Treatment method for enhancing wear resistance of PDC drill bit

Abstract

The invention discloses a treatment method for enhancing the wear resistance of a PDC drill bit, and relates to the technical field of PDC drill bits. In order to solve the problems that a working surface of a traditional PDC drill bit is easy to wear and short in service life, a high-strength armor layer is used for replacing manual welding. The method comprises the following steps: constructing an armor layer structure with a composite sheet mounting hole based on a three-dimensional model of a drill bit main body, and casting a 2-4mm thin-wall armor layer made of a corrosion-resistant tungsten carbide material by adopting a 3D printing mold; through a two-stage preheating and oxygen-acetylene welding process, a DHAg40C silver-based welding material is used for achieving high-strength metallurgical bonding of an armor layer and a drill bit base body, and the slow cooling rate is controlled to be smaller than or equal to 25 DEG C / h. Manual welding is replaced by three-dimensional modeling and embedded design, so that the precision and the wear resistance are improved; 3D printing mold casting and precise welding parameters are combined, and high-strength combination of the armor layer and the body is ensured; and corrosion-resistant tungsten carbide and a silver-based welding material are adopted, so that the erosion resistance is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of PDC bits, and in particular to a treatment method for enhancing the wear resistance of PDC bits. Background Art

[0002] As a core tool for oil drilling, the wear resistance of a PDC (polycrystalline diamond compact) bit directly affects the drilling efficiency and cost. In hard formations or high-abrasion environments, parts such as the edges of the bit blades and the flow channels are extremely prone to failure due to the erosion of high-speed drilling fluid. Traditional processes usually use manual surfacing of a hard alloy layer (such as tungsten carbide) for protection, but there are many defects in the existing technology. For example, manual surfacing depends on the operator's experience and is prone to defects such as pores and cracks in the surfacing layer. Most traditional surfacing layers use ordinary tungsten carbide-cobalt-based materials, and their hardness is difficult to resist high-stress erosion. Manual surfacing is difficult to precisely control the shape and thickness, resulting in too large a gap between the surfacing layer and the bit body. The above problems are particularly prominent in drilling deep wells, ultra-deep wells, and shale formations, and there is an urgent need for a high-precision and highly reliable protection structure and manufacturing process. Summary of the Invention

[0003] The purpose of the present invention is to provide a treatment method for enhancing the wear resistance of PDC bits, solve the problems of low precision and easy shedding of traditional surfacing layers, and significantly improve the wear resistance and service life of the bits.

[0004] The present invention is implemented by the following technical solutions: A treatment method for enhancing the wear resistance of PDC bits, characterized by including the following steps: Step 1, determine the matching shape of the armor layer according to the three-dimensional model of the bit body. The armor layer covers the working surface of the bit body and leaves a composite chip installation hole. Step 2, manufacture a casting mold based on the shape of the armor layer, and use a corrosion-resistant tungsten carbide material to form an integrally formed armor layer finished product through a casting process. Step 3, assemble the armor layer finished product to the working surface of the bit body, and connect the bit body and the armor layer by welding.

[0005] Further, the thickness of the armor layer in Step 1 is designed to be 2 mm - 4 mm, and its three-dimensional contour forms a clearance fit with the working surface of the bit body.

[0006] Further, the casting mold in Step 2 is prepared by a 3D printing process.

[0007] Further, the welding process in Step 3 specifically includes the following steps: First, preheat the bit body and the armor layer; continue heating to a surface temperature of 600°C - 800°C, and perform welding when the surface of the base body presents a bright red state; perform cooling after welding.

[0008] Further, the preheating process in step three is specifically to heat up to 580°C - 620°C and keep warm for 30 minutes.

[0009] Further, in step three, an oxygen-acetylene mixed gas is used as the heat source during welding. Control the oxygen pressure at 0.5 - 0.8 MPa and the acetylene pressure at 0.06 - 0.08 MPa, and use DHAg40C silver-based welding materials for segmental fusion welding to ensure that the solder completely penetrates into the joint interface.

[0010] Further, after welding in step three, it is slowly cooled to below 150°C at a rate of ≤25°C / h.

