EP1529852B1 - Material für gleitbauteile mit selbstschmierung und drahtmaterial für kolbenring - Google Patents

Material für gleitbauteile mit selbstschmierung und drahtmaterial für kolbenring Download PDF

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EP1529852B1
EP1529852B1 EP03761840A EP03761840A EP1529852B1 EP 1529852 B1 EP1529852 B1 EP 1529852B1 EP 03761840 A EP03761840 A EP 03761840A EP 03761840 A EP03761840 A EP 03761840A EP 1529852 B1 EP1529852 B1 EP 1529852B1
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steel
mass
graphite particles
graphite
observed
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French (fr)
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EP1529852A4 (de
EP1529852A1 (de
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Etsuo Fujita
Kunichika Kubota
Yoshiki Masugata
Yoshihiro Minagi
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Proterial Ltd
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Hitachi Metals Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

  • the present invention relates to material for use as sliding parts, e.g. piston rings, cylinder liners and vanes, which are incorporated in automotive engines or other internal combustion engines, as well as usual plain bearings, roller bearings, ball bearings, gears and dies.
  • Materials having excellent wear resistance property have been applied so far to sliding parts such as cylinder liners and vanes.
  • Materials for piston rings used in internal combustion engines, especially automotive engines have been changed from cast steel to steel wire, which is processed to ring forms.
  • the piston rings are produced in such a manner that an ingot with a predetermined composition is hot-worked to wire by forging, hot-rolling or the like, the thus obtained wire is further formed to have a given cross-sectional form corresponding to a small sectional form of a piston ring by drawing or the like, the formed wire is conditioned to have a given hardness, and subsequently the wire is subjected to bending working so as to be a ring form with a predetermined radius of curvature.
  • piston ring which are a top ring, a second ring and an oil ring. These are attached to a piston in the above order from the side of a combustion chamber of an internal combustion engine. Since the top and oil rings are operated under especially severe conditions, employment of steel material has been developed for advanced functionalization in Japan. Such an employment of steel material is a response to demands for further improvement of internal combustion engines in these days. That is, advanced functionalization of internal combustion engines are requested in response to progress of researches on post-internal combustion engines such as electric vehicles. A demand for enhancement of sliding performance has been also intensified in order to deal with diesel engines, which are driven under severe conditions, since diesel engines with a higher internal pressure make an environmental burden smaller than gasoline engines with the provisions that light oil is upgraded and that exhaust gas filters are more functionalized.
  • a steel piston ring is made resistant to abrasion and seizure by subjecting its surface, which is brought into contact with a cylinder liner, to surface-treatment such as nitriding (see the patent literature No. 1).
  • surface-treatment such as nitriding
  • piston rings are exposed to a sulfuric dewing atmosphere due to formation of SO 4 2- from sulfur contained in the fuel. Therefore, piston rings are also required to be resistant to sulfuric acid corrosion, and thus the requirement to piston rings for improved corrosion resistance property is becoming more strict than it was.
  • the present invention is proposed under the above problems, and an object of which is to provide material for sliding parts and wire material for piston rings, wherein the material for sliding parts should be provided with excellent wear resistance property by improving seizure resistance property and nitriding treatment, and wherein the wire material should have excellent property of corrosion resistance to sulfuric acid, excellent productivity and a low friction coefficient.
  • the inventors have researched and examined sliding motions of sliding parts, which are exposed to a sliding atmosphere in a state of fluid lubrication, represented by environments of piston rings, in detail. As a result, the inventors have discovered an optimum metal structure suitable for improvement of seizure resistance property and a decrease in a friction coefficient as well as a chemical composition suitable for realization of the metal structure resistant to sulfuric acid corrosion.
  • a material for use as self-lubricating sliding parts which consists of a steel comprising, by mass, from not less than 0.4 % to less than 1.5 % of C (carbon), 0.1 to 3.0 % of Si, 0.1 to 3.0 % of Mn, from inclusive zero to 0.5 % of Cr, 0.05 to 3.0 % of Ni, 0.3 to 2.0 % of Al, 0.3 to 20 % in total (Mo + W + V) of at least one element selected from the group consisting of Mo, W (tungsten) and V (vanadium), and 0.05 to 3.0 % of Cu, wherein there can be observed graphite particles having an average particle size of not more than 3 ⁇ m in a section of the metal structure of the steel.
  • the graphite particles observed in a section of the metal structure occupy an area rate of not less than 1 % in the overall area of the structural section, and have an average particle size of not more than 3 ⁇ m. More preferably, no vanadium carbides are observed in the structural section.
  • the steel contains 0.3 to 5.0 % in total of at least one element selected from the group consisting of Mo and W, and less than 0.1 % V.
  • a preferable Al content is within a range of 0.7 to 2.0 %.
  • the steel may further contain 1.5 to 3.0 % of Mo and/or not more than 10 % of Co.
  • S (sulfur) and Ca contents of the steel are controlled to be not more than 0.3 % and not more than 0.01 %, respectively.
  • the steel is subjected to nitriding treatment to use as sliding parts.
  • a wire material for use as piston rings which consists of a steel comprising, by mass, from not less than 0.4 % to less than 1.5 % of C (carbon), 0.1 to 3.0 % of Si, 0.1 to 3.0 % of Mn, from inclusive zero to 0.5 % of Cr, 0.05 to 3.0 % of Ni, 0.3 to 2.0 % of Al, 0.3 to 20 % in total (Mo + W + V) of at least one element selected from the group consisting of Mo, W (tungsten) and V (vanadium), and 0.05 to 3.0 % of Cu, wherein there can be observed graphite particles having an average particle size of not more than 3 ⁇ m in a section of the metal structure of the steel.
  • a piston ring made of the wire material has a metal structure in which sulfide inclusions observed in the structural section, being parallel to the periphery of the piston ring, are distributed such that straight lines each passing through a major axis of the respective sulfide inclusion cross one another within a cross angle of not more than 30 degrees which angle is referred to as a degree of parallelism.
  • the graphite particles observed in a section of the metal structure occupy an area rate of not less than 1 % in the overall area of the structural section, and have an average particle size of not more than 3 ⁇ m.
  • the wire material for use as piston rings preferably contains not more than 10 mass % of Co, and further contains not more than 0.3 mass % of S (sulfur) and not more than 0.01 mass % of Ca. Preferably it is subjected to nitriding treatment to use as piston rings.
  • a key aspect of the invention is realization of the particular metal structure of steel, in which fine graphite particles are precipitated in a steel matrix by a proper rate, in order to improve seizure resistance property of steeland lower a friction coefficient of sliding parts such as piston rings.
