EP3830308A1 - Composition de matériau de base, procédé de fabrication d'un élément transversal pour une courroie de transmission à partir d'un tel matériau de base et courroie de transmission comprenant un élément transversal ainsi fabriqué - Google Patents

Composition de matériau de base, procédé de fabrication d'un élément transversal pour une courroie de transmission à partir d'un tel matériau de base et courroie de transmission comprenant un élément transversal ainsi fabriqué

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Publication number
EP3830308A1
EP3830308A1 EP19752108.1A EP19752108A EP3830308A1 EP 3830308 A1 EP3830308 A1 EP 3830308A1 EP 19752108 A EP19752108 A EP 19752108A EP 3830308 A1 EP3830308 A1 EP 3830308A1
Authority
EP
European Patent Office
Prior art keywords
basic material
transverse member
weight
carbon
drive belt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19752108.1A
Other languages
German (de)
English (en)
Inventor
Bert Pennings
Hermen Jan Willem LENDERINK
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from NL1042939A external-priority patent/NL1042939B1/en
Priority claimed from NL1042940A external-priority patent/NL1042940B1/en
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP3830308A1 publication Critical patent/EP3830308A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/76—Adjusting the composition of the atmosphere
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/02—Hardening by precipitation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising
    • C23C8/22—Carburising of ferrous surfaces
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/80—After-treatment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
    • F16G5/00—V-belts, i.e. belts of tapered cross-section
    • F16G5/16—V-belts, i.e. belts of tapered cross-section consisting of several parts

Definitions

  • the present invention relates to a transverse member component of a drive belt comprising an endless tensile element and several such transverse members that are arranged on tensile element, slideably along the circumference thereof.
  • the drive belt is a/o applied in the well-known, variable belt-and-pulley type transmission in the powertrain of a motor vehicle.
  • This particular type of drive belt and its transverse member component are well known in the art, for example from the PCT application published as WO 2017/108206 A1 .
  • the transverse members are resistant to both wear and to metal fatigue.
  • the fatigue strength of the transverse member is determined by the shape thereof that is generally optimized in terms of the stress levels and stress amplitudes that occur during operation of the drive belt.
  • the transverse members may be provided with a compressive residual stress in a surface layer thereof, for example by subjecting these to the known deburring process of stone tumbling after they have been cut from basic material. By such compressive residual stress, the initiation and/or growth of micro cracks from, in particular, surface defects are known to be suppressed, thus improving the fatigue strength thereof.
  • the transverse members For limiting a wear rate of the contact faces of the transverse member to a level that is suitable or at least acceptable in the typical automotive application of the transmission, it is known to provide the transverse members with a material hardness of at least 58 on the Rockwell hardness C-scale (HRC).
  • HRC Rockwell hardness C-scale
  • This hardness value is realized by producing the transverse members from a carbon containing steel and by quench hardening the transverse members.
  • the carbon content in the steel composition of the transverse member basic material lies in the range between 0.60 and 1 .2% by weight, typically 0.75% +/- 0.05% by weight and further includes at least between 0.30 and 0.60% by weight chromium.
  • the basic material of the transverse members also includes between 0.50 and 0.70% by weight manganese and between 0.25 and 0.50% by weight silicon.
  • DIN 1.2003 steel for example, is specified to include between 0.70 and 0.80% by weight carbon, between 0.60 and 0.80% by weight manganese, between 0.25 and 0.50% by weight silicon and between 0.30 and 0.40% by weight chromium with balance iron and with inevitable contaminations whereof the presence of phosphorous and sulfur is typically explicitly limited to 0.030% by weight each.
  • Such conventional quench hardening heat treatment includes the steps of heating the transverse member to above the so-called austenitizing temperature of the steel (e.g. above ⁇ 780 °C in case of DIN 1 .2003 steel composition), for transforming the crystalline structure thereof from ferrite into austenite, and of subsequent quenching, i.e. of cooling the transverse member sufficiently rapidly and to a sufficiently lower temperature, for example 1 10 °C, for, at least predominantly, transforming the austenitic phase into a metastable martensitic phase.
  • austenitizing temperature of the steel e.g. above ⁇ 780 °C in case of DIN 1 .2003 steel composition
  • subsequent quenching i.e. of cooling the transverse member sufficiently rapidly and to a sufficiently lower temperature, for example 1 10 °C, for, at least predominantly, transforming the austenitic phase into a metastable martensitic phase.
  • the transverse member is subjected to the further process step of tempering, i.e. of heating it to a moderate temperature of around 200 °C, for example 185 °C, for about 40 minutes to increase the ductility and toughness thereof and thus to bring its fatigue strength to the required level.
