How does the average body and frame shop heat treat the frame again in the areas weakened by the heat of welding?

It can most definitely can be welded up, but NO Ford dealership would do it.

The welding heat weakens the HS steel.....that is certain. By how much, who knows? Tack on supporting structure adds strength for sure, but how much?

HSS is thinner and stronger. Heat treatment gives it the strength, as opposed to more expensive alloys. You heat it up, you weaken it.

 

I’ve seen this type of damage before from accidents. No matter the how it happens it need fix. Also full frame is cheaper then the front section once you figure added labor of installing a frt section

 

I see the nut on the broke bracket but I don't see the head of the bolt on the opposite bracket. It looks like an empty hole.

 

Good eye!

If part of that bolt had sheared off for whatever reason, it's easy to see how the one remaining mount could get fatigued to the point of breakage.

 

The steel Ford uses is hardly "high strength", this is really just marketing BS as their own documentation indicates that it has the yield strength of normal low-carbon mild steel. They used to use 36,000psi steel for their frames, A36 steel or similar; but they started using 49,300psi steel, 1010-1030 or similar and called it high strength by comparison. Both of these mild steels can be easily welded with standard ER70S6 MIG wire which has an as welded yield strength of 65,500psi. No after weld heat treating is required, but care should be taken to reinforce the repaired area as there was obviously a defect in that area that failed.

The "high strength" steel being used on the frames has nominal thickness of 0.087" for LD frames, 0.100" for HD frames, and 0.110" for HD/HPP frames. Back when Ford used 36,000psi steel for some of the 2009-2014 frames, the nominal thickness was 0.150", and the same year 49,300psi frames were 0.100" and 0.110" nominal thickness by comparison.

I do agree that no Ford dealer will do this, but they aren't welding shops and they don't all have big collision shops where frame repair is a common practice. A Ford dealer will only replace the frame or frame section because that is the only type of repair that is officially approved by Ford. Other types of repairs really need to be looked at on a case by case basis so there's no good way to offer official guidance outside of saying "repairs are not recommended, just replace the whole frame or frame section".

 

In order of preference:

1) Get Ford to pay for the repair
2) Insurance claim
3) Weld and plate

It's a big deal, but it really isn't. Get it fixed and move on.

 

The frame and body components that are HSS are not heat treated after welding anyway. I work for a global tier one supplier of chassis and body structures for all the major auto manufacturers and we shape and weld a lot of really high strength steel and all of it is welded at some point and non of it requires a heat treatment after welding. Regardless, the steel used in the F-150 frames are pretty low tensile steel compared to what is used in other parts of the body structure of other steel vehicles. Like I said, any good welder could easily repair the damage to this frame.

 

Looks like a metal defect. For sure try to get Ford corporate involved. They almost certainly would stand behind something like this if it is a defect.

 

MechEng here. I would reinforce it and weld it. Looks like the frame is mostly 70ksi strength steel. This is hardly "high strength". It's an easy repair for a competent welder.

It appears to me that a crack propagated. I see little to no permanent deformation. Shouldn't have happened.

 

I agree, but without #2. The ONLY reason I would not just go straight to welding and plating is if I didn't have plans to keep the truck forever. Reselling it could provide issues as a future buyer could be scared off, or at the very least it could hurt resell value. I have a Jeep that I have ripped control arm mounts off and have just welded new ones on after plating the area. I never plan on selling that though and I do all of the work on it myself. Even if I were paying a shop to do this fix, that job should cost around $1k MAX (and that is being super generous). For $14k you could almost get a Predator crate engine.