weld brackets ot hydraulic cylinders

Date 10-09-2003 21:05

Without knowing more about your application, what you have described so far scares me. No offense intended.
Where you weld to the cylinder is the big question. The head or the butt might not be a big problem, especially if the unit is welded together as many of them are. But if you want to weld to the cylinder (or the can), it's going to warp somewhat, even with water in the cylinder.
If you weld "cold" to prevent distortion, then you could have penetration problems, lack-of-fusion, etc. If the brackets have much pressure on them, they could break off suddenly. Same scenario if the weld weakens the cylinder, it could rupture.
Then again, it would be a good idea to know what material the hydraulic cylinder is made of. A lot of not-good things could happen.
Is there any way you could clamp, or bolt the brackets to your cylinder? Maybe a little re-design is in order? My opinion is that would be preferrable to welding if you can do it.

Chet Guilford

By jimwelds (**)

Date 10-09-2003 21:45

The wall thickness is 3/16" and the lift weight is 10,000 lbs.

By cawelder (**)

Date 10-10-2003 00:36

I have made this mistake before. Welding on those cylinders will shrink the wall, and cause all kinds of problems. Its very risky.

Chuck

By jimwelds (**)

Date 10-13-2003 23:31

did you fill the cylinder with water, before you did your welding on your culinders? Thanks Jim

By billvanderhoof (****)

Date 10-14-2003 03:09

I think the question here is are these brackets to go in a location where the piston passes by when the lift is in service. If so welding will surely distort the cylinder to some extent whatever is filling it at the time. This would at least limit the service life of the piston seal. The cylinder could be fixed by rehoning it after welding.
Bill

By ssbn727 (*****)

Date 10-14-2003 03:32

Bill, excellent advice, that is provided that cylinder integrity from the inside out is assured afterwards prior to re-entering service!!!

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By MBlaha

Date 10-14-2003 06:56

I agree with you totally Chet. This sounds potentialy dangerous.
Are these new cylinders? If they are not:
1. You may want to concern yourself with the hardness. I have witnessed instense hardening as a result of the high pressure and vibration that often are asociated with hydraulic pumps hoses and cylinders.
2. You may also have perosity problems from oil that has been impregnated in the tube over the life of the cylinder. One little pinhole propegating into the core of the tube will make a considerable leak under pressure.
3, Make sure you know what the type of material is of the part you are going to weld to and match your filler metal accordingly. Some older cylinders were made out of stainless.
4. If lifting 10,000 lbs. make sure your clips or lugs will withstand that heavy of a load. Do you have access to an engineer with welding knowedge?
Please do not take offense, but are you proficient with the type of wire you are thinking of welding this lifting device with? Will fingers, toes, arms and legs, or even entire bodies be in harms way if one of these welds were to fail?

Safety first

Mike

By ssbn727 (*****)

Date 10-14-2003 09:20

Mike,
I have to agree with you and Chet about being concerned with leakage...
If this was something that had to be done for whatever reason which more than likely is economic because of pricing comparisons then, at least perform some sort of NDT (PT or MT or even UT), and hardness testing if possible to find out if there is'nt even the remote possibility of failure from the inside out once the cylinder is put to use...
Jimwelds, Mike is right, safety first!!! Btw, it might be less expensive in the long run to order it to your specs from a variety of hydraulic equipment manufacturers... Most of them do custom work orders for which they will assume liability!!! Jimwelds, will you assume liability???
Food for thought...

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By CHGuilford (****)

Date 10-14-2003 13:54

Actually SSBN, my concern is more about the potential for high pressure leaks with the possibility of fluid injection into the body, and with the possibilty of the brackets tearing off with 10,000 lbs on them. I'm sure it is possible to weld on the cylinder walls under proper circumstances. Mike also voiced similar concerns.
Not that I want to restart a hot discussion I remember from a while back but sometimes the best weld is no weld at all. It might be better to bolt the cylinder to a bracket that could be easily welded to something else. But again, I don't know the application, so it isn't for me to say what is right. As you mentioned, maybe a custom or even off-the-shelf item could do the job.

I'm sure jimwelds is looking at the possibilities, I hope it works out well.

Chet Guilford

By jwright650 (*****)

Date 10-14-2003 14:42

I was watching this post close to see where this would lead. My thoughts when I saw the original post was to jump in and holler "don't weld it". I don't know enough about what types of materials are used in the walls of those cylinders, so I've kept quiet and watched since several have already warned about the safety issues involved.
I see brackets welded to these things all the time, but I'm certain that this is done before the cylinder is ever assembled for the first time. At that point someone could inspect and assure themselves of a service worthy cylinder. A flare bevel-groove weld down both sides of the cylinder, large enough and long enough, to carry the load would most likely cause it to mis-shapen from the heat regardless of welding process. Oil and contaminates would certainly give problems if not thoroghly cleaned. I was hoping we would get more info on the intended use and more of the cirumstances surrounding the cylinder to better advise on the weld/don't weld issue. I feel as most of you as with the present amount of info to advise to steer clear of welding.
John Wright

By RonG

Date 10-14-2003 20:14

Well one thing is for sure, the cylinder tube is finished to very close tolerance.

If you weld on the tube that will go out the window. The piston may lock up at that point or by pass internally reducing the capacity.

By ssbn727 (*****)

Date 10-15-2003 09:22

Chet,
Point well taken!!! I believe we're on the same page here when it comes our concerns...

Respectfully,

SSBN727 Run Silent Run Deep!!!

By jimwelds (**)

Date 10-15-2003 10:26

I change my design, I'll try to post some pictures on the horbat talk, of the cylinder on the machine when it done. Thanks for all the replies Jim

By jimwelds (**)

Date 10-21-2003 00:49

I purchased 4 tie hydraulic tie cilynders. I like to enclose the clyinder in a rectunglar steel boxs of 5/16" steel plate and I like to hold a 1/ 16" tolerence gap larger so the cylinder may be removed for repair. The cylinders are 37 1/4" center of pin to center of pin so the length of the box would be 35". The 4 cylilnder will lift a weigth of 12,000 pounds. The 5/16" plate will be welder to a heaver bracket that we will build. How may the box be constructed is 5/16 to heavey to bend and hold a tolerence of about 1/16" or is welding the plate a better process for construction this box. Thanks Jim

By CHGuilford (****)

Date 10-21-2003 13:19

Jim,
Again, I'm not exactly sure of what you have there, but 5/16" plate can be bent to the tolerances you mentioned. If you don't have a bending brake, you might want to visit a local fabricator who does. They should have the expertise to do it.
Probably the easiest way to do it is to bend 2 L sections of plate, or even cut 2 angles of the right size, and weld the seams up. That way you can control how tight the inside will be
1/16" can be a bit tight, you might want more space and by tacking the halves together, you will be able to adjust the boxes (allow a little for weld shrinkage).

If you make the boxes from plate, just be sure to cut the pieces so the rolling direction is not parallel to the bend lines. And radius the edges. Otherwise you could split the plate when you bends them.

I'm kinda curious, if you are able to, could you post a bit more about what your project is? I would appreciate it and I know other readers will too.
Thanks,
Chet Guilford