Cemented carbide for demanding applications

Abstract

Corrosion- and erosion-resistant cemented carbide for demanding applications, particularly oil and gas stream applications. Cemented tungsten carbide grades based on hard and binder phases containing the following elements are described: Co, Ni, Cr, Mo, and balance WC. Specifically, the binder phase content of the cemented carbide is between 5.1 and 7.5 wt%; the cemented carbide contains 1.7 to 3.3 wt% Co; 2.0 to 3.7 wt% Ni; 0.5 to 1.1 wt% Cr; 0.05 to 0.4 wt% Mo, and balance WC, with the wt% of Co always being less than the wt% of Ni.

Description

Technical Field

[0001] The subject matter of the present invention relates to wear-resistant cemented carbides and manufacturing methods therefor for demanding applications, and more particularly, although not exclusively, to corrosion-resistant and erosion-resistant cemented carbides having a relatively high toughness for a given hardness.

Background Art

[0002] Cemented carbides have been widely used for demanding applications such as tools for rock cutting, machining, excavation or demolition. These highly wear-resistant carbides have been found to be particularly applicable as components in the oil and gas industries, where they are typically used for various fluid flow control components including, for example, choke valves and control valves, cages, valve seats and sealing rings. The suitability of these carbides is largely due to their physical and mechanical properties including, in particular, hardness, toughness, strength and wear resistance. In physically demanding oil and gas applications, conventional cemented carbide components have a relatively short service life. Furthermore, due to limited accessibility (e.g., subsea environments) and long production downtime for inspection, prediction of in-service performance and loading is of great importance.

[0003] Components that control the flow in oil and gas production systems are typically exposed to high-speed fluid flows (>200 m / s), where the fluid is typically mixed with sand / oil / gas / water at various humidities, flow rates and pHs. The operating conditions can also include "acidic" conditions involving associated corrosion, pitting and an increased likelihood of progressive cracking, particularly exposure to H2S.

[0004] With deep sea environments, the conditions of operation (particularly including high variability of the media flow, as well as extreme high pressure and high temperature) are becoming increasingly difficult, meaning that conventional components have a short service life and are prone to high failure rates.

[0005] WO2012 / 045815 describes a cemented carbide material for oil and gas applications, in which the hard phase is combined with a binder phase containing Ni, Co, Cr, Mo and Nb, to provide improved physical and mechanical properties for maximizing the service life.

[0006] WO00 / 000655 discloses a tungsten carbide material for corrosion-erosion resistance when implemented as a choke valve for controlling a media flow, including materials containing Co, Ni, Cr, Mo and residual WC.

[0007] EP1413637 also discloses a tungsten carbide grade for oil and gas applications based on Co, Ni, Cr, Mo and residual WC.

[0008] However, in certain environments in the control of oil and gas fluid flows, existing cemented carbides are not optimized for corrosion resistance and mechanical resistance. In particular, existing cemented carbides exhibit unsatisfactory failure rates when the flow conditions include an acidic medium and intermittent impacts are applied to respective member parts by large solid particles. SUMMARY OF THE INVENTION

[0009] The present disclosure is directed to a cemented carbide material suitable for demanding applications, particularly for use as a component or primary material for member parts of such demanding applications. Also provided is a cemented carbide having desirable toughness, hardness, strength and wear resistance properties to withstand difficult environmental and operating conditions. Also provided is a cemented carbide suitable for use as a tool for metal forming or as a wear part in fluid handling applications. Also provided is a cemented carbide suitable for use as a member part in oil and gas production, including in particular use as a fluid flow member.

[0010] Those objectives are achieved by a cemented carbide material having a relatively high hardness, toughness and transverse rupture strength (T★RS). In particular, the cemented carbide material according to the present disclosure can include a hardness in the range of 1600 - 2000 HV30 (ISO3878:1983). Further, the cemented carbide of the present invention can include a toughness between 9 - 12 MN / m 3 / 2 (Palmqvist, ISO28079:2009). Further, the cemented carbide of the present invention can include a TRS of more than 3000 N / mm 2 (ISO3327:2009).

