Powder high speed steel

Abstract

To provide a powder high-speed steel having excellent wear resistance and toughness.SOLUTION: A powder high-speed steel contains C: 1.0 mass% or more and 1.8 mass% or less, Si: 0.1 mass% or more and 1.0 mass% or less, Mn: 0.1 mass% or more and 1.0 mass% or less, Cr: 6.0 mass% or more and 9.0 mass% or less, Mo: 2.0 mass% or more and 6.0 mass% or less, V: 1.0 mass% or more and 4.0 mass% or less, Co: 0.5 mass% or more and 4.0 mass% or less, Al: 0.000 mass% or more and 0.100 mass% or less, Ti: 0.000 mass% or more and 0.100 mass% or less, Ni: 0.00 mass% or more and 0.50 mass% or less, and Cu: 0.00 mass% or more and 0.50 mass% or less, with the balance being Fe and inevitable impurities. The high-speed steel satisfies the following formulae (1), (2) and (3). 0.001≤Al%+Ti%≤0.100 (1), 5.1≤Cr% / C%≤6.8 (2), 0.75≤(Mo%+V%) / Cr%≤1.25 (3).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This specification discloses a powder high speed steel. [Background technology]

[0002] High-speed steel is used in cutting tools. High-speed steel is also called "high-speed tool steel." High-speed steel obtained by powder metallurgy is called "powdered high-speed steel." Powdered high-speed steel is also called "powdered high-speed steel" or "sintered high-speed steel."

[0003] Japanese Patent Application Laid-Open No. 2004-27354 discloses a powder high-speed steel containing C, Si, Mn, Cr, Mo, and V. This high-speed steel is suitable for parts of plastic molding machines, molds for plastic molding, and the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-27354 A Summary of the Invention [Problem to be solved by the invention]

[0005] Pinion cutters are used in metal cutting. In this cutting, the pinion cutter comes into intermittent contact with the workpiece. This cutter is exposed to an intermittent friction environment. Wear resistance and toughness in this environment are required of the pinion cutter. Wear resistance and toughness are also important properties for other tools. However, there is room for improvement in the wear resistance and toughness of the powder high-speed steel disclosed in JP 2004-27354 A.

[0006] The applicant's intention is to provide a powder high speed steel having excellent wear resistance and toughness. [Means for solving the problem]

[0007] The preferred powder high speed steel is C: 1.0% by mass or more and 1.8% by mass or less Si: 0.1 mass% or more and 1.0 mass% or less Mn: 0.1 mass% or more and 1.0 mass% or less Cr: 6.0 mass% or more and 9.0 mass% or less Mo: 2.0 mass% or more and 6.0 mass% or less V: 1.0 mass% or more and 4.0 mass% or less Co: 0.5% by mass or more and 4.0% by mass or less Al: 0.000 mass% or more and 0.100 mass% or less Ti: 0.000 mass% or more and 0.100 mass% or less Ni: 0.00 mass% or more and 0.50 mass% or less and Cu: 0.00 mass% or more and 0.50 mass% or less The balance is Fe and unavoidable impurities. This high-speed steel satisfies the following formulas (1), (2), and (3). 0.001 ≦ Al% + Ti% ≦ 0.100 (1) 5.1 ≦ Cr% / C% ≦ 6.8 (2) 0.75 ≦(Mo% + V%) / Cr% ≦ 1.25 (3) In these formulas, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Cr% represents the mass content of Cr, C% represents the mass content of C, Mo% represents the mass content of Mo, and V% represents the mass content of V. [Effects of the Invention]

[0008] This powder high-speed steel has excellent wear resistance and toughness. DETAILED DESCRIPTION OF THE INVENTION

[0009] The high-speed steel according to this embodiment is obtained by sintering powder. In other words, this alloy is a sintered body. The powder is typically obtained by atomization. This high-speed steel is obtained through heat treatment. Typical heat treatments include annealing, quenching, and tempering.

[0010] [Metal structure] The metal structure of powder high-speed steel contains a matrix and numerous metal carbides dispersed in the matrix. The base of the matrix is ​​Fe. In the matrix, other elements are dissolved in Fe as a solid solution. The metal carbides are compounds of C and other elements.

