so some not so good news from my X ray results for some control arms for my Land Rover. Im meeting with my engineer to go over some stuff tomorrow.
The material is "750 Carbon Hollow Bar high yield strength aluminium treated fine grained, low alloy calcium treated steel, with improved machinability and welding characteristics". You may know it as A381
Wall thickness for both tube and eye are about 3/8". You can see the joint prep I did on the tube. From memory it left about 1/8" of the tube wall not beveled.
Pre heat was to 570 F.
again, from memory I was at about 130 amps. 2.4mm Tungsten. 1/16th filler.
So can anyone tell from the pics what is going on?
what are thoughts on amps? Given It had that much pre heat, and how the puddle was flowing, I felt any more and I would have had problems. It moved quick!
Pic Is just root, I did a second pass to fill out to OD of tube.
What you are seeing is the line where the 2 pieces meet that was not chamfered. Other than needing another pass of weld all the way around it will hold fine. If you want 100% penetration you need more chamfer and leave a small gap.
Is that a common practice to make those 100% x ray?
No its not. Thats why I said if he put another pass of weld around it it would be fine. I am not sure what its finished purpose is. If its a link for a car or truck or if its a rod from a hydraulic cylinder. From the pics it looks to be made from cold rolled steel if so it must be some kind of link. If it is a link to be used on a race car or truck then it would be good to have 100% penatration .
Many welded hydraulic cylinders only have one pass of weld around them. i just welded one from a 743 bobcat that only had one pass of weld around it. I shamfered it and put 3 passes on it when I fixed it.
My previous posts have no bearing on this. I jumped the gun and I guess I did not read all of the OP's opening post. I did not see it was a link and also did not see that it was a tube.
A 1/16 to 1/8" gap between the parts would have been cheap insurance that it has 100% penetration. I am not so sure that the inside wall of the ring would not show up in the x-ray as a line like that anyway even if it had 100% pen. It might just be showing the line of the piece of ring inside the tube area.
After studying the x-ray I think it has full penatration as is. The line seen is the round rings edge inside the tube. I think your fine just put another bead around it though.
I think it would be more accurate to determine the required amount of weld and it shouldn't require require 100% penetration with the bevel and then filling the groove up with reinforcement. Even if the arm was solid it shouldn't require welding it as if it was made in one piece.
Last edited by Welder Dave; 07-03-2020 at 04:21 PM.
What you are seeing is the line where the 2 pieces meet that was not chamfered. Other than needing another pass of weld all the way around it will hold fine. If you want 100% penetration you need more chamfer and leave a small gap.
I did give it two passes, but wanted to show the root as I thought that more critical for the discussion. It is a upper control arm for the rear of my Land Rover, one half of the wishbone for the rear solid axle. Material is in my opening post.
Is that a common practice to make those 100% x ray?
Modification laws are much different here in Australia. I require a engineer that is registered with DOT. He works within their cans and can nots. Im not sure if it is their requirement or his. I am meeting him today to go over what is needed. I also had lower control arms welded by a proper welder, they got the same results. I have a sample of one end of the trailing arm and im going to see if he will be happy if I make samples of the upper control arm so we can bend test them (Ill make a jig to use a 20t bottle jack)
I would question the validity of the claim that the pictures show a lack of fusion. To me the lines do not correspond to the pieces and I would think they are the end of the welds. I would think the pictures would be much more clear, they appear out of focus.
The X-Ray pictures I have attached (above) were emailed to me. My Engineer has seen them in person from the test lab and stated they did show more. Pretty much only penetrated as far as my bevels. I didnt ask who needs 100% penetration, because at the end of the day that seemed to be his focus/need. I understand his point as he is signing off on my build so wants to be covered.
To be honest, I just saw them as a fillet weld, and from my little understanding of that, its the penetration at the root of the joint (internal corner on the outside surfaces ) that is important. For example, the cut, etch tests I see of fillet welds on you tube never show penetration to the back side of the material from the internal corner. But im just a carpenter so who knows???? Unfortunately, it was never conveyed to me that 100% penetration was needed, all I was told was the welds on suspension arms needed X-Ray, I assumed that ment looking for quality of weld etc and down to joint, not through to back side.
After going over the construction, prep and procedures I did on the arms, he seems happy with the lower links, but still not quite on the uppers (the picks above). I still have a little material left so have offered the idea of welding up the same as above, making a jig to bolt them into, and then bend testing them with a hydraulic ram in his presence. Hopefully they will pass his needs.
Would have been good if they had clarified they need 100% penetration. Same idea as welding weldolets or threadolets on pipe except there's no hole inside. You need a gap and have to run a root pass completely to the inside of the bevel. It looks like your root pass is quite wide where with a gap would be a narrower weld to get the penetration. You may be able to carefully cut the welds with a zip disc and redo them using a gap. May require 3 passes.
Instead of grinding out the welds and re welding, I wanted to see how strong they were, and if strong enough. I was also concerned about changing the alignment of the arms. So I welded up a test piece, being careful to prep it exactly the same, and weld out with exact same preheat, amps, filler etc. I also built a bend test jig to use a port-a power and 25t cylinder. Well we got to at least 2000 psi on the gauge, which equates to 5.15 tons given the cylinder size, and the jig started to deform badly. Pulled the test arm out and zero weld fail, but the arm had deformed noticeably along with starting to bend the 3/4" grade 8 bolt, the 5/8 bit of flat plate as a big washer/spacer between the arm and jig (I made the opening in the jig bigger than arm to test other factory arms)
So all in all a good result. The engineer just requires the test piece to be X Ray tested to show it only has the same penetration as my main arms.
The pics don't show the deformation as good as in person, but its very noticeable. the eye is at least 3/8" wall thickness btw.
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Originally Posted by TimmyTIG
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