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Need Welding Help for Stainless/dissimilar metals to unknown

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Hi,
We have broken exhaust manifold studs in a cast iron block.
The break is flush. The idea is to place a low carbon nut and fill the void with a weld pool that will stick to the broken stainless/alloy stud.
It is non ferrous but seems lighter than normal.
The question,
I am thinking either TIG with ER309LS or a Arcaloy or equivalent. 309/l16 arc weld.
I have a Miller 220 AC/DC so I can do either.
Any experience out there with a 2014 Ford 6.7 diesel exhaust manifold stud project?
Thanks,
Jeff
 

Comments

The stud was twisted off because it was corroded in the tapped hole, why would one think that it can be removed by a weld of questionable quality? As always with broken off studs, the cure is drilling out the broken stud and cleaning out the remnant threads with a tap, or if things go wrong drill out the existing mangled threads and helicoil the hole. Also forget EZ outs, likely they will break off and then there is no getting them out unless you have a EDM machine. Been there, seen that! when anyone came into my shop with broken off EZ outs, I just shook my head and turned them around.
 
Hi,
We have broken exhaust manifold studs in a cast iron block.
The break is flush. The idea is to place a low carbon nut and fill the void with a weld pool that will stick to the broken stainless/alloy stud.
It is non ferrous but seems lighter than normal.
The question,
I am thinking either TIG with ER309LS or a Arcaloy or equivalent. 309/l16 arc weld.
I have a Miller 220 AC/DC so I can do either.
Any experience out there with a 2014 Ford 6.7 diesel exhaust manifold stud project?
Thanks,
Jeff
I have removed countless studs in exactly the manner you are suggesting. The heat during the welding swells the stud and then loosens the corroded stud when it cools. I try to find a nut that is the same alloy as the stud and one size larger than the stud bolt size. Then I put the nut in a lathe and face it off until it is about half as thick as originally. This makes it much easier to get a good weld on the stud. Then I heat up the surrounding casting and put a wrench on the welded nut and wiggle back and forth until I feel it give. Then I add penetrating oil and keep working it back and forth until it screws out. From what I have experienced, unless you have it set in a milling machine, drilling never ends up in the center of the stud. Most back yard guys drill an off center hole with a hand drill and then pound an EZ out in and and break that off in the hole.

The next thing they try is to run a tap down an off drilled hole and either break off the tap or screw up the hole until it is past an easy fix.

Drilling works great if you have the head in a mill where you can get the drill centered. Also, once you have it drilled close to the thread size, take your torch and heat up the remainder of the stud left in the hole. Often times it just peals out of the tapped hole. Then dress up the thread with a tap.

Stainless TIG rod will work for either mild steel nuts or stainless. Good Luck

D
 
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John,
I would agree with you if I had experience.
I don’t. The diesel tech is thinking this is an option as it has worked many times before. The new element into the mix, the unknown alloy that is non ferrous.
He is trying to avoid removing the head.
Flat rate techs, think outside the box.
This fellow is very good.
I’ll let you know what we end up with.
Please know, I appreciate your input as you have been there and done this.
I’m just trying to help a coworker and maybe learn a thing or two at the same time.
 
I work for a Ford dealer, we remove many broken exhaust studs in a month. Most are drilled out and occasionally a nut is welded on to get them out. The studs are stainless but we generally just use the wire feed with ER70 wire. Aint pretty but working at flat rate pay you gotta do what you have access to. I feel that most of the broken exhaust studs come from breaking under tension not twisting off. Sometimes a left hand bit will spin them out with very little drilling. Access to drill is the big thing though.
 
I work for a Ford dealer, we remove many broken exhaust studs in a month. Most are drilled out and occasionally a nut is welded on to get them out. The studs are stainless but we generally just use the wire feed with ER70 wire. Aint pretty but working at flat rate pay you gotta do what you have access to. I feel that most of the broken exhaust studs come from breaking under tension not twisting off. Sometimes a left hand bit will spin them out with very little drilling. Access to drill is the big thing though.
I most often use the MIG with ER70 also but he mentioned that he was using a TIG welder. With good access a TIG is stronger and a better option but in a confined space MIG is easier but not as strong. Sometimes, it takes me a couple of times to get the nut loose but almost always comes out eventually.
 
