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  • 1. Carlevi, Jens
    et al.
    Lundmark, Jonas
    Prakash, Braham
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological performance of different functional surfaces of piston and cylinder bore2005Ingår i: Book of Abstracts: International Tribology Conference KOBE / [ed] N. Ohmae; H. Ishigaki, Tokyo: Japan Society of Tribologists , 2005, s. 211-Konferensbidrag (Övrigt vetenskapligt)
  • 2.
    Kassfeldt, Elisabet
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Lundmark, Jonas
    Tribological properties of hardened high strength Boron steel at combined rolling and sliding condition2009Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 267, nr 12, s. 2287-2293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of hardened high strength steel is found in applications where high wear resistance is required. The wear properties of high strength Boron steel are well known in applications with abrasive wear from stones, ore and other hard material. A unique concept of wear protection of rails is newly presented, a wear resistant cap made of hardened high strength Boron steel.Reducing the wear of rails and wheels and controlling the frictional behavior in the wheel/rail contact are two key issues for railway owners in order to reduce the increasing costs related to higher axle loads, higher speeds, more frequent traffic, etc. Therefore, the aim of this work has been to investigate and compare the tribological properties of Boron steel and UIC 1100 rail steel in contact with Blue Light wheel steel (AAR Class C (69-JDG-8)) under dry and water lubricated conditions in a two-disc tribometer. Advanced analytical instruments including 3D optical surface profiler, micro-hardness indenter, light microscope and SEM/EDS were used to analyze the results.Results from the experiments show that the friction coefficient in tests with Boron steel is more stable both in dry and water lubricated conditions than tests including UIC 1100 rail steel used in todays application. Surface damages seen from water lubricated tests on UIC 1100 rail steel are not seen on the surface of the Boron steel discs. In all tests, the wear decreased when water was added in the contact and friction was slightly decreased.

  • 3.
    Kassfeldt, Elisabet
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Lundmark, Jonas
    Tribological properties of hardened high strength boron steel at combined rolling and sliding conditions2008Ingår i: Proceedings of NORDTRIB 2008: 13th Nordic Symposium on Tribology / [ed] Jaakko Kleemola; Arto Lehtovaara, Tampere University of Technology, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of hardened high strength steel is found in applications where high wear resistance is required. The wear properties of high strength boron steel are well known in applications with abrasive wear from stones, ore and other hard material. A unique concept of wear protection of rails is newly presented, a wear resistant cap made of hardened high strength boron steel. Reducing the wear of rails and wheels and controlling the frictional behaviour in the wheel/rail contact are two key issues for railway owners in order to reduce the increasing costs related to higher axle loads, higher speeds, more frequent traffic etc. The cost of the rail material when replacing a section of the rail is just a small portion of the total cost. Planning, disturbance of traffic and loss of income during the maintenance are some of the larger parts of the total costs. Likewise, the large difference in frictional behaviour in the wheel/rail contact of materials used today creates huge problems. Friction at the rail head needs to be high enough to withstand the traction force when accelerating and braking while the friction at the gauge corner should be low to save energy and give good steering capability of the train. The low friction at the gauge face can be achieved by using rail lubrication but the controlled friction at the rail head at different temperatures and other weather conditions is still a problem. In order to reduce the total costs it is therefore crucial to reduce the time for replacing the rail and increasing the service life of the rail. The ReRail rail cap has the potential to do both.There are almost no results published regarding the tribological properties of Boron steel in contact with other metallic materials for mechanical engineering applications. Therefore, the aim of this work has been to investigate the tribological properties of boron steel in contact with Blue Light wheel steel under dry and water lubricated conditions in a two-disc tribometer. Advanced analytical instruments including 3D optical surface profiler, micro hardness indenter, light microscope and SEM/EDS were used to analyse the results.Results from the experiments show that the friction coefficient in tests with boron steel is more stable both in dry and water lubricated conditions than tests including UIC 1100 rail steel used in todays application. Surface damages seen from water lubricated tests on UIC 1100 rail steel are not seen on the surface of the boron steel discs. In all tests, the wear decreased when water was added in the contact and friction was slightly decreased.

