Friction and Wear in Threaded Surfaces of Rotary Drill Collars

1993 ◽  
Vol 115 (1) ◽  
pp. 23-31
Author(s):  
H. R. Thornton ◽  
E. I. Bailey ◽  
J. S. Williamson
Keyword(s):  
Normal Stress ◽  
Friction And Wear ◽  
Rotation Angle ◽  
Sliding Contact ◽  
Ring Specimen ◽  
Dynamic Coefficients ◽  
Phosphate Coatings ◽  
Heat Treated ◽  
High Normal Stress ◽  
Effect Of Surface

Two surfaces, under high normal stress, in sliding contact provide the basis for friction and wear studies within rotary drill collars. Flat and ring specimens, considering three (3) different contact areas, were rotated to determine the effect of surface finish, coatings, lubricants and normal stress on friction and wear. The 4145 steel specimens were heat-treated to a yield strength of 124,000 lb/in2 (855 MPa) and a Rc hardness of 28. The torque required to rotate the ring specimen was measured as a function of the rotation angle. The friction coefficient was calculated. Seizure and galling were common for metal-to-metal contact. Rust and phosphate coatings break down under the high normal stress. Metal-filled lubricants produce static coefficients of friction (μs) between 0.03 and 0.25 and dynamic coefficients between 0.04 and 0.26. Seizure and galling were not observed.

scholarly journals Evolution of Friction and Permeability in a Propped Fracture under Shear

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Fengshou Zhang ◽  
Yi Fang ◽  
Derek Elsworth ◽  
Chaoyi Wang ◽  
Xiaofeng Yang
Keyword(s):  
Normal Stress ◽  
Shear Loading ◽  
Particle Crushing ◽  
Normal Loading ◽  
Fracture Surfaces ◽  
Frictional Strength ◽  
Transport Response ◽  
Shear Slip ◽  
High Normal Stress ◽  
Proppant Embedment

We explore the evolution of friction and permeability of a propped fracture under shear. We examine the effects of normal stress, proppant thickness, proppant size, and fracture wall texture on the frictional and transport response of proppant packs confined between planar fracture surfaces. The proppant-absent and proppant-filled fractures show different frictional strength. For fractures with proppants, the frictional response is mainly controlled by the normal stress and proppant thickness. The depth of shearing-concurrent striations on fracture surfaces suggests that the magnitude of proppant embedment is controlled by the applied normal stress. Under high normal stress, the reduced friction implies that shear slip is more likely to occur on propped fractures in deeper reservoirs. The increase in the number of proppant layers, from monolayer to triple layers, significantly increases the friction of the propped fracture due to the interlocking of the particles and jamming. Permeability of the propped fracture is mainly controlled by the magnitude of the normal stress, the proppant thickness, and the proppant grain size. Permeability of the propped fracture decreases during shearing due to proppant particle crushing and related clogging. Proppants are prone to crushing if the shear loading evolves concurrently with the normal loading.

scholarly journals Friction and Wear Mechanism of Zirconia in Unlubricated Sliding Contact

1996 ◽  
Vol 104 (1211) ◽  
pp. 659-661
Author(s):  
Masahiro OHGOSHI ◽  
Mitsuhiro FUJITA ◽  
Seiichiro HIRONAKA
Keyword(s):  
Wear Mechanism ◽  
Friction And Wear ◽  
Sliding Contact

Rotation of the principal stress directions due to earthquake faulting and its seismological implications

1995 ◽  
Vol 85 (5) ◽  
pp. 1513-1517
Author(s):  
Z.-M. Yin ◽  
G. C. Rogers
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
Principal Stress ◽  
Stress Drop ◽  
Rotation Angle ◽  
Overburden Pressure ◽  
Rupture Area ◽  
Earthquake Faulting ◽  
Stress Directions ◽  
Before And After

