Strange steel

[Peter Simpson 3Participant @petersimpson3]

I recently purchased some 3/32 x 3/4 En3B flat bar. I cut the bar into 6 inch lengths and reduced it’s width to 1/2 wide. The first step in the project was to mark off the bar approx. one inch from the end of the stock. Then using a vise and a hammer bend the bar to just less than 90 degrees.

As the bar approached 80 degrees it fractured in a strange way. It did no fail across the tight bend. It failed and the break appeared very flakey. I have never seen steel fail like this. I wondered if it was actually spring steel. Before attempting to bend the next length I used my propane torch to raise it to cherry red left it cool. I bent sixteen other lengths with no issues.

Any ideas what caused it ?

[noel shelleyParticipant @noelshelley55608]

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.

[Peter Simpson 3Participant @petersimpson3]

Noel, That is a very good description “”countless layers of mill scale”  The original lengths had a very good external finish, not sure as to why heat treating the bar solves the bending problem ?

[noel shelleyParticipant @noelshelley55608]

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

[bernard towersParticipant @bernardtowers37738]

If it where me I would ask the supplier where in the world it came from.

[duncan webster 1Participant @duncanwebster1]

• 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

[Peter Simpson 3]

On Peter Simpson 3 Said:

The original lengths had a very good external finish, not sure as to why heat treating the bar solves the bending problem ?

It was probably cold rolled if it had a good finish – i.e. fully work hardened. Annealing obviously reverses this.

(It’s still possible that the very end of the bar was a bit funky.)

 

 

[bernard towersParticipant @bernardtowers37738]

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

[Michael GilliganParticipant @michaelgilligan61133]

Strange Steel …

https://youtu.be/szBiPDIokDE?feature=shared

 

MichaelG.

[noel shelleyParticipant @noelshelley55608]

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.

[SamsarandaParticipant @samsaranda]

Michael that video is frightening, steel that’s as brittle as glass, being used as rebar in concrete construction. I note the country of origin, as we gradually decimate our manufacturing industries our economy will increasing rely on imports and the accountants will of course insist on purchasing the cheapest on the market, I think it is a sad future for our historically great manufacturing nation.  Dave W

[Andrew JohnstonParticipant @andrewjohnston13878]

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

 

[mark costello 1Participant @markcostello1]

We used to have a cast iron mold foundry in town. A machinist was milling down a piece of cast iron down and with a surprise tried to cut a ball bearing with a high speed mill cutter. The shape of the bearing was still evident in the bar stock. It was bought to the attention of the cast iron foundry and They joked that a trucker came in and asked what was the price of the raw materials They were buying. When They told Him the price He said He would sell His truck for that much a pound. So They bought it. He took off the gas tank and tires and They cut it all up and it went into the furnace. I have personally had rebar with a clear change of metal in the cut. Bottom was cast iron colored, top was steel colored.

[Dave HalfordParticipant @davehalford22513]

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.

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