[0011] A cemented carbide including a hard phase containing WC and a binder phase, wherein the binder phase content of the cemented carbide is between 5.1 - 7.5 wt%, and the cemented carbide includes 1.7 - 3.3 wt% of Co; 2.0 - 3.7 wt% of Ni; 0.5 - 1.1 wt% of Cr; 0.05 - 0.4 wt% of Mo and 90.0 - 96.0 wt% of WC, and it is characterized in that the wt% of Co is always less than the wt% of Ni, and a cemented carbide is provided.

[0012] Optionally, the cemented carbide includes WC as the remaining wt%.

[0013] In particular, the inventors have identified that the listed elemental composition of a cemented carbide including WC in the hard phase and a binder phase, where the wt% of Co is always less than the wt% of Ni, provides desirable advantageous hardness, toughness, wear resistance and corrosion resistance properties. Thus, a highly erosion-resistant material suitable for use as a member in demanding oil and gas fluid flow applications is provided.

[0014] Furthermore, the elemental composition of the cemented carbide preferably includes 1.7 - 3.3 wt% Co; 2.0 - 3.7 wt% Ni; 0.5 - 1.1 wt% Cr; 0.05 - 0.4 wt% Mo. In particular, in some embodiments, substantially all, most, or the main component wt% of Co, Ni, Cr, and Mo are present in the binder phase. That is, in certain embodiments, a small or relatively small amount (i.e., less than 10 wt%, less than 5 wt%, less than 2 wt%, or less than 1%) of the total wt% of each of Co, Ni, Cr, and / or Mo can be present outside of or exceeding the binder phase. Such small amounts can be present at the grain boundaries between the hard phase and the binder phase or in the hard phase.

[0015] The cemented carbide contains Cr, Mo, and W in one or a combination of free / elemental forms or as compounds combined with any one or combination of other components of the cemented carbide.

[0016] Optionally, there is provided a cemented carbide comprising a hard phase containing WC and a binder phase, wherein the binder phase content of the cemented carbide is between 5.1 - 7.5 wt%, and the cemented carbide consists of 1.7 - 3.3 wt% Co; 2.0 - 3.7 wt% Ni; 0.5 - 1.1 wt% Cr; 0.05 - 0.4 wt% Mo and 90.0 - 96.0 wt% WC, and the wt% of Co is less than the wt% of Ni.

[0017] Optionally, the hard phase of the cemented carbide is at least 87 wt%, 89 wt%, 90 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, 96 wt%. Optionally, the amount of WC in the cemented carbide is at least 90 wt%, or in the range of 90 - 96 wt% or 91 - 95 wt%.

[0018] Optionally, the cemented carbide does not contain nitrides and / or carbonitrides. Optionally, the cemented carbide can contain nitrides and / or carbonitrides present at impurity levels. Optionally, the impurity levels of such nitrides and / or carbonitrides are less than 0.05 wt%, less than 0.01 wt% or less than 0.001 wt%. Optionally, the cemented carbide does not contain Ti, as well as carbides, nitrides and / or carbonitrides of Ti. Preferably, the cemented carbide contains 0 wt% of Ti so as to be compositionally free of Ti.

[0019] Optionally, the carbon content in the sintered cemented carbide is maintained within a predetermined range to further contribute to high corrosion resistance, wear resistance and toughness. Optionally, the carbon content of the sintered material can be held within a range between the free carbon (upper limit) of the microstructure and the starting point of the eta phase (lower limit). Such limit values will be recognized by those skilled in the art.

[0020] Optionally, the magnetic saturation of the magnetic binder phase in the sintered carbide can be expressed as the "predicted" maximum magnetic saturation percentage of the "pure" cobalt content contained in the carbide. According to an aspect of the present invention, the sintered carbide can contain a magnetic saturation between 50 and 100% of the chemically determined content.

