Rod Wear Research Articles

Features wear nodes mechanization wing aircraft operating under dynamic loads

The conducted researches of titanic alloy ВТ-22 at dynamic loading with cycled sliding and dynamic loading in conditions of rolling with slipping. It is established that roller jamming in the carriage increases wear of rod of mechanization of a wing to twenty times. The optimum covering for strengthening wearied sites and restoration of working surfaces of wing’s mechanization rod is defined.

Transfer Solid Lubrication of Aluminum Sliding Contacts

The effects of transfer from solid lubricant sticks of unfilled, glass-filled, and bronze-filled PTFE on the room-temperature wear and friction of trailing primary contacts of aluminum (6061 T6) rods in repetitive intermittent contacts were investigated in a ring-on-rod configuration. The materials of the ring countersurfaces upon which the solid lubricants transferred and against which the trailing aluminum rods wore included steel, aluminum, copper, and an oxide dispersion-strengthened copper alloy. This sliding of the unlubricated copper ring countersurfaces against the aluminum led to the roughening of the copper as large (> 1 mm) aluminum particles embedded themselves upon the countersurface, with consequent transitions in the aluminum wear rate and the coefficient of friction to values exceeding 6 × 10− 3 mm3/Nm and 0.6, respectively, after an incubation period of several initial contacts of lower wear rate and friction. The other ring countersurface materials resulted in similarly high aluminum rod wear rate and coefficient of friction, more nearly from the onset of sliding. The application of unfilled PTFE solid lubricant transfer reduced the aluminum's gouging of the copper countersurfaces and correspondingly reduced the aluminum rod wear rate and the coefficient of friction against the copper, as well as against all other countersurface materials, towards 2 × 10−3 mm3/Nm and 0.3 or less, respectively. Glass- and bronze-filled PTFE transfer lubricants provided reductions in the wear rate of the aluminum rod comparable to or in some cases better than the unfilled PTFE, though the unfilled PTFE transfer lubricant in several cases provided better friction reduction.

The effect of countersurface thermal properties on the melt wear of aluminum

The effect thermal properties of countersurface materials may have on the melt wear of aluminum is investigated. Aluminum (6061 T6) rod specimens were tested in a ring-on-rod configuration against five different ring countersurface materials: stainless steel (304); steel (4130); aluminum (6061 T6); copper (C101); and Glidcop (Al-25). In each test, sliding contact was produced for a brief 2s duration at pressure p = 1.76 MPa and speed v = 5.6 m/s during which friction was measured while rod wear was characterized by post-test mass measurement. At this common combination of contact pressure and sliding speed, heated tests against each countersurface material were conducted at far-field surrounding temperatures of 260, 300 and 330 °C. Aluminum rod wear rates ranged from 102 × 10 −3 mm 3/Nm against stainless steel to 1.23 × 10 −3 mm 3/Nm against copper at 330 °C, from 59.0 × 10 −3 mm 3/Nm against stainless steel to 0.66 × 10 −3 mm 3/Nm against copper at 300 °C, and from 30.9 × 10 −3 mm 3/Nm against stainless steel to 0.68 × 10 −3 mm 3/Nm against copper at 260 °C. Baseline tests were also conducted at room temperature, where rod wear rates all remained below 0.5 × 10 −3 mm 3/Nm as rod melt could not be achieved by sliding contact with any of the ring countersurfaces at such low far-field temperatures for the given contact pressure and sliding speed conditions. In heated tests, rod wear increases with increasing bulk temperature, since a smaller portion of the frictional heat is required to bring the sliding interface to the aluminum rod's melt temperature, thus leaving a greater balance of the frictional heat to go into the aluminum rod's phase change and melt wear. Rod melt wear increases with variation of ring countersurface material as follows: copper; Glidcop; aluminum; steel; stainless steel. This variation was found to be in agreement with the analytical prediction of the ring material's conduction effectiveness in partitioning heat away from the contact interface, thus reducing the heat going into the aluminum rod and its melting.

Downhole Beam Pump Operation: Slippage and Buckling Forces Transmitted to the Rod String

