M7040 LA1153 cracking factory welds, loader

[fast*st]

Have th LA1153 loader on an M7040, 3600 hours and the right side loader mount bracket is cracked all to heck.

The factory bevels that 3/4 thick plate but the weld never penetrated the bevel for more than half the circle. Can split the layers with a pick after grinding it down. Lots and lots of grinding to a clean root then 7018 stick welded.

 

[SidecarFlip]

My experience with the Welding on Kubota stuff is just the opposite. Excellent penetration and good under cut, recently rebuilt an excavation bucket for a customer and had a helluva time gouging the welds off and resorted to a thin kerf cut off wheel to undercut them.

I would never stick weld them myself, bit then I own an ESAB pulse MIG. MIG is the only way to go in that situation where the weld is not in a flat plane. I agree the weld appears cracked in the root but not being there to look at it, not sure if i9t's totally failure prone.

Only time I resort to stick welding now is in the field, using my gas driven welder. In the shop, always pulsed MIG or TIG on alloys.

 

[retired farmer]

Vibration is an enemy of welding. After 3600 hrs. of operation it's possible that was the main cause. However it does appear to be a little light on penetration.

7018 is a good rod for mild steel

 

[SidecarFlip]

Vibration is an enemy of welding. After 3600 hrs. of operation it's possible that was the main cause. However it does appear to be a little light on penetration.

7018 is a good rod for mild steel

I agree. 36K is a lot of imposed stress. Still would MIG it, not SMAW it.

 

[GeoHorn]

Have th LA1153 loader on an M7040, 3600 hours and the right side loader mount bracket is cracked all to heck.

The factory bevels that 3/4 thick plate but the weld never penetrated the bevel for more than half the circle. Can split the layers with a pick after grinding it down. Lots and lots of grinding to a clean root then 7018 stick welded.

7018 is a good rod and stick welding it was also fine, IMO. (Lot of ww2 ships, dozers, and tanks built with sticks and did just fine.)

 

[fast*st]

Vibration is an enemy of welding. After 3600 hrs. of operation it's possible that was the main cause. However it does appear to be a little light on penetration.

7018 is a good rod for mild steel

Normally Id not fret too much but this weld had a lot of stops and starts. Gouging it out with a grinder I was surprised to see the weld area turning blue. We knew we had a problem, cleaning the area when carb cleaner squirted out the opposite side. Chased all the cracks back but the welding dust was gathering on the edge like a magnaflux test so there may be others in the future. I really enjoy having the dye penetrant test available. Oxy torch is the fastest way to de-paint a weld area short of a big sandblaster.

 

[NHSleddog]

7018 is a good rod and stick welding it was also fine, IMO. (Lot of ww2 ships, dozers, and tanks built with sticks and did just fine.)

Most guys that say the MIG is better, don't have very good welding skills. MIG/TIG and stick all have their place. Ask any pro welder.

MIG and stick both have the disadvantage of always pushing material. They can't just "heat/fuse" With my TIG torch you can literally see the tig penetrate into the metal without adding anything.

In my younger years I did most of the welding at my fathers company (80% aluminum then stainless and then everything else). Literally miles of aluminum bead. Yes, I could have done MOST of it easier with the MIG, but not better, TIG was the correct answer most of the time.

 

[GeoHorn]

Gas and TIG is what we use in 99% of all aircraft welding.

 

[fast*st]

Gas and TIG is what we use in 99% of all aircraft welding.

Both of those have applications far and wide. I'm super comfortable with stick myself especially for heavier welds.

 

[Yooper]

Tig welding produces the best weld quality because what you see is what you get. Any issues with weld integrity and you know it immediately. The reason tig isn’t used more is that it is slow.

I prefer mig over stick because of the convenience of not having to stop and put a new rod in.

Welding your loader with 7018 rod is a good choice. The main issue is getting the heat right. Too cold and it will break. Too hot and it will undercut creating stress risers which will break.

 

[fast*st]

Tig welding produces the best weld quality because what you see is what you get. Any issues with weld integrity and you know it immediately. The reason tig isn’t used more is that it is slow.

I prefer mig over stick because of the convenience of not having to stop and put a new rod in.

Welding your loader with 7018 rod is a good choice. The main issue is getting the heat right. Too cold and it will break. Too hot and it will undercut creating stress risers which will break.

Oh heat was good, five layers of beads. I feel I have good puddle visibility and can see any potential issues, pause, needle gun and a whip of the grinder, spark it up again, mig can be so fast that you might miss an issue. The factory had a nice bevel but zero bonding to the plate and a decent attachment to the tube

 

[SidecarFlip]

Not looking at the weld root, only the top of the weld bead. I'd say the welder had the MIG nozzle at the incorrect angle and the amperage not high enough for the gauge of material and should have more closely reviewed his welds. Not withstanding, with that many hours (and stress) on the loader components, the weld, if faulty in the root, would have failed long ago.

