http://www.navytimes.com/news/2009/07/navy_toledocracks_072109w/ (http://www.navytimes.com/news/2009/07/navy_toledocracks_072109w/)
Crack found in hull of submarine Toledo
By Andrew Scutro - Staff writer
Posted : Wednesday Jul 22, 2009 19:48:30 EDT
Sailors discovered a crack in the attack submarine Toledo prior to the boat getting underway in Connecticut, which will likely lead to inspections of other submarines, according to a Navy spokesman.
Crew members last Friday discovered a 21-inch crack in the topside hull, as well as a corresponding one-inch crack in the pressure hull that would have leaked water if the ship was submerged, the spokesman said.
"The submarine was pierside in New London," said Lt. Patrick Evans, spokesman for Submarine Group 2. "The Navy is conducting additional tests to determine the extent of the crack and the proper procedures to repair it."
The width and location of the crack were not yet available.
"After a cause is determined, other submarines will conduct similar inspections," he said.
Because of the one-inch crack in the pressure hull, "water would have entered Toledo if submerged," Evans said.
"Heard it from a friend who, heard it from a friend who, heard it from another..."
Word on the street that I heard is that this weld and some other faulty welds have a single welder in common; records are being pulled and its primarily HIS welds that are being investigated.
It's just rumor-mill at this point, but if it's true, I'd like to send that bastard out to sea in a tube that I welded...
Quote from: G-reg on Aug 01, 2009, 10:41
"Heard it from a friend who, heard it from a friend who, heard it from another..."
Word on the street that I heard is that this weld and some other faulty welds have a single welder in common; records are being pulled and its primarily HIS welds that are being investigated.
It's just rumor-mill at this point, but if it's true, I'd like to send that bastard out to sea in a tube that I welded...
Which, if this is how it turns out, the welder and whichever weld inspector signed off for it might be 'laying some rod' for a while at the shipyard in Leavenworth...
Quote from: HydroDave63 on Aug 01, 2009, 11:33
Which, if this is how it turns out, the welder and whichever weld inspector signed off for it might be 'laying some rod' for a while at the shipyard in Leavenworth...
I welded Submarine pressure hulls for 15 years. I gotta tell ya,if there was a flaw in any welds of this type the people who x-rayed,UT'ed or MT'ed the joint would catch it.You can't "pin" it on the welder.Sure I've had repairs on a few welds in my day.I don't think anyone has not had a "bad" weld at one time or another.That crack could have been a result of sub-standard HY-80 steel that some how slipped through,who knows.I don't think the welder or anyone else for that matter will be going to Leavenworth.
seeing as I am a weld inspector for a living now, I can tell you that NDE will not catch every single indication or problem in a weld. Based on RT film density, contours of the welds, and a host of other variables, you will not catch small indications such as porosity or small slag inclusions. This could always be a problem with low-hydrogen rods. If they weren't properly conditioned, they absorb hydrogen out of the air and it gets trapped in the welds, then over time and cyclic stresses, those tiny hydrogen pockets expand and contract so much that they finally fail. There are any number of reasons that these welds could have failed. The only true way to tell what the failure mechanism is would be to take out that section of the hull and have the samples put through extensive Non-Destructive and Destructive testing. Until that is done, there really isn't any way to say what the cause was.
More to the point: Was it a cracked weld? The article only stated a crack, not a cracked weld. Could have been in the HAZ just as easily. Maybe the weld tested SAT, but the heat treatment skated by a little short and left the HAZ and weld metal grain size just a little too coarse. Enter inter-granular corrosion in the presence of repeated stress cycles and you have a crack. I'm sure they'll chop out a chunk and analyze it. I doubt, though, that we'll ever find out the results.
Quote from: adam_grundleger on Aug 02, 2009, 11:24More to the point: Was it a cracked weld?
According to this article (http://www.dailypress.com/business/dp-biz_toledo-submarine_0722jul22,0,3033376.story), no.
QuoteNeither crack is part of a weld, and therefore is not connected to welding issues at the Newport News yard, the Navy said.
the article keeps refering to the item that cracked as a casting. If it was a steel casting, there could be untold amounts of problems in there from trapped air bubbles, laminations, incomplete fusion of materials, to who knows what. Once again let us not jump to conclusions about welders, weld inspectors, or anyone else.