[0011] [composition] This powder high-speed steel is C: 1.0% by mass or more and 1.8% by mass or less Si: 0.1 mass% or more and 1.0 mass% or less Mn: 0.1 mass% or more and 1.0 mass% or less Cr: 6.0 mass% or more and 9.0 mass% or less Mo: 2.0 mass% or more and 6.0 mass% or less V: 1.0 mass% or more and 4.0 mass% or less Co: 0.5% by mass or more and 4.0% by mass or less Al: 0.000 mass% or more and 0.100 mass% or less Ti: 0.000 mass% or more and 0.100 mass% or less Ni: 0.00 mass% or more and 0.50 mass% or less and Cu: 0.00 mass% or more and 0.50 mass% or less The balance is Fe and unavoidable impurities. The role of each element in this powder high-speed steel will be explained in detail below.

[0012] [Carbon (C)] C combines with other elements to form carbides. These carbides can contribute to the wear resistance of high-speed steel. From this viewpoint, the C content is preferably 1.0 mass% or more, more preferably 1.1 mass% or more, and particularly preferably 1.2 mass% or more. Excess C causes excessive precipitation of carbides, impairing toughness. From this viewpoint, the C content is preferably 1.8 mass% or less, more preferably 1.6 mass% or less, and particularly preferably 1.5 mass% or less.

[0013] [Silicon (Si)] Si contributes to deoxidation in the steelmaking process. Si also contributes to hardenability. From these viewpoints, the Si content is preferably 0.1 mass% or more, and particularly preferably 0.2 mass% or more. Excessive Si impairs the workability of high-speed steel. From the viewpoint of workability, the Si content is preferably 1.0 mass% or less, more preferably 0.9 mass% or less, and particularly preferably 0.8 mass% or less.

[0014] [Manganese (Mn)] Mn contributes to hardenability. From this viewpoint, the Mn content is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more. Excess Mn impairs the workability of high-speed steel. From this viewpoint, the Mn content is preferably 1.0% by mass or less, more preferably 0.9% by mass or less, and particularly preferably 0.8% by mass or less.

[0015] Chromium Cr forms carbides, which contribute to the wear resistance of high-speed steel. Furthermore, Cr dissolves in the matrix of the high-speed steel structure, contributing to corrosion resistance. From these viewpoints, the Cr content is preferably 6.0% by mass or more, more preferably 6.5% by mass or more, and particularly preferably 7.0% by mass or more. Excessive Cr leads to the precipitation of excessive carbides, which impairs the toughness and seizure resistance of the high-speed steel. Excessive carbides lead to crevice corrosion. From these viewpoints, the Cr content is preferably 9.0% by mass or less, more preferably 8.7% by mass or less, and particularly preferably 8.5% by mass or less.

[0016] [Molybdenum (Mo)] Mo forms fine carbides in high-speed steel. These carbides contribute to the hardness and wear resistance of high-speed steel. Furthermore, Mo dissolves in the matrix of the high-speed steel structure, contributing to corrosion resistance. From these viewpoints, the Mo content is preferably 2.0% by mass or more, more preferably 2.5% by mass or more, and particularly preferably 3.0% by mass or more. Excess Mo leads to excessive precipitation of carbides, which impairs the toughness of high-speed steel. From this viewpoint, the Mo content is preferably 6.0% by mass or less, more preferably 5.5% by mass or less, and particularly preferably 5.0% by mass or less.

[0017] [Vanadium(V)] V forms fine and hard carbides in high-speed steel. Therefore, V contributes to the hardness and wear resistance of high-speed steel. From these viewpoints, the V content is preferably 1.0 mass% or more, more preferably 1.5 mass% or more, and particularly preferably 2.0 mass% or more. Excess V impairs the workability of high-speed steel. From this viewpoint, the V content is preferably 4.0 mass% or less, more preferably 3.7 mass% or less, and particularly preferably 3.5 mass% or less.

