How to Weld Steel Balls to Round Pipe

Brazing?

I reckon that's the one too. Have a concave fixture made to hold the ball steady, making sure to have plenty of surface area in contact with the ball so as not to weld the ball to the machine, and fuse it to the pipe on a standard spot welder. Quick. Easy. Cheap.

Stu.

I wouldn't recommend using electro spot welding on anything that has a small volume to surface area, when i was at college the fun was to put steel rods in a spot welder and watch them explode, this is a similar concept.

Resistance, or 'spot' welding as described many times in this thread will be just fine in this application.

This assumes that prep has been taken care of and the operator does know a little about amperage and duration.

Perhaps a little more understanding of the process than raw college kids having fun with things they don't know about.

Cheers,

Stu

I was only making a recomendation from past experience from my years at an engineering training centre (college). Obviously if the current is too high for the application then yes it will cause an explosive effect, but being a small diameter ball the volume to surface area is less therefore the heat created by the current will not disipate quickly potentially making the material molten and because of the inrush of amperage could go pop numpty. who are you to question me?

My comment was added as a safety recommendation to someone who has alimited knowledge of metal joinery. What value did your comment provide?

friction welding?

I heard something () called explosive weld. Never came in contact. It is always others never me anyway

Is used more for welding surfaces for instance in plates made from 2 steel qualities. Is based on the cold welding due to the shockwave which builds up a very high pressure for a short time. The pressure breaks the oxide layer and brings the non oxidised metal sheets into intimate contact. It would not be very adapted to a ball-cylinder surface.

This is also the process initially used to make the Ni clad material from which copper cored (US) coins were produced.

You might want to consider designing a fixture and use the ball similar to a stud in the stud welding process. No filler is used although you may want a tit on the weld side of the ball.

OR - You may want to design a holding fixture so they may be resistance welded using a large spot welding power supply or something similar.

As an afterthought... just where on this pipe do you want to weld the balls? I assumed that you wanted to weld them along the length. If you want to weld them to the ends, get bigger balls (no pun intended).

Hmmmm ......... He really didn't say that he wanted to weld them to the end of the pipe. I just assumed that. Looks like I've been thinking inside the "box".

Ed Weldon

Ya'know I had a similar thought not long ago and my auto body specialist suggested to use the auto body panel glue they've used instead of welding with outstanding results.

Or may be cut a groove in the center of the ball and press the tube in the groove with rollers (as is done in finning) opposite of tube expansion.

This is a new thought process by EW and hence should get one GA/ OT (since I dont GA other than me)

Laser welding..... Micro laser.... If you have any questions and would like to discuss your options give me a call.

Derek Starks
Accurate Welding
www.accuratewelding.us
586.465.5033

this sounds almost like a trick question to make engineers scratch their heads.. and do what engineers do...lol

What is it for, more specifically? do you have pictures?

Cheers,

Chris

chris --Trick question? I guess there's more of that CR-4 than we want to admit. I just take'm at face value. Either way they're fun to answer.

Ed Weldon

Reduce tube id below 15mm with the process like spinning, you will get an arc put the ball &weld it with electrical resistance weld.

That's a neat idea. Design the forming process to move the flat end of the tube close to a cone shape whose elements are approximately tangential to the surface of the ball....... Is that possible?

Ed Weldon

Is essentially similar to notching procedures

The whole discussion is meaningless if you do not specify where the ball has to be "welded": inside? outside? at end? somewhere along the tube?

My suggestions went from the assumption that the ball has to be on the out along the tube.

Nick,

Wouldn't it be nice if the OP had consideration for the discussion to confirm required data, such as you, and others, suggest. The guys have given a lot of good information to help solve his (her?) dilemma, and it deserves feedback.

I'm at the point where, if he can't be bothered, neither can I.

Cheers,

Stu.

Without a sketch, its impossible to give an answer.....also what materials are beings used? are both the tube and and the ball of the same type of metal.....?

If on the side of the tube, make a dimple and eith hard braze or weld, or pass a screw through the tube first and then braze......there are many option.

Friction welding would be also optically excellent.....

I hope you guys are enjoying talking among your selfs , I like to exercise my mind but as the poster has not provided any further information it seems to be that he is not interested so why would I waste my time offering suggestions which are possibly not related !!!

Thanks a lot for the answers and sorry for the delay in details. The balls are spherical and are sourced and are to be welded along the length and not on the end of the tube. Material of both, the tube and the ball/balls is mild steel. The image of the sample i have got is provided at the link below:

http://img440.imageshack.us/gal.php?g=image001a.jpg

They look like they are resistance welded.

Apparently I was right your question concerned "a ball on a tube" not "in a tube" this was the reason I assumed it is along the side.

From all suggestions considering the cost of the operation I would select two possibilities:

- the welding as studs with a capacitor discharge supplying a very high current for a short time. the contact (point contact between ball and tube) is OK for such a process due to the small surface, high current density and local high temperatures obtained. The problem is that the ball can be subject to transverse loads and the weld must accept the bending.

- if above process which will be the cheapest does not offer the required mechanical resistance then friction welding will be the most promising next approach. It will require some tests since as well pressure force as ball spinning speed have to be optimized. For ball spinning a lathe can be used or a drill with a fixture for the tube.

Could not see the sketch. Could have been uploaded on the post itself. But could get the description. Best may be resitance weld.

Not a bad suggestion. Certainly O.K. for a prototype or two. But, for any kind of volume production, the cost will go through the roof.

mmmm. I don't think so. what sort of welding are we comparing this to?

