Fixing Cracks in a Backhoe - Big ! with pics

[thingy]

John,reread your last post again,,still don't know what to tell you other than what I already did,,,, If it was mine,,I would use 7018,,preheat it up to maybe 300 degrees,,shank included,and wouldn't let each weld cool before finishing it,,maybe try and do it in a heated shop or a warm day too,,,,its hard to tell what all this stuff is made of,,,you don't want fast cooling,,,so if whole bucket is warmed up good before starting that would help,,,if you use 7018,,you need to get you some fresh rods that are sealed,,and unless you got a hotrod box,,,would get the smallest pack you can,,,once those lowhydrogen rods are out of box and not in a hot box,,they pick up mosture in a matter of hours,,,,thingy

 

[JimR]

John, You should be able to use standard rod to weld the teeth on. I made a toothbar a few years ago using JD shanks with removable teeth. I just welded them on using my stick welder. I don't even know what rod I used. I think it was 6013. I destroyed the tooth bar but never lost a tooth. My next bar was much heavier. You can look on Ebay as there have been some for sale on there lately.

 

[Egon]

When I bought a replacement cutting edge for my bucket I was told to use a specific rod but can't remember.

Another fellow did the welding. Haven't a clue as to what he used.

 

[thingy]

Oh,forgot to add for the curious,,,would weld that 7018 UPHILL,,,,[it don't work to good down],,,see,,there is a time and place for everything!
But if you knew what you was actually welding,,still would probably go with 7018,,,but there is 8018,,be hard to get a small pack of 8018 though,,bet if you cleaned and preheated,GOOD,kept bucket in a warm place,,,,you would be fine,,,,course this is assuming the weld is nice and,,,,tidy?,,,probably need multi pass stringers,,,using 1/8 rod,dc,,turned up a little? thingy [forgot to add,,thats the way I woulda welded the whole thing]

 

[john_bud]

Uh-oh,

I can see this calls for drastic measures! I'm gonna have to dig out the welding text book I got from the Tech school class. I seem to remember that if you just use a normal weld rod in the 60 or 70 series, the high carbon steel will crack at the edge of the weld as soon as it cools. And with all that mass, it cools fast. I want to avoid that so my welds are nice and strong. Would hate to have to show off bad quality! Will post back If I can find anything out.

jb

 

[thingy]

Ok John,now that it appears we can't come up with a better idea than to weld it with 7018 low hy,,,let me throw this out at ya,,,,,mig is a low hy process,,,70S wire is got the same tensile strength as e-7018,,you are using 70S wire right? they got 80 S wire too?,,,what I'm getting at is,,,,why not weld it with the mig?
We don't know what it is for sure,I'm betting even if it is a higher carbon steel,,the 7018 would cover it..
preheating,and keeping it preheated is the thing,,and,,slow cooling.
And,if you ain't that good with stick......
Like I said,,woulda welded the whole thing with stick or flux core....mig is not good for thick stuff,short circuiting mig in any case,,,but,,it is doable,,if you know what your doing,,it appears you now have alotta sperience with mig,,,just something to think about,,,,would still try and talk to equpement places maybe if I was you,,,but you gotta also remember,,they might not know as much about it as you,,[unless you've seen them work],,,they might know where mild steel and a high strength hardened steel seperate though,,,thingy

 

[thingy]

John,just read your last post,,,,number one,,you want to use 70 at least,[you was using 70 on the boom,,right?],,,number two,,,you are right,,the main thing in welding these hardened steels is preheat,interpass temp and post heat,,,if it is a hardened steel,,if not,,its all good,,thingy

 

[thingy]

John,do you know on some of this real high carbon nickle chrome type steels,,they mointer the heat to the 10's of degrees,,they hook up theromocouples to it to keep it at a cetain temp while welding,and after welding they wrap it up and heat it to 7-800 degrees or more and hold it there for hours sometimes,,and they can only bring the temp up so many hundred degrees an hour and down so many degrees an hour,,they record the heat on charts,heats the key,,,,But,,,like I said,,,would weld it with 7018,,preheat to about 300,,,heat hole bucket up somewhat,so's you don't have a big heat sink,,,and say,,,thats about as good as it gets,,but thats just me,,Another thought,,sometimes its better to go middle of the road on filler metal,,,harder is generally more brittle espiecally if you don't heat treat right,,,now you said what,,ni rod would that be nickle rod? When I hear that,,I think of inconel type rod,,good for hard surfacing maybe,,,but,,,,,thingy

 

[3RRL]

John,
If I were doing it I'd use good old 6011 rod. I'd strip weld it several place (little small welds) until the bucket starts to heat up and then go with longer welds. I think the 6011 with it's penetration will be just the ticket for any kind of steel especially teeth to the bucket edge where you'll find material thickness difference. Knock the slag off each strip before tying them together.
Your project is looking really good. It is a big one.

 

[thingy]

6011,,,might as well use 6010,[which,is a better rod than 6011,,,but],,,,no,,,when you weld on equipement,,you use 70,,,and you use a lowhydrogen type filler,,,you don't use 6011 or 6010,,,unless,,thats all you got and you're just patching something up,[thats just industry norm] but guess we all don't know that,,,,,john is rebuilding this hoe,, A talk with a john deere place,[heavy equipement type place],,or case place,,or catapiller place,,may shead some light,,but I doubt it in this case,,,, still stick with what I said,,thingy