[jumpinjackflash]

OK I have made a lot of small parts from 4130....mostly .040 welded to .060 formed parts. I have metal sheet stored in the building with light oil sprayed on it and wiped down. After I cut my parts on the bandsaw and get them shaped with flap wheel and deburred I usually soak them in acetone for a few minutes outside. Then they are removed and cleaned again with new acetone. They are then wiped off with clean cotton towels and laid out to be welded. Clean enough I thought ? My dedicated diamond wheel .... all my tungstens ground and 70s-2 filler wire cleaned and degreased. Clean gloves- clean workstation. Now following Jody....in question go out and smack it around. Here is where the doubt settled in and I stopped work for today thinking I will have to redo all that has been done. Most of the welds did not bend...just broke off near the weld while beating over flat on anvil. So I chucked one in the vice and grabbed the bracket with vicegrips and managed to rip it off...tearing the metal and weld. Do I have a hydrogen issue with this? It did take quit a bit to tear it off the base in the direction it will be pulled....one I could not get to even start to give way. I had planned to get a weld on the ends...the test was on a completed weld to the edges. Any help appreciated as remaking the brackets now is easy....the ones that took a week of spare time have not been welded yet- lots of die work to form. Got to find out whats going on.

[Coldman]

First of all I have zero experience with 4130, others that have will give their opinion shortly.

From what I can see, the weld is sound and has not failed. The fracture is in the parent metal, which to me suggests hardening due to speed cooling either by cold ambient temperature, draughts or just by nature of the joint with thin material conducting heat away fast. The solution is therefore a little pre-heat and burying the part in sand to slow the cooling rate.

Also pulse will limit heat input to the HAZ and could therefore be helpful.

[LtBadd]

OK I have made a lot of small parts from 4130....mostly .040 welded to .060 formed parts. I have metal sheet stored in the building with light oil sprayed on it and wiped down. After I cut my parts on the bandsaw and get them shaped with flap wheel and deburred I usually soak them in acetone for a few minutes outside. Then they are removed and cleaned again with new acetone. They are then wiped off with clean cotton towels and laid out to be welded. Clean enough I thought ? My dedicated diamond wheel .... all my tungstens ground and 70s-2 filler wire cleaned and degreased. Clean gloves- clean workstation. Now following Jody....in question go out and smack it around. Here is where the doubt settled in and I stopped work for today thinking I will have to redo all that has been done. Most of the welds did not bend...just broke off near the weld while beating over flat on anvil. So I chucked one in the vice and grabbed the bracket with vicegrips and managed to rip it off...tearing the metal and weld. Do I have a hydrogen issue with this? It did take quit a bit to tear it off the base in the direction it will be pulled....one I could not get to even start to give way. I had planned to get a weld on the ends...the test was on a completed weld to the edges. Any help appreciated as remaking the brackets now is easy....the ones that took a week of spare time have not been welded yet- lots of die work to form. Got to find out whats going on.

Have you made this weld successfully in the past? Is the material in the annealed or hardened condition. If it's hardened then I would expect your result.

[Oscar]

Run a file over the portion where it broke and also on the metal far away from the weld joint. If the area of the broken section is very hard and does not file away, or files very very little compared to the other area of the part, then the broken part suffered some martensitic hardening. Welding it too fast (as if it was stainless) or letting it cool to fast in cool ambient air or in the vicinity of a draft might cause it. While I don't agree that "thin material conducting heat away fast", it seems that something else contributed to speed-cooling. You didn't quench it in water did you?

[jumpinjackflash]

It is 4130 Normalized condition from aircraft spruce, .040" sheet. As for a new file on broken section and 1 inch away...seemed about the same to me stroke for stroke...maybe a bit harder on the broken end. Hate to crap can the parts...but would rather be sure. I have made 5 pieces for actual use...I will pick the worst looking one from the lot and try and test it as it will be loaded. Wish I had some way to measure the load on it. Just cant make myself mig them. Any tips on testing at home before just smacking flat? I didn't think I welded fast....machine set at 45 amps, 20cfh. Peddle not all out. Shiny puddle, dab move ahead, repeat. I know it could have cooled a little faster than normal- clamped to a piece of T-6 {2.5" x .065"} tube to keep arc in bottom plate straight. Maybe that is the problem.