[0021] Optionally, the Co / Ni quotient wt% in the cemented carbide is 0.50 to 0.95. The relative amounts of Co:Ni provide enhanced corrosion resistance, particularly resistance to dry erosion, mainly for gas extraction applications. Preferably, the Co / Ni quotient wt% can be in the range of 0.50 to 0.90; 0.55 to 0.85; 0.55 to 0.80; 0.55 to 0.75; 0.60 to 0.75 or 0.60 to 0.70. In particular, a relatively higher wt% of Ni has been found to enhance corrosion resistance, particularly under acidic conditions (pH < 7).

[0022] Optionally, the quotient wt% of Cr / (Co+Ni+Cr+Mo) in the cemented carbide ranges from 0.08 to 0.14. This range enhances corrosion resistance while maintaining desirable mechanical properties including the hardness and toughness required for demanding applications such as oil and gas.

[0023] Optionally, the quotient wt% of Mo / (Co+Ni+Cr+Mo) in the cemented carbide ranges from 0.01 to 0.06. This range enhances corrosion resistance while maintaining desirable mechanical properties including the hardness and toughness required for demanding applications such as oil and gas.

[0024] Optionally, the binder phase of the cemented carbide is at least 4 wt%, or ranges from 4 to 8 wt% or 4 to 7 wt%. The amount (wt%) of the binder phase relative to the WC hard phase has been found to enhance toughness while maintaining hardness at a level suitable for demanding applications. This relative binder content also contributes to enhanced corrosion resistance (especially resistance to dry erosion).

[0025] Optionally, the Co+Ni content in the cemented carbide is at least 4 wt%, or ranges from 4 to 8 wt%, 4 to 7 wt% or 5 to 6.5 wt%. Such a composition contributes to an increase in the toughness of the material of the present invention.

[0026] Optionally, the grain size of WC can range from 0.2 to 2 μm, 0.2 to 1 μm or 0.4 to 0.8 μm of the sintered material determined by linear intercepts. Optionally, the FSSS grain size of the starting WC material can range from 0.4 to 2 μm. Such grain sizes provide enhanced toughness while maintaining hardness. Preferably, the grain size of WC in the sintered material, measured by linear intercepts, ranges from 0.3 to 0.9 μm.

[0027] Optionally, Co is included in the range of 1.7 - 3.3 wt%, 2.0 - 2.6 wt%, 2.1 - 2.5 wt% or 2.2 - 2.4 wt%. Optionally, the cemented carbide contains Ni in the range of 3.3 - 3.7 wt% or 3.4 - 3.6 wt%. Optionally, the cemented carbide contains Cr in the range of 0.7 - 1.0 wt%, 0.75 - 0.95 wt% or 0.8 - 0.9 wt%. Optionally, the cemented carbide contains Mo in the range of 0.1 - 0.4 wt%.

[0028] Optionally, a cemented carbide comprising a hard phase containing WC and a binder phase, wherein the binder phase content of the cemented carbide is between 5.1 - 7.5 wt%, the cemented carbide contains 1.7 - 3.3 wt% of Co; 2.0 - 3.7 wt% of Ni; 0.5 - 1.1 wt% of Cr; 0.05 - 0.4 wt% of Mo and WC contained as a balance, and the wt% of Co is less than the wt% of Ni, is provided.

[0029] Also provided are members for oil and gas applications comprising the cemented carbide claimed herein. Optionally, the member can include any one of a choke valve, a control valve, a valve seat, a plug seat, a frac seat, a cage, a cage assembly, a seal ring, and a member portion of a valve that allows passage of a fluid and / or slurry.

[0030] Also provided is a composition suitable for demanding wear applications such as use as a tool for metal forming or as a wear part involving fluid flow applications. According to one aspect, the cemented carbide of the present invention can be used as a tool for metal forming, including, in particular, use as a die for wire drawing or other members in metal forming. According to one aspect, the cemented carbide of the present invention can be used as a member for controlling fluid flow.

[0031] Also provided is a method of making a cemented carbide comprising a hard phase containing WC and a binder phase, the method comprising preparing a powdered batch comprising raw materials of 1.7 to 3.3 wt% Co; 2.0 to 3.7 wt% Ni; 0.5 to 1.1 wt% Cr; 0.05 to 0.4 wt% Mo and the balance WC (the wt% of Co is always less than the wt% of Ni); compressing the powdered batch to form a preform; and sintering the preform to form an article, wherein the binder phase content of the cemented carbide is between 5.1 and 7.5 wt%.