  • the present invention aims at improvement of durability fully taking peculiar frictional motions between piston rings and cylinders into consideration.
  • metal structure it is possible to attain satisfactory advantageous effects in the above posed subjects which are to improve seizure resistance property of steel and lower a friction coefficient, and on which the prior art has been unsatisfactory even in connection with non-surface-treatment material or nitrided material which is advantageous in a cost of surface-treatment.
  • metal structure with graphite precipitates the present inventors sought for chemical components which enable fully rapid precipitation of fine graphite particles and also be effective in improvement of workability and machinability of steel in order to establish the metal structure as industrially applicable means. Fruitful results are that further improvement in the above effects could be attained by addition of a single element of sulfur or of sulfur and Ca to the steel. This is another key feature of the present invention.
  • a sliding part is mainly designed for fluid lubrication, wherein a fluid film such as oil or water is constantly formed between mechanical elements which are brought into sliding contact with each other under severe conditions. Formation of the fluid film leads to application of buoyancy to a relatively moving fluid, as noted by relative motion of an airplane in the air. The fluid film between sliding parts becomes thicker as viscosity rise of the fluid or an increase of a relative velocity, so that mechanical elements are protected from abrasion.
  • a fluid film such as oil or water
  • the fluid lubricating mode comprises three actions, i.e. (1) wedging, (2) expansion/contraction, and (3) squeezing.
  • the squeezing action (3) is effective even in the state that a relative velocity becomes zero.
  • the squeezing action can be explained as follows, on the presumption that a solid plate is sliding on a base plate in presence of a fluid. On such a presumption, distribution of a pressure, which acts on a surface of the solid plate facing to the base plate, is under the boundary condition that a pressure becomes zero at an edge of the solid plate.
  • the pressure distribution shall be varied according to a domed function in order to generate a positive pressure distribution necessary for maintenance of lubrication.
  • Such pressure distribution is represented by the formula of: ⁇ 2 ⁇ x 2 ⁇ P + ⁇ 2 ⁇ y 2 ⁇ P ⁇ 0
  • ⁇ is a density of a fluid
  • h is a thickness of a fluid film
  • ⁇ is a viscosity coefficient
  • t is a time
  • u is a relative velocity.
  • Formula 3 has three terms. First and second terms, which involve the relative velocity u, correspond to the wedging and the expansion/contraction, respectively, mentioned as the above.
  • the condition that the third term is negative has the physical meaning that a fluid film rapidly decreases in thickness with the provision that the fluid density is constant, resulting in generation of a positive pressure in the fluid film.
  • Such a phenomenon is practically realized by abruptly applying a vertical load to a solid plate, which is sliding on a base plate, so as to squeeze the fluid film. Consequently, a high positive pressure is simultaneously generated by squeezing the fluid film, and the sliding plate hardly comes in direct contact with the base plate. In short, the squeezing action is realized.
  • the inventors have found that the squeezing action is intensified by reforming a sliding surface to a structure, which includes many fine pores. Fine pores in the sliding surface retain a fluid therein and instantaneously supply the fluid therefrom to a dry surface even under the condition that the fluid film is collapsed at a relative velocity being zero. A significant decrease in thickness of the fluid film, which is originated in movement of the fluid, leads to the squeezing action. As a result, seizure is inhibited in the vicinity of upper and lower dead points during reciprocating motion, and a friction coefficient is also decreased.
  • the graphite-precipitated structure according to the present invention is determined in order to achieve the above actions and effects. That is, graphite particles not only act as a solid lubricant but also promote formation of oil-retaining pores after dropout thereof.
  • the pores realize the squeezing action suitable for retention of an oil film.
  • the squeezing action which ensures formation of a stable oil film regardless of pressure fluctuations, is intensified by presence of pores on a sliding surface, as mentioned above.
  • Precipitation of graphite particles is exactly effective for intensification of the squeezing action, and the effectiveness is ensured for normal sliding parts, e.g. sliding bearings, roller bearings or ball bearings and also for sliding parts, e.g. piston rings, cylinder liners, shims of valve lifters, cams, gears, dies or cutting blades, which are difficult to constantly form such a fluid lubricant film due to significant fluctuations of a pressure.
  • the graphite-precipitated structure is also effective for inhibition of adhesive wear, which have become a problem recently, in the case where it is applied to a piston ring attached to an aluminum piston. Since aluminum is scarcely soluble in carbon, adhesive reaction is suppressed.
  • the invention material for use as sliding parts has the structure that graphite particles are distributed therein. It is important to control graphite particles, which are observed in a structural section, to a size of not more than 3 ⁇ m in average. If an average size exceeds 3 ⁇ m, graphite particles are often damaged at peripheries during sliding motion, and graphite debris unfavorably invade sliding planes.
  • the distribution of graphite particles is more effective under the condition that graphite particles observed in a section of the metal structure occupy an area rate of not less than 1 % in the overall area of the structural section. With regard to relatively large graphite particles of not less than 1 ⁇ m, it is more preferable to make the graphite particles to have an average size of not more than 5 ⁇ m or an area rate of not more than 5 % in the overall area of the structural section.
  • the invention means is effective especially for internal combustion engines, which involve reciprocating motion with difficulty to continuously form a fluid film. For instance, graphite precipitates become more effective under the condition that irregular frictional behaviors, wherein the temporary state that a fluid film is collapsed in the vicinity of upper and lower dead points at a relative velocity being nearly zero is turned to a state with a plenty of lubricating oil, are repeated between piston rings and cylinders.
  • a lubricating design which enables retention of a fluid film, is important especially under the condition that the fluid film breaks temporarily due to structural reasons, represented by relative motion between piston rings and cylinder liners. Regardless of the lubricating design, possibility of solid contact rises in correspondence with changes in rotating speeds of engines or structures of sliding parts. In this regard, application of material, wherein graphite particles effective for solid lubrication are dispersed, to such irregular sliding parts ensures sufficient lubrication under various sliding conditions.
  • a diffusion velocity of pores is raised by addition of Al, which has a high diffusion velocity in steel.
  • the higher diffusion velocity accelerates aggregation of pores, which serve as sites for precipitation of graphite particles. Consequently, precipitation of graphite particles is completed in a short time due to the effect of Al and the rapid aggregation of pores. Furthermore, precipitation of graphite particles in a surface layer only is facilitated by nitriding or the like.
