weld the bucket hook correctly

[trombeur]

weld the bucket hook correctly:

Hi, if it's possible, I need some advice.
I would have to weld a hook or a lifting eye to a bucket to be able to attach ropes or chains to lift and move loads safely. clearly I will also have to weld some reinforcement and gusset plates. I was wondering: should I weld it directly or create a slit on the bucket, fit the hook and weld it both internally and externally?
Not knowing the quality of the steel with which the bucket is built, do you think that welding with a basic electrode is sufficient? Can you advise me to preheat the part with the torch and how to adjust the parameters. definitely multi passes, I start with low ampere passes and then use larger electrodes with high parameters, right? thank you

G80 Weld-on Bucket Hook – Vanguard steel Ltd

vanguardsteelvancouver.com

 

[Entropy1]

Depends on the bucket. If the bucket is AR-400 steel (possible) you will want a 400 degree F preheat and use 11018 welding rod (specifically a low-hydrogen rod). Ensure the rod is absolutely dry. If the steel is medium strength (51 ksi) or ordinary strength (36 ksi) you can weld without a preheat. Use an 8018 low hydrogen rod (or 7018 with larger fillet), and make sure the rod is dry.

***Caution*** If the bucket is Komatsu, they use a layered design - e.g. several layers of 1/4" plate, in lieu of a 1" plate. They do this to make the bucket quiet. I'm not sure how many other manufacturers do this. The last thing you want to do is weld a thick hook, with a fat fillet weld, onto 1/4 plate (thinking it's much thicker plate). It will rip off the first time you lift something heavy. In that case you'll want to notch a slot out, and make sure the weld touches each layer.

To achieve preheat, I've seen people build a small charcoal fire on the ground and place the bucket over the fire - then monitor the temperature with a hand-held laser-temp device. Obviously have all your weld prep done prior to preheat. Note: hitting the target preheat will likely cook the grease out of your pin joints. Also - the tempering temperature for some pin-joint bushings (air-hardening tool steels) isn't much higher than 400 degrees F. So don't overheat the bucket. . . . Hold the temperature at 400 degrees F for 1 hour per every inch of thickness (one hour minimum). Don't forget to preheat the hook also (throw it into the kitchen oven while the bucket is heating).

The preheat solves two problems. One, it reduces the chances of carbon-cracking (if your steel is over 0.35% carbon), and it reduces the risk of hydrogen embrittlement cracking - preheat drives out dissolved hydrogen from within the steel's grain structure. Note: this is also why it's so important to dry your rod. With damp rod, the electric arc during welding will literally split the water molecule creating free oxygen & hydrogen - the hydrogen gets pulled into the steel. What makes hydrogen embrittlement cracking so dangerous is that it can happen 24 hours after you're done welding. You can weld it, NDT, and call it good - then the next day when you're not around to hear it crack. . . . . Always preheat and use dry low-hydrogen rod when welding higher strength steels.

 

[Entropy1]

I have successfully used a 500,000 BTU/hr propane torch (harbor freight) to preheat a PC-128 size bucket for welding. I popped out the pins and pulled the bucket. In hindsight I would probably do the charcoal fire option next time. I was constantly fidgeting with the torch, and it took a long time for my weld area to hit 400 degrees F. Note: if the bucket is large, a 500,000 BTU torch will be too small. You don't have to get the entire bucket to 400 degrees - just the area being welded.

The other thing to consider is manipulating (handling) a hot bucket during welding - one advantage for leaving it on the machine. . . .

***Caution*** 6011 is great rod - excellent penetration, very forgiving when welding dirty steel (rust, foundry-oxide layer, some dirt, etc). However 6011 should never be used on AR-400, HY-80, or any other higher strength alloy steel - due to the risk of hydrogen embrittlement cracking (isn't a low-hydrogen rod). It should only be used on ordinary strength low-carbon steel.

Also. One way you can get around the preheat when welding buckets made of higher strength steels, is to use stainless rod (specifically for welding 300 series austenitic stainless steels). I personally don't like this option for several reasons. One, the stainless welds will yield around 35 ksi (2-times less strong than 7018 welds, and 3-times less strong than 11018 welds). Two, when the bucket is exposed to water (basically always), there's a galvanic potential between the stainless and the carbon-steel - where the carbon-steel will sacrifice itself to protect the stainless. The irony being that the stainless doesn't require protection, but it will happily accept it. When wetted with water, the steel will rapidly corrode adjacent to the stainless welds. Only way to prevent this is to keep the welds covered in paint - good luck keeping paint on a bucket. Three, if you ever need to reskin, or otherwise make structural repairs on the bucket, you must completely remove the stainless welds before using the proper low-hydrogen rod (low hydrogen rod is not compatible against stainless steel). Basically, stainless rod "can" be used to limp an old bucket along - without preheat - (fixing cracks, attaching a fresh wear-plate, etc) keeping in mind that the welds are appreciably weaker, and can introduce localized corrosion problems.

***Caution*** do not fall into the trap of using stainless rod to attach your lifting hook without preheat. Stainless results in a low-strength weld.

