How to handle hard pat turning in a few lines
2. At this (lower critical temperature) temperature the steel is very soft, softer than the normal mild steel at room temperature. Hence it is very Important to heat the steel before cutting.
3. Like soft steels, you can't cut hardened steel at any speed. To cut hardened steel you need to have a minimum temperature, called the critical temperature. This means it is necessary to soften steel before cutting.
4. We have to generate heat by rubbing the cBN against the steel, thit is technically called cutting speed which has to be between 80 and 120 meters per min.
5. Suitable feed and depth of cut must be used in order to maintain the cutting zone at a temperature good enough to soften the steel.
6. It is like a Black Smith heating the axe before hammering.
7. A more suitable example to differentiate soft steel and hardened steel cutting would be:
A. Cutting an onion using a knife is like cutting soft steel, you shear the metal.
B. Scooping solidified ice cream using a HOT or very HOT Spoon is like cutting hardened steel - If you don't heat the spoon scooping becomes difficult.
8. cBN - c in lower case and BN in Upper case. c is not the chemical composition, it is the physical structure. B and N are chemical structure B for Boron and N for Nitrogen.
9. Hot hardness describes a metal’s ability to hold its hardness (hardness equivalent to the hardness MOM temperature) during elevated temperatures.
10. cBN can hold its hardness at high temperatures, even when the zonal temperature is red hot it (cBN) retains its hardness.
Thus, it is possible to Turn Hardened Steel, In FACT IT IS SOFTER THAN SOFT STEEL. That is why it is a Myth. "A Myth Called Hard Part Turning'.