Arizona pipeline stacker bracket failure

Worked example of ductile-vs-brittle visual diagnosis. Arizona, ~2015. Big forklift lifting fifty tons of pipeline pipe; the holding container failed; millions of dollars damage. From photos alone Tom saw the steel had bent before breaking — ductile, therefore overload failure. "I didn't even have to go see it."

I remember as a sophomore, Professor Backofen said the longer you think about a tensile test, the less you understand it. The tensile test is a very complex test. Brittle fractures show little or no distortion, they occur in the elastic regime. Ductile failure occurs in the plastic regime. One of the first things I do when I go look at a fracture — sometimes I only look at a photo someone sends me — I'm looking to see if there's any stretch to the metal. Out in Arizona, a year ago, some guys had some big forklift machine lifting pipes for a pipeline. The thing that was holding all these pipes — they were lifting up fifty tons of pipe — and the container on the forklift broke, did a lot of damage, millions of dollars of damage. Someone said, well, why did it fail? I looked at the photos, and the steel bent before it broke. So the steel is ductile. I knew right there it was an overload failure. I didn't even have to go see it. I sent someone else to go look at it.

Tom's insurance-adjuster consulting case. Carbon steel weld on a special bracket on a pipe-stacker forklift failed without I-beam deformation — Tom diagnosed defective welds from a single photograph using the Lincoln Electric reference: properly made fillet weld in mild steel will outpull the metal.

I've seen a picture of it. They were stacking pipe for a new pipeline out in Arizona, and this stacker, which is like a great big forklift that can carry five or six lengths of 40-foot-long pipe — weighs tons, just a huge forklift — well, it broke. They had built a special bracket, just a carbon steel weld. When I looked, there was no deformation of the I-beam. They didn't bend before the weld broke. All I had was a picture — kind of like from here to the back of the room — of the failure of these things that are this size. I called up the insurance adjuster and said, defective welds. He said, how can you tell? I said, the base metal didn't bend before the weld broke. I have a book by Lincoln Electric that's been around for 50 years that says, for mild steel, a properly made fillet weld will outpull the metal for any direction or magnitude of load. Mild steel — not HY80, but most steel weld is mild steel.