[0032] Also provided is a method of making a cemented carbide comprising a hard phase containing WC and a binder phase, the method comprising preparing a powdered batch comprising raw materials of 1.7 to 3.3 wt% Co; 2.0 to 3.7 wt% Ni; 0.5 to 1.1 wt% Cr; 0.05 to 0.4 wt% Mo and 90.0 to 96.0 wt% WC (the wt% of Co is less than the wt% of Ni); compressing the powdered batch to form a preform; and sintering the preform to form an article, wherein the binder phase content of the cemented carbide is between 5.1 and 7.5 wt%.

[0033] Optionally, the step of sintering the preform to form an article comprises a vacuum or HIP treatment. Optionally, the sintering treatment comprises treating at a temperature of 1360 to 1500 °C and a pressure of 0 to 20 MPa.

[0034] Also provided is an article for demanding applications manufactured by the method described herein.

[0035] Also provided is a cemented carbide article obtainable by the method described herein.

[0036] Optionally, Cr can be added in the form of Cr3C2 as part of the powdered batch.

[0037] Optionally, the method can include adding a Cr element. According to such an implementation, the method can further include adding additional carbon so as to achieve the desired carbon wt% in the sintered cemented carbide within the range between the free carbon (upper limit) of the microstructure and the starting point (lower limit) of the eta phase, as recognized by those skilled in the art. Optionally, the WC particle size by FSSS in the powdered batch can be in the range of 0.4 - 2 μm.

[0038] Optionally, the cemented carbide of the present invention is a tungsten cemented carbide.

[0039] The cemented carbide of the present invention can further include carbides, nitrides and / or carbonitrides selected from the group consisting of tungsten, titanium, chromium, vanadium, tantalum, neodymium and molybdenum. Such components can preferably be added to the powder batch as an additive in a small wt% with respect to WC contained in the cemented carbide as most or main component wt% with respect to other components of the material.

[0040] Optionally, the cemented carbide does not contain nitrogen or nitrogen compounds. However, the cemented carbide can contain nitrogen or nitrogen compounds such as nitrides at impurity levels of less than 0.1 wt%, less than 0.05 wt% or less than 0.01 wt%.

[0041] Optionally, there is provided a cemented carbide comprising a hard phase containing WC and a binder phase, wherein the binder phase content of the cemented carbide is between 5.1 - 7.5 wt%, and the cemented carbide consists of 1.7 - 3.3 wt% of Co; 2.0 - 3.7 wt% of Ni; 0.5 - 1.1 wt% of Cr; 0.05 - 0.4 wt% of Mo and 90.0 - 96.0 wt% of WC, and optionally any one or a combination of Fe, Co, Ti, Nb, Ta, V, Re, Ru, Zr, Al and / or Y at impurity levels, and the wt% of Co is less than the wt% of Ni.

[0042] Optionally, the cemented carbide of the present invention can further contain any one of Fe, Ti, Nb, Ta, V, Re, Ru, Zr, Al and / or Y at impurity levels. These elements can exist in either elemental, carbide, nitride or carbonitride form. The impurity level is a level such as less than 0.1 wt% or less than 0.5 wt% with respect to the total amount of impurities present in the cemented carbide.

[0043] Preferably, the cemented carbide exclusively contains carbides. Preferably, the cemented carbide contains WC as the main carbide component by wt%. Optionally, the cemented carbide can contain a small wt% of carbide of either one or a combination of Mo and Cr.

[0044] The cemented carbide typically further contains a metal phase component containing iron, nickel, cobalt, molybdenum or a combination thereof. Such a component can be present in the binder phase.

[0045] Here, specific implementations of the present invention will be described by way of example only with reference to the following accompanying drawings.

