Bending hot rebar
Bending hot rebar
(OP)
Is it allowed to heat #7 or #8 bars to bend the end to form a hook?
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RE: Bending hot rebar
If the proper heating and cooling procedures are used, I don't see why not, depending on the grade. What grade are you using?
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Bending hot rebar
RE: Bending hot rebar
If as reinforcing steel usually cold working is used with rebar bending machines to achieve specific minimum bending radii. I'm sure you know all this, but the purpose is to ensure no change is made to the metallurgical properties of the steel. Will the final shape comply with your local codes?
RE: Bending hot rebar
Someone here will soon give you that reference. Mine is packed away.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Bending hot rebar
"Heating and Bending
Hot bending is not a normal factory operation. It is more likely to be done on-site, generally with poor supervision and inadequate quality control. Since the strength of the steel will be reduced, uncontrolled hot bending is a dangerous practice.
As a general rule, heating Grade D500N bars of any type must be avoided at all times. AS3600-2009 Clause 17.2.3.1 (b) gives a maximum temperature for reinforcement as 600° C. At 600° C the bar is only just starting to change colour. If any colour change is observed whilst heating, the reinforcement should be discarded. If the bar is heated over 450º C, the steel is softened due to changes in the crystalline structure of the metal. Once heated over 450º C the yield strength of the bar is reduced to 250 MPa. The only practical method of monitoring heat in the bar is the use of heat crayons.
Galvanised bars should not be hot bent.
Using Bars after Heating
Overheating beyond 600°C will alter the structure of the steel. 450°C has been found to be a realistic limit because above this temperature the yield stress, while under load, reduces to 250 MPa."
RE: Bending hot rebar
There are days when I wake up feeling like the dumbest man on the planet, then there are days when I confirm it.
RE: Bending hot rebar
ACI 301 would be a reference if it is applicable. You are limited in the heat that may be applied to the bar and the heat that may be applied near existing concrete should the bar already be cast in place.
Is the desire to hot bend because the proper reinforcing bar was not sent to the field?
Onsite fabrication of bars of this size with hand tools using heat as a substitue for proper benders is not a good idea.
Daniel
RE: Bending hot rebar
joe, the short answer is no. Why not just insist on properly sourced material from a reputable fabricator/supplier. If Bubba refuses, then tell him it's on him.
RE: Bending hot rebar
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Bending hot rebar
RE: Bending hot rebar
RE: Bending hot rebar
RE: Bending hot rebar
I agree, Saw first hand what a torch and a pipe and/or sledge hammer will do to a rebar. Rebar broke like glass. Made them replace the are effected and splice new bars. they were not happy since it involved removing formwork.
RE: Bending hot rebar
ht
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
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RE: Bending hot rebar
Dik
RE: Bending hot rebar