• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    patent summary: "perlite rail and method for manufacturing perlite rail". The present invention relates to a method for manufacturing a perlite track according to the present invention which includes: hot rolling a billet which includes by weight%: from 0.70% to 0.90% c; from 0.1% to 1.5% of itself; from 0.01% to 1.5% min; from 0.001% to 0.035% wt; from 0.005% to 0.030% s; from 0.1% to 2.0% cr, the remainder of the composition consists of faith and unavoidable impurities so as to achieve a finishing lamination temperature of not less than 900 ° C to form a rail material; and cooling the rail material at an accelerated rate at a cooling rate of 2 ° c / s to 30 ° c / s from a temperature of 770 ° c to 500 ° c, reheat the resultant or subject the resultant to secondary heating to a temperature within the range of 530 ° C to 580 ° C, retain the resultant at the temperature rate for 20 s to 100 s, and cool the resultant at an accelerated cooling rate from 2 ° c / s to 10 ° c / s to a temperature within the range no greater than 450 ° c.
    公开号:BR112015024651B1
    申请号:R112015024651-6
    申请日:2014-03-25
    公开日:2019-10-08
    发明作者:Tatsumi Kimura；Kiyoshi Uwai；Shigeru Endo；Moriyasu YAMAGUCHI
    申请人:Jfe Steel Corporation；
    IPC主号:
    专利说明:

    Descriptive Report of the Invention Patent for METHOD FOR MANUFACTURING A PERLITE TRAIL.
    FIELD [001] The present invention relates to a perlite rail and a method for making a perlite rail.
    BACKGROUND [002] In cargo transportation and ore rail paths, the loading weight is heavier than the loading weight in passenger cars and, therefore, the load applied to the axle rods of freight cars is high and the environments in the areas of contact between the rails and the wheels are very strict. For use in such environments, the rails are required to be wear resistant and steel having a perlite structure that is conventionally used. In recent years, the load and loading weight of ore have additionally increased in order to accentuate efficiency in rail transport and, therefore, rail wear becomes more severe and the service life of tracks before replacement, is decreased. Because of this, the improvement in the wear resistance of rails is requested in order to increase the useful life of rails before replacement. In addition to this, improving damage resistance is important and a high level of ductility and a high level of toughness are also required.
    [003] Conventionally, many hard rails that have improved the hardness of the rail have been developed. For example, Patent Literature 1, 2, 3 and 4 disclose a hyperereutetoid track with an increased cementite content and a method for making it. Patent Literature 5, 6, 7 and 8 disclose a rail that has a thinner interlayer spacing in a eutetoid carbon steel perlite structure in order to increase hardness.
    [004] In addition, many techniques have been developed to u
    Petition 870190073311, of 7/31/2019, p. 7/18
    2/28 increase the hardness of rails through manufacturing control conditions, such as rolling conditions and cooling conditions. For example, Patent Literature 8 discloses a technique that employs a cooling rate of 1 ° C / s to 10 ° C / s for the surface of a rail top that starts at a temperature equal to or greater than Ar1 until that the perlite transformation takes place on the surfaces of the rail top and on the lateral sides of the rail top and then proceeds to a region at a depth of up to 5 mm from the surface, and then employs a cooling rate from 2 ° C / s to 20 ° C / s for the rail top surface until the perlite transformation is completed in a region at a depth of 20 mm or more from the surface.
    [005] Patent Literature 9 discloses a technique that performs the finishing lamination at a surface temperature of a rail top within the rate of equal to or less than 900 ° C and equal to or greater than a transformation Ar3 or an Arcm transformation point to achieve a cumulative surface area reduction rate of the rail top equal to or greater than 20% and a reaction force ratio equal to or greater than 1.25 and then subject the surface of the rail top that has been subjected to the finishing lamination to accelerated cooling or natural cooling at a cooling rate of 2 ° C / s to 30 ° C / s for a temperature of at least 550 ° C. Patent Literature 9 also discloses a rail that has internal hardness at a depth of 2 mm from the surface of a HV 350 to HV 485 (HB 331 to HB 451) rail top of excellent ductility and excellent wear resistance .
    [006] Patent Literatures 10, 11 and 12 reveal a technique for subjecting a rail top that has been subjected to finish lamination for accelerated cooling and then, after raising the temperature and retaining the temperature, performs another cooling cycle
    3/28 accelerated.
    LIST OF QUOTES
    LITERATURE PATENT [007] Patent Literature 1: Patent No. JP 4272385 [008] Patent Literature 2: Patent No. JP 3078461 [009] Patent Literature 3: Patent No. JP 3081116 [0010] Patent Literature 4: JP Patent No. 3513427 [0011] Patent Literature 5: JP Patent No. 4390004 [0012] Patent Literature 6: Japanese Patent Application Open to Public Inspection No. 2009-108396 [0013] Patent Literature 7: Patent Japanese open to public Inspection No. 2009-235515 [0014] Patent Literature 8: Japanese Patent No. 3731934 [0015] Patent Literature 9: Japanese Patent Application Open to Public Inspection No. 2008-50687 [0016] Patent Literature 10: Japanese Patent No. 4355200 [0017] Patent Literature 11: Japanese Patent No. 4214044 [0018] Patent Literature 12: Japanese Patent Application Open to Public Inspection No. 2010-255046
    SUMMARY
    PROBLEM OF THE TECHNIQUE [0019] Although the techniques disclosed in Patent Literature 1 to Patent Literature 12 provide high hardness of a part of the rail top surface layer, these techniques sometimes fail to achieve sufficiently high hardness. inside under the surface layer. In addition, the technique disclosed in Patent Literature 8 provides hardness of HV 391 or higher (HB 370 or higher in terms of Brinell hardness) on the surface and HV 382 or higher (HB 362 or higher) 20 mm below the top, which is insufficient from the point of view of wear resistance.
    4/28 [0020] The present invention is designed to solve these problems and an objective of the present invention is to provide a perlite rail in which the hardness from the surface to the inside of the rail top can be increased and the resistance to wear is improved and a method to manufacture such a perlite rail.
    SOLUTION TO THE PROBLEM [0021] The inventors of the present invention conducted an intensive research to solve these problems and, as a result, found that part of cementite components in plates that constitute thin perlite lamellae undergoes partial spheroidization that depends on the conditions during cooling after transformation and this, it affects the internal hardness. Therefore, the following provisions were noted.
    [0022] To solve the problem described above and achieve the objective, a pearlite rail, according to the invention, includes a composition that includes in mass%: 0.70% to 0.90% of C; 0.1% to 1.5% Si; 0.01% to 1.5% Mn; 0.001% to 0.035% P; 0.0005% to 0.030% S; 0.1% to 2.0% Cr, remaining of the composition consisting of Fe and unavoidable impurities, and the surface hardness of a rail top is not less than HB 430, and the hardness at a depth of 25 mm from a rail top surface is not less than HB 410.