[Oscar]

I know it could have cooled a little faster than normal- clamped to a piece of T-6 {2.5" x .065"} tube to keep arc in bottom plate straight. Maybe that is the problem.

Bingo. Next time clamp to a same-sized piece of steel 3/16" wall, or to one that's been pre-heated if you feel so inclined.

[jumpinjackflash]

I feel like a real A$$ right now. After all the time spent learning about metals....and shot myself in the foot knowing these things. Guess I had to have someone say look what you've gone and done. I do have some 1/4" wall DOM tubing I can use for a piece to clamp them to. Will preheat before I start this time and weld slow and leave them to cool . Just ordered more steel to remake all those parts. I am getting better at making them though. My haste has made waste again. Thanks guys ! Hopefully normalized will not be a problem...info from their website
4130 STEEL SHEETS
MIL-S-6345A NORMALIZED
Formerly MIL-S-18729C
This chromium-molybdenum alloy is one of the most widely used aircraft steels because of its combination of weldability, ease of fabrication and mild hardenability. It will respond to heat treatment to high strength levels and yet, in the annealed condition, it has adequate strength for many applications. Used for the manufacture of parts and components.

Tensile strength 75,000-85,000 PSI. Sheared to sheet and strip sizes listed below. Subject to availability of normalized sheet, annealed 4130 sheet may be substituted

[jumpinjackflash]

OK I give up. Welded a couple other pieces slowly today on the 1/4" steel table...left to cool slow-no breeze. Broke the same way as before. Do I have a batch of bad .035" filler???? 10 lds of it? Only other filler I have on hand besides 309 is .045" from a different manu. Or could it possibly be something in the way this stuff is natured this thin? One broke right down the middle of the weld...and I thought it was an OK weld. Just hammered flat on the anvil. Something is going on....I am going luny tunes trying to figure this out. Afraid to weld anything else until I find an explanation...willing to mail someone some of the filler wire to test...I am stumped for sure. Maybe not enough penetration of the weld ? Is it possible for the oil to have penetrated too deep for acetone to get out? Looking for anything now.....going crazy

[dirtmidget33]

I do a lot of 4130 one thing I notice is your welds look cold like it is not wetting in. Also with only .035 filler you have to push a lot of wire into weld puddle which might be causing you to weld cold cause you can't feed wire fast enough so you are not running enough amps but dwelling slow and low. suggest trying 1/16 so you can just dab filler instead of push it in. Cut through your weld so you can examine your root.

[dirtmidget33]

Wanted to add while it won't hurt you don't really need to soak in acetone. Way I prep tubing is clean mill scale off using emery cloth, flap disc or dremel Including the inside of tube. Wipe down with acetone. Filler gets acetone wipe also then weld them up. As for metal soaking up and holding acetone it won't. It evaporates quickly and if any was left when you strike arc the stuff ignites in a quick flash yeah didn't let it all dry before. Besides igniting the heat would also evaporate any left behind but it will burn before that.

[Otto Nobedder]

The first thing my EAA library tells me is that 4130 should be welded with E80. That should not be your issue.

I think, in these thin sections, you're dealing with a preheat/postheat issue. The books that deal with this specifically are in storage, but my memory suggests a 350*F preheat and a very slow cool, to approximate a PWHT.

With very small parts, you can actually "normalize" them, though, with a ceramics kiln available at your local hobby "big box store".

Please tell me you know "kiln" is pronounced "kill"... That jackass on TLC's "How It's Made" pisses me off.

Steve S

P.S.
Jody's a member of EAA.
PM him.