[0018] [Cobalt (Co)] Co contributes to the corrosion resistance of high-speed steel. From this viewpoint, the Co content is preferably 0.5 mass% or more, more preferably 0.8 mass% or more, and particularly preferably 1.0 mass% or more. From the viewpoint of cost reduction, the Co content is preferably 4.0 mass% or less, more preferably 3.5 mass% or less, and particularly preferably 3.0 mass% or less.

[0019] [Aluminum (Al)] Al is present in high-speed steel as an oxide. This oxide impairs the toughness of the high-speed steel. From the viewpoint of toughness, the Al content is preferably 0.100% by mass or less, and particularly preferably zero. The inclusion of Al as an unavoidable impurity is acceptable. On the other hand, Al can contribute to the wear resistance of high-speed steel. For example, when the cutting edge of a cutting tool in an intermittent friction environment separates from the workpiece, an oxynitride film is formed at the wear point of the cutting edge due to frictional heat. In tools containing Al, this oxynitride film has high hardness. This oxynitride film can contribute to the wear resistance of the cutting edge. In other words, Al can contribute to the wear resistance of high-speed steel in an intermittent friction environment. From the viewpoint of wear resistance, Al may be intentionally added. The Al content is preferably 0.003% by mass or more, more preferably 0.004% by mass or more, and particularly preferably 0.005% by mass or more. Even if Al remains as an unavoidable impurity, it can contribute to wear resistance if its content is appropriate.

[0020] [Titanium (Ti)] Ti is present in high-speed steel as an oxide. This oxide impairs the toughness of the high-speed steel. From the viewpoint of toughness, the Ti content is preferably 0.100% by mass or less, and particularly preferably zero. The inclusion of Ti as an unavoidable impurity is acceptable. On the other hand, Ti can contribute to the wear resistance of high-speed steel. For example, when the cutting edge of a cutting tool in an intermittent friction environment separates from the workpiece, an oxynitride film is formed at the wear point of the cutting edge due to frictional heat. In tools containing Ti, this oxynitride film has high hardness. This oxynitride film can contribute to the wear resistance of the cutting edge. In other words, Ti can contribute to the wear resistance of high-speed steel in an intermittent friction environment. From the viewpoint of wear resistance, Ti may be intentionally added. The Ti content is preferably 0.003% by mass or more, more preferably 0.004% by mass or more, and particularly preferably 0.005% by mass or more. Even if Ti remains as an unavoidable impurity, it can contribute to wear resistance if its content is appropriate.

[0021] [Nickel (Ni)] Ni impairs the machinability of high-speed steel. From this viewpoint, the Ni content is preferably 0.50 mass% or less, and particularly preferably zero. However, the inclusion of Ni as an unavoidable impurity is permissible. From the viewpoint of production costs, the Ni content is preferably 0.01 mass% or more, more preferably 0.02 mass% or more, and particularly preferably 0.03 mass% or more. On the other hand, Ni can contribute to the corrosion resistance and toughness of high-speed steel. From these viewpoints, Ni may be intentionally added. Even Ni remaining as an unavoidable impurity can contribute to corrosion resistance and toughness if its content is appropriate.

[0022] Copper (Cu) Cu impairs the hardness and wear resistance of high-speed steel. From these viewpoints, the Cu content is preferably 0.5 mass% or less, and particularly preferably zero. However, the inclusion of Cu as an unavoidable impurity is permissible. From the viewpoint of production costs, the Cu content is preferably 0.01 mass% or more, more preferably 0.02 mass% or more, and particularly preferably 0.03 mass% or more. On the other hand, Cu can contribute to the corrosion resistance and toughness of high-speed steel. From these viewpoints, Cu may be intentionally added. Even Cu remaining as an unavoidable impurity can contribute to corrosion resistance and toughness if its content is appropriate.

[0023] [Fe] The powder high-speed steel is an Fe-based alloy. This high-speed steel has excellent toughness. From the viewpoint of toughness, the Fe content is preferably 60 mass % or more, more preferably 70 mass % or more, and particularly preferably 75 mass % or more.

[0024] [impurities] In addition to the aforementioned Ni and Cu, powder high-speed steel also contains unavoidable impurities. A typical example of such an impurity is N. N causes coarsening of carbides and nitrides. Coarse carbides and nitrides impair the toughness of high-speed steel. From the viewpoint of toughness, the N content (by mass) is preferably 300 ppm or less, and particularly preferably 200 ppm or less.