    [0023] It is preferable that the composition additionally includes in% by mass at least one among: no more than 0.15% of V; not more than 0.030% Nb; not more than 1.0% Cu; not more than 0.5% Ni; and no more than 0.5% Mo, the rest of the composition consists of Fe and unavoidable impurities.
    [0024] It is preferred that the composition additionally includes in% by mass one or both of: no more than 0.010% Ca; and not more than 0.1% REM, the rest of the composition consists of
    5/28
    Fe and unavoidable impurities.
    [0025] It is preferable that the rail top has an elastic limit of 0.2% not less than 1,000 MPa, tensile strength not less than 1,450 MPa, elongation not less than 12%, and fracture toughness at room temperature not less than 40 MPa ^ m.
    [0026] To solve the problem described above and achieve the goal, a method for making a perlite rail, according to the present invention includes: hot rolling of a billet that has a composition that includes in% by mass: from 0 , 70% to 0.90% C; from 0.1% to 1.5% Si; from 0.01% to 1.5% Mn; from 0.001% to 0.035% of P; from 0.0005% to 0.030% of S; from 0.1% to 2.0% Cr, the remainder of the composition consists of Fe and unavoidable impurities, in order to achieve a finish laminating temperature of not less than 900 ° C to form a rail material; and cool the track material in an accelerated manner at a cooling rate of 2 ° C / s to 30 ° C / s from a temperature of 770 ° C to 500 ° C, reheat the result or overcome the result by heating secondary at a temperature within the range of 530 ° C to 580 ° C, retain the resultant at the temperature rate for 20 s to 100 s, and cool the resultant in an accelerated manner at a cooling rate of 2 ° C / s to 10 ° C / s for a temperature within the range of not more than 450 ° C.
    [0027] It is preferable that the billet composition additionally includes in% by mass at least one among: no more than 0.15% of V; not more than 0.030% Nb; not more than 1.0% Cu; not more than 0.5% Ni; and not more than 0.5% Mo.
    [0028] It is preferable that the billet composition additionally includes in mass% one or both of: no more than 0.010% Ca; and not more than 0.1% of REM.
    [0029] It is preferred to additionally include the finalization of the
    6/28 accelerated cooling carried out at a cooling rate of 2 ° C / s up to 10üs, at a temperature within a range of 350 ° C to 450 ° C, and then slowly cool the resultant at a cooling rate of no more than 0.5 ° C / s.
    ADVANTAGE EFFECTS OF THE INVENTION [0030] According to the present invention, a hard pearlite rail that has increased hardness from a surface into the top of the rail and that has excellent wear resistance can be provided.
    BRIEF DESCRIPTION OF THE DRAWINGS [0031] Figure 1 is a view illustrating a lamination and cooling pattern in a method of the present invention.
    DESCRIPTION OF MODALITIES [0032] A perlite rail and a method for making a perlite rail of the present invention are explained below in detail in terms of the composition of the perlite rail, the surface hardness, the internal hardness, 0.2% elastic limit, tensile strength, elongation and fracture toughness at room temperature of the rail top and a method for making a perlite rail with the requirements for these items to be satisfied.
    [0033] First, the composition of the perlite trail is explained. In the following explanation, the term% referring to the content of each element that constitutes the rail means percentage by mass (% by mass) unless otherwise indicated.
    C CONTENT [0034] The C (carbon) content is within the range equal to or greater than 0.70% and equal to or less than 0.90%. C is an important element in providing cementite formation, increasing hardness and rigidity and improving the wear resistance of a perlite rail. These effects are exercised, unsatisfactorily, when the C content is
    7/28 less than 0.70%, and therefore the lower limit for the C content is 0.70%. On the other hand, an increase in C content means an increase in cementite content which leads to a decrease in ductility even though an increase in hardness and stiffness is expected. Additionally, an increase in the C content expands the temperature range γ + θ, which promotes the smoothing of the portion affected by hot welding. With these adverse influences taken into account, the upper limit for the C content is 0.90%. Preferably, the C content is within the range equal to or greater than 0.73% and equal to or less than 0.87%.
    Si content [0035] The Si (silicon) content is within the range equal to or greater than 0.1% and equal to or less than 1.5%. Si is added to a rail material as a deoxidizing ingredient and to reinforce a perlite structure. These effects are exercised, unsatisfactorily, when the Si content is less than 0.1%, and therefore the lower limit for the Si content is 0.1%. On the other hand, an increase in the Si content promotes the formation of cracks in the surface of a track and, therefore, the upper limit for the Si content is 1.5%. Preferably, the Si content is within the range equal to or greater than 0.2% and equal to or less than 1.3%.
    Mn CONTENT [0036] The content of Mn (manganese) is within the range equal to or greater than 0.01% and equal to or less than 1.5%. The Mn element has an effect to lower the temperature at which the transformation into perlite takes place and to reduce the interlayer spacing in the perlite and is, therefore, effective in ensuring the low high hardness into a track. Such an effect is exerted, unsatisfactorily, when the Mn content is less than 0.01%, and therefore the lower limit for the Mn content is 0.01%. When Mn is added in a su
    8/28 greater than 1.5%, however, the equilibrium transformation temperature (TE) of perlite decreases and the martensitic transformation occurs promptly. Consequently, the upper limit for the Mn content is 1.5%. Preferably, the Mn content is within the range equal to or greater than 0.3% and equal to or less than 1.3%.
    P CONTENT [0037] The P (phosphorus) content is within the range equal to or greater than 0.001% and equal to or less than 0.035%. When the P content is greater than 0.035%, the toughness and ductility decrease. Consequently, the upper limit for the P content is 0.035%. Preferably, the upper limit for the P content is 0.025%. On the other hand, special or similar refining to reduce the P content results in an increase in the melting process costs and, therefore, the lower limit for the P content is 0.001%.
    S CONTENT [0038] The S (sulfur) content is within the range equal to or greater than 0.0005% and equal to or less than 0.030%. S forms bulky and coarse MnS that extend in the lamination direction to decrease ductility and toughness and, therefore, the upper limit for the S content is 0.030%. When the S content is less than 0.0005%, however, the cost of the fusion process increases significantly, due to the fact that more time is required for fusion processes, for example. Consequently, the lower limit for the S content is 0.0005%. Preferably, the S content is within the range equal to or greater than 0.001% and equal to or less than 0.015%. Cr content [0039] The content of Cr (chromium) is within the range equal to or greater than 0.1% and equal to or less than 2.0%. Cr leads to an increase in the equilibrium transformation temperature (TE) of perlite and contributes to the reduction of interlayer spacing in perlite for
    9/28 increase hardness and stiffness. This requires Cr in an amount equal to or greater than 0.1% and therefore the lower limit for Cr content is 0.1%. When Cr is added in an amount greater than 2.0%, however, welding defects occur more frequently and the hardening capacity increases to facilitate the formation of martensite. Consequently, the upper limit for the Cr content is 2.0%. Preferably, the Cr content is within the range equal to or greater than 0.2% and equal to or less than 1.5%.
    [0040] In addition to those constituent elements included in the chemical composition of a billet, as explained above, the billet may additionally contain the following constituent elements, if appropriate.