 

[skyking1]

I welded on the Gunnebo safety hooks on our mini buckets with 7018 rod. I won't put those on again. The open hook in your first picture is worse than nothing at all.
It can come unhooked and you'd no know until it was too late. They also hook onto things that you don't want to. I dig around a lot of utilities and that open hook on the back looks like a disaster in the making.
The best are solid plates with holes and a shackle. It is a positive connection. I put them up pretty high to keep from snagging things.
The 1 ton Gunnebos are curved to fit the bucket better. I ground it a bit more to get a really good fit. It is forged with a fillet bevel so no need to grind that in.


I tucked it up close to the wedge and out of the way. I won't do that again because most of my ground folks would be better off with a simple hole and shackle.





A couple of months later I was setting 1000 lb type 30's under 12' and that 9' ceiling in the background.

 

[trombeur]

E6011 Welding Electrode'?​

Elettrodi basici Eurotrod BN18 (E7018.1) - Eurosald

Elettrodi 7018.1 basici a basso contenuto di Idrogeno. Disponibili da Eurosald a Padova, Vicenza, Treviso, Venezia, Verona, Pordenone, Trento, Udine

www.eurosald.com

Fiat-Hitachi EX 135​

Eurotrod BN18 è un elettrodo basico 7018.1?
I would like to use the basic 7018. with reverse polarity I think it has more penetration the problem is that I am afraid that hydrogen cracks will form during the cooling phase, I don't know the quality of the steel if it were hardox I think it needs preheating with the torch and the joint welded between one pass and another. they advised me to cut the bottom of the bucket with the torch, create a slit, fit the hook and weld it both externally and internally to have more stability and then weld some reinforcement plates to stiffen and make the welded part more tenacious. I have to think about it, I wouldn't want the hook to come off during traction. Thank you for your contribution.

 

[skyking1]

pre and post heat.
Never get under a load no matter how you attach the hook or plate. You are one blown hose from game over man.

 

[Entropy1]

Propane Torch

Amazing deals on this Propane Torch at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Get one of these propane torches (linked above). Heat the inside of the bucket (opposite of your weld). You want to get the steel around 400 degrees F and KEEP it there for 1 hour. Monitor the temp - don't overheat the steel. You'll likely need a full 20-pound propane tank for the job. Note: If there's a structural void in the bucket where you're welding, you'll have to move the torch to the weld-attachment side and heat directly.

While the bucket is preheating, put the 7018 on a cookie sheet (together with the hook being installed) and bake in the oven for 1 hour (minimum) at 400 degrees F. When you take the rod out of the oven (on a non-rainy day) - you've got about 1 hour to use the rod before it should go back into the oven to redry.

The weld area (bucket and hook) should be absolutely clean - no paint, no dirt, no oil, no rust - shine it up well. Any residual oxide (rust or foundry oxide layer still present on the steel) is a weld contaminant and could result in cracked welds.

You probably don't need to worry about accomplishing a post-weld heat soak. Just let it the bucket slowly air-cool after welding. And remember to regrease your pin joints once everything cools down.

Edit: if it's cold outside (winter), you should put the torch back onto the weld (after welding) to enable slow-cooling. The ideal cooldown rate is about 150 degrees per hour. Some people would say it's just an excavator bucket and not a submarine hull - but those people aren't the ones standing adjacent to a hooked excavator load, are they?

Don't be scared of this weld job. Just understand the risks and how to properly mitigate them. Multiple passes are fine with 1/8" rod - to obtain adequate fillet size. Keep it simple.

 

[Entropy1]

Unrelated story for chit-chat -

I purchased a 1970 Cadillac at a towing auction several years ago (I was after the 500 cid engine). Instead of waiting all day to get the car out of the back of the lot, I asked the towing company to use their 12,000 pound capacity forklift to carry it out - which they did.

They got the car where I wanted it, and then dropped it hard about 10 feet to the ground. I was a bit irritated that he set the car down so fast, and I was trying to give him the snake-eye. But he was looking up. Everyone was looking up. So I looked up also . . . .

There was a very narrow collum of hydraulic oil shooting about 80 feet into the air. The hose parted at the base of the mast cylinder. It let go without any warning. The car came down fast. Anyone under the car would've been dead (or wished they were dead).

Be careful around hydraulics. All hoses can eventually fail without warning. Don't be under the load when it happens. . . . .

 

[skyking1]

Funny failure for me, I was working on a bridge job next to Amtrak's high speed line heading up the valley .
I'm swinging around with a full bucket load out of ways, and the hose fails for the stick. It shoots this fan of fine mist out 50 ft, just as Amtrak goes by at 70.
I'm sure I misted his window!

 

[Entropy1]

Excavators are particularly dangerous due to very high hydraulic operating pressures.

My Komatsu runs at just over 5000 psig. I blew a hose on the main boom and thought someone fired a shotgun next to me.

Same thing skyking experienced - no liquid oil spay - just a mist (a very big mist). Thankfully the bucket was directly over the half-loaded bed of my 5-yard dump. The boom/bucket only dropped a few feet and didn't damage the truck - but it dropped like it was free-falling - no warning whatsoever.

