What is the main difference between corrosion fatigue fracture and stress corrosion fracture of drill pipe?


I. Crack initiation and expansion: Stress corrosion cracks and corrosion fatigue cracks are sent to the material surface. Under strong corrosive media and high stress conditions, stress corrosion cracking can even occur on smooth surfaces (and stress concentration, of course), and the corrosion fatigue cracks are caused by stress concentration without exception.


2. The relationship between subcritical crack expansion rate and stress Advisory factor and frequency: the rate of corrosion fatigue crack growth is affected by frequency. However, in most cases, the stress intensity factor is controlled. Stress corrosion cracking is different, which is mainly controlled by time.


3. Fracture morphology: The singular velocity expansion zone of stress corrosion crack crack is generally rougher than that of corrosion fatigue crack, and there is no shelling mode of corrosion fatigue. A kind of


Drill pipe is an important part of drill string. Its main function is to transfer torque and drilling fluid. The drill pipe is gradually lengthened to deepen the wellbore. Therefore, drill pipe plays an important role in oil drilling.