    CONTENTS OF Cu, Ni, Mo, VE Nb [0041] As for Cu (copper), Ni (nickel), Mo (molybdenum), V (vanadium) and Nb (niobium), at least one element selected from them is , preferably, contained in a content explained below.
    [0042] The Cu content is equal to or less than 1.0%. The Cu element can achieve a higher hardness by hardening the solid solution and also has an effect to suppress decarbonization. To wait for these effects to be achieved, Cu is preferably added in an amount equal to or greater than 0.01%. When Cu is added in an amount greater than 1.0%, however, surface cracking occurs easily during continuous molding or during lamination, and therefore the upper limit for Cu content is 1, 0%. Preferably, the Cu content is within the range equal to or greater than 0.05% and equal to or less than 0.6%.
    [0043] The Ni content is equal to or less than 0.5%. The Ni element is effective in increasing toughness and ductility. The Ni element is
    10/28 also effective in suppressing Cu cracks when added with Cu and, therefore, is preferably added when Cu is added. To achieve this effect, the Ni content is preferably equal to or greater than 0.01%. When Ni is added in an amount greater than 1.0%, however, the hardening capacity increases and the formation of martensite is facilitated and, therefore, the upper limit for the Ni content is 1.0%. Preferably, the Ni content is within the range equal to or greater than 0.05% and equal to or less than 0.6%.
    [0044] Mo content is equal to or less than 0.5%. The Mo element is effective in increasing stiffness. To obtain the effect, the Mo content is preferably equal to or greater than 0.01%. When Mo is added in an amount greater than 0.5%, however, the hardening capacity increases and, as a result, the martensite forms decrease, tenaciously, the toughness and ductility. Consequently, the upper limit for the Mo content is 0.5%. Preferably, the Mo content is within the range equal to or greater than 0.05% and equal to or less than 0.3%.
    [0045] The V content is equal to or less than 0.15%. Element V forms VC, VN, or the like as a fine precipitate in ferrite and through such increased ferrite precipitation, is effective in increasing stiffness. Element V also serves as a hydrogen trapping site and therefore can be expected to exhibit an effect to suppress the delayed fracture. To obtain these effects, V is preferably added in an amount equal to or greater than 0.001%. When V is added in an amount greater than 0.15%, however, these effects reach saturation and the connection cost increases significantly. Consequently, the upper limit for the V content is 0.15%. Preferably, the V content is within the range equal to or greater than 0.005% and equal to or less than
    11/28 than 0.12%.
    [0046] The Nb content is equal to or less than 0.030%. The Nb element increases the non-recrystallization temperature of austenite and, as a result, through the introduction of processing distortion within the austenite during lamination, it is effective in reducing the sizes of colonies and perlite blocks, and thus be effective in increase ductility and toughness. To expect these results to be obtained, Nb is preferably added in an amount equal to or greater than 0.001%. When Nb is added in an amount greater than 0.030%, however, Nb carbonitride is crystallized during the solidification process to compromise cleaning and, therefore, the upper limit for the Nb content is 0.030%. Preferably, the Nb content is within the range equal to or greater than 0.003% and equal to or less than 0.025%.
    Ca and REM contents [0047] As for Ca (calcium) and REM (rare earth metal), in at least one element selected from them, it is preferably contained in a content explained below. Ca and REM are bonded to O (oxygen) and S in steel at solidification time to form oxisulfide granules to increase ductility and toughness and improve delayed fracture properties. To expect these effects to be achieved, Ca in an amount equal to or greater than 0.0005% and / or REM in an amount equal to or greater than 0.005% is preferably added. When an excessive amount of Ca and / or REM is added, however, cleaning is compromised. Consequently, when Ca and / or REM is added, the Ca content is equal to or less than 0.010% and the REM content is equal to or less than 0.1%. Preferably, the Ca content is within the range equal to or greater than 0.0010% and equal to or less than 0.0070%, and the REM content is within the range equal to or greater than
    12/28 that 0.008% is equal to or less than 0.05%.
    [0048] The rest or components other than those explained above in relation to their content are produced from Fe (iron) and unavoidable impurities. As long as the effects of the present invention are not impaired, content of components other than those mentioned above are not excluded. N (nitrogen) can be contained in an amount equal to or less than 0.015% and O can be contained in an amount equal to or less than 0.004%. AlN and TiN compromise the rolling contact fatigue properties and, therefore, the Al (aluminum) content is desirably equal to or less than 0.003% and the Ti (titanium) content is desirably , equal to or less than 0.003%.
    [0049] Then, the surface hardness, the internal hardness, 0.2% elastic limit, the tensile strength, elongation and fracture toughness at room temperature of the perlite rail top, according to present invention, will be explained.
    RAIL TOP SURFACE HARDNESS, AND 25 mm DEPTH INTERNAL HARDNESS FROM RAIL TOP SURFACE [0050] The surface hardness of the rail top is equal to or greater than HB 430 and the internal hardness in one depth of 25 mm from the rail top surface is equal to or greater than HB 410. When the surface hardness of the rail top is less than HB 430 or the internal hardness at a depth of 25 mm from the surface of the rail top is less than HB 410, the resulting wear resistance is not high enough.
    ELASTIC LIMIT TO 0.2%, TENSION RESISTANCE, STRETCHING AND FRACTURE TENACITY AT RAIL TOP ENVIRONMENT TEMPERATURE [0051] Requirements for traction properties of the rail top
    13/28 are preferably met, namely, an elastic limit (YS) of 0.2% equal to or greater than 1,000 MPa, a tensile strength (TS) equal to or greater than 1,450 MPa, an elongation (EL) equal to or greater than 12% and a fracture toughness at room temperature equal to or greater than 40 MPa ^ m. When the elastic limit (YS) at 0.2% is equal to or greater than 1,000 MPa, the elongation (EL) is equal to or less than 12% and the fracture toughness at room temperature is equal to or greater than than 40 MPa ^ m, a high level of resistance to rail damage can be ensured. When the tensile strength (TS) is equal to or greater than 1,450 MPa, a high level of wear resistance can be ensured.
    [0052] Then, an embodiment of a method for making a hard pearlite rail, according to the present invention, from steel having the composition described above is explained. Figure 1 is a view that illustrates a pattern of lamination and cooling in this method.
    [0053] In this method, as listed in Figure 1, a billet having the composition described above is subjected to hot rolling in order to reach a finishing rolling temperature equal to or greater than 900 ° C to form a material rail (A). The billet is formed within a rail material, for example, by hot rolling through common notch rolling or universal rolling. The billet is desirably obtained by continuous casting of molten steel which has a controlled composition through melting processes such as a blast furnace process, hot metal pretreatment, a steel converter process and HR degassing.
