How to Harden Carbon Steel
Increase the durability and hardness of your carbon steel tools by tempering and quenching. Tempering your steel tool restructures the alloy and content of the steel and makes it harder. Read on to find out how to strengthen your carbon steel items.
Instructions
-
-
1
Consult your machinist's handbook to find the tempering heat needed for your steel piece and set your furnace or kiln to that temperature. Be aware of what temperature your steel type begins to warp; support it carefully to minimize warping.
-
2
Choose your quenching agent. This part takes experimentation to find an agent that works best for you. Water brine and mineral oil are common. Fill your tank or barrel at least three-fourths full with the agent, which should be around 60-70 degrees Fahrenheit.
-
-
3
Holding the steel piece with your tongs, heat it evenly in the furnace until the piece glows a mild red.
-
4
Dip the piece into the quenching agent and allow it cool. Consult your handbook for the additional tempering heat necessary for your item. Heat your kiln to that temperature. Allow the quenching agent's temperature to fall back to 60 70 degrees.
-
5
Reheat the steel item in the kiln for a half-hour and then re-submerge it into the quenching agent.
-
1
Tips & Warnings
Find ways to support the piece during heating; using multiple tongs or a support frame can prevent warping. Warping is not uncommon during the quenching of the steel; experiment with different quenching agents and methods to minimize the risk of warping.
Use the proper safety equipment when hardening steel.
