welding 4130

[whee]

Also, I think it is harder to get a good flowing puddle with ER70s2 rod than RG45 rod. Does Bob recommend using RG45 or RG60 rod? I know when I talked to him a while back he said it is fine to weld up miss drilled holes but he was specific about using RG60 rod; made me wonder if uses RG60 for everything.

[dedgemon]

Well, RG45 and RG60 are to two rods classically used with 4130 oxy-acetylene. The ER70S-* rods work great with TIG and are probably fine with gas, but the composition is a bit different. Of course the shielding is quite different with TIG also.

1) Both Mn and Si are deoxidizers but ER70S-2 requires the addition of
small amounts of other powerful deoxidizers.
2) Increasing the Si level generally also provides increasing fluidity
to the molten weld puddle (i.e. it should flow easier). Therefore, the
ER70S-6 should provide a smoother weld bead than ER70S-2. This is
indicated in the usage information listed below. Also note how low the
Si levels are for the gas rods compared to the GTAW rods.


Chemical composition requirements from AWS A5.2 (gas rods) and A5.18
(GTAW rods) [I hope the table layout is readable after posting]

rod carbon Manganese Silicon

R45 0.08 % max 0.50 % max 0.10 % max

R60 0.15 % max 0.90 - 1.4 % 0.10 - 0.35 %

ER70S-2 0.07 % max 0.90 - 1.40 % 0.40 - 0.70 %
plus required small amounts of additional deoxidizers Ti, Zr, and Al

ER70S-6 0.06 - 0.15 % 1.40 - 1.85 % 0.80 - 1.15 %


Usage information from AWS A5.18 (GTAW rods)

ER70S-2: "...primarily used for single-pass welding
of...steels...Because of the added deoxidants, these filler metals can
be used for welding steels that have a rusty or dirty surface, with a
possible sacrifice of weld quality depending on the condition of the
surface. ...[U]sed extensively to produce high quality, high toughness
welds with the GTAW process."

ER70S-6: "...intended for both single- and multiple-pass welding.
They are especially suited for sheet metal applications, where smooth
weld beads are desired, and structural and plate steels that have
moderate amounts of rust of mill scale.

Probably more than anyone wants to know!! :-)

[JakeP]

Looks like, from that data, ER70S-6 is similar in composition to RG60, plus extra silicon.

Here is a short EAA video on the RG series of rods for 4130 aircraft welding: http://www.eaavideo.org/video.aspx?v=1553988082001

He says RG45, RG60, and RG65 are all good, and gives a few caveats for usage. Unfortunately, he doesn't address the ER series.

[dedgemon]

A fair number of people are using the ER70 series with the torch. Like you said its pretty much RG60 with a little more tensile strength. I'm pretty sure I'm not good enough with a torch to tell the difference!

[alaskabearhawk]

My understanding is that S6 is used where additional deoxidizing is needed - 4130 for example. S6 does contain roughly twice the Manganese & twice the Silicon of S2.

According to AWS specs, S2 contains >97% Iron, S6 contains >96% Iron. For practical purposes, identical.

If I remember right a few years back I asked Bob what he uses and it's RG60.

[nichzimmerman]

Kent white of tinmantech.com (he also stars in a couple videos about fuselage construction) is the one who suggests ER70S6 for welding 4130.

[alaskabearhawk]

Posted on first page of comments...

[nichzimmerman]

This morning I ventured from the realm of practice into the excitement of welding my first real part--a set of flap arms. But looks like I got the puddle a little too big on both of them. So which is it: Airworthy? Repairable? Scrap metal?

[bestbearhawk1231]

Nich, I am fighting with the same thing right now. Mine were a bit worse than yours but I elected to rebuild the parts and I am going to try to weld the parts together then radius them afterwards this time around.

As far as filler rod goes, I have tried rg-45, rg-60, 70s2, and 70s6. After quite a bit of practicing, I moved away from the tig rod due to excessive sparking. I use rg-45 on general mild steel used on other projects but stick to rg-60 for my aircraft. I have found that it works a little better on tubing since it doesn't flow like water like the rg-45 and has a tendency to hold in place better on the vertical parts of clusters...a side benefit is that you can get some pretty welds with it since the ripples actually stay in place unlike rg-45. Many aircraft have been built with both rods so I would advise to use what ever rod works best with your style.