I think your choice of rods is great. ER309 is what I would use. They are primarily used for dissimilar metal welds (carbon to stainless steels) in the industry that I work.
 
I work for a Ford dealer, we remove many broken exhaust studs in a month. Most are drilled out and occasionally a nut is welded on to get them out. The studs are stainless but we generally just use the wire feed with ER70 wire. Aint pretty but working at flat rate pay you gotta do what you have access to. I feel that most of the broken exhaust studs come from breaking under tension not twisting off. Sometimes a left hand bit will spin them out with very little drilling. Access to drill is the big thing though.
I don't think it occurred to either of us that the ER70 would stick to the stainless. On my way in this morning I'm going to stop by the welding supply to pick up some 309 arc rod and see if they have it for the mig in .030".
Every one can mig, most guys haven't stick welded in years but this way Joe has options.
These studs are of unknown material to me because of their light weight. Manifold studs have been stainless for decades but this stuff is ????????
 
I try to find a nut that is the same alloy as the stud and one size larger than the stud bolt size. Then I put the nut in a lathe and face it off until it is about half as thick as originally.
My lathe is at the dealership at the moment. That is a good idea. I'll give it a try.
An exhaust stud and manifold lead a tough life, glowing hot to cold, thousands of cycles.
 
Hi Jeff. 309 will stick to a lot of stuff, but you need to figure out what material those studs are. If it is less dense than steel, it is probably not stainless steel. To get a quick idea, make a little scale and measure your 309 against some ER70. You probably will not see a difference. The weld a nut to the exposed stud trick is tried and true. A lot of people swear by it. It has never worked for me.
 
The access or lack of prevented the successful removal of the broken studs. I got all set up, cut a nut down to size (thinned it down on the lathe) placed the nut over the stud, held it with a magnet and I could not get in close enough to see what I was doing #1.
#2, the cylinder head is angled down and away so I could barely see any of the stud.
The TIG experience I do have always worked out best when I could see what I was doing.
I couldn't get my shoulders in close enough.
We are going to pull the head, put it on my Sharp knee mill and use a carbide end mill to get the dang things out.
That's always worked for me.
This happens quite a bit. Sometimes it's a piece of cake, other times are more interesting.
I am going to pick up some 309 stick rod though. You don't need two hands and one foot to stick weld.
Thanks guys!
 
Use what ever welding method you want as long as you can put a lot of heat into the broken bolt. What I have done many times with excellent results is find a thick flat washer that fits over what's left of the broken bolt or stud. Hold it flat against the head, make a nice hot bead right across the hole in the washer welding the washer and broken bolt together. Now immediately without letting things cool down, weld a full size nut to the washer. Weld around the base of the nut and lastly weld the hole in the nut untill it is full. Concentrate the weld on top of where the broken bolt is when you do the last part (just start at the bottom and work your way to the top untill full). Let things cool off, then unscrew your broken bolt. I do this a lot and it always works.
John
 
We ended up removing the head, I decided to use the mill. What the heck, it's at the shop.
We used two 2-4-6 blocks because the head turned sideways was over 9" and I didn't have a hold down set with long enough bolts.
Bolted the 2-4-6 blocks to the table and bolted the head to the 2-4-6 blocks. Worked great.
I found a 3/8 center cut end mill in carbide.
That carbide made mince meat out of the stainless studs.
The truck should be back on the road by noon tomorrow.
 
The welding procedure works best when you weld a flat washer onto the stud first then weld a nut onto the washer. A small scrap of steel/strap with a hole drilled in it also works well. When going with the drilling method make a sleeve out of a rod or bolt that will either fit over the protruding stud or set down into the threaded hole. Through drill the sleeve with a smaller size hole for a pilot bit. The sleeve works great to hit the center every time. I drill up to just under the tap drill size and finish with a tap and an awl or pick to remove little pieces. It also helps to level off the broken stud with a pointed burr tool. The nice thing is that these sleeves can be re-used on the next oops.
 
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