I once had a failure of a boss on some 3/8″ plate ! The boss was pulled off, the area was preped and re welded only for it to happen twice more –  Conclusion ! The plate was the end of a rolling where countless layers of mill scale had been rolled in giving a plate of many layers only may be 1/32″ thick ! It had to be scrapped and a new one fitted ! Noel.

The flaw could be very isolated or the heating annealed the thin layers allowing them to bend rather than break ? Noel.

• If it was black bar then it’s already annealed. We don’t know whether the material away from the end would have exhibited the same problem. I’m with Noel, all the rubbish rolled to the end of the bar, the original steelworks should have cropped it off and chucked it back in the next feed

You dont really get any ends as the stuff is continuosly rolled and cropped, bl***y miles of it.

Bernards comment reminds me ! I once lived at Grangetown (middlesbrough ) Dorman Long Steel, the blast furnaces were outside the back door and 5 miles away was Redcar – one long steel plant. I was told that on some mills the steel came off the rolls at 20 MILES PER HOUR ! I won’t bore you with other tales ! Noel.

Almost certainly a manufacturing defect. Bright drawn mild steel is not guaranteed to be homogeneous. It can have defects, internal and external. I’ve seen both, external craters and internal defects hard enough to break a milling cutter.

Andrew

Flakey steel can be wrought iron, though how you could buy a piece today ??

I have a piece of unknown 6mm bright plate that you can hacksaw and weld. I tried to bend it into a 6″ dia curve with a 10ton bench press. I now have two pieces of the plate still dead flat. It broke with a hell of a bang.