Abstract New results for downhole beam or rod pumps from fairly recent test data are in conflict with traditional relationships. Additional testing is in progress. A pump with large plunger/barrel clearance will cause high fluid slippage. A pump with smaller clearance will cause less fluid slippage, but a tighter fit will tend to increase rod buckling at the pump to a greater degree and may lead to advanced pump and rod wear rates. Therefore, it is important to be able to predict pump slippage and also related forces at the downhole pump. Considerations for pump leakage and example calculations are presented using the older and the new pump slippage relationships. A derivation to account for the pump velocity effects on slippage is also presented. The effect of pump clearances on possible rod buckling above the pump is also studied. Further additional possible causes of rod buckling are presented, discussed, and compared. The results will help the reader to decide on sizing pump clearances to provide leakage for pump lubrication without losing too much on pump efficiency. Several ideas on the sources of rod buckling, such as flow through the travelling valve, and the plunger-barrel interaction are presented and compared. A review of methods to combat rod buckling above the pump is presented. Introduction Pump slippage occurs primarily on the upstroke, occurs through the plunger-barrel interface, and serves to lubricate the plungerbarrel action. Usual industry minimum requirements are quoted to be in the range of 2 – 5% of production to provide lubrication. This figure could come under scrutiny when slippage becomes better defined. If the slippage is too large, then the system becomes inefficient. This can be due to a worn plunger-barrel, and/or travelling valve, or sizing the pump with an excessive clearance. Recent tests(1–3) indicate that older equations(4, 5) used by industry for years may have over-predicted the slippage. If verified, then pumps can be sized with larger clearances, reducing plungerbarrel friction, and possibly eliminating some of the compression at the bottom of the rod string without allowing excessive leakage. In this paper, a derivation of the slippage equation is developed, which also gives a contribution to slippage due to plunger velocity. Since buckling considerations may arise from pump clearance and other factors, rod buckling equations are presented and reviewed. Rods buckle due to outside forces acting up against the bottom of the rod string on the downstroke. It is well known that buoyancy forces do not contribute to buckling(6). Thus, only negative "effective" forces that exclude buoyancy contribute to buckling and "true forces" that include buoyancy should not be used when considering buckling. An example of how to calculate the rod projected area and buoyancy induced pressure forces is presented and examples of calculating "true forces" and "effective forces: are also presented. Contributing factors to rod buckling include the force to slide the plunger in the barrel and also the pressure drop across the travelling valve as the pump travels downward.

Sucker Rod Wear In Directionally Drilled Steamflood Wells

Abstract Husky Oil's Thermal Operations District in the Lloydminster, Saskatchewan area, has had extensive experience with sucker rod wear in directionally drilled steamflood wells. Husky's two major steamflood projects, the Aberfeldy Steamflood Pilot (steam drive) and the Pikes Peak Pilot (cyclic with some post-cyclic stream drive), have drilled and produced directional wells from pads since 1983. As expected, the frequency of wear-related sucker rod failures in directionally drilled wells is much higher than in conventional vertical wells. Through careful data gathering and analyses, Husky has attempted to quantify the degree of incremental wear as well as identify the controlling mechanism(s) (i.e. maximum dog-leg, maximum hole angle, etc.). Rod wear-related problems are described in depth. The frequency and location in the rod string of the wear-related failures are compared with a number of parameters to determine the major factors contributing to rod wear. The various methods and items tested by Husky to reduce and control rod wear are described and discussed. A summary of conclusions based on the data as well as a suggested rod/tubing maintenance program are included in this paper. Introduction Husky Oil Operations Ltd. has been active in the Lloydminster, Saskatchewan / Alberta, heavy oil fields since 1946 and currently operates over 2000 producing wells and five active enhanced oil recovery (EOR) pilots. The Lloydminster operators produce from a series of lower Cretaceous sands at depths between 400 m and 600 m. The sands are reasonably clean, moderately sorted, and poorly consolidated. Porosity can vary between 25% and 35%. Permeability ranges from 0.5 darcies to 8 darcies. The oil produced in the area is dense and viscous. Density is generally between 911 kg/m3 and 980 kg/m3. Viscosity can be as high as 131 Pa •s. The original-oil-in-place in the Lloydminster area has been estimated at 500 million m3(1). Probably less than 10% is recoverable by conventional means, EOR recoveries have been estimated at 25%. Pad Well Completions Husky began drilling EOR wells from pads in 1983. The advantages of pad drilling are well documented and accepted by the operating companies in the area. The close spacing used in the EOR pilots (as low as 1 ha), the reduced cost of fluid injection and production lines, the centralization of facilities, and the large reduction in surface area requirements make pad drilling of EOR wells especially attractive. Husky currently has over 100 pad wells in its EOR pilots. Pad sizes vary between 3 and 14 wells. The wells are typically equipped with 178 mm casing, 89 mm EUE tubing, 22 mm grade C sucker rods, and 64 mm rod (insert) pumps. When the first pad wells were brought on stream in 1983 (at the Pikes Peak Cyclic Steam Pilot), the field personnel were expecting to have significant rod wear problems. The frequency of rod wear-related servicing was higher for the new wells but not alarmingly so. The installation of rod rotators and the implementation of a rod maintenance program kept the problem under control.

Fuel assembly repair and control rod inspections / Brennelement-Reparatur und Abriebuntersuchungen an Regelund Sicherheitselementen.

Approximately 8500 fuel assemblies have been analysed for defects during the past years. Repair equipments and procedures for replacing defective fuel assembly components during outages were provided. Experiences from these activities are given. Various control rod wear inspection methods are described which have been used for several years

Wear resistance of sintered sockets for the ball-ended pins of automobile steering rods

1. Irrespective of the socket material, the wear of the ball-ended pins of the longitudinal steering rod is less than that of the pins of the transverse steering rod. 2. The wear of ball-ended pins depends to a large extent on the socket material: pins operating in conjunction with sintered (two-layer and carburized) sockets wear less than those operating with standard steel 20 sockets. 3. The wear of sockets depends on their material. Thus, two-layer sintered sockets of the longitudinal steering rod wear 7–9 times more rapidly than the same sockets made of the carburized sintered material. The extent of wear of the latter sockets is approximately the same as that of steel 20 sockets, which is of great importance in the case of sockets of the longitudinal and transverse steering rods. 4. The sintered sockets employed in this investigation exhibited no cracking, cleavage, or other defects, which confirmed their adequate reliability under operating conditions.