Excessive sparking...make sure you have a neutral flame, you are keeping the inner cone around 1/8" from the puddle, and you are cleaning off any scale and junk from the metal. I have better luck if I wipe everything down (rods included) with acetone before I weld.

[nichzimmerman]

This thread may be a useful forum to ask very random questions that dont warrant a separate discussion. So here it goes:

On the flap hinge that bolts to the rear spar (4-place) how far back up the bottom side of the tube should the weld go? I just rounded the corner and stopped. It would be difficult going any farther.

[fairchild]

It has been my experience that when you start getting some sparks- (sparkler) - that is the puddle too hot - I think the sparks is the steel burning. Also if you get the
inner cones touching the puddle- that puts pure oxygen into the puddle- same result. I would think that maybe you just need to use less heat. maybe don't be in a hurry
- go cooler and slower........ but hard to tell without seeing it in progress...... but I havnt gas welded much since I got the tig rig.
Gas welding rod has more things in it which scavange out pollutants - Tig rod has some too but not as much as gas rod.
Gas rod seems to give nice clean beads with Tig but gas welding with tig rod seems a little less clean.

Tim

[nichzimmerman]

Another welding question: I was reading my new book, Performance Welding, and the author was adamant that a "power wire brush" (wire wheel?) should not be used to clean 4130 before or after welding because tiny bits of it can get lodged in the parent metal and will be impurities in the weld.

I have used a wire wheel on nearly every weld i have done. Is there truth in his claim? Is it critical? And what is a fella to do...throw his fuselage in the scrap bin? I feel like this should be stated in every homebuilding resource out there if it is critical as he makes it out to be. Thanks.

Nic

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[bestbearhawk1231]

Hi Nich, I think I also have that book...
I believe that the wire brush deal is in the same category as the Uber special ungodly expensive magical filler rod made from unobtanium. I don't see any problems with cleaning with a mild or stainless steel wire brush. I use a stainless brush to knock the slag off of questionable welds. I don't get carried away since the parts will be media blasted before paint. As for welding prep, I wipe down with acetone and get with it. If there is a bit of rust I use a scotchbrite. That said, I live in a very dry part of the country. I have jigs, stands, and tools that I made from mild steel over 10 years ago and never painted that doesn't even have surface rust on it.

[Bdflies]

Another welding question: I was reading my new book, Performance Welding, and the author was adamant that a "power wire brush" (wire wheel?) should not be used to clean 4130 before or after welding because tiny bits of it can get lodged in the parent metal and will be impurities in the weld

I have used a wire wheel on nearly every weld i have done. Is there truth in his claim? Is it critical? And what is a fella to do...throw his fuselage in the scrap bin? I feel like this should be stated in every homebuilding resource out there if it is critical as he makes it out to be. Thanks.



Nic

Sent from my SCH-I535 using Tapatalk

Man, I've enjoyed this thread! I, too, have 'Performance Welding' and a bunch of other welding books. Don't remember the admonition, about no brushes, but it doesn't surprise me. The one that I get the biggest kick out of, is when those guys talk about VAR (vacuum arc remelt) fillermetals, but I won't go into that pile of weeds...
You're always better off cleaning The base metal, before welding, than not. I wouldn't use a brass brush, but carbon steel brushes are fine. Personally, I use a stainless steel brush. I also use a 'scotchbrite' pad to clean the filler rod, before welding. I've seen brushing, grinding, sanding, blasting and chemical fluxes (tig). The brush probably leaves the least contaminates. If you cleaned every weld, good for you Nic. Also, don't forget to degrease the tubing, before welding.


Bill

[dedgemon]

A wire brush is okay, but the real deal is a 3M bristle disc (green). A 2.5" disc on a 90 deg grinder is great for knocking off scale etc. Leaves a great shiny surface. The discs look expensive but they last a long time.

[sjt]

The 3m bristle disk have a ceramic abrasive. I get mine from A-Line Auto Parts; about $8. I concur, they last a long time and do a nice job.

[alaskabearhawk]

I would certainly consider using a white disc (120 grit) instead of the green (50 grit) or yellow (80 grit). All those discs remove a LOT of material in a hurry. If you remove just .007 on a .035 wall tube, you have a spot that has lost 20% of the material thickness in that area near the weld. I also mark "4130 ONLY" on the back of my discs so I don't cross contaminate materials. Just something to think about...