 

[SidecarFlip]

Gas and TIG is what we use in 99% of all aircraft welding.

If you can gas weld you can TIG weld because both are 2 handed. One hand is the heat source flame or tung arc and the other is the filler rod. Only difference is with TIG, you MUST keep the filler rod in the gas envelope. With gas welding it's not all that important.

Way back when, All I welded with was coat hangers (for filler rod) and a gas axe so the transition to TIG was natural for me and I prefer TIG for the ability to weld exotic alloys. Gas and TIG welding is like playing a piano, both hands need to be coordinated. MIG and SMAW is one handed. I refer to my ESAB pulsed MIG as my 'glue gun' The nice thing about MIG versus SMAW is 90% less spatter and cleanup. SMAW is inherently messy and makes a mess, no matter what you weld.

I stck a pile of stuff together with coat hangers, from car frames to implements, those were the days. You can TIG with a SMAW machine but the arc starts are contact only so weld inclusion is always an issue. My gas drive will TIG weld (contact start) but I prefer a high frequency non contact start because it don't impact the tung ball at the tip and there is no weld inclusion which isn't acceptable in aircraft, aerospace or nuclear apps. You cannot certify any weld with inclusions.

When welding mild steel in the shop I always use the pulsed MIG which is fast and renders a weld similar to a TIG weld unless you are doing spray arc, then the weld appearance will be flat and not the 'stacked dime' look so common with TIG. In fact, if I'm using spray arc, I disable the pulse feature on the welder as it's of no use. Only time I use my engine drive is when welding outside where a gas shielding won't work and then it's low hydrogen rod with a properly prepped joint and lots of cleanup after the fact. I do a ton of welding btw.

 

[Yooper]

Oh heat was good, five layers of beads. I feel I have good puddle visibility and can see any potential issues, pause, needle gun and a whip of the grinder, spark it up again, mig can be so fast that you might miss an issue. The factory had a nice bevel but zero bonding to the plate and a decent attachment to the tube

Sounds like you have a good handle on it!

 

[lugbolt]

the factory welds them continuous, in a rotating positioner, via robotic GMAW process

with that said, I have not specifically see a loader frame come out with any issues, but I have seen a couple backhoe issues; one was actually marked "porosity" on the boom, with an arrow pointing toward the upper (stick) pin mounts. I saw nothing wrong physically, but Kubota Replaced that one. And I seen one that had poor weld quality on the lower boom mount, also replaced but against the wish of the manager. Got my butt chewed but it was worth it.

One of many reasons I left. I called Mr. Customer personally and explained it to him and he basically said heck yes, keep it as long as you need to in order to fix it!!

He wasn't in that much of a hurry, it was my assumption that it was just the end of the month when the managers get jittery about getting everything closed out. I don't work that way, never have, never will...fire me if you please but I will never EVER put profit ahead of safety or customer service no matter what I do for work.

 

[fast*st]

the factory welds them continuous, in a rotating positioner, via robotic GMAW process

Well if that's true, that robot needs to be fired and crushed. All the welds on this piece are awful with stops and starts and really poor fusion. Really looks like a brand new welder on his first day after he left the accounting department.

 

[SidecarFlip]

Poop happens... Happened to you I guess....

 

[SidecarFlip]

Most guys that say the MIG is better, don't have very good welding skills. MIG/TIG and stick all have their place. Ask any pro welder.

MIG and stick both have the disadvantage of always pushing material. They can't just "heat/fuse" With my TIG torch you can literally see the tig penetrate into the metal without adding anything.

In my younger years I did most of the welding at my fathers company (80% aluminum then stainless and then everything else). Literally miles of aluminum bead. Yes, I could have done MOST of it easier with the MIG, but not better, TIG was the correct answer most of the time.

Not technically correct. With either process you can either push or pull though it's easier with a MIG gun than a rod and weld position has a lot to do with pushing or pulling as well as finished weld appearance.

 

[NHSleddog]

Not technically correct. With either process you can either push or pull though it's easier with a MIG gun than a rod and weld position has a lot to do with pushing or pulling as well as finished weld appearance.

YES it is very technically correct. There is no arc without burning material. Is that easy enough to understand? How do you establish an arc with either technology without burning/pushing material? Explain that "technically" if you can.

FACT: MIG and stick both have the disadvantage of always pushing material.

Being as ancient as you are I would think you were there as each was invented. I only have about 30 years experience welding (so decades less than you) however I knew the difference in the technologies the first week.

 

[SidecarFlip]

YES it is very technically correct. There is no arc without burning material. Is that easy enough to understand? How do you establish an arc with either technology without burning/pushing material? Explain that "technically" if you can.

FACT: MIG and stick both have the disadvantage of always pushing material.

Being as ancient as you are I would think you were there as each was invented. I only have about 30 years experience welding (so decades less than you) however I knew the difference in the technologies the first week.

Whatever. Not gonna kibbitz with you. Not interested at all. I don't usually comment to your posts just for that reason.