[0025] Another typical impurity is O. O causes the formation of inclusions (oxides). The inclusions can become the starting point for fracture. From the viewpoint of suppressing fracture, the O content (by mass) is preferably 300 ppm or less, and particularly preferably 200 ppm or less.

[0026] Another impurity is tungsten (W). W can contribute to corrosion resistance, but its effect is weaker than that of Mo. On the other hand, W causes primary carbides to become coarse. Coarse primary carbides impair the toughness of high-speed steel. From the viewpoint of toughness, W is not added to the high-speed steel of this embodiment. However, the presence of W as an unavoidable impurity is permitted.

[0027] [Formula (1)] This powder high-speed steel satisfies the following formula (1). 0.001 ≦ Al% + Ti% ≦ 0.100 (1) In this formula, Al% represents the mass content of Al, and Ti% represents the mass content of Ti. As mentioned above, Al and Ti can contribute to the wear resistance of high-speed steel in an intermittent friction environment. From this perspective, it is preferable that high-speed steel contains at least one of Al and Ti. The sum (Al% + Ti%) is preferably 0.001 mass% or more, more preferably 0.004 mass% or more, and particularly preferably 0.006 mass% or more. From the viewpoint of toughness, the sum (Al% + Ti%) is preferably 1.000 mass% or less. Even if Al or Ti remains as an unavoidable impurity, it can contribute to wear resistance if its total content is within the above range.

[0028] [Formula (2)] This powder high-speed steel satisfies the following formula (2). 5.1 ≦ Cr% / C% ≦ 6.8 (2) In this formula, Cr% represents the mass content of Cr, and C% represents the mass content of C. In powder high-speed steels that satisfy formula (2), the ratio (Cr% / C%) is 6.8 or less. The ratio (Cr% / C%) correlates with the amount of primary carbides in the high-speed steel. High-speed steels with a ratio (Cr% / C%) of 6.8 or less have a small amount of primary carbides. This high-speed steel has excellent toughness. This high-speed steel also has excellent corrosion resistance because it has few corrosion origins. From the viewpoints of toughness and corrosion resistance, the ratio (Cr% / C%) is more preferably 6.7 or less, and particularly preferably 6.3 or less.

[0029] [Formula (3)] This powder high-speed steel satisfies the following formula (3). 0.75 ≦(Mo% + V%) / Cr% ≦ 1.25 (3) In this formula, Mo% represents the mass content of Mo, and V% represents the mass content of V. In powder high-speed steels that satisfy formula (3), the ratio ((Mo%+V%) / Cr%) is 0.75 or more. The ratio ((Mo%+V%) / Cr%) correlates with the proportion of precipitated carbides and primary carbides. High-speed steels with a ratio ((Mo%+V%) / Cr%) of 0.75 or more have a large amount of Mo in the matrix and therefore excellent corrosion resistance. High-speed steels with a ratio ((Mo%+V%) / Cr%) of 0.75 or more have a large amount of precipitated carbides containing Mo or V and therefore excellent hardness, wear resistance, and seizure resistance. From these viewpoints, the ratio ((Mo%+V%) / Cr%) is more preferably 0.76 or more, and particularly preferably 0.78 or more. Powder high-speed steels that satisfy both formulas (2) and (3) are particularly preferred.

[0030] [Formula (4)] In this specification, the ratio R1 is calculated by the following formula. R1 = (Al% + Ti% + Si%) / (Ni% + Cu% + Co%) In this formula, Si% represents the mass content of Si, Ni% represents the mass content of Ni, Cu% represents the mass content of Cu, and Co% represents the mass content of Co. In the powder high-speed steel according to this embodiment, the ratio R1 is 0.20 or more and 1.50 or less. In other words, this high-speed steel satisfies the following formula (4). 0.20 ≦ (Al% + Ti% + Si%) / (Ni% + Cu% + Co%) ≦ 1.50 (4) As mentioned above, Al and Ti contribute to the formation of an oxynitride film under intermittent friction conditions. Si also contributes to the formation of this oxynitride film. On the other hand, Ni, Cu, and Co inhibit the formation of this oxynitride film. In a high-speed steel having a ratio R1 of 0.20 or more, a sufficient oxynitride film can be formed. This high-speed steel has excellent wear resistance under intermittent friction conditions. From this viewpoint, the ratio R1 is more preferably 0.25 or more, and particularly preferably 0.27 or more.

