Concrete Reinforcing Bar

For some reason every new blacksmith is familiar with or has some rebar.

It is terrible material for anything other than what it was designed for. A few smiths have used it to make tools but it should be a material of last resort. A few artists use it for its "industrial" texture.

REBAR varies a great deal. It is one of those products that is sold based on ASTM minimum performance specifications which do not specify the exact material. OLD rebar is pretty trashy stuff being rolled from the cut off ends of billets that often had pipes, inclusions and cold shuts. NEW modern rebar is a much better product but still meets a performance spec not a material spec..

REBAR typically comes in three grades. Structural, Intermediate and Hard grade. Hard grade was often made from re-rolled railroad rail (50 - 75 point carbon) or scrap from making same. Structural grade is roughly the same as A36 structural steel. Intermediate is most common. Chemically phosphorus is limited to 0.11%.

The problem with using scrap rebar in blacksmithing as in using any other scrap is determining exactly what you are working with.

The textures rolled onto rebar vary from manufacturer to manufacturer and can be an identifier or even make it collectable like old barbed wire.

RE-BAR Structural Intermediate Hard
Tensile 55-75 Kips 70-90 Kips 80 Kips min
Yield (min) 33 Kips 40 Kips 50 Kips
Concrete Engineering Handbook, LaLonde and Janes

-- guru Sunday, 12/27/98 21:36:21 GMT

Is rebar good for tool making ? Can it be hardened ?

Mark - Tuesday, 01/16/01 19:29:13 GMT

Rebar: Mark, There are three different grades of rebar with different hardenabilities. Then there is OLD rebar which is generally non-specific as to specs or quality. No version is designed to be used as a tool steel. It IS done but I don't recommend it. You are much better off to use spring steel or recyle old tools.

- guru Tuesday, 01/16/01 19:44:42 GMT

Rebar: Concrete reinforcing rod (rebar) is specified in three grades by minimum strength. This means there is not a specific material spec. So it can be plain carbon OR alloy steel. Since the specs are minimums the strongest can be used to replace the lower two grades. Steel much stronger than needed can also be used. I believe the high strength grade can be satisfied by a medium carbon steel (30 to 40 point carbon).

Long ago rebar was made from "scrap". This was cut off ends of billets that has a core shrink and produces bar with a cold shut. It also varied in carbon content from one place in the bar to another. Pretty nasty stuff but it met the specs of the time. It is not unusual to come across this material today.

Sound like a vague answer? Its a vague material. Every piece you use may different from the next. I prefer not to use it except for what is was designed for. Old spring steel is too easy to come by and is a much better material. Using scrap like springs you still don't know exactly what you have but you know it was a better quality material to start with. You also have some clue to what it might be.

- guru - Friday, 01/19/01 04:52:22 GMT

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