Will this tab hold 35000lbs?

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I had a post started but can't seem to find it.below are a few pics of a tab that I plan to TIG weld in 2 or 3 passes.  It will be used to lift aprox 35K lbs.  I really don't have any experience with industrial type stuff like this (mostly .375 wall or thinner).  It just seems like a lot of weight. For those of you who see this sort of stuff every day, will it be OK? or is there not enought weld surface.By the way machine is a Syncrowave 180, 3/32 tng, 1/8 filler.1tab is 1" x 1.5" Z!!P- thanks for the dime idea! Attached Images
Reply:You actually mean 3 thousand 5 hundred LBS..Correct?If so then tack the corners..then a good deep root where the champher is first..Then another fillet on top..then I'd "stitch " weld it all the way around twice..I tig alot of liquid filled cooling drums and when full weigh way more than that..Never a problem with breakage or leaking..But you just be pushing the limits out of your machine..when I do this I'm at 250 amps......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:no I mean 35,000 pounds! as in 17.5 tons.I assume this would change your answer?The lift will only be a short vertical lift a few inches.
Reply:Just one lift point on a 35k pick? Or do you have multiple sling points? That will change the weight at each shackle point and reduce the vertical load. Depending on the spread and angle of the sling you may increase the stress on the load points. The use of spreader bars..... How heavy is the base metal this shackle pad will be welded to?_________________Chris
Reply:Thanks for the reply!.  The tab (shackle pad) will be welded to 7" thick round stock , 12" long.  (about 100lbs).and yes, this will be the only lift point.  The lift is intended to test the strength of some clamps that will be clamped around the round stock.
Reply:Personally I would  use a MIG that with a dualshield... If I were welding that I would use 1/16" Lincoln outershield 70, with my Linclon DC-600 power source I would set it up like this..... 32 OVC... approx 300 - 350 IPM or a little better on the wire speed, with a 75-25 mix... Fillet size according to the print..._________________Chris
Reply:Your best bet would to run a 7018 1/8 rod.  Run a root pass then put a weave over it. Or some stringers.  Maybe 140 amps.  That first pass is important burn it in there good.
Reply:I have a boilermakers manual and you need a lug that is 7.5 inches long at the base in order to safely lift 21 tons.   The lug has to be made from 3 inch plate. You need a 7/8 fillet both sides.  The shackle you put through the hole will have a very large pin diameter!The hole will be 2.5 inches!  You will need to do a multiple pass weld and the bar will have to be preheated.  The grain in the bar is running longitudinally and your lug is welded to the circumference???  If so the lug could pull out of the bar simply because you are putting tension through the laminations of the bar.  It is like gluing a piece of plywood to the side of a log.  I would be gouging a trough about an inch into the bar before starting my weld so that I would have an inch of weld in the bar before I start the actual fillet.  You need a machine that can pump out at least 250 plus amps wire feed.  The lug as described can withstand a side load of 20 degrees.  Another way to look at this is that you have 1.5 square inches of bar in tension.  Yield strength of regular steel is 40,000 pounds per square inch.  You have a limit around 60,000 pounds with no safety factor.  That assumes your weld holds and that little hole for the shackle does not tear out.Last edited by lotechman; 01-28-2007 at 07:57 PM.
Reply:i would  say you  could  get  enough weld on the  clip  but the  clip is  not  big  enoughthe  clip  needs  a  hole  that is 1 5/8  min. for  a  1 1/2 inch   shackle (this is  a  20 ton  shackle)  and it  should  have the  same 1 1/2 inch of  materail on the  outside of  the  hole ..and  generally  the  thickness of  the  material is  about the  same  as  the  shackle  pin (1/1/2)... in my opinion..go  big  or  stay home...lug  6 to  8 inches  wide
Reply:What am I saying!  Weld it up then turn on your camera phone.  You could make some good money on U-Tube.     Seriously, I am alarmed that someone would ask you ro weld this up for testing.
Reply:definately a bigger lug and weld with either stick or dualshield wire!
Reply:To tell you the truth I never even looked at the lug as far as the size of it.... I would go with a lager lug as well._________________Chris
Reply:I dont want to hear about any Darwin Award recipients on this board.Would a 4 point distributed system work better?  That's alot...no, ALOT of weight.ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Thanks for all the replys. Your answers confirm my concerns about weight/vs weld area and overall strength.  I am not really sure of any alternative ways to test these clamps.  The size of the cylinders is set, and I need to simulate a static load from the base of these cylinders, thus the tab.I talked to a buddy this pm and he has access to a load testing machine up to 55 tons.  I may make a mock up piece and let him pull it untill it breaks.Anybody want to speculate on breaing point?(the tab is to be welded to the flat  (bottom) side of the cylinder).
Reply:The fillet leg length on each side of the lug would have to be 2/3rds of the thickness for full strength.  With the preparation you have shown and a half inch fillet in addition my guess is that the pin hole will tear out.  I am guessing that you have about 1/2 of an inch of meat on both sides of the pin hole.  That makes for a full square inch in cross section.  My guess is that you will see stretching of the hole at 20 tons load.   As for the condition of the shackle pin????   I am doubting that you will be able to get more than a five ton shackle on that hole.  Shackles have easily five to one safety factor.