 

[Willie B]

I like the Swedish hook, but worry the latch mechanism is easily damaged. To be absolutely sure, I'd weld it to a piece of plate steel first.
Then I'd preheat to 400 degrees F & use either dual shield, or 7018 rod to weld to bucket.

A bucket is a inflexible workpiece. It ain't going to move much as weld cools & contracts. If weld doesn't have sufficient ductility, it'll pull the weld away from the bucket. A 7018 filler will "give" a little bit as it cools to reduce internal stress. Be aware a good 7018 weld has 70,000 PSI tensile strength.

 

[digger doug]

A 7018 filler will "give" a little bit as it cools to reduce internal stress. Be aware a good 7018 weld has 70,000 PSI tensile strength.

Yup ^^^ and my neighbor weld shop that did allot of excavator stick repair welds
always used 7018 for that reason, as well as the 30% elongation.

 

[skyking1]

I like the Swedish hook, but worry the latch mechanism is easily damaged. To be absolutely sure, I'd weld it to a piece of plate steel first.
Then I'd preheat to 400 degrees F & use either dual shield, or 7018 rod to weld to bucket.

A bucket is a inflexible workpiece. It ain't going to move much as weld cools & contracts. If weld doesn't have sufficient ductility, it'll pull the weld away from the bucket. A 7018 filler will "give" a little bit as it cools to reduce internal stress. Be aware a good 7018 weld has 70,000 PSI tensile strength.

Willie, that's exactly why I won't do the gunnebo again. I already damaged one with the other bucket picking it up and moving it. It got stuck in there like it had eyeballs.

 

[Welder Dave]

Thousands of bucket hooks have been welded with 7018 with no special prep at all. Don't use 6011. If there's a name on the bucket you should be able to find out what material it's made from. Some buckets may be made with AR400 but not necessarily all of the bucket, maybe just the cutting edge, wear bars or side cutters. A propane weed burner shouldn't take too long to preheat to 300-400 deg's. Warmed welding rods are sufficient. Again thousands of buckets have been welded with low hydrogen rods right out of the package or even an already opened package. Being dry is the important factor. It's also not uncommon for some welders to ground out the rod on the plate for a couple seconds to heat it up and remove any moisture. If you can't find out what material the bucket it is, try center punching it or grinding a bit and comparing the sparks to mild steel sparks. If it center punches easily it's probably nothing exotic. For a little extra margin of strength use a rod like 8018 which is actually 8018C-3. The C3 means it has 1% nickel added that gives extra toughness. If the bucket is T1 steel or AR400 then use 11018. Don't use 11018 if the bucket is a lower grade steel. It could crack. Not very common to have to cut a slot and weld from the inside. Pics. of the bucket and the size of the machine would be a big help. If it's on mini/midi excavator it won't be anything fancy. If it's on 50 ton excavator, then it's a lot more critical.

 

[skyking1]

Yes, I've never seen an entire bucket made out of AR. It's always just wear plates.
You knock them around long enough on the job and see the slivers that come off of the common parts of the bucket you know it's not wear plate.
Edit:
I just rolled in from a job site and jumped up on the step and took a picture of my 3-ft bucket. You can see the slivers I'm talking about. AR is not going to give up slivers like that, t1 is not going to give up slivers like that.

 

[Entropy1]

Well this post has come full-circle. I should've just stuck with the first paragraph within my first post and omitted everything else. . . .

The only other thing of value to add (not mentioned yet) would be to make sure the hook is intended to be weld-attached. Example: don't try to weld-attach a 4150 forged & heat-treated rigging hook. The best case is you'll anneal the hook within the heat affected zone. Worst case is you'll form martensite and crack the base material. Thus ensure the hook is suitable for welding.

 

[skyking1]

@Willie B here's my damaged gunnebo. Even though it is welded way up high I was reaching out with the mini and I'll be dangnabit if that cutting edge on the cleanup bucket saw it's way in there and the resulting leverage pried it open.
The only good news is I rarely use that 18". I just got 3 hooks when I got them.

 

[terex herder]

I'm with skyking. Never weld an open hook on a bucket. Use an eye and shackle. I've heard of to many times someone rolled the bucket to far in search of a little more lift and the chain slid out of the hook. Same thing as throwing a chain over a tooth. Just don't do it, ever.

 

[skyking1]

Oh and the snagging thing. They will grab whatever it is you don't want.
I was on a sewer main job in town running loader, and all of a sudden things came to a halt and the CATV line at the intersection was dancing. You know the big thick monster cable.
FYI if you want to pick heavy structures with a big hoe, weld a hook up on the end of the boom. It is a lifting beast that way.
The 450 had a nice hook up there off to one side near the end, a safety latch hook.
He managed to click that big ass cable into that safety hook!!
The pipe guys had to take the ladder out of the hole, and climb on the boom and pry that hook open while they extricated that cable. Quick reflexes on the operator's part and no harm done.
I successfully found and worked under and around a residential phone service only to break it with the hook on the back of the bucket when I was all done. It happens.

 

[Welder Dave]

I've seen larger hoes where they take the bucket off and have a lifting apparatus/hook to replace the bucket. That's the safest way when you're doing heavy lifts. Maybe it's an OHSA requirement?