Section 3: Heat treat

80% receiver blanks and bending flats come in a "Softened" state and need to be heat treated for long life and proper function. The ejector on the left lower rail also needs to be hardened. Since most finishes that you will apply to the completed firearm will require that it be baked at 400 degrees or more we will only concern ourselves with spot heat treating the FCG holes and the ejector. The hammer and trigger pin holes on both sides of the receiver need to be hardened due to the amount of stress they receive during the life of the rifle. 

You will need the following tools                                                You will need to following materials 

MAPP gas torch                                                                           Sand paper

Pliers                                                                                            Pail of water

Work Gloves

There are two steps to heat treating metal for an AK receiver. The first is to harden it by taking it up to 1500 degrees F and then quenching it. This will make it very hard but also very brittle. The second step is to temper it by taking the metal up to 800 degrees F and letting it air cool. MAPP gas will heat the metal to the proper temperatures in a reasonable span of time. The way to gauge the temperature of the metal is by color. When the metal gets to a bright glowing orange/yellow it is time to quench it in the pail of water. Sand the treated area to bare metal and reheat it until it is a gray/blue. At this point set it aside to air cool. Do the ejector (Left lower rail) first to get a feel for the process.

You will also need to heat treat the hammer and trigger holes (FCG). These are the pivot pin holes located on both sides of the receiver. Heat and quench each hole and then temper them individually and let them air cool.

CYA message: This web page is posted for informational and educational use only. Any other use of the information on this website is solely at the user's risk