Reply:Rigging is designed with a safety factor when it is made and if I'm not mistaken it usually is 5x the rated load.
Reply:lotechman- so you think the pin will tear out of the tab before the welded tab breaks loose?  The shackles are destruction tested @ 6x the rated working load.Still- no guesses as to failure load rate?
Reply:Also, which method would yeild best results in this case.a 180 amp tig weld (multiple passes) or a couple passes with a 200A Mig?
Reply:Originally Posted by zapsterthen I'd "stitch " weld it all the way around twice....zap!
Reply:I would go with a bigger tab also, and as mentioned a bigger hole in it.  What will you get to go in that little hole that can support the weight?As for dualshied, etc....  I would absolutely not use it, or any other form of mig weld on it.  Fact is that they are more likely to allow inclusions of slag and/or have lack of fusion...due to cold starts, and lumpiness.  I'd tig weld it and be done, knowing that the weld would pass a 100% xray inspection.
Reply:Originally Posted by Engloid  I'd tig weld it and be done, knowing that the weld would pass a 100% xray inspection.
Reply:Originally Posted by TEKThat would be ok for you, but what of us mortals?  I'd probably multi-pass with 7018---
Reply:Atleast when you do the test let us see what happened........pics would be nice.
Reply:hopefully tommorow - test results posted for sure.
Reply:find the shackle you're gonna use for starters, a crosby 17 ton shackle pin is somewhere between 1 1/8 to 1 3/4 inch i forget.  for the love of god don't use anything from india or china.  what are you using for rigging?If you like the idea of TIG remember that you still have to create a fillet weld that has a leg length of 2/3rd the thickness of the plate.  That is a little more than 5/8 inch.  Your bevel prep will have to be wider in order to get fusion in the root with TIG.  You will need at least 200 F preheat on the bar so that the weld does not cool too rapidly after welding and aid in proper fusion.  I still think that if you do a properly sized weld the plate will tear at both sides of the hole.
Reply:I went to China recently, and can tell you that they have no standards for making anything.  They have no idea what welding certifications are....much less standards for composition of filler metals or any metals.
Reply:If the pin through your lug is mild structural steel with a tensile yield strength of 36,000 psi and a shear strength of 18,000 psi, then for a factor of safety of 5 and calculating the needed strength based on double-shear of the pin you would need a pin 6 inches in diameter.Make the pin out of an alloy steel with tensile strength of 100,000 psi and a shear strength of 50,000 psi, and then the required pin diameter for a factor of safety of 5 and based on double shear is 3.5 inches.Your lug is WAY too small.Instead of welding a 'shark-fin' lug onto the surface of the 7 inch diameter shaft, how about a big lug with two holes in it.  One 7 inch diameter hole for the big shaft and the other hole to suit the tensile machine attachment point.  Weld the tab to the 7 inch shaft if you like.  Of course that means you have a lug that's now at least 9-10 inches wide and maybe 15 inches long made out of 1 inch or 2 inch thick mild steel.Yeah, I tend to build things strong.
Reply:Originally Posted by EngloidI would go with a bigger tab also, and as mentioned a bigger hole in it.  What will you get to go in that little hole that can support the weight?As for dualshied, etc....  I would absolutely not use it, or any other form of mig weld on it.  Fact is that they are more likely to allow inclusions of slag and/or have lack of fusion...due to cold starts, and lumpiness.  I'd tig weld it and be done, knowing that the weld would pass a 100% xray inspection.
Reply:I'm thinking the hole will tear out.DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:Originally Posted by TEKThis is a contradiction of terms. You can not "stitch" weld "all the way around".Stitch weld is better defined as skip weld. You weld an inch, you skip an inch, you weld an inch, you skip an inch. Stitch weld.Airwolf, go with lotechman on this. No way is that tab big enough!!
Reply:Originally Posted by Airwolf.....below are a few pics of a tab that I plan to TIG weld in 2 or 3 passes.  It will be used to lift aprox 35K lbs.  I really don't have any experience with industrial type stuff like this (mostly .375 wall or thinner).  It just seems like a lot of weight.....
Reply:Originally Posted by MoonRiseIf the pin through your lug is mild structural steel with a tensile yield strength of 36,000 psi and a shear strength of 18,000 psi, then for a factor of safety of 5 and calculating the needed strength based on double-shear of the pin you would need a pin 6 inches in diameter.