Labor: welder vs. ordinary laborer (add to the welding option the set-up time per tube)

Materials: welding materials, jigs, vs. blind fasteners which when bought by bulk reduces the unit price

Overhead: Electricity for welding machines vs. daylight

if we moved the production venue to China, where salary disparity between low-skilled and skilled labor is quite appreciable (and where you'd hope to reduce production cost), the manual method will prove more cost efficient. the more adept the installer becomes, the faster he gets. but with welding, you can't speed up the welding rate!

IMHO the best (and lowest cost) method for welding these balls is percussive or percussion welding. It is sometimes called stud welding. An arc is initiated between the two surfaces and while the surfaces are molten, they are forced together. This action extinguishes the arc, and the weld rapidly cools. Resistance welding will be problematic for this application because the pipe will tend to collapse. I suggest you contact the manufacturers of stud welding equipment.

I would definately use this mehtod if there's a lot to do, we used this process ourselves when a there was a large volume to be done.

Otherwise can use TIG, MIG and you can use stick if you good at it as long as the ball is heavier gauge than 1.2mm

I think I should have uploaded the images earlier, anyways, the balls are welded as I have seen after cutting the pipe. Also, I would like to mention is that there is slight pressure mark on the pipe (the opposite side of the ball). Which seems like it is spot welded. Since, we do not have spot welding in-house what capacity of machine would be required for it??

18KVA will handle metal 2.5mm thick.

It would be possible to weld ball without a location recess on the pipe but your set up blocks will have to be more sophisticated to hold every thing in place.

I agree that it would be slow for a production set up. I did not see where he needed to mass produce these things. When I did it I only made a few of the pieces. I put 6 balls per piece and made 50 or so pieces. It took me around eight man hours and to make a small jig and do the welding on these. When I build furniture I get paid more for the one of a kind artsy aspect of it than being able to mass produce it. After I got used to it I could do them very quick this way because all you really have to do is make an arc for a very short time to fuse the side wall of the pipe to the ball bearing. I am sure a stud welding technique would be faster and you could use less skilled workers. I am not overly experienced with stud welding but I was thinking that the two matting surfaces has to be flat.

Its just struck me, the title of this blog:-

How to Weld Steel Balls to Round Pipe!

Sounds like the Tin Man has a problem with his "nether regions!!!!

Maybe we should bet the titles more carefully?

GA.

S.

I all ready mentioned this in post 26.

Maybe I should have GA or do members of this forum not read all posts before commenting?

Check #2

But that is life (I don't bother about GAs) - If I am the first to give it let others get GA I pat by back myself.

OK already!!!

S.

OK,

• Lets suppose is a very high number of these artifacts.
• Also suppose quality of the weld is above cost.
• Speed and efficiency are a must

Then,

• I will set two production lines meeting in a SPOT-WELD.
• In One of the lines I will cool off the pipe.
• In the other line I will heat the steel ball.

SPOT-WELD,

• Jig both parts in the desired position, once is attained immediately SPOT-WELD in a ringed negative arround the pipe ball positive in a clamped inside pipe way.

NOTES:

• Temperature of ball and pipe to coincide with shrink and expand factors to attain a tight configurateion
• Amps of SPOT-WELD to be such to attain a bond necessary for the usage.

Thanks

I would heve preferred an indexed pipe movement in a table slot. like the hydraulic punches. Insted of the punch, the ball may be clamped in a spring loaded socket (to maintain the contact pressure during welding). The ball may be held in the socket by vacuum (hold the ball, suck out the air. and after the welding is done release the vacuum.

In the spot welding we do, the contacts are usually copper to reduce the contact resistance (for you to avoid welding the ball to the socket)

In your case, if it is really mass production, uou may create a line , the table indexed to move in X direction, and the ball on a rotating drum in perpendicular direction. may be at least 2 to 4 arms on the drum, as one gets welded, the other socket atop gets a ball dropped on it.

If you use an end mill to spot face the pipe, and make the spot face deep enough that the ball is supported around part of its perimeter, you will be able to form a projection weld using a resistance welder. Following previous advice, you can use a V shaped lower electrode to locate the pipe and a countersunk upper electrode to locate the ball. It will take about 3000 amps of weld current to fuse the ball to the annular contact line between the ball and the countersunk hole. Weld time should be kept to about 1-2 cycles to avoid collapsing the pipe. Required weld force will be about 250 pounds. We can make test welds for you if you like.

I have to agree with the resistance welding being the best option. That is if I am correct in assuming that is what they are doing when they weld car bodies.

The end product looks as if it will be chrome plated and cover up any imperfections but then I am just going of the pictures linked to.

Looks plated to me.

Also if it is plated wont that improve the strength of the weld? This is just me learning a bit more because the only welding I actually do is MIG.

Chrome plating or nickel pleted steel do not create problem in spot welding. Some details on spot weld is available here. http://www.makeitmetal.com/resources/CH13_SpWeld.htm

Resistance welding seems to be the way to go but an alternative with less jigging would be to stud weld a threaded stud on to the pipe & have a blind threaded hole in the ball. You could use thread lock to make the fit permanent.

Good idea, but wouldn't it make sense to stud weld the ball directly to the pipe as suggested in #29?

Sorry for the late reply, I've been on holiday.

This all depends on quantity, for a low number the cost of special jigging is prohibitive, for larger quantities the direct method would pay for itself.

Value analysis would never validate your suggestion since it introduces cost there where NOT needed.

Your suggestion would be valid in case of disassembly constrains which are not present.

We have, as engineers, to think economically especially today!

Red Green would use Duct Tape!