  • Addition of Al is also suitable for an alloy design of a nitriding hardened steel, since Al is a nitriding hardening element.
  • Another element Cr which has the same nitriding hardening effect, unfavorably impedes precipitation of graphite particles as a fundamental technological gist of the present invention and also causes significant degradation of corrosion resistance to sulfuric acid. In this sense, addition of Cr is avoided as much as possible, but Al is alloyed as the most important element for the purpose.
  • Nitriding of graphite steel has been regarded as material inappropriate for precipitation of graphite, since precipitation of graphite particles in the nitriding steel is accompanied with the disadvantage that a nitrided layer is embrittled by presence of graphite particles of not less than 10 ⁇ m in size, which act as faults, in the nitrided layer. According to the present invention, the disadvantage is suppressed by reforming graphite precipitates to fine particles.
  • Reformation of graphite precipitates to fine particles may be achieved by either one of (1) introduction of work strains to divide graphite precipitates, (2) inclusion of Al 2 O 3 or the like and (3) dispersion of BN, TiC or the like, which serves as a site for precipitation of graphite.
  • the method (1) puts restrictions on manufacturing conditions, and the method (2) needs difficult processing for dispersion of Al 2 O 3 or the like.
  • the remaining method (3) also needs difficult processing as for high- carbon steel, since proper dispersion of BN, TiC is achieved only by strict control of trace components.
  • the inventors have studied precipitation of fine graphite particles from various aspects and discovered that precipitation of a Cu-Al intermetallic compound in a steel matrix is effective for the purpose.
  • the Cu-Al intermetallic compound i.e. a secondary phase, which serves as a site for precipitation of graphite, is precipitated at a relatively low temperature of not higher than 800°C, so as to enable formation of a stable structure with fine graphite particles in a short time. Since Cu and Al contents are controlled at levels for inhibiting embrittlement according to the present invention, a graphitic structure is formed as a lubricant phase without degradation of mechanical strength. Moreover, the additive Cu is also effective for improvement of corrosion-resistance to sulfuric acid.
  • a sliding part of the present invention is characterized by the alloy design suitable for employment of steel material, which still has properties of cast steel, in order to impart mechanical strength, wear resistance property and corrosion-resistance to sulfuric acid, which are necessary to cope with deterioration of environments, as well as sliding properties. Chemical components of the sliding part will be understood from the following explanation:
  • Si is added as a conventional deoxidizing agent and also as an accelerator for precipitation of graphite. Si is also effective for improvement of corrosion resistance to sulfuric acid.
  • a lower limit of Si is determined at 0.1 mass %.
  • the additive Si suppresses softening of steel during annealing, and the effect of Si is important especially in low-alloy steel.
  • a Si content is preferably determined at a value of not less than 1.0 mass % in order to raise high-temperature strength without annealing softening.
  • an upper limit of Si is controlled to 3.0 mass %, since excess Si unfavorably raises a A 1 temperature. Therefore, the Si content is determined within a range of 0.1 to 3.0 mass %, preferably 0.5 to 3.0 mass %, more preferably 1.0 to 3.0 mass %.
  • Mn is added as the same deoxidizing agent as Si. At least 0.1 mass % of Mn is necessary for deoxidation, but excess Mn impedes precipitation of graphite. In this sense, an upper limit of Mn is controlled to 3.0 mass %, and a Mn content is determined within a range of 0.1 to 3.0 mass %.
  • Cr is an effective nitriding hardening element, but unfavorably suppresses decomposition of semi-stable cementite and strongly impedes precipitation of graphite. Also Cr significantly deteriorates corrosion resistance property to sulfuric acid. Therefore, an upper limit of Cr content is controlled to 0.5 mass. In this sense, a Cr content is determined within a range of 0 to 0.5 mass %, preferably 0 to 0.3 mass %.
  • Ni is an accelerator for precipitation of graphite and also effective for inhibition of red shortness, which often occurs in Cu-alloyed steel, but unfavorably raises solubility of carbon in Fe, resulting in poor workability in an annealed state. Therefore, a Ni content is determined within a range of 0.05 to 3.0 mass %, preferably 0.6 to 1.5 mass %.
  • Al is an element effective for raising nitriding hardness as well as Cr. Since an increase of Cr is necessarily avoided in the invention alloy design, nitriding hardness is ensured at a value suitable for the purpose by addition of Al.
  • the element Al acts as a graphite former, promotes diffusion of pores and also forms a Cu-Al phase, which serves as a site for precipitation of graphite, together with Cu.
  • Al is an effective element for precipitation of fine graphite particles in a short time, so that an Al content shall be not less than 0.3 mass %.
  • An upper limit of Al is controlled to 2.0 mass %, since an increase of Al raises an A 1 temperature as well as Si. Therefore, an Al content is determined within a range of 0.3 to 2.0 mass %, preferably 0.7 to 2.0 mass %.
  • Mo is a carbide former, which does not impede precipitation of graphite so much in comparison with Cr but improves heat-resistance of steel. Molybdenum carbide restrains a steel matrix at a thermoforming step, which follows a bending step in a piston ring-manufacturing process, resulting in improvement of dimensional stability. However, excess Mo impedes decomposition of cementite as well as Cr.
  • the effect of Mo on impedance of graphitization is weak, but the additive Mo remarkably improves heat-resistance and dimensional stability during heat-treatment.
  • Mo is added at a ratio of 0.3 mass % or more.
  • an upper limit of Mo is controlled to 20 mass %, since precipitation of graphite is impeded as an increase of Mo.
  • V and W have the same effects as Mo. Therefore, at least one element selected from the group consisting of Mo, W and V is added at a ratio within a range of 0.3 to 20 mass % in total.
  • a ratio of V is preferably controlled to a value less than 0.1 mass % with 0.3 to 5.0 mass % in total of Mo and W.
  • the element Mo intensifies a squeezing action of graphite and promotes formation of a fluid film at a high pressure, resulting in improvement of seizure resistance property and a decrease in a kinetic friction coefficient.
  • sulfuric acid corrosion resistance property is improved by addition of Mo. Therefore, the amount of a single additive Mo is preferably controlled within a range of 1.5 to 3.0 mass %.
  • Cu is an important element as well as Al, for precipitation of a Cu-Al intermetallic phase and rapid formation of a stable structure with fine graphite particles.
  • the additive Cu is also effective for improvement of sulfuric acid corrosion-resistance. In this sense, it is necessary to control a ratio of Cu in relation with Al, and a Cu content is determined at a value of not less than 0.05 mass %, preferably not less than 0.2 mass % for realizing effects of Cu and the Cu-Al phase.
