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Discussion Starter #1
Sorry if there is already an ansewer, but we need to do some significant reinforcement on our 1300L frames like what is done at the factory on the U1650's and the U1350's as well as the early 2450 6x6's.

Does anyone know for a fact that the frames have been stress relieved by heat or other methods and or then hardend from the factory???
staight framed machines for sure have been, but the older Unimogs seem realitively soft and very weldable.
I'll put up photos when I figure out how to do it again...

Thanks in advance everyone
 

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Unimog S 404.114
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No modifications may be made to the chassis (MB scope of delivery) without the approval of Daimler AG. In the case of the following modifications, the
TE/OVG-B Equipment Team of Daimler AG must be consulted in advance:
• Shortening or lengthening of the chassis overhang
• Drilling and welding on the chassis frame or on the axles

source:
https://bb-portal.mercedes-benz.com/techdaten/mbasdata/prd/ar_kat/DE/en/ARL_unimog_Teil_A_en.pdf

more:

https://bb-portal.mercedes-benz.com/portal/ar_unimog.html?&no_cache=1&L=

gut mog! justus.
 

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404.1 ragtop Doka
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I don't have any idea.
But, the local builders (Baja racers) seem to agree that chrome moly and such have too many fracture issues and have gone back to mild steel. They consider the weight differences to be minor compared to enduring the race without troubles.
 

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2015 Rubicon Unlimited (Let the shame be upon me!)
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A lot of very nice Unimog...
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Discussion Starter #5
I know we did get some ansewers, but nothing conclusive or I think realavant to the U1300l I believe. Unless I just missed it.
We are looking at replicating the U1350 frame reinforcment for our LandArk BOV project.
 

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To further this along, according to Hoesch-Hohenlimburg/ThyssenKrupp

E460 TM & E500 TM are compatible under DIN EN 10 149-2, 1995 to S460MC & S500MC and carry Material Numbers 1.0982 & 1.0984.

Hoesch calls them HSM460 & HSM500.

These E class steels do not have a direct equivalent in ASME standards however any reputable provider should be able to source the right materials.

Crossing the welding standard DIN 1913 E5154 B10 gives us a welding electrode number of E7018, Low Hydrogen.

It reads to me that as long as your steel & rod is compatible and your geometry conforms; do what you feel you have to.
 

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'76 1300L,HE351CW,H15P Winches,Konis,Hydraulics,All Gears,10mm Plungers,Aftercooler,Lots of Littles
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The frame should be welded per the book.

That means, pre and post heat, monitoring your interpass temperatures and controlling your weld parameters to stay in the right transfer mode (assuming GMAW).

Anything short of this may work or may not.

ALL HSLA and CrMo steels need PWHT to temper the martinsite formed during welding. Untempered martinsite cracks. Always. Maybe not today, or tomorrow, but eventually. I have watched a 4140 cylinder (12" dia, 2" wall) crack while sitting on a pallet in the shop...BANG....

C.
 

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416L Doka and U1200
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Reminds me of when I learned to weld cast iron 30 years ago. I was told the following:
1.) 100%of the weld is based on the pre heating.
2.) 100% of the weld is based on the rod choice.
3.) 100% of the weld is based on post weld heating.
I asked how that is possible and his reply was that 99% of the welders can weld cast iron but less than 1% of the welds last.
We had Two pits filled with charcoal bricketts for pre and post heating. And a vacuume chamber for rod storage (converted refrigerator) I swore secrecery on rod choice.
I need a beer.
Later
 

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'76 1300L,HE351CW,H15P Winches,Konis,Hydraulics,All Gears,10mm Plungers,Aftercooler,Lots of Littles
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Brian,
Ni Rod?

C.
 

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'76 1300L,HE351CW,H15P Winches,Konis,Hydraulics,All Gears,10mm Plungers,Aftercooler,Lots of Littles
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Grin.

C.
 

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Non MB 1975 Volvo C304, 1958 Kramer U540, 1959 unimog Westfalia 411
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I believe nickel is preferred but I may recall 7018 being sucessfully used and the all critical pre and post heating. I recall a cast handle being broke on a threader and was told it was useless to try and weld, well it's still in use almost twenty years later.
 

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Discussion Starter #15
I'll get pics up when I can Get up to where the U1350's are being stored. It may be a couple weeks though.
I grew Up in Nebraska so pretty familiar with welding cast on ag equipment, but my reading in the Mecedes frame modification isn't reall getting into the pre and post heating.
I am getting electrode DIN specs and and some description as to how to go about attacking the welded frame w/ MIG, but no mention of pre and post heat according to Unimog as far as I have seen. Am I missing it???
We are not welding a crack, we are increasing the vertical section by around 18-23% and adding another lower flange to as well.
This is what Unimog does at the factory on some models. It is a substantial ammount of welding and reinforcement.
Will put up pics when I can.
If I'm missing something please let me know in semi laymen's terms if possible.

Thanks!
 

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Pre and post heating is still going to be of benefit to avoid embrittlement issues via martinsite aging. I have a entire tome on maraged steel application, production and fabrication if you need reference help.

I take it you are looking to slit the frame rails and then plug & stitch weld plating to reform?
 

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U1550L/37 Doka, U1700L/38, Merc 1017A
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I'll get pics up when I can Get up to where the U1350's are being stored. It may be a couple weeks though.
I grew Up in Nebraska so pretty familiar with welding cast on ag equipment, but my reading in the Mecedes frame modification isn't reall getting into the pre and post heating.
I am getting electrode DIN specs and and some description as to how to go about attacking the welded frame w/ MIG, but no mention of pre and post heat according to Unimog as far as I have seen. Am I missing it???
We are not welding a crack, we are increasing the vertical section by around 18-23% and adding another lower flange to as well.
This is what Unimog does at the factory on some models. It is a substantial ammount of welding and reinforcement.
Will put up pics when I can.
If I'm missing something please let me know in semi laymen's terms if possible.

Thanks!

what is the intention for this modification? are you increasing the payload or just adding implements like a crane?
 

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A lot of very nice Unimog...
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Discussion Starter #19
We are moving the whole rear axle load to the end of the chassis and increasing the GVW. This is part of our LandArk 6X6 project.
 

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U1550L/37 Doka, U1700L/38, Merc 1017A
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We are moving the whole rear axle load to the end of the chassis and increasing the GVW. This is part of our LandArk 6X6 project.
i see. i will be doing this exact mod in a couple of months or so as well. already talked to some people regarding the material but forgot the exact details now. will likely make a pattern and then just press brake the bend like the L shape profile. i bleive the factory also adds another reinforcing flat bar welded to the bottom as well.

are you also reinforcing the inner rear part where the spring hanger cross tube is?
 
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