Brief Description of the Drawings

[0046]

Figure 1

Modes for Carrying Out the Invention

[0047] A wear-resistant cemented carbide grade is provided that has relatively high toughness and exhibits enhanced corrosion and erosion resistance. The inventors have determined that such physical and mechanical properties can be achieved by a binder phase content in the range of 5.1 to 7.5 wt% with respect to the WC hard phase, and the cemented carbide having a composition of 1.7 to 3.3 wt% Co; 2.0 to 3.7 wt% Ni; 0.5 to 1.1 wt% Cr; 0.05 to 0.4 wt% Mo and 90.0 to 96.0 wt% WC. The contribution to the desired physical and mechanical properties can also be achieved by controlling the amount of Co relative to Ni, in particular by maintaining the wt% of Co below the wt% of Ni.

[0048] The cemented carbides of the present invention are particularly suitable for demanding applications where such components are susceptible to corrosion and mechanical erosion, potentially high wear, including use as components in oil and gas production. Further, the carbides of the present invention are also suitable for use as tools for metal forming.

Examples

[0049] Cemented carbides according to the present invention were produced using conventional powder metallurgy methods including milling, compressing, forming and sintering hip treatments. In addition to comparative test pieces, cemented carbide materials according to the present invention were prepared.

[0050] Each of the sample mixtures Grades A - I was prepared from powders forming the hard components and powders forming the binder. The following preparation method corresponds to Grade B in Table 1 below, having starting powdered materials: WC 95.24 g, Cr3C2 0.82 g, Co 2.05 g, Ni 3.58 g, C 0.05 g, Mo 0.31 g, PEG 2 g, ethanol 50 ml. It will be recognized by those skilled in the art that this is the relative amount of powdered materials possible, and appropriate adjustments are required to create a powdered batch and achieve the fully sintered final composition of the cemented carbides in Table 1.

[0051] A homogeneous mixture was obtained and the powder was wet milled with a lubricant and an anti-caking agent until granulated by drying and sieving. The dry powder was compressed to form a green part with the aforementioned standard shape and sintered at 1350 - 1500 °C and 5 MPa using SinterHIP.

[0052] Table 1 shows the composition (wt%) in detail, along with further characterization of grades A - I according to the present invention. TIFF0007698580000001.tif106170

[0053] Hardness tests were carried out on grades A - I according to ISO 3878 and toughness tests were carried out according to Palmqvist ISO 28079. Vickers indentation tests were performed using 30 kgf (HV30) to evaluate the hardness. Palmqvist fracture toughness was calculated according to TIFF0007698580000002.tif18170.

[0054] where A is a constant of 0.0028, HV is the Vickers hardness (N / mm2), P is the applied load (N), and ΣL is the total length of the cracks in the imprint (mm). The results are shown in Table 2. TIFF0007698580000003.tif87170

[0055] Table 3 shows Examples grades B and G in detail, along with Comparative Examples 1 - 4, according to various different compositions and particle sizes of the WC starting material. The particle size of the starting material was reduced according to standard milling and sintering procedures, and thus it will be recognized that the grain size of the final fully sintered material (determined by linear intercept) can be less than (at most, or approximately half) the particle size of the starting material, as determined by a Fisher Model 95 Sub - Sieve Sizer (trademark) (FSSS).

[0056] The linear intercept method (ISO4499-2:2008) is a method for measuring WC grain size. The grain size measurement is obtained from SEM images of the microstructure. For nominally two-phase materials, such as cemented carbides (hard phase and binder phase), information on the grain size distribution is obtained by the linear intercept technique. A line is drawn on a calibrated image of the cemented carbide microstructure. When this line cuts off WC particles, the length of the line (l i ) is measured using a calibration rule (where i = 1, 2, 3,... n for primary, secondary, tertiary,... nth order particles). At least 100 particles were counted for measurement. The average WC grain size is defined as follows. TIFF0007698580000004.tif13170TIFF0007698580000005.tif73170