  • excess Cu causes an increase of hardness in an annealed state and degrades workability of steel, so that an upper limit of Cu is controlled to 3.0 mass %. Therefore, a Cu content is determined within a range of 0.05 to 3.0 mass %, preferably 0.2 to 3.0 mass %.
  • sulfur is conventionally added as an organized extreme-pressure additive to engine oil, which is supplied to an internal combustion engine, for improvement of lubrication and inhibition of seizure.
  • the inventors have hit upon inclusion of sulfide MnS in a steel matrix on the contrary.
  • the sulfide serves as a sulfur source for forming an in situ sulfide film on a fresh plane, which is exposed by frictional heat, and the sulfide film effectively improves lubricating performance.
  • the invention means, excellent lubricating performance is almost permanently ensured due to distribution of the lubricant in the steel material without necessity of adding a plenty of a lubricant for improvement of lubricity at predetermined parts or without disappearance of lubricating performance, which often occurs during exchange of engine oil containing the extreme-pressure additive.
  • Another conventional means for an increase of chromium carbide in steel for use as a piston ring aims at reduction of a surface area of a piston ring, which comes in contact with a cylinder liner, and enhancement of wear resistance property of the piston ring, to which a sliding energy is applied at a high rate per unit area, in order to balance abrasion between the piston ring and the cylinder liner.
  • seizure resistance property is improved by distribution of chromium carbide
  • distribution of chromium carbide is directed to prevention of partial bearing from abnormal rising, by such a situation, which is essentially caused by non-uniform contact, as to promote abrasion of the cylinder liner for increase of a contact area.
  • the distribution of chromium carbide makes the piston ring compatible with the cylinder liner at the beginning of attachment, but becomes ineffective on abrasion properties, e.g. adhesive abrasion, with durability.
  • the invention material for use as sliding parts is further improved in seizure resistance property by addition of sulfur at a proper ratio.
  • the element sulfur is mostly formed to MnS by reaction with Mn, and the reaction product MnS acts on engine oil as a lubricant to exhibit lubricity. Consequently, a friction coefficient is decreased, and seizure resistance property is improved.
  • Seizure is the phenomenon that rubbing surfaces are clung together due to transfer of atoms therebetween.
  • the transfer of atoms is promoted by thermal oscillation in the state that the rubbing surfaces are heated at a high temperature due to frictional heat.
  • a temperature of the rubbing surface is represented by a monotonously increasing function in relation with a friction energy, i.e. (a friction coefficient x bearing x a slip velocity. That is, as a decrease in a friction coefficient, a temperature hardly rises, resulting in improvement of seizure resistance property.
  • Addition of sulfur is effective for such a decrease in the friction coefficient, but excess sulfur causes degradation of mechanical properties with the fear that steel wire would be broken down in a drawing step for manufacturing steel piston rings. Therefore, an upper limit of sulfur is controlled to 0.3 mass %.
  • a sulfur content is preferably determined within a range of 0.01 to 0.3 mass %, more preferably 0.03 to 0.3 mass %.
  • the inventors have also found that an increase of a forging rate, which is applied to material containing up to 0.3 mass % of sulfur in a manufacturing process, effectively improves mechanical properties of sliding parts. That is, the mechanical properties are upgraded as an increase of the forging rate.
  • the increase of a forging rate advantageously prevents the steel wire from fracture and breakage during bending.
  • the forging rate is defined by a sectional ratio of an ingot to a product profile in a piston ring-manufacturing process.
  • the forging rate is represented by a ratio of (a sectional area of an unforged ingot) / (a sectional area of a bent product), with respect to a section of steel material perpendicular to a forging or drawing direction or a small section of a piston ring as a final product.
  • a sectional reduction ratio from steel wire to a piston ring product is negligible small for realization of the above effects, so that the forging rate may be evaluated by a ratio of (a sectional area of an unforged ingot) / (a sectional area of steel wire, which is forged and drawn but unbent). As the forging rate is higher, the material is more heavily forged.
  • sulfide inclusions are more oriented along a longitudinal direction of steel wire and elongated in a state corresponding to a peripheral stress, which is mainly applied to a piston ring. Consequently, unfavorable effects of sulfide inclusions on mechanical properties are substantially eliminated.
  • Degradation of mechanical properties is typically prevented by reforming sulfide inclusions to a shape with an aspect ratio (a major axis size / a minor axis size) of 3 or more. In other words, poor orientation of sulfide inclusions with an aspect ratio of 3 or more along a peripheral direction leads to degradation of mechanical properties.
  • distribution of sulfide inclusions is controlled to the state that a parallelism (an angle at an acute side) between straight lines, each of which passes through a major axis of a separate sulfide, is held within a range of not more than 30 degrees, in order to provide steel wire useful as piston rings or material useful as sliding parts.
  • the forging rate is preferably determined at a value of 500 or more.
  • Fig. 5 is a set of schematic views, which illustrate microstructures of unforged steel with a forging rate of 1 (as cast) and forged steel with a forging rate of 500 in an unetched state observed by an optical microscope, and schemes for explaining measurement of a parallelism of sulfide inclusions.
  • Two of sulfide inclusions with an aspect ratio of 3 or more are arbitrarily selected, an angle at an acute side between straight lines (a line-A and a line-B), each of which passes through a major axis of a separate sulfide, is measured, and the measurement is repeated over a whole of the microscopic view. The same measurement is further repeated for at least ten microscopic views. A maximum value among the measured angles is evaluated as the parallelism.
  • a line-A' parallel to the line-A may be regarded as an auxiliary line.
  • sulfide which is observed as a connected particle in a 400 times microscopic view, is regarded as a separate inclusion, and a straight line, which passes through a major axis of the separate inclusion, is determined as a measuring line.
  • the unforged steel with a forging rate of 1 has the structure that sulfide inclusions are distributed with a parallelism more than 30 degrees, but the forged steel with a forging rate of 500 has the structure that any parallelism is controlled to a value of not more than 30 degrees.
  • the figure of 30 degrees is a designed value according to rupture mechanics.
  • Fig. 6 is a graph, which illustrates analytical results by G. R. Irwin, "Analysis of Stresses and Strains Near the End of a Crack Transversing a Plate", Trans. ASME, Ser. E, J. Appl. Mech., Vol.24, No.
  • K 1 is a a stress intensity factor
  • ⁇ is an angle between a stress direction and a crack-propagating direction
  • ⁇ is a stress
  • a is a length of a crack.