[0031] [Formula (5)] In this specification, the ratio R2 is calculated by the following formula. R2 = (Al% + Ti%) / (Ni% + Cu%) In the powder high-speed steel according to this embodiment, the ratio R2 is equal to or greater than 0.02 and equal to or less than 0.15. In other words, this high-speed steel satisfies the following formula (5). 0.02 ≦ (Al% + Ti%) / (Ni% + Cu%) ≦ 0.15 (5) As mentioned above, Al and Ti contribute to the formation of an oxynitride film under intermittent friction conditions. On the other hand, Ni and Cu inhibit the formation of this oxynitride film. In a high-speed steel having a ratio R2 of 0.02 or more, a sufficient oxynitride film can be formed. This high-speed steel has excellent wear resistance under intermittent friction conditions. From this viewpoint, the ratio R2 is more preferably 0.03 or more, and particularly preferably 0.05 or more. Powder high-speed steel that satisfies both of the above formulas (4) and (5) is particularly preferred.

[0032] [Powder metallurgy method] The high-speed steel according to the present invention can be obtained by powder metallurgy. In powder metallurgy, metal powder is first produced by gas atomization, water atomization, disk atomization, pulverization, or the like. This metal powder is then compressed in a high-temperature atmosphere to solidify, thereby obtaining a compact. A preferred pressing method is hot isostatic pressing. In hot isostatic pressing, powder is compressed under isotropic pressure at high temperature. Preferably, an inert gas such as argon gas or helium gas is used as the pressurizing medium.

[0033] This compact is then subjected to hot working. Further heat treatment of this compact results in powder high-speed steel. A typical heat treatment is "annealing-quenching-tempering." These heat treatments result in the precipitation of desired metal carbides.

[0034] Hereinafter, an embodiment of a cutting tool will be described. The material of this cutting tool is the powder high-speed steel described above. That is, this powder high-speed steel has the following properties: C: 1.0% by mass or more and 1.8% by mass or less Si: 0.1 mass% or more and 1.0 mass% or less Mn: 0.1 mass% or more and 1.0 mass% or less Cr: 6.0 mass% or more and 9.0 mass% or less Mo: 2.0 mass% or more and 6.0 mass% or less V: 1.0 mass% or more and 4.0 mass% or less Co: 0.5% by mass or more and 4.0% by mass or less Al: 0.000 mass% or more and 0.100 mass% or less Ti: 0.000 mass% or more and 0.100 mass% or less Ni: 0.00 mass% or more and 0.50 mass% or less and Cu: 0.00 mass% or more and 0.50 mass% or less The remainder is Fe and unavoidable impurities. This powder high-speed steel satisfies the following formulas (1), (2), and (3). 0.001 ≦ Al% + Ti% ≦ 0.100 (1) 5.1 ≦ Cr% / C% ≦ 6.8 (2) 0.75 ≦(Mo% + V%) / Cr% ≦ 1.25 (3) In these formulas, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Cr% represents the mass content of Cr, C% represents the mass content of C, Mo% represents the mass content of Mo, and V% represents the mass content of V. [Example]

[0035] The effects of the powder high-speed steel according to the examples will be clarified below, but the scope of the present disclosure should not be construed as being limited based on the description of these examples.

[0036] [Example 1] The molten metal was atomized to obtain a powder. This powder was filled into a cylindrical steel can. The steel can was vacuum degassed and then sealed. A compact was obtained by hot isostatic pressing under an argon gas atmosphere at a pressure of 200 MPa and a temperature of 950°C. This compact was then forged, rolled, hot extruded, and annealed to obtain a round bar with a diameter of 50 mm. Test pieces for hardness measurement, abrasion test, and impact test were cut from this round bar. These test pieces were quenched at approximately 1100°C and tempered for three hours to obtain test pieces made of the powder high-speed steel according to Example 1. An appropriate tempering temperature was selected within the range of 500°C to 600°C to adjust the hardness of the test pieces to 64HRC or more and 65HRC or less. The composition of this powder high-speed steel is shown in Tables 1 and 2 below. In addition to the elements shown in Tables 1 and 2, this powder high-speed steel contains unavoidable impurities.