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  • 4.
    Kassfeldt, Elisabet
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Lundmark, Jonas
    Prakash, Braham
    Sundgren, Anders
    Gleim AB.
    Wear properties of hardened high strength boron steel for rail cover2007Ingår i: High tech in heavy haul: Proceedings. International Heavy Haul Conference / [ed] Thomas Nordmark; Per-Olof Larsson-Kråik, Luleå: Luleå tekniska universitet, 2007, s. 539-546Konferensbidrag (Refereegranskat)
  • 5.
    Lundmark, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Rail grinding and its impact on the wear of wheels and rails2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Rail grinding has been employed since the 1980s in maintaining optimal rail profile as well as in the elimination of surface defects such as corrugations and head-checks. Likewise, the wheel sets also require re- turning to remove surface defects and restore the desired profile. The influence of surface roughness in the wheel/rail contact has been a concern for railway owners since the introduction of rail grinding as a maintenance strategy. Presently, there are no scientifically derived guidelines regarding the surface topographies of ground rails and re-turned wheels. There is thus a need to establish well defined guidelines regarding the surface topographies for new surfaces on the rails and wheels in order to minimize grinding cost/time and improve wheel/rail performance. This thesis concerns the influence of surface roughness of wheel/rail surfaces on running-in behaviour, wear, friction and resultant surface damage. The results presented in this thesis are based on both field measurements and experimental simulations in the laboratory. A two-disc rolling/sliding test machine has been used in the experimental work to simulate the wheel/rail contact. The test specimens were manufactured from actual wheel/rail parts. The maching/finishing parameters were chosen in such a way as to obtain different surface roughness on the test specimens. A Design of Experiment approach (DOE) has been used to conduct experiments and to analyse the results. Results obtained from the field measurements show that the surface roughness of a newly ground rail changes rapidly during the initial stages following grinding. It was also concluded that there is a considerable variation of the surface roughness of re-turned wheels depending on which workshop performed the turning operation. Experimental results show that the surface roughness of the test specimens in certain material pairs do influence wear, friction and resultant surface damage. There is also a significant difference in the tribological behaviour of tests run in dry conditions and those run with water lubrication.

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  • 6. Lundmark, Jonas
    et al.
    Höglund, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Prakash, Braham
    Running-in behaviour of rail and wheel contacting surfaces2006Ingår i: AITC-AIT 2006: 5th International Conference on Tribology ; 20 - 22 September 2006, Parma, Italy, 2006, s. 33-Konferensbidrag (Refereegranskat)
  • 7. Lundmark, Jonas
    et al.
    Kassfeldt, Elisabet
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Hardell, Jens
    Prakash, Braham
    Influence of initial surface topography on tribological performance of the wheel/rail interface during rolling/sliding conditions2007Ingår i: High tech in heavy haul: Proceedings. International Heavy Haul Conference. Specialist Technical Session / [ed] Thomas Nordmark; Per-Olof Larsson-Kråik, Luleå: Luleå tekniska universitet, 2007, s. 673-680Konferensbidrag (Refereegranskat)
  • 8. Lundmark, Jonas
    et al.
    Kassfeldt, Elisabet
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Hardell, Jens
    Prakash, Braham
    The influence of initial surface topography on tribological performance of the wheel/rail interface during rolling/sliding conditions2009Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 223, nr 2, s. 181-187Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of surface roughness in a rail/wheel contact has been a concern for railway owners since the introduction of ‘rail grinding' as a maintenance strategy. Presently, there are no well-defined guidelines regarding the surface topographies of ground rails and re-turned wheels. There is thus a need to establish scientific guidelines regarding the surface topographies for the rails and wheels in order to minimize grinding costs/time and to improve rail/wheel performance. This study is aimed at investigating the influence of surface topographies of wheels and rails on running-in behaviour, wear, friction, and the resultant surface damage through experimental simulation in the laboratory. A two-disc rolling/sliding test machine has been used in this experimental work. Two different roughness values were produced on both the rail and wheel test specimens. A design of experiment approach has been used to conduct experiments and to analyse the results. The results show that the surface roughness values of the specimens in some material pairs do influence wear, friction, and resulting surface damage.

  • 9.
    Vuorinen, Esa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Pino, David
    Luleå tekniska universitet.
    Lundmark, Jonas
    Prakash, Braham
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Wear characteristics of surface hardened ausferritic Si-steel2007Ingår i: Journal of Iron and Steel Research International, ISSN 1006-706X, E-ISSN 2210-3988, Vol. 14, nr 1, supp 1, s. 245-248Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High strength steels can be produced by austempering of Si-containing steels. It is possible to achieve high toughness and good wear resistance in these steels. Surface hardening of this group of steels can further increase the surface hardness and wear resistance and in combination with high strength in the bulk, also the fatigue strength. Surface hardening by laser-hardening has been performed on steel 55Si7 after austempering of the steel in order to create a ferritic-austenitic carbide free microstructure. Tempering effects and hardness values have been studied. Optical as well as scanning electron microscopy has been used together with x-ray diffractometry in the characterization of the micro-structural changes. Wear resistance testing of austempered and laser hardened samples respectively of the Si-alloyed steel have been reported and also compared with that of the conventional Cr-alloyed steel. The results of the specific phase transformation from austenite to martensite during wear process will be reported

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