  • Facilitation of propagation i.e. an abrupt increase of a stress intensify factor corresponds to an angle of 30 degrees.
  • the inclusions can be regarded as cracks due to poor kinetic bonding strength, it is understood that distribution of the inclusion with controlled deviation of orientation within a range of not more than 30 degrees, i.e. orientation arrangement of elongated inclusions, is important to inhibit propagation of cracks.
  • material which contains not more than 0.3 mass % of sulfur, is preferable for use as sliding parts in order to further improve seizure resistance property.
  • Controlled addition of sulfur is typically meaningful in wire material, which is formed to a product profile with a high forging rate, for use as piston rings.
  • the effect of sulfur is more enhanced by addition of Ca together with sulfur.
  • the element Ca which has a strong reducing power, is included in MnS, so that Ca is likely to ooze out onto a seized surface. Ooze of Ca inhibits formation of oxides on the seized surface but facilitates formation of lubricious sulfides. However, excess Ca is unfavorable for hot-workability, so that an upper limit of Ca is preferably controlled to 0.01 mass %.
  • a Ca content is preferably determined within a range of 0.0001 to 0.01 mass %, more preferably 0.0005 to 0.01 mass %, for achievement of the above effects.
  • Addition both of sulfur and Ca is also effective for improvement of machinability and grindability other than seizure resistance property.
  • distribution of MnS and precipitation of graphite particles improve machinability of steel. Due to the improved machinability, a corner of steel material is machined to an objective profile with a small radius of curvature, so that piston rings with a high oil-scraping power can be manufactured with ease.
  • the invention material for use as sliding parts and piston rings may contain Co for improvement of corrosion-resistance, especially sulfuric acid corrosion-resistance.
  • the element Co as well as Mo intensifies a squeezing effect of graphite and promotes formation of a fluid film at a high pressure, resulting in improvement of seizure resistance property and a decrease in a kinetic friction coefficient.
  • Such effects of Co are noted at a ratio of not less than 0.5 mass %.
  • Co is an expensive element, and further improvement is not expected by excess Co. Therefore, a Co content is preferably controlled to not more than 10 mass %, more preferably within a range of 2 to 5 mass %.
  • the invention steel material for use as sliding parts and piston rings contains the above elements at specified ratios and the balance being substantially Fe. Other elements are controlled to not more than 10 mass %, preferably not more than 5 mass %, in total.
  • the invention steel material may further contain one or more of the following elements within specified ranges of:
  • a preferable condition of the present invention is to make the metal structure to contain nonmetallic inclusions occupying an area rate of not more than 2.0 % in the overall area of the structural section, whereby preventing fracture in a drawing process during forming steel material to wire and occurrence of breakage during forming the wire to a coil.
  • the specified structure is typically suitable for a piston ring-manufacturing process accompanied with forming and processing fine wire, in order to establish a manufacturing process with high productivity.
  • Nitriding further improves seizure resistance and wear resistance properties, as an additional effect in the present invention.
  • Nitriding may be combined with other surface treatment such as PVD or Cr-plating, since excellent seizure resistance property is imparted to steel material regardless of surface-treatment.
  • surface treatment such as PVD or Cr-plating
  • Such surface-treatment is conventionally applied to a main sliding surface of the piston ring, which comes in contact with a cylinder liner, but un-applicable to its friction surface, which cmes in contact with a piston.
  • inhibition of adhesive abrasion can not be expected by the conventional surface-treatment.
  • the invention material which has excellent seizure resistance property and resists to adhesive reaction without necessity of surface-treatment, is extremely useful as piston rings.
  • the invention material may be subjected to intercalation processing, whereby foreign molecules or ions are inserted into a laminar molecular structure of graphite for further improvement of sliding characteristics by immersion in a CuCl 2 solution for instance, due to its metal structure with a graphite phase.
  • graphite particles in the intercalation-processed state act as a polymerization catalyst. Therefore, the material is reformed to a state suitable for polymerization of a lubricating oil by a polymer coat (coating with a polymer film) or intercalation-processing as pre-treatment, in order to provide sliding parts, which maintain self-lubricity originated in polymerizing reaction during sliding motion.
  • Specimen No. 1 to 6 satisfy definitions of the present invention.
  • Specimen No. 11 to 16 are comparative steels, wherein Specimen No. 16 corresponds to JIS SUS440B, used for conventional piston rings.
  • Table 1 Specimen No. Chemical compositions (mass %) C Si Mn Cr Al s Mo W V Mo+W Mo+W+V Ca Ni Cu Co Fe 1 0.42 1.85 2.83 0.25 0.31 0.29 0.5 ⁇ 0.01 ⁇ 0.01 0.5 0.5 0.0002 2.96 0.1 ⁇ 0.01 bal.
  • Each ingot was hot-worked to wire material of 9 mm x 9 mm in section size at a forging rate of approximately 598, except Specimen No. 13.
  • Specimen No. 13 was forged but was not formed to a test piece due to fracture during hot-working in succession to forging.
  • the wire material was annealed and then subjected to quench and tempering under predetermined conditions so as to moderate its hardness to around 45HRC.
  • a surface structure of the quenched and tempered wire material was observed in an unetched state by an optical microscope for measuring distribution of graphite particles, i.e. an average particle size and an area rate of graphite particles, which shared the surface structure.
  • the distribution of graphite particles was investigated by image analysis of ten views, which were observed by a 1000 times optical microscope.
  • a size of a graphite particle was represented by a diameter of a real circle, which had the same area as an inspected graphite particle.
  • Specimen No. 1 to 6 had the structure that graphite particles of 0.3 to 2 ⁇ m in average size were distributed with the area rate of 0.5 to 5 %.
  • Figs. 1 to 4 are microphotographs illustrating distribution of graphite particles in Specimen No. 3 and 14. Precipitation of fine graphite particles is detected in a matrix of Specimen No. 3, but graphite particles in a matrix of Specimen No. 14 are coarse. The difference in particle size between Specimen No. 3 and 14 is explained as follows: Since Specimen No. 4 contains Cu and Al at proper ratios, fine Cu-Al intermetallic particles precipitate in prior to precipitation of graphite and act as sites for precipitation of graphite, resulting in fine graphite particles. On the other hand, the Cu-Al intermetallic phase is ineffective in Specimen No.
  • Table 2 shows distribution of graphite particles in all the Specimens including Specimen No. 3 and 14. Distribution of graphite particles was not detected in any matrix of Specimen No. 11, 12, 15 and 16.
