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View Full Version : Is steel rebar useful for HMS projects?



browniesharp
04-18-2008, 04:00 PM
I've collected an assortment of rebar over the last 30 years in mixed sizes but mostly 3/4 or 1 inch diameter. Is this a decent steel for machining (lathe turning) or is it variable in quality like the cast iron in window weights?

lynnl
04-18-2008, 04:03 PM
What I've tried to turn in the lathe (about 5/8") I would classify as some of the crappiest metal I've ever tried to cut.

Best use I've found for it is as the sacrificial anodes for electrolytic derusting.

Fasttrack
04-18-2008, 04:25 PM
Yep ... once in a blue moon you find a piece that machines well and is usefull for stuff, once you get the ridges knocked off of it, but most of the time its pretty well crap. It works good as rebar, annodes, or the misc weld/fab projects that come up. For instance, I use rebar to make tongs for my forge, make handles for oddball tools, etc. Basically anywhere you need a bit of cheap leverage or reinforcement, rebar comes in handy.

Al Messer
04-18-2008, 06:51 PM
I have had terrible experience with trying to machine re-bar any time I've tried it. BEST SCROUNGED STEEL I've found for machining is damaged hydraulic rams that have had to be replaced. I don't know what it is, but it turns beautifully, has a nice finish and is resistant to rust.

snowman
04-18-2008, 06:55 PM
It's great. I take it to the scrap yard and trade it for aluminum, every fifteen pounds of rebar gets me a pound of aluminum.

oldtiffie
04-18-2008, 09:10 PM
Makes great fubar.

Steve Steven
04-18-2008, 09:15 PM
Forty years ago, when I was in engineering school, we were given a piece of rebar by our graduate assistant to cut, polish, etch and make drawings of the resulting matrix we found.

He began to become very agitated about our sketches, saying they "weren't right". Turns out he was expecting something like 1018 steel, and we were seeing something else.

Long story short, he dug into where the steel came from and found out it came from a small remelting plant down the road from us, and the rebar had been rolled directly (without remelting) from railroad rails!

Steve

lazlo
04-18-2008, 09:42 PM
Construction-grade rebar in the 'States is governed by ASTM A615, which you can't read or download unless you're an ASTM member, but I've read that like the bolt standards, it doesn't specify an alloy, just minimum mechanical properties. If I remember correctly, there's 40, 50 and 60 Kpsi rebar.

My experience, like everyone else's, is that rebar from Home Depot or Lowes, which surely doesn't even meet the Grade 40 ASTM standards, machines like dogsh!t. Which is surprising to me, since even A36 (structural steel) machines OK.

oldtiffie
04-18-2008, 09:57 PM
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My experience, like everyone else's, is that rebar from Home Depot or Lowes, which surely doesn't even meet the Grade 40 ASTM standards, machines like dogsh!t. Which is surprising to me, since even A36 (structural steel) machines OK.

You're surprised!!

How surprised do you think the dog feels?

Willy
04-18-2008, 10:01 PM
It must be my turn to take a quote from Wikipedia:

Grades
Rebar is available in different grades and specifications that vary in yield strength (http://en.wikipedia.org/wiki/Yield_strength), ultimate tensile strength (http://en.wikipedia.org/wiki/Ultimate_tensile_strength), chemical composition (http://en.wikipedia.org/wiki/Chemical_composition), and percentage of elongation (http://en.wikipedia.org/wiki/Elongation_%28materials_science%29).
The grade designation is equal to the minimum yield strength of the bar in ksi (http://en.wikipedia.org/wiki/Pound-force_per_square_inch) for example Grade 60 rebar has a minimum yield strength of 60ksi. Rebar is typically manufactured in grades 40, 60, and 75.
Common specification are: [2] (http://en.wikipedia.org/wiki/Rebar#cite_note-1)

ASTM (http://en.wikipedia.org/wiki/ASTM) A615 Deformed and Plain Billet-Steel bars for concrete reinforcement
ASTM A616 Rail-Steel Deformed and Plain bars for concrete reinforcement
ASTM A617 Axle-Steel Deformed and Plain bars for concrete reinforcement
ASTM A706 Low-Alloy Steel Deformed and Plain bars for concrete reinforcementHistorically in Europe, rebar comprised mild steel material with a yield strength of approximately 250 N/mm˛. Modern rebar comprises high-yield steel, with a yield strength more typically 500 N/mm˛. Rebar can be supplied with various grades of ductility (http://en.wikipedia.org/wiki/Ductility), with the more ductile steel capable of absorbing considerably greater energy when deformed - this can be of use in design against earthquakes (http://en.wikipedia.org/wiki/Earthquake) for example

lazlo
04-18-2008, 11:21 PM
You're surprised!!

How surprised do you think the dog feels?

Well, I wait for it to come out first -- that helps ;)

fishfrnzy
04-19-2008, 01:08 AM
addinig to the prvious info:

A615 is remelted "whatever" steel that will give the minimum yields that the specs require. It has hard spots and is not mixed very well as to the distribution of alloy contents. It will machine and weld like crap. It is brittle and is not suitable to weld for structural purposes.

ASTM A706 is weldable rebar and should be used any time welding is required. It to comes in various grades but the chemistry is more closely controlled and therefore it is more ductile. It is frquently used welded to "embeds" on tilt up buildings, concrete colunm caps, and bridge bearing plates.