Why did steel crack when heated and bent

[Canus]

Not familiar with that brand shackle but would doubt its quality. Shackles should be forged NOT cast. Am aware cast shackles are coming into the USA from China. I also suspect any rigging hardware that is painted as the paint can hide flaws in the metal preventing proper inspection prior to use. Also NEVER modify rigging hardware in any way. If you need a connector end for a winch cable purchase the proper size thimble and cable clamps and install them properly.

 

[RaisedByWolves]

Thanks for the comments. I understand the safety concerns. I have another recent post asking the question of "how to attach a hook to a cable end" there are some good suggestions there and I will post what my final solution is there. This should be a link https://www.hobby-machinist.com/threads/attach-hook-to-cable-end.109735/

In this post I was interested in the question of why the steel part cracked when I heated and bent it? And how can you bend or forge something without causing cracks. Perhaps I had it too hot or not hot enough or some alloys cannot be bent even when red hot? Can galvanizing or paint make the steel weak when it is heated? I have seen an effect like this when trying to weld metal that had previously been brazed. If a part was heated and forged into a shape how come I can't reheat it and forge it into another shape? Have others seen this?
I suspect the right answer is only work with known alloys and use an oven for proper heat treating. But when all you have is a pile of scrap metal, a torch and welder...

You can, but only with a factory full of machinery to progressively shape the part.

This goes into the flow of the metal in the die and how that shapes the grain structure.

You were going against the grain so to speak.

 

[RaisedByWolves]

Not familiar with that brand shackle but would doubt its quality. Shackles should be forged NOT cast. Am aware cast shackles are coming into the USA from China. I also suspect any rigging hardware that is painted as the paint can hide flaws in the metal preventing proper inspection prior to use. Also NEVER modify rigging hardware in any way. If you need a connector end for a winch cable purchase the proper size thimble and cable clamps and install them properly.

I’m not saying you are wrong about cheap cast shackles, but that one is indeed forged.

If it weren’t forged there would be sprue marks ground off on two high points rather than the line of snagging shown around the periphery.


.