  • tempering process step also the material hardness of the steel is reduced as compared to such hardness immediately after the process step of quenching.
  • the quench hardened steel has a micro or crystalline structure of mainly martensite, typically with some austenite remaining present as well (so-called“retained austenite”).
  • WO2017/108206 describes the known carburizing heat treatment applied to the transverse members. This latter heat treatment includes the process step of heating the transverse members to above the so-called austenitizing temperature of the basic material concerned (e.g. above ⁇ 780 °C in case of DIN 1 .2003 steel) in a carbon-containing gas atmosphere.
  • the carbon potential of the gas atmosphere exceeds the carbon content of the basic material concerned.
  • the surface layer of the transverse members is enriched with carbon. More specifically, a carbon potential of 0.9 is applied, or, generally speaking, between 0.1 and 0.25 higher than the carbon content in %-by-weight of the basic material concerned.
  • a nitrogen-containing gas is added to the gas atmosphere, such that the surface layer of every transverse member is enriched not only with carbon, but also with nitrogen.
  • the above known processes provide the transverse members with a considerable resistance against wear, as well as a considerable fatigue strength. Still, it remains an ever present desire in the art to further reduce wear and/or to further increase fatigue strength of the transverse members.
  • the robustness and service life of the transmission as a whole may be improved thereby, on the other hand the driving power to be transferred by the transmission may be improved and/or the transmission may be reduced in size.
  • the fatigue strength of the transverse member can be further optimized by adding a surprisingly small amount of vanadium of between 0.05 and 0.15 % by weight to the known basic material steel composition with an optimum of about 0.10% by weight. It has been observed that already by the said small amount of vanadium to the basic material, a grain size refinement effect is obtained that improves not only the fatigue strength of the basic material, but also the workability thereof. In particular, a growth of the austenite grains in the austenitizing is suppressed by the presence of vanadium at the grain boundaries. Such grain size refinement effectively reduces the size of defects formed on the cut surfaces of the transverse members in blanking (so-called“galling” defect).
  • a precipitation hardening effect can be favorably obtained in the quench hardening heat treatment of the transverse members after the blanking thereof.
  • Such precipitation hardening occurs by the formation of very fine vanadium carbides and/or vanadium nitrides dispersed throughout the transverse member.
  • vanadium when adding less than 0.05% by weight vanadium such effect is hardly noticeable and above 0.15% by weight vanadium unwanted side-effects start to become relevant, such as an increase in brittleness.
  • the aforementioned positive effects of vanadium are favorably enhanced by adding a minimal amount of niobium of less than 0.03% by weight to the basic material steel composition.
  • This surprisingly small amount of niobium was found to support and enhance the grain refinement forming effect of vanadium and to form niobium precipitates, i.e. niobium carbides and/or niobium nitrides as well, dispersed throughout the transverse member as well.
  • the quench hardening heat treatment itself is delicately but relevantly fine-tuned in a surprising manner.
  • the quench hardening process step of tempering is carried out at a temperature of between 250 and 375 °C, preferably around 300 °C. At such relative high tempering temperature the vanadium and/or niobium precipitates nucleate and grow to their optimum size within the present context.
  • the duration of neither the austenitizing nor the tempering process step of the quench hardening heat treatment needs to be extended to allow for such precipitate formation.
  • the duration of the tempering process step can remain close to the conventionally applied 40 minutes or so, i.e. can have a value between 30 and 60 minutes depending on the specific composition of the basic material.
  • the thus modified process step of tempering is carried out in protective gas atmosphere that is, in particular free of oxygen.
  • the vanadium and/or niobium precipitates are naturally formed more abundantly and/or coarser closer to the surface of the transverse member than towards its core, because of the local abundance of nitrogen and/or carbon originating from the surrounding process gas in the process steps of austenitizing and/or of tempering.
  • a minimum presence of nitrogen of 0.005% by weight is specified for the basic material steel composition.
  • the nitrogen content is at most 0.015% by weight to avoid brittleness, also in view of the relatively high tempering temperature according to the present invention. In this way, the fatigue strength of the transverse member is optimally enhanced by the vanadium and/or niobium precipitates.
  • Figure 1 provides a schematically depicted example of the well-known continuously variable transmission provided with two pulleys and a drive belt.
  • Figure 2 provides a schematically depicted cross-section of the known drive belt incorporating steel transverse members and a tensile element.
