Welding high strength bolts, fastners

[Glenn]

Welding High Strength Anchor Bolts

Question: Can welding be performed on high strength anchor bolts and fasteners?
Answer: The short answer is that in most cases, welding is not allowed on high strength bolts.

Now comes the problem:
If I want to secure the high strength bolt from turning, and it is recommended NOT to weld it, what other means could be used to secure the bolt head to the metal so there is no way it can get loose and turn?

Placing a wrench on the bolt head and then welding the wrench to the metal, seems to me to be wasteful of the wrench. Not to mention what the someone would think when they tried to remove the bolt years later, only to find wrench that was holding the bolt head WELDED in place. (grin)

[saintjohnbarleycorn]

I am not sure if I follow you exactly, and the size of the bolt might make a difference, but what about drill and thread a hex head, either in the top or diagonal?

[saintjohnbarleycorn]

if not practical. I wouldn't think if you tigged a corner it would heat the majority of the bolt head up and weaken it.
or If it doesn't get hot in its current position, epoxy?

[Ice Czar]

easy enough to "box" the bolt head with some small stock
no need to waste a wrench. its the other end with the nut and lockwasher that needs a good dose of Loctite.

of course we weld bolts or more commonly nuts to our shop equipment all the time, easier to just drill and weld than to drill and tap. On alot of older equipment its common to see square head bolts or nuts that are prevented from backing out on one side by a wall or added tabbox

[Daryl]

Any fastener can be retained with what some call French-locks or Tab-locks. These are washers that have two or more long tabs that extend outward and are placed under the head of the bolt before it is threaded in. Once torqued down, one tab is bent downward over the edge of the piece, while the other is bent upward and over one flat of the bolt head. A common place to see these was on the small block Chevys up to the mid-70's. Another common place is where a PTO has been installed on a manual transmission (these washers are almost always included in the Eaton and Chelsea brand kits). As for placing them where there is no edge to bend downward, drilling a shallow hole in the surface a short distance away from the bolt hole will allow you a point to which you can push part of the tab into.
I hope this helps.

[Ten Hammers]

Many times fasteners have holes for safety wire ( aviation example ). I have in the past had an instance or 2 when I drilled a nut and attached safety wire to it then securing the wire to fixture. This allows any removal to take place nicely. The tabloc washers are kinda hard to find locally. I have re-read the original topic and will assume for the sake of arguement this is a bolt going into a blind hole or a tapped block. The safetywire I spoke of was on the nut end. THis can apply to either end of the bolt. Castlenuts work as well. Green, red loctite or Epoxy works but of course you may need an impact to remove. Loctite will hold a short bushing on a piece of shafting that is chucked in a lathe to reduce the OD of the bushing.

[evfreek]

Hi. I think that from the standpoint of fabrication, there are no standard engineering practices that involve welding to high strength bolts. It is just a tacky thing to do . (Sorry about that; I really am.) Still, I have done it in situations which call for a hack. One example is for a quick and dirty bending fork. The high strength bolts are substantially more resistant to bending. Tom Clark uses 1050, and that works pretty well. A lot of these high strength bolts are something similar, or have some CrMo in them. Might be able to see this in a spark test. Don't count on it unless you are an expert. Normal HSLA rules apply. Select the welding rod (I use 10018, lo hy is important). Preheat. Peen (maybe). Overweld and grind the last layer of weld off.

There are cold welding compounds given in some of the old machinist reference texts. They act like the opposite of never-seize, and can be thought of as "always-seize". They usually contain some sort of acid, and will create corrosion in the joint. For bolts, they are as strong as welding, and the bolt will fail first if you try to turn it. I am not recommending this, and I have never tried it, but it is something to think about. I would be afraid of corrosion induced stress cracking.

[ThomasPowers]

Loctite, they make a version for almost *any* use case.

[R Funk]

I have run into this problem at work.

The legal way is to weld keystock to piece that the bolt goes thru so that it prevents if from turning.

Just make certain that it is okay to weld that keystock to the piece. For example it is not permissible to weld on the flange of an ASME pressure vessel unless the welder has an ASME R stamp and the proper paperwork is completed.

[Alan B]

Taking a chisel and cutting an "x" on the face of the metal straddling the bolt hole will give texture for the head to bite into. You could also take a good sharp center punch and punch a line along the edges of the bolt head in the base metal. This creates a raised bump for the head to press against.

[sstreckfuss]

Any fastener can be retained with what some call French-locks or Tab-locks. These are washers that have two or more long tabs that extend outward and are placed under the head of the bolt before it is threaded in. Once torqued down, one tab is bent downward over the edge of the piece, while the other is bent upward and over one flat of the bolt head. A common place to see these was on the small block Chevys up to the mid-70's. Another common place is where a PTO has been installed on a manual transmission (these washers are almost always included in the Eaton and Chelsea brand kits). As for placing them where there is no edge to bend downward, drilling a shallow hole in the surface a short distance away from the bolt hole will allow you a point to which you can push part of the tab into.
I hope this helps.

We use these at my work on aluminum housings that have stainless bolts on them. I am assuming that this is due to the low toque value used so as not to strip out the threaded aluminum housing. I have never seen one fail although when in their final assembly state they have little stress. They are sometimes a pain to install though as they like to slip to a nonperpendicular location (flat part of tab not located at the flat part of the housing where it is to be bent over). Sorry if that is not clear.

[Hillbillysmith]

Just to let you know, with proper preheat and post heat-treatment, you SHOULD be able to weld it. But you NEED to KNOW the proper preheat/post heat-treatment specs to do so. But if you CAN'T weld it, then weld little pieces of flat stock on the member that you are bolting. If you can't do that, then depending on how much torque you are putting on the bolt, then you should be able to use epoxy or locktite. If you want it to just stay in place without backing out, then use either a lock washer, a lock nut, or both in combination with each other.

BTW, shouldn't this be in the welding/fabrication section??????