AMP - Aviation Maintenance Technician Powerplant Practice Exam

Cylinder barrels can be hardened through various processes such as nitriding, honing, quenching, and tempering. However, honing involves the smoothing or polishing of the barrel's surface and does not contribute to its hardening. Quenching and tempering also do not directly harden the cylinder barrel. Quenching involves rapidly cooling the heated barrel in a liquid to increase its strength, but does not change its hardness. Tempering is a process of reheating the quenched barrel to a specific temperature, which helps to decrease its brittleness but does not harden it. Nitriding, on the other hand, involves introducing nitrogen into the surface of the barrel, forming a hard and wear-resistant layer, thereby hardening the cylinder barrel. This makes it the correct option for the process of hardening cylinder barrels.