    [0054] The finishing lamination temperature equal to or greater than 900 ° C means that the lamination is performed within the austenite recrystallization region. The temperature equal to or less
    14/28 than 900 ° C constitutes a region of partial recrystallization or a region of non-recrystallization where the lamination results in the introduction of processing distortion into austenite, which facilitates the transformation of perlite to increase interlayer spacing into perlite, leading to a significant decrease in hardness, mainly in internal hardness. Therefore, the finishing laminating temperature is equal to or greater than 900 ° C. The upper limit to this is not particularly specified. However, when the lamination is complete at a temperature greater than 1,000 ° C, the toughness and ductility decrease and, therefore, the finishing lamination temperature is preferably equal to or less than 1,000 ° C.
    [0055] Subsequently, as listed in Figure 1, the accelerated cooling of the additionally formed rail material is started at a temperature equal to or greater than 770 ° C (cooling start temperature) at a cooling rate equal to or greater than 2 ° C / s and equal to or less than 30 ° C / s for a temperature equal to or less than 500 ° C (cooling temperature) (BCD).
    [0056] After lamination, the accelerated cooling of the rail top surface needs to be started equal to or greater than 770 ° C. When accelerated cooling starts below 770 ° C, the difference between the temperature in the rail top surface layer and the internal temperature at a depth of 25 mm from the rail top surface is small and the transformation of perlite starts at the surface of the rail top to produce heat transformation that slows down a cooling rate inside, which results in the yield of a bulky and coarse internal lamella structure and decreased internal hardness. Consequently, the cooling start temperature needs to be equal to or greater than 770 ° C. The cooling start temperature is preferably equal to
    15/28 or greater than 800 ° C. The upper limit to this is not particularly specified. However, since the finishing laminating temperature is equal to or greater than 900 ° C, the cooling start temperature can be equal to or less than 900 ° C.
    [0057] The cooling rate during accelerated cooling is within the range equal to or greater than 2 ° C / s and equal to or less than 30 ° C / s. When the cooling rate is less than 2 ° C / s, supercooling cannot be ensured to occur and the surface hardness of the rail top decreases. When the cooling rate is above 30 ° C / s, however, bainite and martensite which have disadvantageous effects on wear resistance are easily formed. Preferably, the cooling rate is within the range equal to or greater than 2.0 ° C / s and equal to or less than 10 ° C / s.
    [0058] In order to allow the perlite transformation on the surface of the rail top to be carefully completed, the cooling needs to be continued at a temperature equal to or less than 500 ° C. Consequently, the cooling stop temperature of the accelerated cooling here is equal to or less than 500 ° C. This is due to the fact that when the cooling stop temperature is above 500 ° C, the surface of the rail top softens. When cooling at a cooling rate equal to or greater than 2.0 ° C / s equal to or less than 10 ° C / s is maintained at a temperature within the range equal to or less than 200 ° C , however, it forms martensite. Consequently, the cooling stop temperature is preferably equal to or greater than 200 ° C.
    [0059] Subsequently, as listed in Figure 1, the resultant is reheated or subjected to secondary heating to a temperature within the range equal to or greater than 530 ° C and equal to or less than 580 ° C (temperature of reheating / secondary heating), retained at a temperature rate equal to or greater than 20 if
    16/28 equal to or less than 100 s (holding time), and then cooled down in an accelerated manner at the cooling rate equal to or greater than 2 ° C / s equal to or less than 10 ° C / s for a temperature within the range equal to or less than 450 ° C, preferably equal to or greater than 350 ° C and equal to or less than 450 ° C (cooling stop temperature) (EFGH).
    [0060] In order to allow the transformation of pearlite to proceed successively from the surface to a depth of 25 mm from the rail top after the rail top surface has been cooled in such an accelerated manner to a temperature equal to or less than 500 ° C, reheating or secondary heating must be continued at a temperature within the range equal to or greater than 530 ° C and equal to or less than 580 ° C. In other words, a secondary reheat / heat temperature less than 530 ° C potentially leads to bainitic transformation, and therefore the lower limit of the secondary reheat / heat temperature is 530 ° C. On the other hand, in order to ensure super-cooling to occur in order to achieve a fine interior perlite structure, the upper limit of the secondary reheat / heating temperature is 580 ° C. This is due to the fact that when reheating or secondary heating is continued to a temperature greater than 580 ° C, the internal hardness decreases.
    [0061] When increasing the temperature to a range equal to or greater than 530 ° C and equal to or less than 580 ° C, which is the secondary reheat / heat temperature, the heat trapped inside the rail top or the heat due to the transformation heat released when the perlite transformation proceeds successively from the surface to the inside of the rail top can be used, or forced heating can be carried out using an external heat source (with the gas burner, through induction heating, or simila17 / 28 res).
    [0062] The time for which the resultant is retained at a temperature within the range equal to or greater than 530 ° C and equal to or less than 580 ° C, which is the secondary reheat / heat temperature, needs to be equal to or greater than 20 s. When the retention time is less than 20 s, insufficient pearlite transformation occurs mainly in the surface layer of the rail top. When the retention time is greater than 100 s, however, part of the cementite compounds in slabs obtained after the transformation of spheroidized perlite to decrease the internal hardness, in particular. Consequently, the retention time is within the range equal to or greater than 20 s and equal to or less than 100 s.
    [0063] After a retention time equal to or greater than 20 s and equal to or less than 100 s has elapsed, accelerated cooling needs to be performed immediately. The cooling rate of the accelerated cooling here is within the range equal to or greater than 2 ° C / s and equal to or less than 10 ° C / s. This is particularly important in this method in order to prevent the decomposition of cementite compounds in slabs formed by the transformation of perlite into spheroids. When the cooling rate is below 2 ° C / s, cementite spheroidization is not sufficiently suppressed, whereas when the cooling rate is above 10 ° C / s, bending, warping and / or the like occur to a great extent.
    [0064] The accelerated cooling here needs to be continued until a temperature equal to or less than 450 ° C. This is due to the fact that when the cooling stop temperature is greater than 450 ° C, part of the cementite compounds in plates spheroidizes and softens. When accelerated cooling is continued to a temperature below 350 ° C, however, hydrogen is left in the
    18/28 inside the steel, which can give rise to the risk of delayed fracture, and therefore the accelerated cooling is preferably terminated at a temperature equal to or greater than 350 ° C. Consequently, the cooling stop temperature for accelerated cooling here is within the range equal to or less than 450 ° C and is preferably within the range equal to or greater than 350 ° C and equal to or less than 450 ° C.
    [0065] After the accelerated cooling is finished at a temperature within the range equal to or greater than 350 ° C and equal to or less than 450 ° C, slow cooling is preferably performed at a cooling rate equal to or less than 0.5 ° C / s (I), as listed in the Figure. 1.
    [0066] This is due to the fact that, after accelerated cooling to a temperature within the range equal to or greater than 350 ° C and equal to or less than 450 ° C, it is carried out in order to suppress cementite spheroidization , it is preferable to release hydrogen from inside the steel. When the cooling rate is greater than 0.5 ° C / s, after the end of the accelerated cooling, the risk of hydrogen left inside the steel causing a delayed fracture cannot be completely avoided. Therefore, the cooling rate here is preferably equal to or less than 0.5 ° C / s. Similar risks increase when the slow cooling is finished at a temperature greater than 200 ° C, and therefore slow cooling is desirably continued at a temperature equal to or less than 200 ° C.
