FMTV frame steel.... weldability?

[ramdough]

Anyone know the FMTV frame material (alloy and temper)?

Any special welding requirements (preheat/post-heat)?

Thanks


Sent from my iPhone using Tapatalk

 

[DiverDarrell]

Everything is bolted or huck bolted to the frame, may give indication of weldability.

 

[Rebuilder]

It can be welded like any other steel but you'll lose the temper and create a weak spot around the weld.

 

[big block 88]

Frame welding is a no no boss. It can be done just fine but its gonna be brittle on the edges of the welds.

 

[DrillerSurplus]

In the drilling business we modified many trucks to mount different kinds of equipment on them. The modifications usually involved attaching various components and/or lengthening the frame.
I don’t have much time today, but I wanted to do a quick response since welding on the frame often involves serious safety issues (like attaching a trailer hitch) and can get you red tagged and parked at the scales. Federal DOT regulations say you must follow manufacturers’ recommendation and most manufacturers just say “Don’t weld” DOT 393.201 (d) re welding
Here are a couple of links from welding forums welding forum re truck frames . . welding web forum re welding frames

A quick google search indicates the frames for the FMTV are supposed to be 110,000 PSI steel which definitely requires special welding techniques, very different from mild steels. We welded a lot of P110 casing which is very similar. If the proper welding technique is not used, the area around the weld becomes very brittle, cracks and breaks very easily- sort of like trying to weld cast iron.

The proper welding technique requires pre-heating to 500+ degrees, low hydrogen wire or rod like 11018 rather than the typical 7018 or 6010 and several other important steps. As DiverDarrell points out, almost everything is bolted/huck bolted on, it’s for a reason. We bought a magdrill to be efficient at bolting to the frame. (Even bolting has requirements that should be followed.)

With all that said, there are still times that you need to weld to the frame. Ford has some detailed guidelines for aftermarket builders/up-fitters, including frames with 110,000 psi steel.
Modifying truck frames Ford Bulletin Q18.pdf Welding Truck Frames Ford Bulletin Q140.pdf

 

[snowtrac nome]

I will find I have to extend the rear of my frame to I do plan on proper procedures. as stated sometimes upfitters need to add on to the rear of the frames or extend them that is where proper procedures and fish plating comes in to play.

 

[doghead]

Anyone know the FMTV frame material (alloy and temper)?

Any special welding requirements (preheat/post-heat)?

Thanks


Sent from my iPhone using Tapatalk

What did you have in mind?

 

[Jbulach]

The proper welding technique requires pre-heating to 500+ degrees,

Use caution on this part, mild preheats and slow cool downs are "almost" always good. However higher pre and post heats are a lot more specific depending to materials.
That said there are numerous frame materials, and depending on what you are planing, you really need find the steel type and or heat treating it has been subjected too.

 

[ramdough]

I read somewhere that GXV extended an M1083 by 4'. I was trying to figure out what they did and what the correct way to do it is. I don't plan on extending the frame inside the wheelbase, but I am considering extending behind the rear in a 1088.

When I build a camper, I would like to move my bumper back further and my tow hitch (derated of course). I think a 1085 would be ideal, but I am not sure if I want to rely on finding one of those.

I am just trying to learn more before I make too many design decisions.

At this point, I am not looking at welding on the stock frame.

Thanks


Sent from my iPhone using Tapatalk

 

[DrillerSurplus]

Jbulach is correct, you should make sure of what the frame material is. I should have been specific that the welding I was referring to was for 110,000 psi.

Ford's bulletin Q-140 specifies preheat of 500-600 degrees for frame materials 50,000 to 120,000 psi steel.

 

[doghead]

You should be able to just buy frame rail material and inner "sleeve" material at a good frame or spring shop(big trucks) and simply bolt it all together for what you described your goal is.

 

[ramdough]

You should be able to just buy frame rail material and inner "sleeve" material at a good frame or spring shop(big trucks) and simply bolt it all together for what you described your goal is.

