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yube weld

yube weld

yube weld

(OP)
I am new to this group so please be understanding.   I need to know the best way to weld a piece of 4” A-36 steel tube (1” thick) back together to create the strongest joint without making the part any larger in diameter.  This part sees “severe duty” in all climates.  If more information is needed please let me know.

Thanks

RE: yube weld

Rebevel both ends and do a full penetration weld, which I suspect should be followed by heat treatment since its over 3/4" thick.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: yube weld

What does "severe duty" in all climates mean??????

RE: yube weld

(OP)
The tube needs the end cut off to perform some machining operations to it then put back together, not broke.  The part in question is on a winch truck in the oil fields.  Severe duty means this part will be abused until it fails. All climates means that the part may be at 0 deg. F one minute and 600+ deg. F the next. I need to take into account, freezing, internal corrosion, thermal expansion of water and steel.......

My biggest worry is the type of failure, I cannot have a catastrophic failure where parts start flying everywhere and someone gets hurt or worse. I was hopeing there was an ASME code for this.

Thanks

RE: yube weld

I would use a different steel - quenched and tempered 4340.

RE: yube weld

(OP)
No, This arm is about 25' long and sees mechanical loads.

RE: yube weld

600ºF, thermal expansion of water and steel???

If no pressure, why are you worried about thermal expansion of water and steel?  If water's inside this thing, you're making pressure there, especially if its gets heated to 600F.  

If not pressure containing, better to try a bar shape.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: yube weld

(OP)
I was thinking of using a sleeve inside to reinforce the joint.  I was concerned obout the effect of moisture between the sleeve and the tube.  Trapped miosture could freeze and turn to super heated steam when heated.  Both could cause problems.  Trapped moisture could also excelerate corrosion iside the tube where the user would not be able to see them.  

RE: yube weld

A sleeve inside an already small 4" won't have much cross-sectional area or enough geometry to give you much bending or torsional stress resistance either.  I wouldn't look for that repair to last long.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: yube weld

a sleeve on the outside would have better properties and you'd have an easier time with the weld, but I assume there is some reason you don't want to do that.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: yube weld

(OP)
The arm sits in a trough on the side of the bed that is 4 1/2" wide.  There is not much room for the O.D.as it is.  Is there a weld fitting designed for this application?  I usually have ASME and ASTM material to review but my current employer does not have them.

I am begining to think that I just need to tell the plant to find another way to machine the end of this tube without cutting it off.  What do you think?  By the way thanks for your help.

RE: yube weld

If there's no clearance for an outside sleeve, I think your best bet is just weld it back like its a pipeline joint, ie. square cut both ends, bevel both ends to 30º line them up and weld into the bevel with tack, root, filler and cap weld passes.  With a good weld, you'll recover the full strength of the pipe.  With the 1" thickness, I would think you would want to preheat the joint before welding and don't let it cool quickly afterward.  You want slow cooling to try to prevent cracking in the weld.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: yube weld

(OP)
I am not sure how good the welders are here so I'm not sure if they could handle what you mentioned, they primarily do fab welding not structural. If I have a choice, I would rather find an alternative to cutting the part in the first place.  If I have no choice, I will take your advice. Thanks

RE: yube weld

Well.. if it was designed run 'till fail, it did, so just repair it anyway you can and see how long it lasts the next time.  What else can a guy do?

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: yube weld

Quote:

With the 1" thickness, I would think you would want to preheat the joint before welding and don't let it cool quickly afterward.  You want slow cooling to try to prevent cracking in the weld.

I would highly recommend a 250 deg F preheat and use low hydrogen electrodes; E7018 H4.

RE: yube weld

69mustang,

Here's a shot in the dark.  What code mill are you running in that bad boy?  Mine is an S code.

Good luck,
Latexman

RE: yube weld

(OP)
I will have to find out.

RE: yube weld

I am assuming this is a gin pole for a hvy duty oilfield winch truck and it has been deformed where the A frame sits?  If that's the case I would not risk cutting and welding, better to replace the gin pole.

There will be liability issues if it breaks under a load.  

I would especially suggest this if, as you say, the welder quality is suspect.

There are manufacturers that can provide a replacement.  If my assumptions are correct and you need a source, let me know.  I don't know contacts off hand (maybe Leland) but I know the guy to call.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy

Website: www.oil-gas-consulting.com

RE: yube weld

(OP)
Greg,

BINGO, you win, except the part is in production, not broke in the field.  I too am a consultant; EMI has employed me to make sure that things go well.  The manufacturer wants to cut the end of the gin pole off to machine it, and then put it back on somehow.  I have told them to find a better way that did not include the above process.  I will keep you in mind during my employment with EMI.  Thanks for your help everyone.

Happy Holidays

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