Abstract Earthquake faulting results in stress drop over the rupture area. Because the stress drop is only in the shear stress and there is no or little stress drop in the normal stress on the fault, the principal stress directions must rotate to adapt such a change of the state of stress. Using two constraints, i.e., the normal stress on the fault and the vertical stress (the overburden pressure), which do not change before and after the earthquake, we derive simple expressions for the rotation angle in the σ1 axis. For a dip-slip earthquake, the rotation angle is only a function of the stress-drop ratio (defined as the ratio of the stress drop to the initial shear stress) and the angle between the σ1 axis and the fault plane, but for a strike-slip earthquake the rotation angle is also a function of the stress ratio. Depending on the faulting regimes, the σ1 axis can either rotate toward the direction of fault normal or rotate away from the direction of fault normal. The rotation of the stress field has several important seismological implications. It may play a significant role in the generation of heterogeneous stresses and in the occurrence and distribution of aftershocks. The rotation angle can be used to estimate the stress-drop ratio, which has been a long-lasting topic of debate in seismology.

Tribological Performance Optimization of Electroless Nickel Coatings Under Lubricated Condition

2018 ◽  
pp. 250-280 ◽  
Author(s):  
Santanu Duari ◽  
Arkadeb Mukhopadhyay ◽  
Tapan Kumar Barman ◽  
Prasanta Sahoo
Keyword(s):  
Performance Optimization ◽  
Friction And Wear ◽  
Electroless Nickel ◽  
Heat Treating ◽  
Wear Depth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Electroless Ni ◽  
Scanning Electron

The present chapter aims to determine optimal tribo-testing condition for minimum coefficient of friction and wear depth of electroless Ni-P, Ni-P-W and Ni-P-Cu coatings under lubrication using grey relational analysis. Electroless Ni-P, Ni-P-W and Ni-P-Cu coatings are deposited on AISI 1040 steel substrates. They are heat treated at suitable temperatures to improve their hardness. Coating characterization is done using scanning electron microscope, energy dispersive X-Ray analysis and X-Ray diffraction techniques. Typical nodulated surface morphology is observed in the scanning electron micrographs of all the three coatings. Phase transformation on heat treating the deposits is captured through the use of X-Ray diffraction technique. Vicker's microhardness of the coatings in their as-deposited and heat treated condition is determined. Ni-P-W coatings are seen to exhibit the highest microhardness. Friction and wear tests under lubricated condition are carried out following Taguchi's experimental design principle. Finally, the predominating wear mechanism of the coatings is discussed.

scholarly journals The Effect of Surface Texturing on Dry Gross Fretting

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 92 ◽  
Author(s):  
Agnieszka Lenart ◽  
Pawel Pawlus ◽  
Slawomir Wos ◽  
Andrzej Dzierwa
Keyword(s):  
Friction And Wear ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Disc Surface ◽  
Abrasive Jet Machining ◽  
Wear And Friction ◽  
Steel Disc ◽  
Disc Configuration ◽  
Effect Of Surface ◽  
Ball On Disc

The effect of steel disc surface texturing on dry gross fretting in a ball-on-disc configuration was studied. Dimples were created with abrasive jet machining. The tribological performance of sliding pairs, steel–steel and steel–ceramics, was experimentally studied. The character of surface texturing effect was related to the dominant wear type. During steel–steel contact, the presence of dimples on disc surfaces could lead to increases in wear and friction. However, the escape of wear debris into dimples could result in reductions of friction and wear in the steel–ceramics configuration.

The effects of e-beam irradiation induced cross linking on the friction and wear of polyamide 66 in sliding contact

Wear ◽  
2010 ◽  
Vol 268 (7-8) ◽  
pp. 905-910 ◽  
Author(s):  
R. Feulner ◽  
Z. Brocka ◽  
A. Seefried ◽  
M.O. Kobes ◽  
G. Hülder ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Sliding Contact ◽  
Cross Linking ◽  
Beam Irradiation ◽  
Polyamide 66
Sign in / Sign up

Export Citation Format

Share Document