    [0067] By the method thus explained, a hard perlite rail that has high hardness (high rigidity), excellent toughness, and excellent ductility can be obtained and, more specifically, the perlite rail of the present invention that has hardness, in in other words, rail top surface hardness equal to or greater than HB 430 and internal hardness at 25-mm equal to or greater than HB can be obtained
    19/28
    410. The reason the surface hardness of the rail top and the internal hardness at 25-mm of the rail top (hardness at a depth of 25 mm from the surface of the rail top) of the perlite rail according to the present invention is equal to or greater than HB 430 and equal to or greater than HB 410, respectively, is that these values need to be satisfactory in order to obtain sufficiently high wear resistance. By the method of the present invention thus explained, a hard perlite rail that meets the requirements for tension properties, in other words, an elastic limit (YS) of 0.2% equal to or greater than 1,000 MPa can be obtained, tensile strength (TS) equal to or greater than 1,450 MPa, elongation (EL) equal to or greater than 12%, and fracture toughness at room temperature equal to or greater than 40 MPa ^ m. When the elastic limit (YS) at 0.2% is equal to or greater than 1,000 MPa and the elongation (EL) is equal to or greater than 12%, a high level of resistance to rail damage can be ensured. When the tensile strength (TS) is equal to or greater than 1,450 MPa, a high level of wear resistance can be ensured.
    [0068] In particular, the reason why the method provides high hardness, in other words, rail top surface hardness equal to or greater than HB 430 and internal hardness at 25-mm equal to or greater than HB 410 is that, by using a specific retention time for secondary reheating / heating during which the perlite transformation is allowed to happen and specific conditions during cooling after the secondary reheating / heating, cementite spheroidization is suppressed. The perlite structure is a layered structure composed of hard cementite and soft ferrite, in which the shorter the distance between layers (interlayer spacing), of this layered structure, the harder the perlite structure can be without compromising toughness and strength. ducti
    20/28 lity. However, after hot rolling a billet into a rail shape, when a relatively high temperature is maintained during the cooling process after the completion of the perlite transformation, cementite is converted into a sphere that is more thermally stable, through of which a thin lamellar structure cannot be maintained. This phenomenon occurs only when the retention time in step E in Figure 1 is not greater than 100 s or when the cooling rate in step G is less than 2 ° C / second. Such cementite spheroidization reduces hardness and stiffness to a great extent.
    [0069] For each rail manufactured by the method explained above, a rail manufactured by the method explained above in which the retention time in step E in Figure 1 has been modified to be greater than 100 s, and a rail manufactured by the method explained above in Since the cooling rate in step G was modified to be less than 2 ° C / second, the inventors of the present invention observed a perlite structure in a region at a depth of 25 mm from the top of the rail and evaluated the degree of spheroidization of cementite. Specifically, the observation of a region at a depth of 25 mm from the surface of the rail top was performed by randomly selecting 30 observation fields with a scanning electron microscope at a magnification of 20,000 times, and the spherical state of cementite was evaluated using a spheroidization rate (C) calculated by Formula (1).
    [0070] The spheroidization rate (C) = number of cementite compounds that has an aspect ratio of less than 20 (A) / total number of cementite compounds (B) x 100 ... (1) [0071 ] The results demonstrated that the rail manufactured by the method of the present invention that satisfies the internal hardness at a depth of 25 mm from the surface of the rail top equal to or
    21/28 greater than HB 410 has a spheroidization rate (C) of less than 5%. The results also demonstrated that the rail manufactured with a retention time in step E not greater than 100 s and the rail manufactured with a cooling rate in step G not less than 2 ° C / second has internal hardness at a depth of 25 mm from the rail top surface not less than HB 410 and a spheroidization rate (C) equal to or greater than 5%. This indicates that, by spheroidization of cementite suppression, the internal hardness increases in a region at a depth of 25 mm from the surface of the rail top.
    EXAMPLES [0072] Table 1 lists the chemical compositions (in mass percentage) of tracks in a standard example, inventive examples, and comparative examples taken as samples for this example. In this example, the steel that has a chemical composition listed in Table 1 has been melted, heated, hot rolled, and cooled to yield a 61.69 kg (136 pounds) rail or a 63.96 kg (141 pounds) rail . The contents of Al, Ti, N and O listed in Table 1 refer to their contents as unavoidable impurities. Table 2 lists the manufacturing conditions for the standard example rails, inventive examples and comparative examples.
    TABLE 1
    Steel Chemical Composition (in percentage by mass) Ç Si Mn P s Cr Ass Ni Mo V Nb Here REM Al You N O THE 0.78 0.56 0.54 0.015 0.004 0.77 - - - 0.058 - - - 0.001 0.001 0.0043 0.0015 B 0.80 0.55 1.18 0.018 0.005 0.26 - - - - 0.011 - - 0.002 0.001 0.0052 0.0021 Ç 0.83 0.57 1.49 0.012 0.004 0.82 - - - - - - - 0.001 0.002 0.0035 0.0010 D 0.78 0.26 0.81 0.02 0.005 - 0.36 0.31 - 0.06 - -0.002 0.001 0.0042 0.0015 AND 0.83 1.06 0.41 0.017 0.003 0.87 - - - - - 0.0022 - 0.001 0.001 0.0039 0.0012 F 0.75 0.81 0.62 0.017 0.005 0.77 - - 0.12 - - - 0.008 0.003 0.001 0.0045 0.0018 G 0.68 0.63 1.26 0.015 0.005 0.76 - - - 0.042 - - - 0.002 0.002 0.0038 0.0010 H 1.05 0.55 0.31 0.016 0.005 0.54 - - - - - - - 0.001 0.001 0.0053 0.0012
    22/28 * The contents of Al, Ti, N and O refer to their contents as unavoidable impurities. TABLE 2
    Steel Conditions Finishing lamination temperature (° C) Cooling start temperature (° C) Cooling Rate (° C / s) Cooling stop temperature (° C) Secondary reheat / heat temperature (° C) Retention time (s) Cooling Rate (° C / s) Cooling stop temperature (° C) Cooling Rate (° C / s) Comments THE TO 1 920 730 4.8 450 550 30 2.5 380 0.4 Standard Example THE A2 920 800 5 450 550 30 2.5 380 0.4 Inventive Example THE A3 950 830 7 430 530 30 5 350 0.4 Inventive Example THE A4 940 820 5 440 560 20 4 300 0.4 Inventive Example THE A5 920 730 4.8 450 550 30 2.5 380 0.4 Comparative Example THE A6 930 790 1 450 530 20 2 390 0.4 Comparative Example THE A7 950 820 40 390 550 60 2.5 380 0.4 Comparative Example THE A8 920 800 5 550 590 30 3 400 0.4 Comparative Example
    Steel Conditions Finishing lamination temperature (° C) Cooling start temperature (° C) Cooling Rate (° C / s) Cooling stop temperature (° C) Secondary reheat / heat temperature (° C) Retention time (s) Cooling Rate (° C / s) Cooling stop temperature (° C) Cooling Rate (° C / s) Comments THE A9 900 810 6 400 510 20 1.8 380 0.4 Comparative Example THE A10 950 840 5 460 540 150 2.5 380 0.4 Comparative Example THE A11 920 800 5 450 540 10 2.5 400 0.4 Comparative Example THE A12 930 800 5 480 550 40 0.4 380 0.4 Comparative Example THE A13 950 820 5 450 570 40 2.5 270 0.4 Inventive Example THE A14 930 800 4.5 480 530 30 3 380 3 Inventive Example B B1 930 850 5 450 540 30 3 380 0.4 Inventive Example Ç C1 920 800 4 480 570 20 3 380 0.4 Inventive Example D D1 950 810 5 450 540 30 2.5 390 0.4 Inventive Example AND E1 930 820 6 420 550 30 3 400 0.4 Inventive Example F F1 930 800 5 450 550 30 3 400 0.4 Inventive Example G G1 930 820 5 470 550 30 2.5 400 0.4 Comparative Example H H1 940 850 5 460 540 30 3 380 0.4 Comparative Example
    0073] Then, the resulting rails were evaluated on the hardness and microstructure of the rail tops. The results are listed in Table 3.
