Machining Rebar

[jtrout13]

I am wondering if anyone might have a clue about machinability of rebar (it's something used in the USA to hold together reinforced concrete pieces)? I found a large chunk of it about 6 inches long, 1 inch in diameter in my yard this morning, apparently it fell off a truck passing by my house. The thought occurred to me, this would be ideal for the column of a wobbler-type engine, and unique use the rebar, instead of throwing it away.

Any ideas?

 

[Deanofid]

It's kind of bottom of the barrel iron. They do make it to a specific recipe, and I don't mean it's junk. It machines kind of like A36 HRS, in my experience. You can get a decent finish on it, but you will have to work at it a bit. It's isn't particularly hard, but kind of tough, and chips do not come off so nice. I find that the tool sort of gouges off chips, rather than making a nice cut.

Heck, you've got it there. Give a piece a try to see if it will work for you. It's surely strong enough for engine columns.

 

[Ken I]

Like Dean said - bottom of the barrel stuff.

It's high tensile and very tough, makes great chisels and prybars and can be hardened.

However it is typically made by continuous casting from relatively small strands with no regards for cleanliness - so you can expect a lot of inclusions. This doesn't affect its properties as rebar but is lousy from a machining point of view.

With continuous casting all the junk in creation comes out with the strands. Starting with large strands, the reduction to smaller diameters improves the size of the defects but not the total % contents.

Continuous casting with induction and Argon stirring (ie quality controlled) and off bottom drawing reduces both the total % and size of the defects.

Top / Bottom poured ingots - the heavy / light junk is removed by cropping the ends.

Electoslag refined (from a cropped billet) produces the best results and most tool steels are produced this way.

There is an order of magnitude difference in the amount and size of inclusions with each step.

All steels are not created equal. Not by a long way.

FYI

Ken