  • Seizure resistance property was evaluated by a frictional abrasion test at a superhigh pressure, using a frictional abrasion tester shown in Fig. 7 under the following conditions.
  • a time, at which the rotating torque abruptly rose, was regarded as initiation of seizure, and a load at the time was evaluated as a scuffing load.
  • a kinetic friction coefficient was calculated from a rotating torque of the opposite part at a load of 10 MPa.
  • the numeral 1 is a test piece
  • the numeral 2 is an opposite part
  • the mark F is a load, respectively.
  • a profile of a sliding surface a square of 5 mm ⁇ 5 mm in size
  • a friction velocity 2 m/second
  • a pressure applied to a friction surface an initial pressure of 1.5 MPa an increase rate of 0.5 MPa/minute
  • a lubricant oil motor oil #30
  • the lubricating oil was dropped at a rate of 10 cm 3 /minute only at an initial stage but stopped thereafter.
  • An opposite part JIS FC250 (grey cast iron with hardness of 100 HRB)
  • FIG. 8 Wear resistance property was evaluated by a reciprocating abrasion test, wherein a test piece of 8 mm in diameter and 20 mm in length was rubbed with an opposite part (FC250) of 20 mm in diameter by reciprocating motion for measuring a wearout width of the test piece.
  • a reciprocating abrasion tester is schematically illustrated in Fig. 8 , while the other abrasion conditions are under-mentioned.
  • the numeral 1 is a test piece
  • the numeral 2 is an opposite part
  • the mark F is a load
  • the mark OIL is a lubricating oil, respectively.
  • a sliding distance per cycle 130 mm
  • a maximum sliding velocity 0.5 m/second
  • Table 2 shows measurement results of scuffing loads, kinetic friction coefficients and wearout widths together with hardness of nitrided layers.
  • Results in Table 2 prove that all the Specimen No. 1 to 6, which satisfy the definitions of the present invention, are excellent in seizure resistance and wear resistance properties due to high scuffing loads and small widths of wearout. Especially, Specimen No. 3 to 6 have small kinetic friction coefficients and properties suitable for use as sliding parts. On the other hand, all the comparative Specimens, which do not satisfy the specified distribution of graphite particles in the present invention, are inferior in seizure resistance property. Poor wear resistance property of Specimen Nos. 11 or 15 is caused by insufficient nitriding hardness due to shortage of Cr and Al as nitriding hardening elements.
  • Specimen No. 1 and 15 in Table 1 were hot-rolled to a coil of 5.5 mm in diameter and then processed to a flat wire profile of 1.5 mm x 3.1 mm in section size by drawing and cold-rolling.
  • Specimen No. 1 was formed to the objective profile without troubles, but Specimen No. 15 was broken in a drawing step due to its poor cold-workability.
  • a metal structure of each billet of Specimen No. 1 and 15 was microscopically observed in an undrawn state along a direction perpendicular to a rolling direction and analyzed for measuring the area rate of nonmetallic inclusions. The area rate of nonmetallic inclusions was 1.86 % in Specimen No. 1, but 2.23 % in Specimen No. 15. Comparison of the observation results indicates that breakage of Specimen No. 15 was caused by excess nonmetallic inclusions at a ratio above 2.0 % in addition to excess sulfur.
  • Each of Specimen No. 1 to 6, 11 and 12 was processed to a flat wire profile of 1.5 mm x 3.1 mm in section size under the same condition as Example 2, heated 30 minutes at 1000°C, quenched and tempered to hardness of around 510 HV.
  • the processed test piece was machined 10 times by a grinding cutter at a rotational frequency of 10000 r.p.m and a feed rate of 1 mm/second, for investigating occurrence frequency of burrs.
  • Table 4 shows test results on the occurrence frequency of burrs.
  • Table 4 Specimen No. Occurrence frequency of burrs Note 1 0 Invention specimens 2 0 3 0 4 0 5 0 6 7 11 8 Comparative specimens 12 10
  • An ingot which had the same chemical composition as Specimen No. 1 in Table 1, was separately prepared.
  • the ingot was hot-worked to wire of 3.0 mm x 3.0 mm in section size with a forging rate, which was varied within a range of 1 to 10,000.
  • the hot-worked wire was conditioned to hardness of 400 HV by quench and tempering.
  • the hardness-conditioned wire material was subjected to a three-point flexure test with a span of 30 mm.
  • the test results are meaningful for judging feasibility whether quenched and tempered wire material is formed to a piston ring with a predetermined curvature by roller bending or not.
  • Table 5 shows the test results.
  • Table 5 Specimen No. Forging rate Parallelism (degrees) Evaluation of breakage 1-1 1 84.5 B 1-2 10 45.2 B 1-3 500 27.8 A 1-4 2000 11.5 A 1-5 10000 3.5 A
  • the metal structure wherein sulfide inclusions are distributed with a parallelism of not more than 30 degrees, is excellent in mechanical properties and effective for suppression of breakage during bending wire material to a ring profile.
  • the parallelism and the aspect ratio of sulfide inclusions which were observed on a surface structure parallel to a periphery of a piston ring, were not substantially changed between the wire material and a piston ring, which was manufactured by bending the wire material.
  • the parallelism of sulfide inclusions which are observed on a surface structure of wire material, reflects a structure of a piston ring, which is manufactured from the wire material by bending. Distribution of sulfide inclusions with a parallelism of not more than 30 degrees is effective for improvement of mechanical properties of piston rings, without fears of fatigue fractures, which often occur in conventional engines. In this sense, the specified control of the parallelism is especially suitable for wire material for use as piston rings.
  • Each ingot was hot-worked to wire material of 9 mm x 9 mm in section size with a forging rate of approximately 598.
  • the wire material was annealed and then conditioned to hardness of around 40 HRC by quench and tempering. Thereafter, a surface structure of the quenched and tempered wire material was observed in an unetched state for measuring distribution of graphite particles (an average size of graphite particles and the area rate of graphite particles, which shared the surface structure).
  • the distribution of graphite particles was investigated by analyzing 10 images, which were observed by a 1000 times optical microscope. Table 7 Specimen No.
  • Average size of graphite particles ( ⁇ m) Area rate of graphite Particles in the overall area of the structural section (%) Area rate of graphite particles of 1 ⁇ m or more in size in the overall area of the structural section (%) Average size of graphite particles of 1 ⁇ m or more ( ⁇ m) 21 0.55 1.69 0.41 1.15 22 0.50 2.05 0.14 1.20 23 0.75 3.50 0.70 1.33
  • any of Specimen No. 21-23 had a structure with fine graphite precipitates.
