Why Did This Weld Fail

[deereman75]

that pic's worthy of child endangerment charges! WHAT THE HE## ARE YOU THINKING??? MikeD74t[/QUOTE]

That's a little harsh. He posts a lot of pics that ore not his personal stuff. You don't even know if that was his child. Even if it was, I am sure the kid did not burn 5lbs of rods. Probably just made some sparks then went on to something else.[/QUOTE]

I have to agree with that. All but 4 of the pics I have posted were not mine. When I saw that picture, I just assumed it was a pic he found on the internet, and posted for us to get a laugh. I have done that a few times.

 

[rjmack]

if you look at the first picture, the ram doesn't appear to have been welded exactly in the center of the clevis.

i don't think the weld was run in cold, just a poor joint design coupled with the wrong rod for the first pass.

i don't know that you should use 6010 or 6011 on that type of material... probably not.

wire feeder with er70s might have been a better choice.

also, the cross section where it broke is very small... all things being equal, more si's = more p's... more p's = more strong. for the most part (heat and material compatibility issues aside), it's all about psi.

i agree with the slow cooling thing and it is probably better to take the cyl apart first.

btw, assembly does look kind of cheap, in that the ram is not threaded on the end.

 

[JB4310]

that pic's worthy of child endangerment charges! WHAT THE HE## ARE YOU THINKING??? MikeD74t[/quote]

That's a little harsh. He posts a lot of pics that ore not his personal stuff. You don't even know if that was his child. Even if it was, I am sure the kid did not burn 5lbs of rods. Probably just made some sparks then went on to something else.[/quote]

Oh please, I hope he didn't think that was my kid! That would be stupidly dangerous to a child. It was supposed to be a graphic reference to child production line. Though it doesn't look like a production, so I guess I can see where someone might think it was my one pic.
But the picture is so outrageous, (that's why I used it) I doubt many would come to that conclusion.

Sorry for the confusion.

I must disagree.

To get a professional weldor to re-weld that without making a design change you would have to find one that has a sign above his door that reads IDIOT WELDING SHOP.

What big change could there be? it's a clevis welded to the end of a rod, like has been the case since there were hydraulic cylinders.

JB

 

[CharlieTR]

I think there was not enough surface area welded for the forces used on that piece. If you are going to fix it, I think you should drill as big a hole in that yoke as possible and weld in that hole, as well as around the shaft.

 

[F250DSLPWR]

Good fit up of the two pieces are extreemly important in high weld stress areas. Work to get the parts to fit together as best as possible. Bevel the edge to allow full penetration. Be sure to clean off any paint, oil or grease. Any contaminates will make the weld porus and not strong. Looking at your weld there was not good penetration and the weld was not hot enough. I had a similar weld break on a clevis holding a hay bale spear onto a FEL bucket. Lucky I didn't get hurt when it broke. This was a factory weld that broke not something I built or welded. It is fixed now, the right way.

When you weld this back together, be sure to extend the cylinder rod and then cover it with tape. Extending the rod will help protect the cylinder seal. Cover the rod with tape so that the weld splatter will not ruin the rod and seal.

If you are worried about it breaking again. Drill and tap a bolt hole in the clevis and also one in the rod end (may be difficult) cut threads into the rod end, fasten it with both a bold and a weld.

 

[RoyJackson]

What big change could there be? it's a clevis welded to the end of a rod, like has been the case since there were hydraulic cylinders.

JB

Sometimes the costs of manufacturing result in design compromises.
I agree with SandburRanch that a redesign of the cylinder end could allow a better joint design, but that would increase production costs (and end user prices) considerably.
In the aerospace industry, that cylinder end would probably be machined to better fit the clevis...or the whole assembly may be machined. Be pretty expensive though.

BTW, for all we know, this may have been a poorly executed repair weld.

 

[SandburRanch]

What big change could there be? it's a clevis welded to the end of a rod, like has been the case since there were hydraulic cylinders.

JB

For starters change the clevis design to provide a hole for the rod to go through and weld on both sides of the clevis. And to take it a step farther bevel both sides of the hole.

The people that built that just hoped it would hold until the warranty ran out.

 

[JB4310]

For starters change the clevis design to provide a hole for the rod to go through and weld on both sides of the clevis. And to take it a step farther bevel both sides of the hole.

The people that built that just hoped it would hold until the warranty ran out.

Well I agree with you and Roy it could be designed better, but if done right the first time, I don't think it's necessary. It's a HTL (looks like) that's rated for a few thousand pounds, holding an implement on the back of a compact tractor. Probably cost ~$150.00
Butt welds are holding our world together

JB

 

[Shield Arc]

Best weldors in the world don't have a chance when it comes to bad design and bad joint prep.

Hind sight is always 20/20, I would have ground a bevel on the shaft, and put three passes on it, and would have much rather, (as already mentioned) use Tig.

 

[weldermike]

I would put back both pieces back on machine,check, and bevel angle corectly, extend cylender to protect from heat, and tack together. Remove cylender, wrap wet rag around the base to protect seal, pre heat with torch, and I would lay a slow, heavy weave pass, on the hot side with a 7018, cover with a welding blanket let cool slow and should be fine. If have any any anti spatter nozzle gel, smear up the ram to protect from spatter.