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  • 1.
    Taghipour, Ali
    et al.
    Sintef Petroleum AS.
    Ytrehus, Jan David
    Sintef Petroleum AS.
    Lund, Bjørnar
    Sintef Petroleum AS.
    Skalle, Pål
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Lund, Martin
    Luleå University of Technology, Professional Support, Centralverkstaden.
    Prakash, Braham
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Friction and wear characteristics of steel on rock under water and oil based lubricated sliding conditions2015In: Tribology - Materials, Surfaces & Interfaces, ISSN 1751-5831, E-ISSN 1751-584X, Vol. 9, no 2, p. 85-91Article in journal (Refereed)
    Abstract [en]

    In recent years, drilling extended reach wells have become more and more common in the petroleum industry to optimise the oil and gas production. Extended reach wells are defined as wells that have two times more horizontal step out than true vertical depth. High friction (frictional torque) and drag are two of the mechanical limiting factors while drilling longer horizontal wellbores. There are numerous methods and tools developed to lower the drillstring friction. Drilling non-circular wellbores is a new concept with potential to minimise the mechanical friction by reducing drillstring and sidewalls contact area. However, this will cause an increase of contact pressure owing to the reduced contact area between drillstring and the formation. This article presents results obtained from an experimental study pertaining to the friction behaviour using a pin on disc set-up with steel pin and granite disc in the presence of water and oil based lubricants. These tests have been designed to represent frictional contact conditions between a rotating steel drillstring and the wellbore wall at different contact pressures. Test results show that the friction coefficient decreases with an increase of contact pressure in wet condition for both water and oil based lubricants. It is also observed that the friction factor increased by adding sand and phyllite particles to the water based lubricant. Considering the wear scars, the friction coefficient shows reduction with increased contact pressure in all tests with and without particles for both water and oil based lubricants.

  • 2.
    Hardell, Jens
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Yousfi, Amine
    Luleå University of Technology.
    Lund, Martin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Pelcastre, Leonardo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Prakash, Braham
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Abrasive wear behaviour of hardened high strength2014In: Tribology - Materials, Surfaces & Interfaces, ISSN 1751-5831, E-ISSN 1751-584X, Vol. 8, no 2, p. 90-97Article in journal (Refereed)
    Abstract [en]

    Abrasive wear in industrial applications such as mining, materials handling and agricultural machinery constitutes a large part of the total wear. Hardened high strength boron steels are known for their good wear resistance and mechanical properties, but available results in the open literature are scarce. This work aims at investigating how different quenching techniques affect the two-body abrasive wear resistance of hardened high strength boron steels. Furthermore, the wear as a function of depth in thicker hardened high strength boron steel plates has also been studied. The material characterisation has been carried out using microhardness, SEM/energy dispersive spectroscopy and three-dimensional optical surface profilometry. The results have shown that water quenched and tool quenched high strength boron steel had similar wear resistance. The main wear mechanisms appear to be microcutting combined with microfatigue. Workhardening during the abrasion process has been found to affect the abrasive wear.

  • 3.
    Hardell, Jens
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Yousfi, Amine
    Luleå University of Technology.
    Lund, Martin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Pelcastre, Leonardo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Prakash, Braham
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Abrasive wear behaviour of hardened high strength boron steel2013Conference paper (Refereed)
  • 4.
    Lingesten, Niklas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Marklund, Pär
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lund, Martin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundin, Joakim
    Volvo Construction Equipment.
    Mäki, Rikard
    Volvo Construction Equipment.
    Apparatus for continuous wear measurements during wet clutch durability tests2012In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 288, p. 54-61Article in journal (Refereed)
    Abstract [en]

    Wet clutches are used in many applications today such as automatic transmissions and limited slip differentials in cars as well as in heavy duty equipment such as wheel loaders. The present study is concerned with the wear and engagement behavior of wet clutches in the latter type of application. A test rig is developed in which the wet clutch engagement is monitored during an arbitrary number of test cycles.This rig has many similarities with the SAE #2 test rig in that they are both inertia type test rigs. However, the test rig presented here has several original parts from heavy duty equipment in production incorporated into it. The data collection includes a continuous measurement of the position of the piston used to apply force on the clutch pack in addition to the separator disc temperatures, hydraulic actuating pressure and torque transfer characteristics. The measurements of the piston position can then be related to the clutch wear during a long test series.

  • 5.
    Lund, Martin
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundin, Joakim
    Volvo Construction Equipment.
    Mäki, Rikard
    Determining power and energy limits of friction systems for automatic transmissions: test equipment and methods2009In: Proceedings of the World Tribology Congress 2009: Sunday 6th to Friday 11th, September, 2009, Kyoto, Japan, Tokyo: Japan Society of Tribologists , 2009, p. 862-862Conference paper (Other academic)
    Abstract [en]

    When designing automatic transmissions the performance of friction elements such as wet clutches and wet brakes is vital to the performance and durability of the transmission. In order to achieve high performing friction systems, correct selection of friction lining and transmission fluid is required. This is combined with the need for correct mechanical design with respect to torque capacity and power/energy capacity. In the later stages of development, the friction system performance can be tuned by means of the clutch control system. This is due to the control strategy together with vehicle inertia and rotating inertias in the powertrain influencing the power and energy introduced in the clutches. In order to develop the correct mechanical design and set correct levels of freedom for the clutch control optimization, the designers need to know how much the friction system can be stressed before the transmission durability begins to be influenced in a harmful way.This paper presents methods used to determine the energy and power limits of the friction systems. Data are presented from two different test stands: One similar to an SAE #2 test stand. The latter is a novel test equipment designed to monitor clutch wear and friction under different conditions in order to find the limits of energy and power at which the friction lining durability is affected in a negative way. The test stand is built at Luleå University of Technology. Several genuine Volvo parts are used while other parts are acquired or manufactured. Several design aspects were taken into consideration. Among them was easy access for assembly/disassembly of the clutch. A list of specification requirements was put together and the test stand was designed to meet these. A list of performance attributes:- The total inertia of the system is 0.63 kgm2- The system can be braked in less than 0.5 s- The system is accelerated in less than 10 s- The wear of the clutch is measured- The temperature is measured inside the clutch- The torque transmitted by the clutch is measured- The rotation speed of the system is measured- The pressure activating the clutch is measured- The pressure is controlled with high accuracy by a fast servo solenoid valveThe inertia of the system, the rotation speed and the braking time can be changed such that different power/energy levels can be achieved. The new test stand is described in detail showing the design considerations taken to make the methods reliable.

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