[0057] Hardness (ISO3878), toughness (Palmqvist, ISO28079) and TRS (ISO3327:2009) tests were carried out on grades B and G (partially), as well as Comparative Examples 1-4. The test pieces for determining the flexural strength were cylinders of type C (cylindrical cross-section with dimensions of 40×3 mm2). The samples were placed between two supports and loaded at their centers until failure occurred (three-point bending). The maximum load was recorded and averaged over at least five samples per test. The results are shown in Table 4 together with the respective magnetic cobalt contents. TIFF0007698580000006.tif76170

[0058] The corrosion rates of grades B and G and Comparative Examples 1-4 were evaluated and the results are shown in Table 5. The surface roughness (Ra) of the samples was 0.036 μm. The corrosion rate (mm / year) was estimated using the mass loss with respect to the immersion time under the following simulated test conditions. 1) Immersed for 212 hours at 25 °C in synthetic seawater (3.56% wt NaCl) with pH 6 under aerated conditions. 2) Immersed for 212 hours at 60 °C in synthetic seawater (3.56% wt NaCl + 0.1 M H2SO4) with pH 1 under aerated conditions.

[0059] The mass loss corrosion rate (mm / year) was calculated according to the previous simulation test conditions using the following formula (ASTM G31-72, "Standard Practice for Laboratory Immersion Corrosion Testing of Metals"): Corrosion rate = 8.76×10 4 ×((weight loss (g)) / (exposed surface area (cm 2 ²)×density (g / cm 3 ³)×immersion time (hours)) was estimated. TIFF0007698580000007.tif72170

[0060] The dry erosion resistance of the grades in Table 5 was tested using an air-sand erosion rig according to the following formula (ASTM G76-07, "Standard Test Method for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets" - Determination of Material Loss by Gas Jet Solid Particle Impingement Erosion Using a Jet Nozzle Type Erosion Apparatus) as a guideline. The particle size range was 181 μm to 251 μm, the collision angle was 90°, the erodent supply rate was approximately 10 g / min, the flow rate was 200 ± 20 m / s, and the separation distance between the sample and the nozzle was 30 mm. The results are shown in Table 6. TIFF0007698580000008.tif75170

[0061] The cemented carbide material of the present invention according to grade G exhibited high wear resistance (erosion resistance) along with enhanced toughness and corrosion resistance. In particular, FIG. 1 is a graph of standardized mass loss and toughness for grades B and G of the present invention and Comparative Examples 1-4. Line 10 is the minimum pass limit for toughness, and line 11 is the minimum pass limit for dry erosion resistance for the demanding oil and gas exploration conditions. As can be seen, sample G meets the requirements for both toughness and dry erosion resistance according to the test methods described herein.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter described in the present invention pertains.

[0063] Unless otherwise indicated, any reference to "wt%" refers to the mass fraction of the component relative to the total mass of the cemented carbide.

[0064] When a range of values is provided, such as a concentration range, percentage range, or ratio range, each value intervening to the smallest unit of the lower limit between the upper and lower limits of that range, as well as any other described or intervening value in the described range, is understood to be included in the subject matter described, unless the context clearly indicates otherwise. The upper and lower limits of these smaller ranges may independently be included in the smaller range, and such embodiments are also included in the subject matter described, provided that there are no specifically excluded limit values within the described range. When the described range includes one or both of the limit values, ranges excluding either or both of the included limit values are also included in the subject matter described.

[0065] As used hereinbefore and elsewhere in this specification, the terms "a" and "an" are to be understood as referring to "one or more" of the listed components. The use of the singular form will be apparent to those skilled in the art to include the plural, unless specifically stated otherwise. Accordingly, the terms "a", "an" and "at least one" are used interchangeably herein.

[0066] Unless otherwise indicated, all numerical values representing properties such as amounts, sizes, weights, reaction conditions, etc. of components used in this specification and the claims are to be understood to be modified in all instances by the term "about". Accordingly, unless the contrary is indicated, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the subject matter of the present invention. At the very least, and not as a limitation on the application of the doctrine of equivalents to the claims, each numerical parameter should at least be construed in light of the reported significant digits and by applying ordinary rounding techniques.

[0067] Throughout this application, the language "comprising" is used in the description of various embodiments, but it will be understood by those skilled in the art that in some instances, embodiments may alternatively be described using the language "consisting essentially of" or "consisting of".