    23/28
    TABLE 3
    Steel Conditions Top microstructure Cementite spheroidization Surface Hardness (HB) Internal hardness at 25mm (HB) 0.2% YS (MPa) TS (MPa) HEY (%) KIC (MPa ^ M) Wear resistance * 1 UT * 2 Defect attributable from UT to hydrogen Comments THE TO 1 Perlite No 450 383 921 1370 13.8 38 1.0 No Standard Example THE A2 Perlite No 465 410 1,020 1,480 13.4 44 0.83 No Inventive Example THE A3 Perlite No 471 416 1,043 1,493 14.2 43 0.8 No Inventive Example THE A4 Perlite No 462 412 1,053 1478 13.9 44 0.82 No Inventive Example THE A5 Perlite No 450 383 921 1,370 13.8 38 1.26 No Comparative Example THE A6 Perlite No 410 372 821 1,212 14.3 37 1.12 No Comparative Example THE A7 Partially from Bainita No 473 426 938 1,460 12.8 40 1.26 No Comparative Example THE A8 Perlite No 428 382 916 1,397 12.6 38 1.08 No Comparative Example THE A9 Partially from Bainita Yes 431 380 900 1,376 12.3 38 1.26 No Comparative Example THE A10 Perlite Yes 433 391 922 1,421 12.2 38 1.0 No Comparative Example THE A11 Partially from Bainita No 435 386 833 1385 12.6 39 1.33 No Comparative Example THE A12 Perlite Yes 426 371 800 1,312 11.3 38 1.12 No Comparative Example THE A13 Perlite No 458 415 1,026 1,453 12.8 43 0.85 Yes Inventive Example THE A14 Perlite No 462 412 1,034 1,473 12.4 44 0.83 Yes Inventive Example B B1 Perlite No 450 410 1033 1462 12.8 44 0.85 No Inventive Example
    24/28
    Steel Conditions Top microstructure Cementite spheroidization Surface Hardness (HB) Internal hardness at 25mm (HB) 0.2% YS (MPa) TS (MPa) HEY (%) KIC (MPa ^ M) Wear resistance * 1 UT * 2 Defect attributable from UT to hydrogen Comments Ç C1 Perlite No 448 410 1024 1450 13.5 45 0.86 No Inventive Example D D1 Perlite No 458 418 1029 1489 13.1 43 0.86 No Inventive Example AND E1 Perlite No 476 421 1093 1526 13.8 45 0.78 No Inventive Example F F1 Perlite No 433 412 1000 1450 13.2 46 0.86 No Inventive Example G G1 Perlite No 383 352 721 1275 12.8 43 1.33 No Comparative Example H H1 Perlite No 451 402 1006 1468 8.3 35 0.84 No Comparative Example
    * 1: A wear volume of a specimen relative to a wear volume in the Standard Example was set to 1. * 2: Whether the UT defect attributable to hydrogen was observed.
    25/28
    26/28 [0074] The surface hardness of the rail top (surface hardness) was measured after removing a decarbonized layer with an emery. The internal hardness at a depth of 25 mm from the surface of the rail top (internal hardness at 25-mm) measured was the hardness at a depth of 25 mm from the surface of a section C that has been cut from the top of rail and then polished. The microstructure of the rail top was evaluated through microscope observation of the microstructure of the surface layer and the microstructure at a depth of 25 mm. Subsequently, a scanning electron microscope was used to observe 30 observation fields selected at random at a magnification of 20,000 times, followed by image processing to determine the aspect ratio (horizontal-to-vertical ratio) of each cementite compound. in a perlite structure, and then the resulting aspect ratio was used to calculate a spheroidization rate (C) defined by Formula (1). A sample that has a spheroidization rate (C) of less than 5% was assessed as having no cementite spheroidization observed, while a sample that has a spheroidization rate (C) equal to or greater than 5% was assessed as having cementite spheroidization observed. The tensile test was performed at room temperature in accordance with AREMA standards for specimen collection. The fracture toughness test was performed in accordance with ASTMA 399 by KIC at room temperature on a CT specimen collected from 2.29 cm (0.9-inch) from a section C of the rail top. The delayed fracture was assessed based on the presence or absence of an increase in a defect at the top of the track by a UT test. Wear resistance was assessed by measuring the wear volume of a specimen that has an outer diameter of 30 mm and a width of 8 mm, from a region at a depth of 20 mm from its surface.
    27/28 rail top surface after eighty thousand rotations in a two-roll wear tester with a contact stress of 1,200 MPa and a specific slip of - 10%, and then determines the wear volume ratio relative to the standard example . The test was carried out in atmospheric air using a lining material that has a hardness of HB 370.
    [0075] As listed in Table 3, each of the tracks of the inventive examples which has a chemical composition within the scope of the present invention and which is manufactured under conditions within the scope of the present invention and has a perlite structure on the top of the rail and has high hardness, in other words, surface hardness equal to or greater than HB 430 and internal hardness at 25-mm equal to or greater than HB 410. The rail top of each rail also has 0.2% elastic limit (YS) equal to or greater than 1,000 MPa, tensile strength (TS) equal to or greater than 1,450 MPa, elongation (EL) equal to or greater than 12%, and fracture toughness at room temperature a or greater than 40 MPa ^ m. Thus, each of the tracks was rated as excellent.
    [0076] In contrast, the rails of the standard example and the comparative examples that have a chemical composition outside the scope of the present invention and that are manufactured under conditions outside the scope of the present invention have bainite formed on the top of the rail and therefore have low wear resistance or have a pearlite structure with low hardness and therefore have low wear resistance, low ductility and / or low toughness.