[0037] [Examples 2-20 and Comparative Examples 1-5] Powder high-speed steels of Examples 2-20 and Comparative Examples 1-5 were obtained in the same manner as in Example 1, except that the compositions were as shown in Tables 1 and 2 below.

[0038] [Comparative Examples 6-10] A round bar was obtained in the same manner as in Example 1, except that the composition was as shown in Table 2 below. Test pieces for hardness measurement, abrasion test, and impact test were cut out from this round bar. These test pieces were quenched at approximately 1100°C and then tempered for three hours to obtain test pieces made of powder high-speed steel according to Example 1. Attempts were made to adjust the tempering temperature so that the hardness of the test pieces would be 64 HRC or more and 65 HRC or less, but the hardness did not reach 64 HRC. The tempering temperature was selected within the range of 500°C to 600°C to maximize the hardness.

[0039] [Specific wear rate (condition 1)] A test piece measuring 20 mm in length, 20 mm in width and 5 mm in height was set in an Ohkoshi type abrasion tester, and the specific abrasion rate was measured under the following conditions. Testing equipment: "OAT-U" by Tokyo Testing Machine Co., Ltd. Ring: SCM420 (hardness: 88HRB) Friction speed: 2.38m / S Wear distance: 200m Final load: 61.8N The results are shown in Table 3 below.

[0040] [Specific wear rate (condition 2)] A test piece measuring 20 mm in length, 20 mm in width and 5 mm in height was set in an Ohkoshi type abrasion tester, and the specific abrasion rate was measured under the following conditions. Testing equipment: "OAT-U" by Tokyo Testing Machine Co., Ltd. Ring: SCM420 (hardness: 88HRB) Friction speed: 2.38m / S Wear distance: 200m (20m x 10) Final load: 61.8N Repeat count: 10 times (5 minute intervals) The test consisted of measuring the amount of wear at a distance of 20 m, after which the test was stopped for 5 minutes. This measurement and stop was repeated 10 times. The results are shown in Table 3 below.

[0041] [Shock Value] A test piece measuring 10 mm in length, 10 mm in width, and 50 mm in length was prepared. This test piece had a notch. The notch size was "10R, 2 mmC." This test piece was subjected to a Charpy impact test in accordance with the provisions of "JIS Z 2242:2005," and the impact value was measured. The results are shown in Table 3 below.

[0042] [comprehensive evaluation] Each powder high speed steel was graded based on the following criteria: S: Specific wear volume under condition 2 is 0.3 × 10 -8 mm 3 / N·mm and impact value is less than 20J / cm 2 That's all. A: Specific wear volume under condition 2 is 0.3 × 10 -8 mm 3 / N mm or more 0.5×10 -8 mm3 / N·mm and impact value is less than 20J / cm 2 That's all. B: Specific wear volume under condition 2 is 0.5 × 10 -8 mm 3 / N mm or more, 1.0×10 -8 mm 3 / N·mm or less, and the impact value is 20J / cm 2 That's all. F1: Specific wear volume under condition 2 is 1.0 × 10 -8 mm 3 / N·mm or more, and the impact value is 20J / cm 2 That's all. F2: Specific wear volume under condition 2 is 1.0 × 10 -8 mm 3 / N·mm or more, and the impact value is 20J / cm 2 is less than. The results are shown in Table 3 below.

[0043] [Table 1]

[0044] [Table 2]

[0045] [Table 3]

[0046] As shown in Table 3, the powder high-speed steels of the examples were excellent in all evaluation items. From the above evaluation results, the superiority of these powder high-speed steels is clear.

[0047] [Disclosure items] Each of the following sections is a disclosure of a preferred embodiment.