[0068] Having thus described the subject matter of the present invention, it will become apparent that the subject matter of the present invention can be modified or varied in many ways. Such modifications and variations are not to be regarded as a departure from the spirit and scope of the subject matter of the present invention, and it is intended that all such modifications and variations be included within the scope of the following claims.

Claims

1. A cemented carbide having a hard phase containing WC and a binder phase, wherein the cemented carbide contains Co in an amount of 1.7 to 3.3 wt% based on the total amount of the cemented carbide, contains Ni in an amount of 2.0 to 3.7 wt% based on the total amount of the cemented carbide, contains Cr in an amount of 0.5 to 1.1 wt% based on the total amount of the cemented carbide, contains Mo in an amount of 0.05 to 0.4 wt% based on the total amount of the cemented carbide, and contains WC in an amount of 90.0 to 96.0 wt% based on the total amount of the cemented carbide, wherein WC is used as a remainder, the quotient wt% of Co / Ni in the cemented carbide is 0.55 to 0.75, the quotient wt% of Cr / (Co + Ni + Cr + Mo) in the cemented carbide is in the range of 0.08 to 0.14, the quotient wt% of Mo / (Co + Ni + Cr + Mo) in the cemented carbide is in the range of 0.01 to 0.06, the Co + Ni content in the cemented carbide is at least 4 wt% based on the total amount of the cemented carbide, and the grain size of the sintered WC is in the range of 0.2 μm to 1 μm determined by linear intercepts, cemented carbide.

2. The cemented carbide according to claim 1, wherein the grain size of the sintered WC is in the range of 0.3 μm to 0.9 μm determined by linear intercepts.

3. The cemented carbide according to claim 1, containing Co in the range of 1.7 wt% to 2.6 wt% based on the total amount of the cemented carbide.

4. The cemented carbide according to claim 1, containing Ni in the range of 3.3 wt% to 3.7 wt% based on the total amount of the cemented carbide.

5. The cemented carbide according to claim 1, containing Cr in the range of 0.7 wt% to 1.0 wt% based on the total amount of the cemented carbide.

6. The cemented carbide according to claim 1, containing Mo in the range of 0.1 wt% to 0.3 wt% based on the total amount of the cemented carbide.

7. A member for oil and gas applications, comprising the cemented carbide according to claim 1.

8. The member according to claim 7, selected from the group consisting of choke valves, control valves, valve seats, plug seats, flack seats, cages, cage assemblies, seal rings, and member parts of valves that allow passage of fluids or slurries.

9. A tool for metal forming, comprising the cemented carbide according to claim 1.

10. A member for fluid handling, comprising the cemented carbide according to claim 1.

11. A method of making a cemented carbide article having a hard phase and a binder phase, the method comprising Preparing a powdered batch comprising raw materials of 1.7 to 3.3 wt% of Co, 2.0 to 3.7 wt% of Ni, 0.5 to 1.1 wt% of Cr, 0.05 to 0.4 wt% of Mo, and 90.0 to 96.0 wt% of WC, based on the total amount of the cemented carbide article; Compressing the powdered batch to form a preform; Sintering the preform to form a cemented carbide article comprising, WC is used as a remainder, and the quotient wt% of Co / Ni in the cemented carbide article is in the range of 0.55 to 0.75, the quotient wt% of Cr / (Co + Ni + Cr + Mo) in the cemented carbide is in the range of 0.08 to 0.14, the quotient wt% of Mo / (Co + Ni + Cr + Mo) in the cemented carbide is in the range of 0.01 to 0.06, the Co + Ni content in the cemented carbide is at least 4 wt% based on the total amount of the cemented carbide, and the grain size of the sintered WC is in the range of 0.2 μm to 1 μm determined by linear intercepts, method.

12. The method according to claim 11, wherein sintering the preform to form a cemented carbide article includes vacuum or HIP treatment.

13. The method according to claim 11, wherein sintering includes treating at a temperature of 1360 to 1500 °C and a pressure of 0 to 20 MPa.

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