  • Figure 3 schematically indicates the three stages of the conventional quench hardening process that is applied as part of the overall manufacturing method of the transverse member and that includes the steps of austenitizing, quenching and tempering.
  • Figure 4 provides a graph illustrating the relationship in between a carbon activity ac and an equilibrium carbon content ECC in %-by-weight in the process step of austenitizing for three austenitizing temperatures.
  • Figure 5 provides a graph in the form of a so-called Kitagawa-diagram illustrating the positive influence of a grain size refinement, a defect size reduction and precipitation hardening effect of the transverse members in accordance with the present invention on the fatigue strength thereof.
  • Figure 6 is a photographed cross-section of a steel sample showing (white) iron carbides at the grain boundaries of the micro-structure.
  • Figure 1 shows the central parts of a known continuously variable transmission or CVT that is commonly applied in the drive-line of motor vehicles between the engine and the driven wheels thereof.
  • the transmission comprises two pulleys 1 , 2 that are each provided with a pair of conical pulley discs 4, 5 mounted on a pulley shaft 6 or 7, between which pulley discs 4, 5 a predominantly V-shaped circumferential pulley groove is defined.
  • At least one pulley disc 4 of each pair of pulley discs 4, 5, i.e. of each pulley 1 , 2, is axially moveable along the pulley shaft 6, 7 of the respective pulley 1 , 2.
  • a drive belt 3 is wrapped around the pulleys 1 , 2, located in the pulley grooves thereof for transmitting a rotational movement and an accompanying torque between the pulley shafts 6, 7.
  • the transmission generally also comprises activation means that -during operation- impose on the said axially moveable pulley disc 4 of each pulley 1 , 2 an axially oriented clamping force that is directed towards the respective other pulley disc 5 of that pulley 1 , 2, such that the drive belt 3 is clamped between these discs 4, 5 of the pulleys 1 , 2.
  • These clamping forces not only determine a friction force between the drive belt 3 and the respective pulleys 1 , 2, but also a radial position R of the drive belt 3 at each pulley 1 , 2 between the pulley discs 4, 5 thereof, which radial position(s) R determine a speed ratio of the transmission between the pulley shafts 6, 7 thereof.
  • FIG. 2 An example of a known drive belt 3 is shown in more detail in figure 2, in a cross- section thereof facing in its circumference direction.
  • the drive belt 3 incorporates an endless tensile element 31 in the form of two sets of flat and thin, i.e. of ribbon-like, flexible metal rings 44.
  • the drive belt 3 further comprises a number of transverse members 32 that are mounted on the tensile element 31 along the circumference thereof.
  • each set of rings 44 is received in a respective recess or slot 33 defined by the transverse members 32 on either lateral side thereof, i.e. on either axial side of a central part 35 of the transverse members 32.
  • the slots 33 of the transverse member 32 are located in-between a bottom part 34 and a top part 36 of the transverse member 32, as seen in radial direction relative to the drive belt 3 as a whole.
  • the transverse members 32 are provided with contact faces 37 for arriving in friction contact with the pulley discs 4, 5.
  • the contact faces 37 of each transverse member 32 are mutually oriented at an angle f that essentially matches an angle of the V-shaped pulley grooves.
  • the transverse members 32 take-up the said clamping force, such that when an input torque is exerted on the so-called driving pulley 1 , friction between the discs 4, 5 and the belt 3 causes a rotation of the driving pulley 1 to be transferred to the so-called driven pulley 2 via the likewise rotating drive belt 3 or vice versa.
  • the transverse member 32 components of the drive belt 3 are intermittently clamped between the respective pairs of pulley discs 4, 5 of the pulleys 1 , 2.
  • clamping obviously results in a compression of the bottom part 34 of the transverse members 32, tensile forces are generated therein as well, in particular in a transition region between the bottom part 34 and the central part 35 thereof.
  • the transverse members 32 are not only subjected to wear, but due the said intermittent clamping thereof also to metal fatigue loading.
  • transverse members 32 It is well-known and generally applied to manufacture the transverse members 32 from steel basic material, such as 75Cr1 (DIN 1 .2003) steel, typically by means of a blanking process, and to quench harden the steel as part of the overall production process of the drive belt 3.
  • the heat treatment of quench hardening comprises three process steps I, II and III that are schematically illustrated in figure 3.
  • a first process step I a batch of the transverse members 32 are heated in an oven chamber 60 to a temperature substantially above the austenitizing temperature of the steel in question in order to provide these with a crystalline structure of austenite, i.e. so-called austenitizing.
  • the transverse members 32 are typically placed in a neutral process gas, such as a mixture of nitrogen, hydrogen and a carbon containing gas such as carbon monoxide.
