High-entropy metal alloy for surface strengthening of drilling bit, preparation method of high-entropy metal alloy and drilling bit

Abstract

The invention discloses a high-entropy metal alloy for surface strengthening of a drilling bit, a preparation method of the high-entropy metal alloy and the drilling bit. The high-entropy metal comprises the following raw materials in percentage by atomic number: 38-40% of Fe, 19-20% of Ni, 19-20% of Co, 19-20% of Cr and 2-3% of TiB2. Metal is solidified to the surface of the drill bit through a laser cladding method, the abrasion resistance, corrosion resistance and high-temperature resistance of the drill bit for well drilling are improved, the service life of the drill bit is greatly prolonged, nickel, iron, cobalt, chromium, titanium diboride and the like are mixed for use, it is guaranteed that the drill bit has sufficient toughness, hardness, high-temperature abrasion resistance and fatigue resistance during use, and the service life of the drill bit is prolonged. And the condition that the surface cladding layer is extruded to deform and fall off under the high-temperature working condition and is inconvenient to use is avoided. The drill bit is high in Fe content, low in development cost, simple in technological process, high in operability, wide in application prospect and suitable for laboratory research and production machining.

Description

Technical Field

[0001] The invention relates to the field of high entropy alloys, and in particular to a high entropy metal alloy for surface strengthening of a drilling bit, a preparation method thereof, and a drill bit. Background Art

[0002] The working environment of drill bits is harsh, and they have to face high temperature, strong corrosion, wear and tear, etc. Ordinary drill bits have low hardness, are easy to wear, and have poor impact resistance. At the same time, when digging pits, the drill bit rotates with the vertical shaft and moves axially at the same time. The drill bit needs to withstand large friction and impact resistance. Traditional drill bits are generally made of high-speed steel and high-quality carbon tool steel, but they have low hardness and poor impact resistance, which makes the drill bits often unable to meet processing requirements and easily lead to drill bit breakage. Although carbide steel drill bits can meet processing requirements, they are expensive and costly.

[0003] Due to the diversity of drill bits, the worn surface is not necessarily a straight line or a regular curved surface. Therefore, traditional multi-axis machine tools are difficult to repair automatically. As a result, manual measurement and manual repair are still used. This is not only slow and the data is inaccurate, but also requires very high process technology, proficiency and concentration of the operator. At the same time, the high temperature generated by laser cladding, laser reflection or irradiation, air dust pollution caused by powder splashing and other operating environment pollution problems will cause harm to the health of the operator.

[0004] Therefore, how to provide a low-cost alloy steel drill bit with a simple preparation process is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The object of the present invention is to provide a high entropy metal alloy for surface strengthening of a drilling drill bit and a preparation method thereof, and a drill bit, so as to solve the problems raised in the above-mentioned background technology.

[0006] The present invention uses a laser cladding method to solidify the metal onto the surface of the drill bit, improves the wear resistance, corrosion resistance, and high temperature resistance of the drilling drill bit, and greatly extends the service life of the drill bit. Nickel, iron, cobalt, chromium, titanium diboride, etc. are mixed to ensure that the drill bit has sufficient toughness, hardness, and high temperature wear resistance and fatigue resistance during use, and avoids the surface cladding layer from extruding and falling off in high temperature conditions, which is inconvenient to use. The high entropy metal alloy described in the present invention has a high Fe content, low development cost, simple process flow, strong operability, and broad application prospects. It is not only suitable for laboratory research, but also suitable for production and processing.

[0007] To achieve the above purpose, the present invention provides the following technical solution: the components and atomic ratios of the alloy in the present invention are: Fe 39%, Ni 19.5%, Co 19.5%, Cr 19.5%, TiB 22.5%.

[0008] The present invention provides a method for preparing a high entropy metal alloy for surface strengthening of a drilling drill bit, the method comprising the following steps:

[0009] The raw materials of the high entropy metal alloy material include, by atomic percentage, 38-40% Fe, 19-20% Ni, 19-20% Co, 19-20% Cr, and 22-3% TiB;

[0010] The preparation method of the high entropy metal alloy material adopts laser cladding. The laser process parameters adopted in the laser cladding process include: laser power 600w~1200w, laser scanning speed 4mm / s~10mm / s, running speed 8m / min~20m / min, spot diameter 3mm~8mm, alloy powder conveying speed 8g / min, overlap rate 30%, laser head swing frequency 4~10Hz, laser spot swing amplitude 1mm~3mm.

[0011] In some embodiments of the present invention, the Fe content is 39% by atomic number percentage.

[0012] In some embodiments of the present invention, the Ni content is 19.5% by atomic number percentage.

[0013] In some embodiments of the present invention, the Co content is 19.5% by atomic number percentage.

[0014] In some embodiments of the present invention, the Cr content is 19.5% by atomic number percentage.