    [0077] As explained, according to the present invention, by controlling the chemical composition of a billet and the cooling conditions, spheroidization of cementite compounds in slabs after the transformation of perlite can be sufficiently suppressed. Consequently, a rail can be obtained that has a hardness
    28/28 high, in other words, rail top surface hardness equal to or greater than HB 430 and hardness at a depth of 25 mm from the rail top surface equal to or greater than HB 410 and strength to excellent wear. In addition, a fine perlite lamellar structure can be obtained over the entire rail top from the surface to the inside of the rail top, and therefore a rail that has excellent ductility, excellent fracture toughness and strength can be obtained to excellent damage. As a result, a perlite rail that has high hardness from the surface into the top of the rail and a method for making such a perlite rail can be stably provided. The rail of the present invention can be used appropriately as a rail which is required to be wear resistant mainly for heavy cargo or similar rail transport.
    [0078] The modalities of the present invention are explained above. The scope of the present invention, however, is not limited to these modalities which are described to constitute merely the disclosure part of the present invention. In other words, other modalities, examples, techniques for operation, and the like developed based on those modalities by those skilled in the art and the like are also included in the scope of the present invention.
    INDUSTRIAL APPLICABILITY [0079] According to the present invention, a hard pearlite rail can be provided which has increased hardness from the surface to the inside of the rail top and which has excellent wear resistance.
    权利要求:
    Claims (4)
    [1]
    1. Method for making a pearlite rail, characterized by the fact that it comprises:
    hot rolling a billet having a composition consisting of, in% by mass:
    0.70% to 0.90% C;
    0.1% to 1.5% Si;
    0.01% to 1.5% Mn;
    0.001% to 0.035% P;
    0.0005% to 0.030% S;
    0.1% to 2.0% Cr, optionally at least one of:
    not more than 0.15% V;
    not more than 0.030% Nb;
    not more than 1.0% Cu;
    not more than 1.0% Ni; and not more than 0.5% Mo, optionally one or both of:
    not more than 0.010% Ca; and no more than 0.1% REM, and the remainder of the composition consists of Fe and unavoidable impurities, in order to achieve a finish laminating temperature of not less than 900 ° C to form a rail material; and cool the track material in an accelerated manner at a cooling rate of 2 ° C / s to 30 ° C / s from a temperature of 770 ° C to 500 ° C, reheat the resultant or subject the resultant to secondary heating for a temperature within a range of
    Petition 870190073311, of 7/31/2019, p. 8/18
    [2]
    2. Method for making a pearlite rail, according to claim 1, characterized by the fact that the billet composition includes, in mass%, at least one of:
    not more than 0.15% V;
    not more than 0.030% Nb;
    not more than 1.0% Cu;
    not more than 1.0% Ni; and not more than 0.5% Mo.
    2/2
    530 ° C to 580 ° C, retain the resultant at a temperature rate for 20 s to 100 s, and cool the resultant in an accelerated manner at a cooling rate of 2 ° C / s to 10 ° C / s to a temperature within of a range no greater than 450 ° C.
    [3]
    3. Method for manufacturing a pearlite rail, according to claim 1 or 2, characterized by the fact that the billet composition includes, in mass%, one or both of the following:
    not more than 0.010% Ca; and not more than 0.1% of REM.
    [4]
    4. Method for manufacturing a pearlite rail according to any one of claims 1 to 3, characterized by the fact that it further comprises:
    terminate the accelerated cooling performed at a cooling rate of 2 ° C / s to 10 ° C / s, at a temperature within the range of 350 ° C to 450 ° C, and then slowly cool the resultant at a cooling rate of not more than 0.5 ° C / s.
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112015024651B1|2019-10-08|METHOD FOR MANUFACTURING A PERLITA RAIL
    US20190338402A1|2019-11-07|Method for manufacturing railway vehicle wheel
    ES2769275T3|2020-06-25|Sheet steel and procedure for its manufacture
    CA3009461A1|2017-06-29|Steel material having excellent hydrogen induced cracking | resistance for pressure vessel and manufacturing method therefor
    JP2009108397A|2009-05-21|Pearlitic steel rail of high internal hardness type excellent in wear resistance and fatigue failure resistance, and manufacturing method therefor
    BR112015011302B1|2020-02-27|HOT-LAMINATED STEEL SHEET AND ITS PRODUCTION PROCESS
    ES2716881T3|2019-06-17|Steel rail with high carbon content, based on perlite, which has excellent ductility and production process
    BR112012018552B1|2019-01-22|high strength cold rolled steel sheet and production method thereof
    BR112013029160B1|2018-11-21|vehicle crash energy absorbing element
    JP5282506B2|2013-09-04|Internal high hardness type pearlitic steel rail with excellent wear resistance and fatigue damage resistance and method for manufacturing the same
    JP6872616B2|2021-05-19|Steel materials for pressure vessels with excellent hydrogen-induced cracking resistance and their manufacturing methods
    BR112016022007B1|2021-05-11|rail and manufacturing method
    US20190003004A1|2019-01-03|Vehicle part having high strength and excellent durability, and manufacturing method therefor
    JP4333444B2|2009-09-16|High-strength hot-rolled steel sheet having excellent elongation characteristics, stretch flange characteristics, tensile fatigue characteristics, and impact resistance characteristics, and a method for producing the same
    JP6801747B2|2020-12-16|Manufacturing method for austenitic rails
    JP2005314796A|2005-11-10|High strength hot rolled steel sheet having excellent elongation property, stretch flange property and tensile fatigue property, and its production method
    JP5141332B2|2013-02-13|Internal high hardness type pearlitic steel rail excellent in delayed fracture resistance and method for manufacturing the same
    JP2010180443A|2010-08-19|Method for heat-treating high-carbon pearlitic rail
    JP6064515B2|2017-01-25|rail
    RU2479645C1|2013-04-20|Round hot-rolled bar stock
    BR112012007636B1|2018-11-21|duct tube steel having favorable strength and ductility, and its manufacturing method and quality control method
    JP5874376B2|2016-03-02|High-strength steel sheet with excellent workability and method for producing the same
