Heat exchanger fell off the truck

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80,000 lb nat gas heat exchanger being trucked to a heat treating facility.Inspection report said that there was no cribbing under the saddles.  Driver turned a corner and the weight of the HX caused the saddles to rock on the trailer bed deflecting the bed allowing the boomers on the outside-turn side to get slack allowing the hooks to disengage.  Trailer exited the turn causing HX to rock to the inside.  HX rolled off the trailer and landed on a nozzle.  Nozzle tore out at shell.  No one injured.Proposed repair is to cut out a 16" x 16" section at the damaged nozzle, inspect / replace / re-hydro the tubes, weld on an oversized "patch" with new nozzle, re-hydro the shell, re-stamp the data plate....three weeks turnaround.Lessons learned...trailers bend....distribute the load.Interesting to note the almost perfect tear-out at the HAZ....almost looks like it was cut w/ a torch and template. Attached ImagesMiller 211 w/ spool gunMiller Dynasty 200DXLongevity 60i IGBT plasmaO/A w/ crappy chinese torch/gaugesSouth Bend 10K latheGrizzly 4029 10x54 millGrizzly 7x12 hor bandsawangle grnders, bench grnder, bench belt sndr7.5 hp 80gal cmprsor
Reply:JB weld ?
Reply:Originally Posted by BTDLessons learned...trailers bend....distribute the load.
Reply:If you need a backup welder, I can head that way with my 110v millermatic.....
Reply:I can chew up some gum quick.. Stick it on, be good as new. Yes in deedy, good as new. Ok OK  Really Take pics looks interesting.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:I like to hook all chains and boomers to the trailer so that even if they get slack, they won't come unhooked.  It also makes it easier to chain down.Miller 250x & Lincoln V205-TSmith Oxy-Prop torch
Reply:The failure in the HAZ isn't entirely surprising; depending on what steel is used in the shell of the heat exchanger.  Cr-Mo alloys are often used in applications where there's high temperatures present because they retain their strength  at high temps better than mild steel.  That mode of failure could be normal for mild steel also; depending on a lot of factors like the thickness of the base metal relative to the weld deposit and the welding procedure used.Cr-Mo alloys will almost certainly have varied mechanical properties across the weld deposit, HAZ, and base metal.  It can be normal for the HAZ to have the lowest strength or lowest toughness(most brittle) of all the metal involved in the weldment.  It all depends on the welding procedure used.Actually, looking at the photo, even though the crack propagated around the toeline of the weld bead, you can see some ductile behavior in the rest of the weldment.  It bent before/during cracking.  This is the way it's supposed to fail; which is a pleasant surprise since I'm sure the designer didn't factor in rolling off a truck, at highway speeds, into the design....Sounds like it could be a tricky repair, depending on what the HX is made of.  Please keep us posted; I for one would love to see some photos after the repair is complete.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Correction: the HX is 55,000 lbs dry wt.Shell design press./temp is 260 psig/500 F.  (That's the shell side..the part that was damaged.  The tube side is 6,600 psig)Shell is 28" OD x .500" wall SA-516-70N.Nozzle is 6" Sch XH (.432" wall) SA-106.WPS for this nozzle calls for GTAW root ER-70S-2 and SMAW fill and cap E-7018. I'll post the photos of the repair when the job is complete.This photo shows the HX on the trailer that was used to transport the HX thru  sandblast/paint.  This is not the same trailer that was used to transport the HX to the heat treater.  Notice the cribbing under the saddles.The mfg's procedure for sandblast/paint is pretty cool.They bought an old paint booth from the New York Transit Authority.It's really two booths each large enough for a city bus or a subway car.The first booth is for sandblasting and the second is for painting.They contract with the trucker to transport the exchangers to the clients with the  understanding that the trailers have to stay at the shop for a couple of weeks.The exchangers are loaded onto the trailers after fab then rolled into the blastbooth then the paint booth...they never leave the trailer.  Then off to the job site it goes. Attached ImagesMiller 211 w/ spool gunMiller Dynasty 200DXLongevity 60i IGBT plasmaO/A w/ crappy chinese torch/gaugesSouth Bend 10K latheGrizzly 4029 10x54 millGrizzly 7x12 hor bandsawangle grnders, bench grnder, bench belt sndr7.5 hp 80gal cmprsor
Reply:Destructive testing at it's best?