Proper heat treating after bending?

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I am repairing a lawn dethatcher, and a 1/4" mild steel bracket was bent.  I heated it up to dark cherry with my oxy/fuel torch and bent is back to its original shape.  My question is, isn't the metal now softer than before?  My welding instructor indicated that an oil cooling bath was best followed by water cooling to restore original hardness. What would you do in this situation?Chris
Reply:Tempering is a huge topic.But if you have heated it up hot to bend and allowed it to cool slowly it going to be fairly well anealed. Depends on the aloy though.If you heat it up hot and water quench it it will be very hard but brittle, then the next step is to reheat it slowly to the temper color and alow it to cool very slowly.Here is a good guide for color change to get the right degree of hardness you are loking for. The harder it is also in general the more brittle it will be. http://www.anvilfire.com/index.php?bodyName=/FAQs/temper_colors_hardness.htm&titleName=Temper%20Colo  rs%20and%20Steel%20Hardness%20:%20anvilfire.comLincoln PT185 TIGLincoln 175 MIGLincoln 240 amp AC StickLind Needle Arc plasma welderPlasma cutter, soon???
Reply:One thing though is different alloys will have slightly different color changes at the same temperature. I grafted a piece of 5150 steel onto a cheep mild steel axe head and heated them both up to 450 deg, the 5150 was a straw color and the mild more blue. So color is not always fool proof indicator of temperature.Just how the hardening goes will depend on carbon content, if the base metal has little carbon it won't harden much.Lincoln PT185 TIGLincoln 175 MIGLincoln 240 amp AC StickLind Needle Arc plasma welderPlasma cutter, soon???
Reply:Its low carbon mild steel.  Heating nor rapid quenching will have a negligable impact on hardness/softness.  Just leave it be, and don't worry about it.