  • Graphite particles of not more than 1 ⁇ m in size were distributed the area rate of 1 to 4 %, as noted in Table 7.
  • Relatively large graphite particles of 1 ⁇ m or more had an average particle size within a range of 1 to 1.5 ⁇ m and the area rate of less than 1 % in any of Specimen No. 21 to 23. Namely, it is understood that most of graphite precipitates are fine particles, and an the area rate of the relatively large graphite particles to all the graphite particles was controlled to a value less than 1/4.
  • a kinetic friction coefficient was calculated from a torque and a load applied to an opposite part, at every moment when a load rose step by step.
  • Fig. 9 shows a relationship between a reciprocal value of a load and a kinetic friction coefficient.
  • a profile of a sliding surface a square of 5 mm x 5 mm
  • a friction velocity 1 m/second
  • a pressure onto a friction surface 1.5 MPa at an initial stage but raised at a rate of 0.5 MPa/minute
  • a lubricating oil motor oil #30 continuously dropped at a rate of 10 cm 3 /minute
  • JIS FC250 grey cast iron
  • Fig. 9 is a diagram, so-called as “Stribeck's diagram", for representing conditions of a load, which is applied to a frictionally sliding part, in relation between by load characteristics (abscissa) and a friction coefficient (ordinate). Lubricating situations can be evaluated by the diagram.
  • the abscissa axis is represented by a reciprocal value of a load, since a friction velocity is kept at a constant value of 1 m/second.
  • the side (a low-stress side, i.e.
  • a range indicated by the arrow rightward from a plot (an extreme value), where a friction coefficient is smallest, corresponds to a region where fluid lubrication is achieved without damage of a lubricating film.
  • the left side (a heavy-stress side) corresponds to a region where both of fluid and solid lubrications occur due to direct contact of solid parts together.
  • the relation in Fig. 9 indicates that fluid lubrication can be more achieved without damage of a fluid film even under a heavy stress, as a plot (an extreme value), where a friction coefficient is smallest, shifts leftwards in the diagram.
  • a plot at the left end of each curve corresponds to a load, when the frictional abrasion test was stopped due to occurrence of seizure.
  • the leftist plots of Specimen No. 22 and 23 shifted leftwards (toward a heavier-stress side) due to addition of Mo and Co in comparison with Specimen No. 21, resulting in further improvement of seizure resistance property.
  • the kinetic friction coefficients are decreased as a whole.
  • the effects of graphite precipitates on sliding characteristics are further intensified by addition of Mo and/or Co.
  • steel material excellent in seizure resistance property with a small friction coefficient is bestowed with self-lubricity without necessity of surface-treatment, so that the steel material is applicable to various sliding parts with less energy loss caused by friction.
  • the steel material is processed to piston rings, which are less aggressive to cylinder liners and pistons, due to simultaneously controlled distribution of sulfide inclusions. Consequently, the present invention contributes to remarkable improvements of internal combustion engines in environmental ability and durability.
  • the steel material is processed to sliding parts or piston rings at a saved manufacturing cost in a short lead time due to its excellent workability and machinability. Namely, the present invention, which provides material for use as sliding parts excellent from aspects both of performance and processing, is a truly profitable technology in an industrial point of view.
  • the material proposed by the present invention is useful as sliding parts, such as piston rings, cylinder liners or vanes, which are built in internal combustion engines of automotive engines or the like, as well as sliding bearings, roller bearings, ball bearings, gears and dies.

Claims (10)

  1. Material zur Verwendung bei selbstschmierenden Gleitbauteilen, das aus einem Stahl besteht, der bezüglich seiner Masse besteht aus:
    zwischen nicht weniger als 0,4 % und nicht weniger als 1,5 % C,
    0,1 bis 3,0 % Si,
    0,1 bis 3,0 % Mn,
    von einschließlich 0 bis 0,5 % Cr,
    0,05 bis 3,0 % Ni,
    0,3 bis 2,0 % Al,
    0,3 bis 20 % insgesamt (Mo + W + V) von zumindest einem Element aus der Gruppe Mo, W und V,
    0,05 bis 3,0 % Cu,
    wahlweise nicht mehr als 10 % Co,
    wahlweise nicht mehr als 0,3 % S,
    wahlweise nicht mehr als 0,01 % Ca und
    dem Rest aus Fe und unvermeidlichen Unreinheiten,
    wobei Graphitpartikel mit einer durchschnittlichen Partikelgröße von nicht mehr als 3 µm in einem Querschnitt der Metallstruktur des Stahls zu beobachten sind.
  2. Material nach Anspruch 1, wobei die im Strukturquerschnitt beobachteten Graphitpartikel einen Flächenanteil von nicht weniger als 1 % bezüglich der Gesamtfläche des Strukturquerschnitts belegen und eine Partikelgröße von nicht mehr als 3 µm aufweisen.
  3. Material nach einem der Ansprüche 1 oder 2, wobei im Strukturquerschnitt keine Vanadiumkarbide zu beobachten sind.
  4. Material nach einem der Ansprüche 1 bis 3, wobei der Stahl bezüglich seiner Masse 0,3 bis 5,0 % insgesamt (Mo + W) von zumindest einem Element aus der Gruppe Mo und W sowie weniger als 0,1 % V enthält.
  5. Material nach einem der Ansprüche 1 bis 4, wobei der Stahl bezüglich seiner Masse 0,7 bis 2,0 % Al enthält.
  6. Material nach einem der Ansprüche 1 bis 5, wobei der Stahl bezüglich seiner Masse 1,5 bis 3,0 % Mo enthält.
  7. Material nach einem der Ansprüche 1 bis 6, wobei der Stahl einer Nitrierungsbehandlung unterzogen worden ist, um bei Gleitbauteilen verwendet zu werden.
