What can result from overtightening a flareless tube fitting?

Overtightening a flareless tube fitting can indeed lead to the cutting edge damaging the tube itself. Flareless fittings are designed with a cutting edge that bites into the tube when the fitting is tightened. This creates a seal that prevents leaks. However, if excessive force is applied, the cutting edge can cut too deeply into the tube material, compromising its integrity. This can lead to issues such as weakened structure, potential failure of the fitting under pressure, or even catastrophic leaks.

In contrast to this, other options suggest different failure modes that are less relevant to the mechanics of flareless fittings. For instance, while leakage is a concern with improper fitting, it generally arises from a failure to seal properly, not specifically from overtightening causing deep cuts. Similarly, wearing out of the tube or fracturing of the fitting might occur under different stress conditions or from material fatigue, but the primary risk associated with overtightening is the risk of excessive cutting. Thus, focusing on the consequences of overtightening highlights the critical nature of applying the correct torque to maintain the integrity of the fitting and ensure proper operation.