  • a neutral process gas such as a mixture of nitrogen, hydrogen and a carbon containing gas such as carbon monoxide.
  • the amount, i.e. the partial volume of the carbon containing gas in the process gas, is chosen such that the so-called carbon potential of the process gas is essentially equal to the carbon content of the steel to be processed.
  • transverse members 32 are neither enriched with nor depleted from carbon at the surface thereof.
  • the hydrogen favorably promotes the decomposition of the carbon monoxide, while ensuring that the process gas remains non-oxidizing by reacting with oxygen forming water vapor:
  • Kl (ac ⁇ PH2O) / (Pco ⁇ PH2) [2] with Px representing the partial pressure in %-by-volume/100 in the process gas of a respective gas“x” and ac representing the so-called carbon activity of the process gas.
  • Ki of the above decomposition reaction [1 ] can be approximated by:
  • the thus determined carbon activity ac of the process gas can be related to an equilibrium carbon content at the surface of the transverse members 32, i.e. a (surface) carbon content that is in equilibrium with the process gas.
  • the graph of figure 4 provides such relationship between carbon activity ac and equilibrium carbon content ECC in %-by-weight for three austenitizing temperatures.
  • the transverse members 32 are placed in a neutral process gas, whereof the carbon activity ac is defined such that the equilibrium carbon content ECC according to the graph of figure 4 is essentially equal to the carbon content of the basic material of the transverse members 32.
  • a second process step II the batch of transverse members 32 are quenched, i.e. are rapidly cooled to form a (meta-stable) microstructure largely composed of supersaturated martensitic crystals.
  • the cooling of the transverse members 32 is typically realized by immersing these in an oil bath 70.
  • the batch of transverse members 32 are re heated in an oven chamber 80 after being austenitized and quenched, in order to increase the ductility and toughness thereof, i.e. so-called tempering.
  • the processing temperature applied in this third process step III i.e. the tempering temperature
  • the tempering temperature can be as low as 185 degrees Centigrade, such that it can take place in air.
  • a so-called Kitagawa-diagram is included that illustrates the improvement in the fatigue strength of the transverse member 32 that can be realized when applying the technical teaching of the present invention.
  • a defect size DS in a tested part is correlated to a critical fatigue load CFL, i.e. a fatigue load FL that ultimately leads to the fatigue fracture of the tested part, on a double logarithmic scale.
  • the dashed line illustrates the critical fatigue load CFLc of the conventional transverse member 32
  • the solid line illustrates the critical fatigue load CFLn of the novel transverse member 32, i.e. a transverse member 32 embodying the technical teaching of the present invention.
  • the arrow ⁇ illustrates a fatigue strength improvement irrespective of the defect size DS related to the said increase in residual compressive stress at the surface of the transverse member 32, whereby the complete critical fatigue load line shifts to the right in the Kitagawa-diagram;
  • the arrow ⁇ illustrates an additional fatigue strength improvement mainly for relatively small defects related to the said increase in material hardness of the transverse member 32, whereby the bend-point in the critical fatigue load CFL shifts upwards and to the right in the Kitagawa-diagram;
  • the arrow ® illustrates an indirect fatigue strength improvement by a reduction in defect size related to the said grain size refinement of the basic material improving the workability thereof.
  • the transverse members 32 are toughened further by carburizing or carbo- nitriding these.
  • the amount, i.e. the partial volume of the carbon containing gas in the process gas in austenitizing is chosen such that the resulting carbon activity ac corresponds to an equilibrium carbon content ECC (see figure 4) that is higher than the carbon content of the steel basic material, such that the transverse members 32 are enriched with carbon at the surface thereof.
  • the equilibrium carbon content ECC is set 0.1 to 0.25 higher than the carbon content in %-by-weight of the basic material, e.g. at 0.9 for a steel basic material containing 0.75% by weight carbon.
  • iron carbide networks may form at the grain boundaries of the steel basic material.
  • Figure 6 provides a rather extreme example of such micro-structure with iron carbide precipitates appearing in white at the grain boundaries.
  • iron carbide networks facilitate intergranular fatigue fracture and should preferably be avoided by including vanadium in the steel basic material in the above-defined amount.
