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Posted by bitternut on July 3, 2007, 9:38 pm
Please log in for more thread options The loader is on my neighbors tractor and is a 4000 series tractor that is
only three or four years old. He bought it used and he has no idea how the
loader got the cracked weld. I have not seen the bad weld yet so I have no
idea what it looks like. I don't live there but own property next to his and
he asked me to weld it up for him. I will have to haul my welder there so
maybe I will wait until I get a look at the crack. I have a Dynasty 200DX as
well as the wire welder so I could also use tig or stick. I will see if I
can find out what kind of steel they use for manufacture.
As for drilling a small hole at each end of the crack I have done that many
times and never had a repeat failure. I was shown that over 45 years ago
when I was an apprentice and it always seemed to work.
>>> "bitternut" wrote:
>>>I need to repair a cracked weld on one of the arms of a recent vintage
>>>John Deere loader. I plan on drilling a small hole at each end of the
>>>crack and grinding a v in the crack. I would then weld it up with a HH
>>>175 and .035 flux core wire. Does this sound reasonable or should it be
>>>repaired with another method of welding?
>>>
>
> If you could post a photo of the crack and the surrounding structure, it
> would be very helpful and would certainly improve the quality of the
> advice for repair.
>
> For a recent machine I would contact JD with the model and serial number
> and request guidance as to the material used in construction and for
> repair suggestions. This failure may be a known problem and there could
> be a secret warranty or service letter to deal with the issue. Ask your
> dealer AND send the factory an email and hope.
>
> If this is just a failed factory filet weld then the repair is fairly
> simple, just completely remove the faulty weld (ArcAir and/or grinder) and
> redo. However if the actual plate material has cracked then the repair
> is a lot more difficult. The following comments are general suggestions
> for cracks in the plate material or in butt welds.
>
>> Sounds good to me.
>
> Not to me, YMMV.
>
>> I don't use flux core very much, but the times I have used it - things
>> came out ok.
>>
>> I just rest a little better at night when I use a DC+ E6011 arc weld.
>
> IMHO this is a job for low hydrogen, minumum E7018 and maybe E8018 or
> E11018 depending on the age of the loader and the material it is made of,
> the newer machines are much more likely to be constructed from high
> tensile or T1 (E11018) material but this is also dependent on the
> particular model, YMMV. The E7018 is more ductile but the higher tensile
> rods have good notch toughness and can be superior for low temperature
> impact and shock loads. I suspect that the material is pretty thin and
> suspect/suggest 3/32" rod size both for increased control and to limit the
> heat input. Preheat with a torch both as a favor to the steel and to
> ensure there is no moisture or oil residue in the crack or weld area.
> Post heat to allow slow cooling.
>
>> Your technique (drilling a hole at each end of the crack and grinding a
>> groove for the filler) is perfect.
>
> Why would you want to drill a hole? This is steel not glass or plastic and
> IMHO repair should be a 100% penetration root pass in a properly prepared
> groove. The repair should begin and end in sound uncracked steel as any
> crack (or undercut) left in the root will act as both a notch and a stress
> raiser. The secret is in the root and it should be as close to perfect as
> possible. Many people like to use straight polarity (for the lowhydrogen
> root only) to control excessive burn through. Exx10 or 11 is preferable
> to a poorly made lowhydrogen root and you will likely be grinding most of
> it away preparing the groove for the second pass..
>
>> If you doubt the strength of your welds at all and the vintage JD is not
>> a show tractor, after you finish with your FCAW, you could finish
>> everything off by putting a piece of 1/4-inch plate over the area. It
>> would be like a big band-aide. Ugly? Yes, but splash a little green JD
>> paint on there, and in another 2 years, you won't even know it is there
>> anymore!
>
> The problem with 'fish plates' or other reinforcement (including welds
> that are excessively high or proud of the surface) is that they make that
> area stiffer than the surrounding structure and just chase the stress to a
> new location or cause a crack at the toe of the repair. There should be
> NO undercut in the final pass and the weld must be free of any slag
> inclusions, a small angle grinder with a very thin grinding disk works
> well for both groove prep and to clean between passes. Keep the groove as
> narrow as possible. I like to save additional reinforcement plates for
> use later if the initial repair fails and there are several tricks that
> can help to reduce their tendency to decrease flexibility and concentrate
> stress. Fish plates are not a substitute for a proper repair.
>
> I do not know the value of this machine but if it is a larger or more
> valuable unit then there is good economic reason to do the repair properly
> and it may be worthwhile to hire a professional, YMMV
> Good luck.
>
>
>
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>Deere loader. I plan on drilling a small hole at each end of the crack and
>grinding a v in the crack. I would then weld it up with a HH 175 and .035
>flux core wire. Does this sound reasonable or should it be repaired with
>another method of welding?
>