[0048] [Item 1] C: 1.0% by mass or more and 1.8% by mass or less Si: 0.1 mass% or more and 1.0 mass% or less Mn: 0.1 mass% or more and 1.0 mass% or less Cr: 6.0 mass% or more and 9.0 mass% or less Mo: 2.0 mass% or more and 6.0 mass% or less V: 1.0 mass% or more and 4.0 mass% or less Co: 0.5% by mass or more and 4.0% by mass or less Al: 0.000 mass% or more and 0.100 mass% or less Ti: 0.000 mass% or more and 0.100 mass% or less Ni: 0.00 mass% or more and 0.50 mass% or less and Cu: 0.00 mass% or more and 0.50 mass% or less It contains The balance is Fe and unavoidable impurities, Powder high-speed steel that satisfies the following formulas (1), (2), and (3): 0.001 ≦ Al% + Ti% ≦ 0.100 (1) 5.1 ≦ Cr% / C% ≦ 6.8 (2) 0.75 ≦(Mo% + V%) / Cr% ≦ 1.25 (3) (In these formulas, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Cr% represents the mass content of Cr, C% represents the mass content of C, Mo% represents the mass content of Mo, and V% represents the mass content of V.)

[0049] [Item 2] 2. The powder high-speed steel according to item 1, further satisfying the following formula (4): 0.20 ≦ (Al% + Ti% + Si%) / (Ni% + Cu% + Co%) ≦ 1.50 (4) (In this formula, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Si% represents the mass content of Si, Ni% represents the mass content of Ni, Cu% represents the mass content of Cu, and Co% represents the mass content of Co.)

[0050] [Item 3] 3. The powder high-speed steel according to item 1 or 2, further satisfying the following formula (5): 0.02 ≦ (Al% + Ti%) / (Ni% + Cu%) ≦ 0.15 (5) (In this formula, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Ni% represents the mass content of Ni, and Cu% represents the mass content of Cu.) [Industrial Applicability]

[0051] The powder high-speed steel is suitable for applications in environments of not only intermittent friction but also continuous friction, and can be used in a variety of applications, such as cutting tools, molds, injection molding machines, die sets, punches, hand tools, machine tools, and blades.

Claims

1. C: 1.0% by mass or more and 1.8% by mass or less Si: 0.1% by mass or more and 1.0% by mass or less Mn: 0.1% by mass or more and 1.0% by mass or less Cr: 6.0% by mass or more and 9.0% by mass or less Mo: 2.0% by mass or more and 6.0% by mass or less V: 1.0% by mass or more and 4.0% by mass or less Co: 0.5% by mass or more and 4.0% by mass or less Al: 0.000% by mass or more and 0.100% by mass or less Ti: 0.000 mass% or more and 0.100 mass% or less Ni: 0.00 mass% or more and 0.50 mass% or less and Cu: 0.00 mass% or more and 0.50 mass% or less It contains The balance is Fe and unavoidable impurities, A powder high-speed steel that satisfies the following formulas (1), (2), and (3). 0.001 ≦ Al% + Ti% ≦ 0.100 (1) 5.1 ≦ Cr% / C% ≦ 6.8 (2) 0.75 ≦(Mo% + V%) / Cr% ≦ 1.25 (3) (In these formulas, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Cr% represents the mass content of Cr, C% represents the mass content of C, Mo% represents the mass content of Mo, and V% represents the mass content of V.)

2. 2. The powder high-speed steel according to claim 1, further satisfying the following formula (4): 0.20 ≦ (Al% + Ti% + Si%) / (Ni% + Cu% + Co%) ≦ 1.50 (4) (In this formula, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Si% represents the mass content of Si, Ni% represents the mass content of Ni, Cu% represents the mass content of Cu, and Co% represents the mass content of Co.)

3. 3. The powder high-speed steel according to claim 1, further satisfying the following formula (5): 0.02 ≦ (Al% + Ti%) / (Ni% + Cu%) ≦ 0.15 (5) (In this formula, Al% represents the mass content of Al, Ti% represents the mass content of Ti, Ni% represents the mass content of Ni, and Cu% represents the mass content of Cu.)

Images