The effect of friction welding on the mechanical properties and corrosion fatigue resistance of titanium alloy drill pipe

Abstract

Titanium alloys are the best candidates to replace steels for drill pipes in horizontal wells. However, friction welding (FW) may significantly change the properties of titanium alloy drill pipes. In this work, the microstructure, tensile and impact mechanical properties, and corrosion fatigue performance of the FW zone were compared with those of the base alloy. The results show that the base material is mainly composed of equiaxed globular α (hcp)‐Ti, while the acicular α + β (bcc)‐Ti is dominant in the FW zone. Due to these differences in microstructure, the FW zone has higher strength but lower stiffness and toughness than the base alloy. In addition, the fatigue performance and corrosion resistance of the material decrease in drilling fluid. These results indicate that FW zones in titanium alloy drill pipes might be the weakest region where crack, fracture, and corrosion are more likely to occur.

Effect of Piercing Temperature on Stress—Strain Distribution and Dimensional Accuracy for Ti80 Titanium Alloy Seamless Tubes Based on Numerical Simulation

“…The constitutive equation data were input into DEFORM-3D (SFTC Inc., Toronto, ON, Canada) to determine the plastic flow stress of Ti80 alloy, as shown in Figure 6. In order to obtain more accurate results of temperature parameters, it cannot be empirically considered that about 90% of plastic work is converted into heat [25,26]. The integral expression of the work heat conversion coefficient β int is as shown [27,28]:…”

Resistance of fatigue crack propagation induced by large α colony in a Ti‐Al‐V‐Mo‐Zr alloy

“…The α + β Ti alloys have received extensive attention in the field of oil and gas exploitation due to their moderate strength, high ductility, and excellent corrosion resistance. [5][6][7] As a newly developed α + β Ti alloy, Ti-Al-V-Mo-Zr is expected to be a candidate material for the oil and gas extraction industry. However, very little investigation into microstructure tailoring and fatigue behavior has been done on this alloy.…”

“…The drilling pipe is prone to micro‐cracks caused by impact load during operation, and the cracks propagate rapidly under the action of cyclic load, resulting in the fracture failure of the drilling pipe. The α + β Ti alloys have received extensive attention in the field of oil and gas exploitation due to their moderate strength, high ductility, and excellent corrosion resistance 5–7 . As a newly developed α + β Ti alloy, Ti‐Al‐V‐Mo‐Zr is expected to be a candidate material for the oil and gas extraction industry.…”

Resonant Fatigue Tests on Polished Drill Pipe Specimens

“…[40][41][42], where it was suggested that aluminium alloys, such as, for example, the superficially treated 2024 aluminium alloy, could be valid alternatives to steel due to their specific strength, their lightness compared to steel, and for their resistance to corrosion. In some situations, titanium alloys have also been promoted as good alternatives to steel for drill pipes in horizontal wells [43].…”