[0015] In some embodiments of the present invention, the TiB2 is 2.5% by atomic number percentage.

[0016] In some embodiments of the present invention, the raw materials of the high entropy metal alloy material include, by atomic percentage, 39% Fe, 19.5% Ni, 19.5% Co, 19.5% Cr, and 22.5% TiB.

[0017] In some embodiments of the present invention, the maximum stress of the high entropy metal alloy material is 920-930 MPa, for example, 925 MPa or 930 MPa.

[0018] In some embodiments of the present invention, there are twins in the alloy unit cell structure of the high entropy metal alloy material, and the twins appear as parallel lines or band structures.

[0019] In some embodiments of the present invention, the laser power is 900w-1200w, for example, 900w or 1200w.

[0020] In some embodiments of the present invention, the laser scanning speed is 6 mm / s to 8 mm / s.

[0021] In some embodiments of the present invention, the running speed is 12m / min to 20m / min.

[0022] In some embodiments of the present invention, the diameter of the light spot is 5 mm to 8 mm.

[0023] In some embodiments of the present invention, the laser head oscillates at a frequency of 4 to 8 Hz.

[0024] In some embodiments of the present invention, the laser spot swings by 2 mm to 3 mm.

[0025] In some embodiments of the present invention, the method for preparing the high entropy metal alloy for surface strengthening of a drilling drill bit comprises the following steps:

[0026] (1) Weigh the raw materials according to the atomic percentage: Fe 39%, Ni 19.5%, Co 19.5%, Cr 19.5%, TiB2 2.5% (Fe, Co, Cr, Ni are all pure elements with a purity of >99.8%, and TiB2 purity >99.8%);

[0027] (2) Grinding the substrate material to remove the oxide layer, and then cleaning the processed surface of the substrate material with acetone or anhydrous ethanol;

[0028] (3) According to the setting process parameters, the laser power is 1500w-3000w, the laser scanning speed is 10mm / s-14mm / s, the running speed is 8-20m / min, the spot diameter is 3mm-8mm, the alloy powder conveying speed is 3g / min-10g / min, the overlap rate is 30%-70%, the laser head swing frequency is 3Hz-8Hz, and the laser spot swing amplitude is 1mm-3mm;

[0029] (4) Use jet powder supply to make the material enter the focal area of ​​the laser beam;

[0030] (5) Laser irradiation is performed to rapidly heat up the cladding material and melt it instantly;

[0031] (6) Finally, the cladding material is cooled naturally to form a cladding layer.

[0032] The present invention also provides a high entropy metal alloy material for the surface of a drilling bit, which is prepared by the preparation method of the high entropy metal alloy material as described above.

[0033] The present invention also provides a drill bit for drilling, which includes a carbon steel drill bit and a high entropy metal alloy coated on the surface of the carbon steel drill bit, wherein the high entropy metal alloy is the high entropy metal alloy material for the surface of the drilling drill bit as described above.

[0034] In some embodiments of the present invention, the composition of the carbon steel drill bit is: C<0.25%, Mn0.7%~0.9%, Si<0.4%, and the balance is Fe, and the percentage refers to the mass percentage.

[0035] In the present invention, Fe refers to iron, Co refers to cobalt, Cr refers to chromium, Ni refers to nickel, Ti refers to titanium, B refers to boron, C refers to carbon, Si refers to silicon, and Mn refers to manganese.

[0036] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0037] The reagents and raw materials used in the present invention are commercially available.

[0038] The positive and progressive effects of the present invention are:

[0039] (1) The content of Fe in the present invention is higher than that of other elements such as Co, Cr, Ni and TiB2, and the content of Fe element is greatly increased, thereby reducing the development cost.

[0040] (2) The process adopted by the present invention is a laser cladding process, which is simple to operate and easy to control, thereby improving production efficiency and facilitating the industrial application of alloys.

[0041] (3) The cladding layer will form a dense passivation film, which effectively prevents the diffusion of oxygen ions and makes the drill bit more corrosion-resistant.

[0042] (5) The cladding layer has excellent strength-ductility synergy. The unit cell structure and mechanical twins will also be formed after further strain, thereby improving the work hardening ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 are (a) Nyquist plot and (b) Bode plot;

[0045] Figure 2Engineering stress-strain curves of the specimens under different processing conditions;

[0046] Figure 3 Schematic diagram of the alloy crystal cell structure on the drill bit surface in Example 2. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation plans.

[0048] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0049] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0050] Ordinary carbon steel drill bit: the composition is C <0.25%, Mn 0.7% ~ 0.9%, Si <0.4%, the balance is Fe, the percentage refers to the mass percentage.

