and cooling cycles that are found in a boiler are much harsher than on other types of process piping in general
Glenn Brooks
Posts: 2930
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: SMAW rods for boiler construction

Post by Glenn Brooks »

I am certainly no expert. But have heard some people say 6010 forms better shaped root passes than 7010, and also is preferable to work because the 6010 flux produces a liquid flux, whereas 7010 is a cellulos flux product that burns with a gaseous flux - which can create lots of slag intrusion problems pretty quickly in a root pass if the rod hasn't been heated and dried properly. So Iam guessing weld pass geometry formation and potential slag intrusion/voids are the reasons.

Standard pressure vessel welding technique is to use 6010 for root passes. Then 7010 is used for making a final covering pass. Also, the 7010 puddle lays flatter and spreads better, hence might distribute expansion and shrinkage stresses on the surface of your boiler more evenly.

Hopefully some of the pressure vessel welders will comment.

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Marty_Knox
Posts: 1724
Joined: Thu Jan 09, 2003 6:50 pm
Location: Michigan, USA

Re: SMAW rods for boiler construction

Post by Marty_Knox »

Have you run much 7010? I prefer 7018; in fact, I use Lincoln Excalibur 7018 almost exclusively.
jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Re: SMAW rods for boiler construction

Post by jlakes85 »

Hi Marty,

No, I've never run 7010. Just 6010(red) and Lincoln Excalibur 7018. I was watching some guys on YT out on the pipeline, pancake helmets and all: I think they used 6010 or other xx10 rods for all passes using downhill technique.. definitely not as pretty to look at as a 7018 fill/cap, but much faster than traditional uphill 6010/7018. I'm guessing another big advantage is not having to mess with ovens on site to keep the 7018 rods in code condition, but again I think even that 600 psi pipeline doesn't deal with nearly as severe a thermal cycling as a boiler, which is where an xx10 rod might show it's limitation in this regard
BClemens
Posts: 475
Joined: Sat Oct 08, 2016 10:04 pm
Location: Gloucester, VA (Sassafras)

Re: SMAW rods for boiler construction

Post by BClemens »

7018 rod has an additional benefit and that is to greatly reduce hydrogen embrittlement (that is if the flux is dry). 6010 is a great tacker rod.
User avatar
cbrew
Posts: 3161
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: SMAW rods for boiler construction

Post by cbrew »

Marty, what about Tig. I know its a much slower pace.
If it is not live steam. its not worth it.
Marty_Knox
Posts: 1724
Joined: Thu Jan 09, 2003 6:50 pm
Location: Michigan, USA

Re: SMAW rods for boiler construction

Post by Marty_Knox »

cbrew wrote:Marty, what about Tig. I know its a much slower pace.
We do a lot of TIG. Depending on the fitup, we will do the root pass with 6010 or TIG. We use ERS70-2 for the filler with TIG. The TIG may be slower, but it makes for a smaller, neater weld with very little cleanup.
User avatar
cbrew
Posts: 3161
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: SMAW rods for boiler construction

Post by cbrew »

Marty_Knox wrote:
cbrew wrote:Marty, what about Tig. I know its a much slower pace.
We do a lot of TIG. Depending on the fitup, we will do the root pass with 6010 or TIG. We use ERS70-2 for the filler with TIG. The TIG may be slower, but it makes for a smaller, neater weld with very little cleanup.
ok Cool,
I am finally to the point in my "skill development" to weld my first boiler following the Washington state spec.
i do have a welding mentor to help as needed.
If it is not live steam. its not worth it.
jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Re: SMAW rods for boiler construction

Post by jlakes85 »

Hi Marty,

Do you know if the code explicitly forbids XX10 rods for all passes on a power boiler? I can't shake this curiosity.. Thanks again.

-jlakes85
Marty_Knox
Posts: 1724
Joined: Thu Jan 09, 2003 6:50 pm
Location: Michigan, USA

Re: SMAW rods for boiler construction

Post by Marty_Knox »

I know you can run 6010 for all the passes. I never bothered to look up or ask about 7010.
jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Re: SMAW rods for boiler construction

Post by jlakes85 »

Hi Marty,

Sounds good..I can see it being easier to just deal with once nice size box of 6010 and call it a day, you Hough the results won't be nearly as good looking
Boiler Builder
Posts: 30
Joined: Wed Nov 22, 2006 5:28 pm
Location: Washington State, at least today

Re: SMAW rods for boiler construction

Post by Boiler Builder »

The only difference between 6010 and 7010 is the 60xx signifies a minimum as welded tensile strength of 60,000 psi whereas the 70xx signifies a minimum as welded tensile strength of 70,000 psi.
Post Reply