[0011] The treatment method for enhancing the wear resistance of PDC bits according to the present invention has the following beneficial effects: By replacing manual surfacing with three-dimensional modeling and embedded design, the accuracy and wear resistance are improved; Combining 3D printing die casting and precise welding parameters to ensure a high-strength combination of the armor layer and the body; Using corrosion-resistant tungsten carbide and silver-based welding materials significantly improves the erosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0013] Figure 1 It is a schematic diagram of a PDC bit processed by the method of the present invention; In the figure, 1 - armor layer, 2 - bit body, 3 - composite insert hole, 4 - working surface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0015] Accordingly, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0016] As Figure 1 shown, a processing method for enhancing the wear resistance of a PDC bit includes the following steps: Step 1: Determine the specific shape of the armor layer 1 according to the three-dimensional model of the bit body 2. The armor layer 1 is located on the working surface 4 of the bit body 2, and composite button mounting holes 3 are reserved thereon.

[0017] Step 2: Manufacture a casting mold according to the determined shape of the armor layer 1, and perform a casting process with a high-strength surfacing material to form a finished product of the armor layer 1.

[0018] Step 3: Install the finished product of the armor layer 1 on the working surface 4 of the bit body 2, and weld the armor layer 1 and the bit body 2 together.

[0019] In the above Step 1, the size of the armor layer 1 needs to meet the bit design requirements. It is an important part of the bit. The thickness of the armor layer 1 is 2 mm - 4 mm.

[0020] In the above Step 2, the armor layer 1 is cast with corrosion-resistant tungsten carbide material. The casting mold is manufactured by 3D printing.

[0021] In the above Step 3, the following specific requirements are included: First, heat up the bit body 2 and the armor layer 1. The preheating temperature is 580°C - 620°C. After reaching the preheating temperature and holding for 30 minutes, prepare for welding.

[0022] Continue heating. When the bit body 2 and the armor layer 1 show a "sweating" (bright red) state at a surface temperature of 600 - 800°C, immediately perform welding.

[0023] During welding, use oxygen and acetylene gas for welding. The oxygen pressure is 0.5 - 0.8 MPa, and the acetylene pressure is 0.06 - 0.08 MPa. Slowly melt the silver-based welding material DHAg40C into the welding position step by step.

[0024] After welding is completed, slowly cool down while maintaining the temperature (generally for more than 6 hours). It can be taken out only when the temperature drops below 150°C.

[0025] Since the armor layer 1 is matched according to the original data of the PDC bit and is formed into a surfacing layer with extremely high precision in one step during the manufacturing process, and has the characteristics of high hardness and erosion resistance.

[0026] In the above embodiments, the basic principles, main features and advantages of the present invention are described. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, any modifications and changes made by those skilled in the art should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for enhancing the wear resistance of a PDC drill bit, characterized in that: The following steps are involved: Step 1: determining the matching shape of the armor layer (1) according to the three-dimensional model of the drill bit body (2), wherein the armor layer (1) covers the working surface (4) of the drill bit body (2) and reserves a composite sheet mounting hole (3); Step 2: manufacturing a casting mold based on the shape of the armor layer (1), and using corrosion-resistant tungsten carbide material to form an integrated armor layer (1) finished product through a casting process; Step three, assembling the finished armor layer (1) onto the working surface (4) of the drill bit body (2), and connecting the drill bit body (2) and the armor layer (1) by welding.

2. A method for enhancing the wear resistance of a PDC drill bit according to claim 1, characterized in that: In the step 1, the thickness of the armor layer (1) is designed to be 2 mm to 4 mm, and its three-dimensional contour forms a clearance fit with the working surface (4) of the drill body (2).

3. A method for enhancing the wear resistance of a PDC drill bit according to claim 1, characterized in that: The casting mold in step 2 is prepared by 3D printing technology.

4. A method for enhancing the wear resistance of a PDC drill bit according to claim 1, characterized in that: The welding process in step three specifically comprises the following steps: first, preheating the drill body (2) and the armor layer (1); continuing to heat to a surface temperature of 600° C.-800° C., and welding when the surface of the substrate appears bright red; and cooling after welding.

5. A method for enhancing the wear resistance of a PDC drill bit according to claim 4, characterized in that: The preheating process in step 3 is specifically to raise the temperature to 580°C-620°C and keep it warm for 30 minutes.

6. A method for enhancing the wear resistance of a PDC drill bit according to claim 4, characterized in that: In the step 3, oxygen-acetylene mixed gas is used as a heat source during welding, the oxygen pressure is controlled to be 0.5-0.8 MPa, the acetylene pressure is controlled to be 0.06-0.08 MPa, and DHAg40C silver-based welding material is used for segment-by-segment fusion welding to ensure that the solder completely penetrates into the joint interface.

7. A method for enhancing the wear resistance of a PDC drill bit according to claim 4, characterized in that: In the step 3, after welding, the temperature is slowly cooled to below 150° C. at a rate of ≤25° C. / h.

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