Untempered 100 ksi bridge plate (mill processing failure)

Bob Summers's scuttlebutt explanation for a plate with 160 ksi strength and 5 foot-pound Charpy toughness — it slipped through the mill without tempering.

We had a problem with a piece of quenched and tempered plate, 100 ksi steel like HY100, but it was a lower chemistry because it wasn't quite as thick. It was a bridge steel. I was reading about it in the Bethlehem Steel report — I don't remember if it was Bethlehem Steel plate or just a problem the Federal Highway Administration had. The Charpy toughness was like 5 foot-pounds. It was terrible. I didn't understand this. I was asking Bob Summers, the grand old man of welding — a Lehigh grad at Bethlehem Steel, one of our grand old men of welding. I said, "Bob, how can this steel be so bad?" He said, "Well, scuttlebutt is it went through the mill without tempering. It had 160 ksi strength and it was glass brittle because they hadn't bothered to temper it. It slipped through the process without getting tempered."