  • These vanadium carbides are favorably formed as scattered, nanometer sized precipitates, rather than as larger networks of iron carbides at the grain boundaries.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat Treatment Of Articles (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

L'invention concerne un composant d'un élément transversal (32) pour courroie de transmission (3), à utiliser dans une transmission à variation continue, ladite courroie de transmission (3) comprenant un certain nombre de tels éléments transversaux (32) coulissants en son sein par rapport à la circonférence d'un élément de traction sans fin (31) de la courroie. L'élément transversal (32) est constitué d'acier au carbone comprenant entre 0,60 et 1,2 % en poids de carbone et entre 0,30 et 0,60 % en poids de chrome. Selon l'invention, l'acier au carbone comprend en outre une quantité relativement faible de vanadium comprise entre 0,05 et 0,15 % en poids pour améliorer remarquablement et favorablement la résistance à la fatigue de l'élément transversal (32).
EP19752108.1A 2018-07-27 2019-07-25 Composition de matériau de base, procédé de fabrication d'un élément transversal pour une courroie de transmission à partir d'un tel matériau de base et courroie de transmission comprenant un élément transversal ainsi fabriqué Withdrawn EP3830308A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
NL1042939A NL1042939B1 (en) 2018-07-27 2018-07-27 A method for manufacturing a transverse member for a drive belt from a low alloy carbon steel including a small amount of vanadium
NL1042940A NL1042940B1 (en) 2018-07-27 2018-07-27 Basic material composition, method for manufacturing a transverse member for a drive belt from such basic material and a drive belt comprising a thus manufactured transverse member
PCT/EP2019/025250 WO2020020491A1 (fr) 2018-07-27 2019-07-25 Composition de matériau de base, procédé de fabrication d'un élément transversal pour une courroie de transmission à partir d'un tel matériau de base et courroie de transmission comprenant un élément transversal ainsi fabriqué

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Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2112810B (en) * 1982-01-02 1986-03-19 Aichi Steel Works Ltd Steels for vehicle suspension springs
JPH06220579A (ja) * 1993-01-22 1994-08-09 Sumitomo Metal Ind Ltd 軟窒化鋼
JP3737952B2 (ja) 2001-02-16 2006-01-25 本田技研工業株式会社 Ｃｖｔベルト用押しブロックおよびその製造方法
JP4390526B2 (ja) * 2003-03-11 2009-12-24 株式会社小松製作所 転動部材およびその製造方法
JP2005068482A (ja) * 2003-08-22 2005-03-17 Daido Steel Co Ltd ベルト式ｃｖｔ用エレメントとその製造方法
JP2005120444A (ja) * 2003-10-17 2005-05-12 Daido Steel Co Ltd 冷間打抜き加工用鋼、それを用いた部材
CN100540706C (zh) * 2005-07-05 2009-09-16 杰富意钢铁株式会社 强度、延展性以及韧性优良的机械结构用钢及其制造方法
EP1964935B1 (fr) * 2005-12-20 2012-02-22 Kito Corporation Chaine a maillons presentant une excellente tenacite a basse temperature et procede de traitement thermique de ladite chaine
CN101435484A (zh) * 2008-11-21 2009-05-20 苏州环球链传动有限公司 马氏体不锈钢链条及其在污水处理设备上的应用
EP2370708B1 (fr) * 2008-11-28 2013-01-09 Robert Bosch GmbH Procédé de fabrication d une courroie de transmission, courroie de transmission et procédé de commande d une transmission à variation continue comprenant une courroie de transmission de ce type
JP5530763B2 (ja) * 2009-05-13 2014-06-25 新日鐵住金株式会社 低サイクル曲げ疲労強度に優れた浸炭鋼部品
NL1037185C2 (en) * 2009-08-10 2011-02-14 Bosch Gmbh Robert Transverse element for a drive belt, drive belt and method for manufacturing such a transverse element.
JP5594521B2 (ja) * 2010-06-21 2014-09-24 本田技研工業株式会社 ベルト式ｃｖｔのエレメント用鋼及びこれを用いたエレメント
US9051634B2 (en) * 2011-10-25 2015-06-09 Nippon Steel & Sumitomo Metal Corporation Steel sheet
CN103423377B (zh) * 2013-08-16 2015-08-26 杭州萧山佳吉机械配件厂 一种易装配抗扭曲强度高的拖链及其制备方法
GB2535782A (en) * 2015-02-27 2016-08-31 Skf Ab Bearing Steel
CN104989787A (zh) * 2015-03-24 2015-10-21 山东金恒力机械制造有限公司 高强度梯形链条及其制造方法
NL1041640B1 (en) 2015-12-22 2017-07-03 Bosch Gmbh Robert Transverse element for a drive belt, drive belt and method for manufacturing such a transverse element.

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JP2021533256A (ja) 2021-12-02
CN112400032A (zh) 2021-02-23

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