That is probably exactly what I will do, or find a donor frame to steal from.

Thanks.

 

[Jbulach]

Jbulach is correct, you should make sure of what the frame material is. I should have been specific that the welding I was referring to was for 110,000 psi.

Ford's bulletin Q-140 specifies preheat of 500-600 degrees for frame materials 50,000 to 120,000 psi steel.

Most modern frames are going to fall in the 100-130ksi range. Yield strength is only one very small pieces of the puzzle in determining heating/ welding process when welding frames together. Always be careful to know what the maximum allowed preheat is, as well if post heat is acceptable.

 

[tennmogger]

Could you extend the subframe and leave the main frame untouched?

 

[Oxyacetylene]

In the drilling business we modified many trucks to mount different kinds of equipment on them. The modifications usually involved attaching various components and/or lengthening the frame.
I don’t have much time today, but I wanted to do a quick response since welding on the frame often involves serious safety issues (like attaching a trailer hitch) and can get you red tagged and parked at the scales. Federal DOT regulations say you must follow manufacturers’ recommendation and most manufacturers just say “Don’t weld” DOT 393.201 (d) re welding
Here are a couple of links from welding forums welding forum re truck frames . . welding web forum re welding frames

A quick google search indicates the frames for the FMTV are supposed to be 110,000 PSI steel which definitely requires special welding techniques, very different from mild steels. We welded a lot of P110 casing which is very similar. If the proper welding technique is not used, the area around the weld becomes very brittle, cracks and breaks very easily- sort of like trying to weld cast iron.

The proper welding technique requires pre-heating to 500+ degrees, low hydrogen wire or rod like 11018 rather than the typical 7018 or 6010 and several other important steps. As DiverDarrell points out, almost everything is bolted/huck bolted on, it’s for a reason. We bought a magdrill to be efficient at bolting to the frame. (Even bolting has requirements that should be followed.)

With all that said, there are still times that you need to weld to the frame. Ford has some detailed guidelines for aftermarket builders/up-fitters, including frames with 110,000 psi steel.
Modifying truck frames Ford Bulletin Q18.pdf Welding Truck Frames Ford Bulletin Q140.pdf

Any information on bolting to the frame? One day I would like to make one of the hitches that is sort of a 3 point design, with part of it resting in the pintle and two legs going back up to the frame rails.

 

[ramdough]

Could you extend the subframe and leave the main frame untouched?

My current plan is to either find a 1085 that I can afford, take the bed off, then shorten the frame, or buy a 1088, bolt on a frame extension to move the pintle back further and then add my camper subframe.

No welding on the truck frame.


Sent from my iPhone using Tapatalk

 

[DiverDarrell]

Additionally you want to have some kind of flex mount for your camper box, to allow for frame twist underneath. Look for pictures of how the box is mounted on a 1079, and on the older 2.5 and 5 ton trucks. You can easily extend the frame with fish plates and such. If I turn mine into an explorer camper, instead of longer, I will go wider with slide outs.

 

[scottmandu]

it depends on what your welding how large and area etc. The frame members for the LMTV are heat treated steel so it will need to be re-treated after welding.

 

[quickfarms]

Any information on bolting to the frame? One day I would like to make one of the hitches that is sort of a 3 point design, with part of it resting in the pintle and two legs going back up to the frame rails.

Why not just use the class V curt hitch?

 

[quickfarms]

Normally the welding of truck frames is a big no no.

It can lead to some very close scrutiny by law enforcement.

I see the commercial officers roll past vehicles all the time looking for a reason to pull them over.

Welding truck frames is possible and commonly done on highway trucks by highly qualified welders.

If you are asking how to do it then you should not be doing it.

A vehicle that goes off highway adds a new level of issues to welding the frame due to the flexing and the preferred method is simply to replace the frame rails.

It would be cheaper and better in the long run to find the correct vehicle