  8. Drahtmaterial zur Verwendung bei Kolbenringen, das aus einem Stahl besteht, der bezüglich seiner Masse besteht aus:
    zwischen nicht weniger als 0,4 % und nicht weniger als 1,5 % C,
    0,1 bis 3,0 % Si,
    0,1 bis 3,0 % Mn,
    von einschließlich 0 bis 0,5 % Cr,
    0,05 bis 3,0 % Ni,
    0,3 bis 2,0 % Al,
    0,3 bis 20 % insgesamt (Mo + W + V) von zumindest einem Element aus der Gruppe Mo, W und V,
    0,05 bis 3,0 % Cu,
    wahlweise nicht mehr als 10 % Co,
    wahlweise nicht mehr als 0,3 % S,
    wahlweise nicht mehr als 0,01 % Ca und
    dem Rest aus Fe und unvermeidlichen Unreinheiten,
    wobei Graphitpartikel mit einer durchschnittlichen Partikelgröße von nicht mehr als 3 µm in einem Querschnitt der Metallstruktur des Stahls zu beobachten sind, und
    wobei im Strukturquerschnitt beobachtete Sulfideinschlüsse, die parallel zum Umfang des Kolbenrings verlaufen, so verteilt sind, dass gerade Linien, die jeweils durch eine Hauptachse des entsprechenden Sulfideinschlusses hindurchgehen, einander innerhalb eines Kreuzungswinkels von nicht mehr als 30 Grad kreuzen, wobei der Winkel als Parallelitätswinkel bezeichnet wird.
  9. Drahtmaterial nach Anspruch 8, wobei in einem Querschnitt der Metallstruktur beobachtete Graphitpartikel einen Flächenanteil von nicht weniger als 1 % bezüglich der Gesamtfläche des Strukturquerschnitts belegen und eine durchschnittliche Partikelgröße von nicht mehr als 3 µm aufweisen.
  10. Drahtmaterial nach Anspruch 8 oder 9, wobei der Stahl einer Nitrierungsbehandlung unterzogen worden ist, um bei Kolbenringen verwendet zu werden.
EP03761840A 2002-07-01 2003-06-30 Material für gleitbauteile mit selbstschmierung und drahtmaterial für kolbenring Expired - Fee Related EP1529852B1 (de)

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Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004062564B4 (de) * 2004-12-24 2008-08-07 Mahle Ventiltrieb Gmbh Schaufellagerring eines Turboladers eines Kraftfahrzeug-Verbrennungsmotors
CN101384841B (zh) 2006-02-28 2012-07-04 日本活塞环株式会社 活塞环
KR100800362B1 (ko) * 2006-08-22 2008-02-01 주식회사 엘티 강선소재로 제조된 녹방지 리드스크류의 제조방법
SE531889C2 (sv) 2007-01-26 2009-09-01 Sandvik Intellectual Property Blyfritt automatstål och användning därav
JP2010031835A (ja) * 2008-06-23 2010-02-12 Nissan Motor Co Ltd 内燃機関用オイルリング及びピストン
BRPI0805606A2 (pt) * 2008-12-15 2010-09-14 Whirlpool S.A composição de materiais particulados para formação de produtos autolubrificantes em aço sinterizado, produto em aço sinterizado autolubrificante e processo de obtenção de produtos autolubrificantes em aço sinterizado
DE102009010727B3 (de) * 2009-02-26 2011-01-13 Federal-Mogul Burscheid Gmbh Stahlgusswerkstoffzusammensetzung zur Herstellung von Kolbenringen und Zylinderlaufbuchsen
DE102009015009B3 (de) 2009-03-26 2010-12-09 Federal-Mogul Burscheid Gmbh Kolbenring
CN101906597A (zh) * 2010-08-14 2010-12-08 武汉钢铁(集团)公司 一种环保型高性能石墨化易切削钢
CN103469108B (zh) * 2013-09-05 2015-10-21 无锡双友石化机械有限公司 扩径锥体及其制作工艺
WO2015117208A1 (pt) * 2014-02-07 2015-08-13 Mahle Metal Leve S/A Second piston ring and automotive piston
JP6422044B2 (ja) * 2016-09-20 2018-11-14 日立金属株式会社 摺動構造体および摺動構造体の摺動方法
CN107119224A (zh) * 2017-04-12 2017-09-01 滁州市东华模具制造有限公司 一种抗冷冲模具材料的制备方法
CN107419166A (zh) * 2017-07-04 2017-12-01 广东省材料与加工研究所 一种高强耐磨蚀合金钢材料及其制备方法
JP6472938B1 (ja) * 2017-10-30 2019-02-20 Ｔｐｒ株式会社 圧力リング、内燃機関、圧力リング用線材および圧力リング用線材の製造方法
WO2019087562A1 (ja) * 2017-10-30 2019-05-09 Ｔｐｒ株式会社 圧力リング、内燃機関、圧力リング用線材および圧力リング用線材の製造方法
JP7292322B2 (ja) * 2021-04-12 2023-06-16 トクセン工業株式会社 オイルリング用線

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2014440A (en) * 1928-01-13 1935-09-17 Gen Motors Corp Method of heat treating piston rings
DE1458487B1 (de) * 1963-08-24 1970-09-24 Schladitz, Hermann, 8000 München Verfahren zur pulvermetallurgischen Herstellung selbstschmierender, Trockenschmiermittel enthaltender Werkstoffe
AT287404B (de) * 1966-10-10 1971-01-25 Max Dr Ing Koehler Kolbenring und Verfahren zu seiner Herstellung
JPS60155645A (ja) * 1983-08-31 1985-08-15 Sumitomo Metal Ind Ltd デイスクブレ−キロ−タ用鋼
JPH04329850A (ja) * 1991-04-26 1992-11-18 Hitachi Metals Ltd 防振材料およびその製造方法
CN2114505U (zh) * 1992-03-16 1992-09-02 南通市化工机械厂 无泄漏自润滑磁力传动反应釜
FR2690166A1 (fr) * 1992-04-16 1993-10-22 Creusot Loire Procédé de fabrication d'une tôle plaquée comportant une couche résistant à l'abrasion en acier à outil et tôle plaquée obtenue.
DE69522792T2 (de) * 1995-01-17 2002-05-29 Sumitomo Electric Industries Verfahren zur Herstellung von wärmebehandelten Sintereisen-Formteilen
DE19654893C2 (de) * 1996-07-25 1999-06-10 Federal Mogul Burscheid Gmbh Kolbenringe von Verbrennungskraftmaschinen aus einer Gußeisenlegierung
JP3101726B2 (ja) * 1996-11-01 2000-10-23 日本高周波鋼業株式会社 ピストンリング用合金鋼およびその製造方法
US6139598A (en) * 1998-11-19 2000-10-31 Eaton Corporation Powdered metal valve seat insert
US6527879B2 (en) * 1999-06-25 2003-03-04 Hitachi Metals Ltd. Self-lubricating piston ring material for internal combustion engine and piston ring
CN1272529A (zh) * 2000-05-30 2000-11-08 宝山钢铁股份有限公司 金属热加工用润滑剂

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KR100701812B1 (ko) 2007-04-02
CN1665950A (zh) 2005-09-07

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