    KR102164116B1|2020-10-13|Steel plate having excellent hic resistance and manufacturing method for thereof
    JP6137043B2|2017-05-31|Rail manufacturing method
    BR112019006502A2|2019-08-13|steel plate
    同族专利:
    公开号 | 公开日
    EP2980231A4|2016-12-21|
    US20160083820A1|2016-03-24|
    EP2980231A1|2016-02-03|
    WO2014157252A1|2014-10-02|
    CN105051220A|2015-11-11|
    EP2980231B1|2018-12-19|
    AU2014245320B2|2017-05-25|
    JPWO2014157252A1|2017-02-16|
    CA2907609A1|2014-10-02|
    BR112015024651A2|2017-07-18|
    AU2014245320A1|2015-10-22|
    CN105051220B|2017-05-31|
    JP5892289B2|2016-03-23|
    CA2907609C|2017-12-19|
    US10253397B2|2019-04-09|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP3081116B2|1994-10-07|2000-08-28|新日本製鐵株式会社|High wear resistant rail with pearlite metal structure|
    JP3078461B2|1994-11-15|2000-08-21|新日本製鐵株式会社|High wear-resistant perlite rail|
    JP3731934B2|1996-03-11|2006-01-05|新日本製鐵株式会社|Manufacturing method of deep and high strength rail|
    JP3513427B2|1999-05-31|2004-03-31|新日本製鐵株式会社|Pearlitic rail excellent in wear resistance and internal fatigue damage resistance, and method of manufacturing the same|
    JP4272385B2|2002-04-05|2009-06-03|新日本製鐵株式会社|Perlite rail with excellent wear resistance and ductility|
    AU2003236273B2|2002-04-05|2005-03-24|Nippon Steel Corporation|Pealite based rail excellent in wear resistance and ductility and method for production thereof|
    JP4214044B2|2003-12-01|2009-01-28|新日本製鐵株式会社|Method for producing high carbon steel rails with excellent wear resistance and ductility|
    JP4355200B2|2003-12-01|2009-10-28|新日本製鐵株式会社|Method for producing high carbon steel rails with excellent wear resistance and ductility|
    JP2005171327A|2003-12-11|2005-06-30|Nippon Steel Corp|Method for manufacturing pearlite-based rail having excellent surface damage-resistance and internal fatigue damage-resistance, and rail|
    CN100519812C|2005-12-29|2009-07-29|攀枝花钢铁公司|Pearlite like high strength low alloy rail steel producing method|
    JP5145795B2|2006-07-24|2013-02-20|新日鐵住金株式会社|Method for producing pearlitic rails with excellent wear resistance and ductility|
    JP4390004B2|2007-03-28|2009-12-24|Ｊｆｅスチール株式会社|Internal high-hardness pearlite steel rail with excellent wear resistance and fatigue damage resistance and method for producing the same|
    JP5292875B2|2007-10-10|2013-09-18|Ｊｆｅスチール株式会社|Internal high-hardness pearlitic steel rail with excellent wear resistance, fatigue damage resistance and delayed fracture resistance, and manufacturing method thereof|
    JP5141332B2|2008-03-27|2013-02-13|Ｊｆｅスチール株式会社|Internal high hardness type pearlitic steel rail excellent in delayed fracture resistance and method for manufacturing the same|
    JP5326343B2|2008-04-28|2013-10-30|新日鐵住金株式会社|Manufacturing method of high internal hardness rail|
    JP5282506B2|2008-09-25|2013-09-04|Ｊｆｅスチール株式会社|Internal high hardness type pearlitic steel rail with excellent wear resistance and fatigue damage resistance and method for manufacturing the same|
    JP5391711B2|2009-02-04|2014-01-15|新日鐵住金株式会社|Heat treatment method for high carbon pearlitic rail|
    JP5267306B2|2009-04-24|2013-08-21|新日鐵住金株式会社|High carbon steel rail manufacturing method|
    CN101818312B|2010-01-19|2012-07-25|钢铁研究总院|Corrosion resistant heavy rail steel with excellent strength-toughness, fatigue resistance and abrasive resistance|
    EP3604600A1|2010-06-07|2020-02-05|Nippon Steel Corporation|Method of manufacturing a steel rail|EP3249069B1|2015-01-23|2020-04-08|Nippon Steel Corporation|Rail|
    CN105018705B|2015-08-11|2017-12-15|攀钢集团攀枝花钢铁研究院有限公司|A kind of hypereutectoid rail and preparation method thereof|
    CN105483347A|2015-12-10|2016-04-13|内蒙古包钢钢联股份有限公司|Heat treatment technology for pearlite steel rail hardening|
    CN108431265B|2015-12-15|2020-04-14|杰富意钢铁株式会社|Rail steel and wheel steel selection method|
    JP6459955B2|2015-12-25|2019-01-30|Ｊｆｅスチール株式会社|rail|
    CN106086370B|2016-06-24|2018-10-09|成都先进金属材料产业技术研究院有限公司|A kind of method reducing rail residual stress and gained rail and its application|
    CN108070780A|2016-11-17|2018-05-25|无锡市千柏材料科技有限责任公司|A kind of pearlite chrome-moly steel and its heat treatment method|
    WO2018174095A1|2017-03-21|2018-09-27|Ｊｆｅスチール株式会社|Rail and method for producing same|
    CN107557557A|2017-08-07|2018-01-09|包头钢铁（集团）有限责任公司|A kind of burning optimization on line method for being used to eliminate rail abnormal structure|
    CN107675084B|2017-10-10|2019-05-10|攀钢集团研究院有限公司|High-carbon high-strength tenacity pearlite steel rail and its manufacturing method|
    WO2019102258A1|2017-11-27|2019-05-31|Arcelormittal|Method for manufacturing a rail and corresponding rail|
    AU2019242158B2|2018-03-30|2021-08-05|Jfe Steel Corporation|Rail and method for manufacturing same|
    JP6610844B1|2018-03-30|2019-11-27|Ｊｆｅスチール株式会社|rail|
    CN109234611A|2018-08-16|2019-01-18|包头钢铁（集团）有限责任公司|The milling method of rail, the smelting process of rail and rail|
    WO2020054339A1|2018-09-10|2020-03-19|日本製鉄株式会社|Rail, and method for manufacturing rail|
    JP6737427B1|2018-09-28|2020-08-12|日本製鉄株式会社|Railway wheels|
    CN109207691A|2018-10-30|2019-01-15|攀钢集团攀枝花钢铁研究院有限公司|The production method of heavy haul railway rail|
    WO2020255806A1|2019-06-20|2020-12-24|Ｊｆｅスチール株式会社|Rail and manufacturing method therefor|
    CN110527816B|2019-09-30|2021-06-15|武汉钢铁有限公司|Heat treatment method for reducing fatigue crack propagation rate of steel rail|
    CN110592496B|2019-10-29|2020-06-12|内蒙古科技大学|Pearlite rail steel and preparation method thereof|
    CN110951944A|2019-11-27|2020-04-03|包头钢铁（集团）有限责任公司|High-strength and high-hardness rare earth steel rail material subjected to online heat treatment and production method thereof|
    CN112176258A|2020-09-30|2021-01-05|江苏省沙钢钢铁研究院有限公司|Wire rod for 2500 MPa-grade steel strand and manufacturing method thereof|
    法律状态:
    2018-11-13| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-05-07| B07A| Application suspended after technical examination (opinion) [chapter 7.1 patent gazette]|
    2019-08-13| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2019-10-08| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 25/03/2014, OBSERVADAS AS CONDICOES LEGAIS. (CO) 20 (VINTE) ANOS CONTADOS A PARTIR DE 25/03/2014, OBSERVADAS AS CONDICOES LEGAIS |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2013067168|2013-03-27|
    JP2013-067168|2013-03-27|
    PCT/JP2014/058367|WO2014157252A1|2013-03-27|2014-03-25|Pearlite rail and method for manufacturing pearlite rail|
    [返回顶部]