[0051] Comparative Example 1

[0052] No laser cladding was performed and the test was conducted with a normal carbon steel drill. Figure 1 As shown in Figure b, Comparative Example 1 has a smaller semicircle in the high frequency band, indicating that its surface has a thinner oxide layer or a lower corrosion rate. The tensile curve of Comparative Example 1 shows the highest stress value before the maximum stress point, indicating that this material or the material under the treatment condition has the highest tensile strength. At the same time, Comparative Example 1 continues to show a higher stress value after reaching the maximum stress, indicating that this material or the material under the treatment condition has a better plastic deformation ability.

[0053] Example 1

[0054] (1) Weigh the raw materials according to the atomic percentage: Fe 39%, Ni 19.5%, Co 19.5%, Cr 19.5%, TiB2 2.5% (Fe, Co, Cr, Ni are all pure elements with a purity of >99.8%, and TiB2 purity is >99.8%).

[0055] (2) Grind the base material (ordinary carbon steel drill bit) to remove the oxide layer, and then use acetone or anhydrous ethanol to clean the processed surface of the base material.

[0056] (3) Settings: laser power 900W, laser scanning speed 6mm / s, running speed 12m / min, spot diameter 5mm, alloy powder conveying speed 8g / min, overlap rate 30%, laser head swing frequency 4Hz, laser spot swing amplitude 2mm.

[0057] (4) Using jet powder supply to make the material in step (1) enter the focal area of ​​the laser beam.

[0058] (5) Performing laser irradiation to rapidly heat the cladding material in step (1) and instantly melt it on the surface of the base material in step (2).

[0059] (6) Finally, the cladding material is cooled naturally to form a cladding layer.

[0060] Compared with comparative example 1, embodiment 1 has a higher impedance curve and better performance, and has a larger semicircle in the high frequency band, indicating that its surface has a thicker oxide layer or higher corrosion resistance. At the same time, embodiment 1 can withstand a greater maximum stress, has better tensile properties, and has a shorter laser ablation processing time.

[0061] Example 2

[0062] (1) Weigh the raw materials according to the atomic percentage: Fe 39%, Ni 19.5%, Co 19.5%, Cr 19.5%, TiB2 2.5% (Fe, Co, Cr, Ni are all pure elements with a purity of >99.8%, and TiB2 purity is >99.8%).

[0063] (2) Grind the base material (ordinary carbon steel drill bit) to remove the oxide layer, and then use acetone or anhydrous ethanol to clean the processed surface of the base material.

[0064] (3) Settings: laser power is 1200w, laser scanning speed is 8mm / s, running speed is 20m / min, spot diameter is 8mm, alloy powder conveying speed is 8g / min, overlap rate is 30%, laser head swing frequency is 8Hz, laser spot swing amplitude is 3mm.

[0065] (4) Using jet powder supply to make the material in step (1) enter the focal area of ​​the laser beam.

[0066] (5) Performing laser irradiation to rapidly heat the cladding material in step (1) and instantly melt it on the surface of the base material in step (2).

[0067] (6) Finally, the cladding material is cooled naturally to form a cladding layer.

[0068] Compared with Example 1, Example 2 has a higher impedance curve and better performance, and shows relatively stable modulus and phase angle changes in the entire frequency range, indicating that it has better corrosion resistance under these conditions. It can withstand a larger maximum stress, has better tensile properties, and has a shorter laser cladding processing time.

[0069] Effect Example

[0070] (1) The drill bits in Comparative Example 1, Example 1, and Example 2 were taken to detect their modulus Z and the engineering stress-strain curves of the test pieces under different processing conditions.

[0071] The meaning of modulus Z and its detection method are: Z is impedance, + and - represent anode and cathode. The sinusoidal voltage U and current I on the material are measured, and then the formula Z = U / I is used to obtain the result; the specific detection conditions are: at 25℃±2℃, free corrosion in 0.1mol / L sulfuric acid solution for 30 minutes to keep the potential stable, the scanning speed is 1mv / s, and the voltage range is -1.2V~+0.4V.

[0072] The meanings of stress and strain values ​​and their detection methods are as follows: Stress is the internal force generated by the interaction between the various parts of an object when the material is deformed due to external factors; strain is the elongation within the gauge range of the specimen divided by the initial value of the gauge length.

[0073] The material tensile strength test measures the strength of the material in a tensile state by applying a tensile force. During the test, the sample needs to be placed on the tensile tester and the applied tensile force is gradually increased until the material breaks. The material's tensile strength and yield strength and other parameters can be obtained through the stress-strain curve recorded by the test machine.

[0074] Depend on Figure 1 , Figure 2 It can be seen that ordinary carbon steel drill bits have good strength but poor corrosion resistance. The corrosion resistance of the drill bits after cladding in Example 1 and Example 2 is significantly improved, indicating that the cladding layer of laser cladding has a significant effect on the wear resistance and corrosion resistance of the drill bit. In addition, the laser cladding in Example 1 and Example 2 is successfully adhered, indicating that the material is easier to process, and the cladding layer has stable adhesion and is not easy to fall off.

