Why Did This Weld Fail

[jonyyuma]

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.

I like your repair idea the best, seems like some of the stronger ones are done like that?a

 

[weldermike]

If he can afford to lose an inch or so of throw out of the cylender. Depends on how much it extends.

 

[cdaigle430]

I am interested in hearing opinions on why this weld failed from the experienced welders. I hope the pictures have enough detail to allow a diagnose. If not, let me know and I can snap a few more pictures.

***EDIT***
Thanks for all the responses and advice. To answer a few question brought out in the thread:

This is a side link for a CAT 1 three point.
It had just a few hours of use before it failed using a Bush Hog 5 foot box blade.
It was fabricated state side by a hydraulic side link provider.
The clevis mounts at about a 14 degree angle to the ram.
No, I am not going to fix this, I will either return for refund or take to a local welding shop for repair.

What I am looking for now and from what I'm reading in the thread is this is fixable once the ram is ground to an angle so that there is 100% butt made between the clevis and the rod.

Thanks for all your input, I am not that knowledgeable on welding.

Looks like the the weld itself was done improperly. The other thing I noticed is the two pieces were not proprly prepared-need a v channel all around and the two pieces need to be butt together for maximum penetration.

 

[weldermike]

And was never heat treated prior to welding. The end of the ram would have been blue. Think it was poor craftmanship from the factory, topped off with a just as poor fix. If fixed correctly, it should last forever.

 

[Hooked_on_HP]

Yes there are problems with the weld. The main problem is with the design of the side link. The OP stated that the clevis was welded on at a 14deg angle. A hyd cyl is designed to push or pull straight. With the clevice being at an angle it is flexing at the weakest point. In this case it was the weld. If the weld hadn't broke the shaft of the cyl. would have eventually. It also put side load on the packing of the cyl causing it to fail prematurly. Have you ever seen a hyd. cyl designed that way.
Bill

 

[Brad_Blazer]

The original weld was just too small. Look at the cross-sectional area of the break compared to everything else. It didn't matter how good the bond was, there simply wasn't enough material, not to mention it didn't even cover the entire circumference. More bevel, more penetration, more and/or bigger passes would all be in the direction of goodness.

The one time I did it, it looked like this:

I had to shorten the extended rods on the 2 hydraulic cylinders I got for the stabilizers. I didn't want to ruin the blade on my big band saw so I used the hand-held. I started out by marking the cut circle with a wrapped sheet of paper and extra fine sharpie.


The band saw wouldn't touch the hard chrome so I used an air cutoff tool to cut a groove all the way around the circle.

The cut ends came out pretty good.

I beveled the edges and used a bent piece of welding rod as a spacer. The space helps prevent a sharp notch at the root.

Set the SA200 on about 140 amps (DC). I decided to try out the 1/8" 7018AC rods that came in a variety pack in a screw top plastic rod can. Did a test weld to check the settings and then had at the rod end.

This is a good angle on an otherwise not too purdy weld. It's tough to make it look good with a series of short welds on a relatively small diameter.

Here's the second cylinder. This time I used 3/32 6011 for the root pass. It made a smaller weld and should be tougher in the notch. The rest is still 7018. That blue thing is an old WET T-SHIRT. (I have no idea what is up with that font. :)

 

[Brad_Blazer]

Yes there are problems with the weld. The main problem is with the design of the side link. The OP stated that the clevis was welded on at a 14deg angle. A hyd cyl is designed to push or pull straight. With the clevice being at an angle it is flexing at the weakest point. In this case it was the weld. If the weld hadn't broke the shaft of the cyl. would have eventually. It also put side load on the packing of the cyl causing it to fail prematurly. Have you ever seen a hyd. cyl designed that way.
Bill

The angled clevis is not ideal but it may be required for clearance due to the angle of the drag link or lift arm as a compromise vs. an even longer clevis which would reduce the space available for the cylinder. Since typical loading would be in tension, the buckling failure mode should be rare. I am guessing that the cylinder seals can tolerate that much offset in the load.

 

[JB4310]

It was just a bad fab job, any one of us amateur welders could do a better job, regardless of design. OP says it was domestic made but probably just assembled here from outsourced parts.

Anyway, throw a weld on there like brad shows in his pics and that thing would be around till the end of time, especially in a cat 1 tilt application.

My repair would be simple, not as involved as others but I think it would hold up to it's application just fine.
Clean the parts up with grinder, put some bevel on the rod, tack opposite sides and single pass with 1/8" 7018 @ 140-150 amps. That's it, it would have to do since that's about all I'm capable of

JB

 

[weldermike]

I agree, its a ten minute fix! And will last forever, I have a little miller maxstar and a little yamaha generator with some dewalt cordless tools just for doing field repairs, they are a life saver.

 

[deereman75]

I think that a hack like myself could fix it better. I would tack and do a root pass with 6011, and do a cover pass with 7018ac. I bet my weld would be better then the one already on there (but not my much) and it would be all the way around. I am sure most people on here are much better welders then me, so take my advise with a grain of salt.