When it comes to titanium knives, the devil is in the details. Talk to hunting enthusiasts and they'll point to the light and tough blade, which is resistant to cracking and chipping, noncorrosive in the murkiest of forests, and stable in hot or icy weather. Cut a steel knife with a titanium blade, and the sight — titanium cutting through steel as if through rubber — will make even veteran hunters break a giggle. The process does hardly any structural damage to most titanium blades. If you own a knife made from a more economical titanium alloy, you can increase the rigidity with a solution treating process, followed by age treating.
Things You'll Need
Oil or water bath
Call the manufacturer to inquire about the type of alloy your piece is made of. Titanium alloys come in alpha, beta or alpha-beta alloys.
Thoroughly clean the furnace in which the titanium will be hardened. Prepare sheets of stainless steel on which to air-cool titanium.
Set the furnace temperature to the correct specifications: 1,800 to 1850 degrees Fahrenheit if titanium part is alpha alloy; 1,750 to 1,775 degrees if alloy is alpha-beta alloy; and 1,425 to 1,475 degrees if the alloy is beta alloy.
Charge the titanium alloy into furnace, employing the charging tongs, and make sure you wear the protective garb. Heat the titanium sheets and thin plates for up to 30 minutes, and thicker parts for up to one hour.
Remove the titanium pieces from the furnace using the charging tongs.
Quench the titanium part in a suitable quenching media: a water bath or air for alpha-beta and beta titanium alloys, and an oil bath for alpha alloys. If quenching is done in a bath, quench the thick sections first, the cylindrical pieces straight up, and the flat pieces on edge. Move the titanium part through air or agitate the quenching medium to break down steam bubbles.
Reheat the furnace to temperatures of between 1,050 and 1,010 degrees for alpha titanium alloys, 900 to 1,100 degrees for alpha-beta alloys and 800 to 900 degrees for beta alloys.
Charge the cooled titanium part in furnace.
After a minimum of two hours, remove the titanium piece and allow it to air cool. Lay the titanium piece on steel sheets to cool.
Choose electric, gas, or oil furnace that retains a minimum 3 percent level of oxygen.
Avoid controlled atmosphere furnaces that use hydrogen, nitrogen and cracked ammonia. Do not let the titanium make direct contact with the flame.