[0075] Table 1

[0076] serial number Maximum stress Comparative Example 1 950MPa Example 1 925MPa Example 2 930MPa

[0077] According to Table 1, laser cladding has little effect on the tensile properties of the drill bit.

[0078] (2) Take the drill bit in Example 2 and obtain its surface SEM image, as shown in Figure 3 shown.

[0079] Depend on Figure 3 It can be seen that twins are generated in the crystal cell structure of the drill alloy in Example 2. The twins appear as parallel lines or banded structures, which can significantly improve the hardness, toughness, strength and wear resistance of the material. In addition, the formation of twins is closely related to stacking faults. The twin boundaries have lower interface energy than ordinary grain boundaries, which makes the twin boundaries more stable. Cellular structure appears in material processing, which can prevent the movement of dislocations, thereby increasing the material's ability to resist deformation.

[0080] The above is only a specific implementation of the invention, but the protection scope of the invention is not limited to it. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the invention. Therefore, the protection scope of the invention should be based on the protection scope defined in the claims.

Claims

1. A method for preparing a high entropy metal alloy material for a drilling bit surface, characterized in that: The raw materials of the high entropy metal alloy material include, by atomic percentage, 38-40% Fe, 19-20% Ni, 19-20% Co, 19-20% Cr, and 22-3% TiB; The preparation method of the high entropy metal alloy material adopts laser cladding. The laser process parameters adopted in the laser cladding process include: laser power 600w~1200w, laser scanning speed 4mm / s~10mm / s, running speed 8m / min~20m / min, spot diameter 3mm~8mm, alloy powder conveying speed 8g / min, overlap rate 30%, laser head swing frequency 4~10Hz, laser spot swing amplitude 1mm~3mm.

2. The method for preparing the metal alloy material for the surface of a drilling drill bit according to claim 1, characterized in that: The maximum stress of the high entropy metal alloy material is 920-930 MPa; And / or, there are twins in the alloy unit cell structure of the high entropy metal alloy material, and the twins appear as parallel lines or band structures.

3. The method for preparing the metal alloy material for the surface of a drilling drill bit according to claim 1, characterized in that: In terms of atomic percentage, the Fe is 39%; And / or, in terms of atomic percentage, the Ni is 19.5%; And / or, in terms of atomic percentage, the Co is 19.5%; And / or, in terms of atomic percentage, the Cr is 19.5%; And / or, in terms of atomic percentage, the TiB2 is 2.5%.

4. The method for preparing the metal alloy material for the surface of a drilling drill bit according to claim 1, characterized in that: The raw materials of the high entropy metal alloy material include, by atomic percentage, 39% Fe, 19.5% Ni, 19.5% Co, 19.5% Cr, and 22.5% TiB.

5. The method for preparing the metal alloy material for the surface of a drilling drill bit according to claim 1, characterized in that: The laser power is 900w-1200w; And / or, the laser scanning speed is 6 mm / s to 8 mm / s; And / or, the running speed is 12m / min to 20m / min.

6. The method for preparing the metal alloy material for the surface of a drilling bit according to claim 1, characterized in that: The light spot diameter is 5mm to 8mm.

7. The method for preparing the metal alloy material for the surface of a drilling drill bit according to claim 1, characterized in that: The laser head oscillation frequency is 4 to 8 Hz; And / or, the laser spot swings by 2 mm to 3 mm.

8. The method for preparing a high entropy metal alloy material for a drilling bit surface according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Weigh the raw materials according to the atomic percentage: Fe 39%, Ni 19.5%, Co 19.5%, Cr 19.5%, TiB22.5%; (2) Grinding the substrate material to remove the oxide layer, and then cleaning the processed surface of the substrate material with acetone or anhydrous ethanol; (3) Setting process parameters include: laser power 600w~1200w, laser scanning speed 4mm / s~10mm / s, running speed 8m / min~20m / min, spot diameter 3mm~8mm, alloy powder conveying speed 8g / min, overlap rate 30%, laser head swing frequency 4Hz, laser spot swing amplitude 1mm~3mm; (4) Use jet powder supply to make the material enter the focal area of ​​the laser beam; (5) Laser irradiation is performed to rapidly heat up the cladding material and melt it instantly; (6) Finally, the cladding material is cooled naturally to form a cladding layer.

9. A high entropy metal alloy material for the surface of a drilling bit, characterized in that: The high entropy metal alloy material is prepared by the preparation method of the high entropy metal alloy material according to any one of claims 1 to 8.

10. A drill bit for drilling, characterized in that: It comprises a carbon steel drill bit and a high entropy metal alloy coated on the surface of the carbon steel drill bit, wherein the high entropy metal alloy is the high entropy metal alloy material for the surface of a drilling drill bit as claimed in claim 9.

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