Reply:Oooops, bad math on my part up above (don't calculate critical formulas late at night when you are tired!)   The mild steel pin with a shear stress limit of 18,000 psi needs to be 2.5 inches in diameter for a Fs=5, based on double shear of the pin.The alloy steel pin with a shear stress limit of 50,000 psi needs to be 1.5 inches in diameter for Fs=5 based on double shear of the pin.If you make the double-hole lifting block out of mild structural steel 2 inches thick and 10x18 inches with a 7 inch diameter hole for your main shaft and the hole center is located 6 inches from the end and a 2.5 inch diameter hole for your lifting pin with that hole center located 4 inches from the other end, you would have a localized safety factor of only 2.34  based on equivalent stress and tensile yielding and 2.15 based on shear stress near the 2.5 inch hole with most of the rest of the block having a safety factor of 5+.  The block would weigh ~78 pounds.The attached fille has a picture of the lifting lug block and the safety factors color-coded for a 35,000 pound load.  I turned the block sideways to get the image size to upload OK, the load was applied inline stretching the two holes apart.  The image exaggerates the deformation of the holes into an oblong shape, actual deformations are calculated at 0.002 inch maximum. Attached Images
Reply:Thats cool moonrise!
Reply:As for Zap stating stitch weld, I'm sure he ment to stitch prior to welding so tacks or welds donot crack!
Reply:Originally Posted by MoonRiseOooops, bad math on my part up above (don't calculate critical formulas late at night when you are tired!)
Reply:Thanks for all the replys, I made a mock up piece and will have it yield tested tonight.  Below are pics of the test piece.3 passes 2 root and one, stitch.And yes, this will be a one time use piece. Attached Images
Reply:Deleted By MeI guess MoonRise isn't the only one who wasn't thinking clearly...... I thought the pick weight was 35 tons and not 35,000pounds. So forget my excavator comparison..... more like picking up 1/2 that excavator. OOPS!!Last edited by lorenzo; 01-29-2007 at 06:54 PM._________________Chris
Reply:The analysis was done quickly.  Fix bottom half of the big hole and apply 35k load to top of small hole.  Find material in the materials library for "structural steel", looked pretty close to an A36 steel.  Hit "solve".  Look at pretty picture and figure out it would probably survive, but didn't quite meet Fs=5 and could be optimized and prettied up some.I did not put a cross-pin through the small hole for this analysis.  I'll try to remember and redo that load case tomorrow.
Reply:Lorenzo,regarding comparing 35 tons to 35,000 pounds as the load.  That's just the proof-test with a Fs=2.
Reply:Originally Posted by MoonRiseLorenzo,regarding comparing 35 tons to 35,000 pounds as the load.  That's just the proof-test with a Fs=2.
Reply:Airwolf...... Where in the heck is your company's mechanical engineer? I'd hate to see OHSA show up there and people are "guessing" whether something is designed correctlywith that much a stake.  Most places would want a PE to sign off on something as dangerous as that lift or pull.....  How will it be tested anyway ? lifted with what ? Even offering an opinion on a forum like this exposes yourself to some level of liability.... the ONLY thing I agree with the Japanese is that we have too many lawyers !!!!you guys should work in the aviation industry where it is guaranteed you will have a law suit with every failure, whether you had anything to do with it or not, specially if you have an insurance !   That's the main reason I'm not full time in the aviation business for sure.Hope it all works out SAFELY what ever you do. That's what I think everybody here wants.Not a beginner, not a pro !
Reply:Originally Posted by AirwolfThanks for all the replys, I made a mock up piece and will have it yield tested tonight.  Below are pics of the test piece.3 passes 2 root and one, stitch.And yes, this will be a one time use piece.
Reply:I saw the pics..I give it a reluctant thumbs up...When I first replied I thought 35 hundred lbs..But after seeing it..If possible do that one more time...I see whats going on here..too bad there's no room for gusetts......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:OK, so I ran another pretty picture.   All materials mild structural steel (36,000 psi yield).Dimensions of big disk = 7 inch OD x 4 inch thickDimensions of lug = 1.5 inch thick x 5 inch wide x 7 inch tallHole through lug = 2.6 inch dia, center of hole 3 inch from top of lugPin = 2.5 inch OD x 12 inch longWeld fillets = full-penetration .75 inch filletsThe pin would weigh 17 pounds, and the full welded lifting lug would weigh 57 pounds.Gravity is on, and the temperature is 71.6 deg F.The bottom of the lug disk was fixed, and a uniform 35,000 pound load was applied to pull up on the pin.The color-coding is for the safety factor based on tensile yield stress, and the worst-case value is calculated as 1.3.  That's the red color.  The weld area is just fine.  But the pin and the pin hole aren't so good. Attached Images
Reply:What kind of program you runnin moonrise?
Reply:Test is complete, thanks again for all the replys.   Short answer is this:Pre-pull welds tested with magnaflux- both passedtest unit pulled to 55,000 lbs, at which point the smaller of the two shackle pins (1") started to bend.Post test welds also passed magnaflux testing.I will post some pics in the AM.very cool program Moonrise!!By the way, I am simply building these units per someone elses request and based soley on thier design.   I am stating CLEARLY on several documents as much.
Reply:I did the solid models in Pro/Engineer first, then just rolled the geometry into the ANSYS for the analysis.Now I don't remember if I listed the right safety factor on the pin or not.  I'll have to doublecheck the results file tomorrow.
Reply:I usually prefer to minimize the number of components in things, less things to fail.Just a thought ..can the billet your lifting  be longer and simply drill a hole though that?No lug to fail?