[dirtmidget33]

Ok last add on I promise wanted also to say that normalized or annealed material is what you to weld on. Some have tried welding on hardened material but becomes very brittle in HAZ some chassis failures where caused from this. If item is to be heat treated after welding then hardened material is used sometime along with different filler. I have not welded or worked with material in hardened state so info is what others have told me about. Seen a few chassis failures in the last few years breaking in HAZ by certain builders, this concerns me and have not been able to determine if it is material failures or welder failures. Me personally afraid of and will not use the stuff from China, only German or American 4130

Otto typing same time as I was

Motor sports use ER70-S2 for elongation over ER80-D2

[LtBadd]

From Welding Design website

"The heat from welding makes the base material expand during heating and contract when cooling. This creates residual tensile stresses around the weld that can cause cracking or shorten the life of the part. Typically, AISI 4130, 4140, and 4340 require a stress relief after welding to eliminate these residual stresses."

Here is the link http://weldingdesign.com/welding-qa/pos ... ess-relief

take a look at the preheat and interpass temperature chart

Also from Miller's website http://www.millerwelds.com/resources/ar ... oly-Tubing

[big gear head]

Would 4130 wire make it better or worse?

[Oscar]

4130 wire has high carbon, just like 4130 sheet/tube/etc. So worse.

[LtBadd]

Would 4130 wire make it better or worse?

Well, 4130 matches the base metal and would need PWHT (post weld heat treatment) so in your situation it would be worse

[jumpinjackflash]

Went out and burnt some more filler today...made a weld on .040 molly...cut in 3 pieces...going to look at nugget on 1, bend the other, and anneal at 900 F and cooled in sand as suggested before bending it. Both pieces broke in the same manor tested. I welded a piece of DOM tubing...smashed flat with barely a split starting. Everything molly broke..even using another vendors .045 filler wire. Done a 2 pass weave with .035 filler on molly and it took a good beating before it gave up the ghost...still dumbfounded. Everyone else seems to get along with molly no problems without having the issues I have doing nothing but clean-prep and welding. Thanks for all the help.....not sure where to go from here.

[jumpinjackflash]

See...flat as a pancake...no splits or anything. Maybe I should sell my TIG machine to pay for welding school....

[Oscar]

Went out and burnt some more filler today...made a weld on .040 molly...cut in 3 pieces...going to look at nugget on 1, bend the other, and anneal at 900 F and cooled in sand as suggested before bending it. Both pieces broke in the same manor tested. I welded a piece of DOM tubing...smashed flat with barely a split starting. Everything molly broke..even using another vendors .045 filler wire. Done a 2 pass weave with .035 filler on molly and it took a good beating before it gave up the ghost...still dumbfounded. Everyone else seems to get along with molly no problems without having the issues I have doing nothing but clean-prep and welding. Thanks for all the help.....not sure where to go from here.

I can't tell what I'm looking at in Pic #2. Is the orientation wrong?

[motox]

are you using material from the same stock.
maybe you might try getting some material from
a different source and see if you get different
results.
craig

[jumpinjackflash]

Pic #2 is a weave I tried...cut off a piece and beat flat on the anvil. Maybe I am not testing this right...not sure if this will bend sharply at the weld and not crack thinking back on the bending radii needing to be about 3 times thickness to avoid cracking. I might be partly chasing my tail. If I tried a butt weld what would be a good way to test it other than a pull test? What would be a good test other than what I am doing to test?

[aeroplain]

Much fuss in the Home-built world about "normalizing" all welds. I've never found a definitive, but with the weave on a small part, that is just what happened. Heat is fully soaked. A friend of mine said " if you get the torch out to normalize, why not just weld with it and be done?" The TIG welds are so neat and clean it's what I want to use on my project, so, I'm with you. I'm not sure what you're building, but if the OX5 in your avatar is your power plant, I can see your concern; however, if your fuselage get's flattened or bent like your testing, you may have bigger issues. I'd say find an IA at your local EAA chapter to give some guidance.

[Otto Nobedder]

Putting the torch to it is "post weld heat treatment."

Sticking the whole thing in a big-arse oven is "normalizing."

Just to make the distinction clear to any potential aircraft home-builders.

Steve S