Large-size ultra-short high-performance non-magnetic stabilizer blank forging process

Abstract

The invention relates to a large-size ultra-short table high-performance non-magnetic stabilizer blank forging process which is suitable for forging of a non-magnetic stabilizer with the diameter of a large table of a finished product being 381.0-660.4 mm, the diameter difference between the large table and a small table being 130-410 mm, the length of the small table at one end being smaller than 250 mm and the yield strength being higher than 758 MPa. The process comprises the steps of heating, cogging with an electro-hydraulic hammer, cogging with a precision forging machine, forming with the electro-hydraulic hammer and strengthening with the electro-hydraulic hammer. On the premise of not machining an intermediate blank, low-temperature deformation strengthening is achieved on the root portion of the step of the stabilizer and the inclined table, the mechanical performance of the root portion of the step of the large-size non-magnetic stabilizer can be effectively improved, and the large-size ultra-short table non-magnetic stabilizer with excellent performance is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of austenitic non-magnetic stainless steel forging, and in particular relates to a large-scale ultra-short table high-performance non-magnetic stabilizer blank forging process. The process is suitable for the forging of non-magnetic stabilizers with a finished large table diameter of 381.0mm to 660.4mm, a large table and a small table diameter difference of 130mm to 410mm, a small table length at one end of less than 250mm, and a yield strength higher than 758MPa. Background Art

[0002] Non-magnetic stabilizers are primarily used in oil and gas production drill string systems to mitigate in-hole vibrations of the drill pipe's elastic system, reduce eccentric wear on the drill bit and drill pipe, and prevent well deviation. The service environment of non-magnetic stabilizers dictates that they must possess low magnetic permeability, high corrosion resistance, and superior mechanical properties.

[0003] The non-magnetic stabilizer is a stepped structure with a large center stage and smaller stages at both ends. Since its raw material is austenitic stainless steel, the matrix structure does not undergo solid-state phase transformation during processing, so higher mechanical properties must be achieved through deformation strengthening. The existing process routes for forging non-magnetic stabilizers in the industry include: (1) hydraulic press / precision forging machine blanking + precision forging machine forming + precision forging machine strengthening; (2) precision forging machine blanking + machining forming + hydraulic press strengthening; (3) electro-hydraulic hammer blanking + electro-hydraulic hammer forming + electro-hydraulic hammer strengthening.

[0004] With the continuous development of the oil and gas drilling industry, higher requirements are placed on the mechanical properties of non-magnetic stabilizers, especially the mechanical properties of the step roots. At the same time, large-scale, ultra-short-step non-magnetic stabilizers have also emerged. However, the above existing processes have the following problems: (1) The process of hydraulic press / precision forging machine blanking + precision forging machine forming + precision forging machine strengthening has a large deformation resistance during the strengthening process, which can easily lead to damage to parts such as the precision forging machine connecting rod, hammer head and bolts, seriously affecting the production rhythm and production cost. In addition, the slope of the precision forging machine hammer head is small (usually 10° or 15°), while the slope of the finished step of the non-magnetic stabilizer is large (usually 45°). When the size of the small table is short, the small table and the step root position need to be machined and turned, and cannot be strengthened, resulting in the mechanical properties of the small table and the step root being lower than other positions, which cannot meet the technical requirements and use requirements of the short table high-performance stabilizer; (2) The process of forging with a precision forging machine, machining and strengthening with a hydraulic press is to produce a step by turning after forging, and then the stabilizer is forged with a hydraulic press. This process complicates the production process and destroys the complete metal flow line, thus extending the manufacturing cycle and increasing production costs. In addition, the root of the step remains a weak point during service, which can easily cause the stabilizer to fail during service. (3) In the process of electro-hydraulic hammer blanking + electro-hydraulic hammer forming + electro-hydraulic hammer strengthening, the electro-hydraulic hammer forging deformation is uneven, and the slopes at the steps need to be machined after strengthening. The mechanical properties of the step roots and slopes cannot meet the technical requirements and usage requirements.

[0005] In summary, the existing non-magnetic stabilizer forging process cannot meet the market performance requirements for the steps and roots of large-scale ultra-short-table high-performance non-magnetic stabilizers. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a large-scale ultra-short platform high-performance non-magnetic stabilizer blank forging process, in which the diameter of the finished product large platform is 381.0mm~660.4mm, the difference in diameter between the large platform and the small platform is 130mm~410mm, the length of the small platform at one end is less than 250mm, and the yield strength is higher than 758MPa. The process route of electro-hydraulic hammer blanking + precision forging machine blanking + electro-hydraulic hammer forming + electro-hydraulic hammer combined with hammer strengthening is adopted. The root of the stabilizer step and the inclined platform are deformed and strengthened without machining the forging intermediate billet. While simplifying the production process, as many complete metal streamlines as possible are retained, and an ultra-short platform non-magnetic stabilizer with excellent mechanical properties including the small platform and the step root is obtained.

[0007] The object of the present invention is achieved as follows: a large-scale ultra-short table high-performance non-magnetic stabilizer blank forging process, comprising the following steps: Step 1) Using a non-magnetic stainless steel electroslag ingot as a blank; heating the non-magnetic stainless steel electroslag ingot at a heating temperature of 1150° C. to 1220° C.; Step 2) The non-magnetic electroslag ingot is upsetting and drawing by electro-hydraulic hammer to a diameter of φ600mm-φ750mm, which is convenient for forging by precision forging machine; Step 3), returning to the furnace for heating, heating the blank to 1150°C~1180°C; Step 4) Use the precision forging machine to continue forging the blank to the forging blank shape, and forge the diameter of the large table and the small table to 1.1 to 1.3 times the diameter of the forging blank; Step 5) Use an electro-hydraulic hammer to forge the slope left by the precision forging machine to the size of the small intermediate billet; Step 6), returning the intermediate billet to the furnace for heating, heating the billet to 1050°C~1150°C, and keeping the temperature for 1h~3h; Step 7), water cooling after leaving the furnace, the water temperature is 20℃~35℃, the water cooling time is determined according to the diameter of the intermediate billet, and is controlled within the range of 1.2s / mm~1.5s / mm; Step 8) After water cooling, the temperature of the forging is increased by conducting the residual heat of the core of the billet to the surface of the forging. When the surface temperature reaches 450℃~480℃, an electro-hydraulic hammer is used in combination with a hammer to perform strengthening forging. The electro-hydraulic hammer is used in combination with a hammer to forge the intermediate billet to the forging size. Step 9) Cool the finished forging to room temperature and unload.

[0008] The positive effects produced by the present invention are as follows: 1. The forging process of the present invention can be used to strengthen the small platform and the root of the step of the large-scale ultra-short platform stabilizer, and produce large-scale ultra-short platform high-performance non-magnetic stabilizers that meet technical requirements and usage requirements; 2. The process of the present invention can avoid damage to the parts of the precision forging machine during the strengthening forging process; 3. The process of the present invention can save the machining process of the intermediate blank and retain the complete metal flow line, thereby improving the mechanical properties of the stabilizer and shortening the production cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of the deformation of electroslag ingots during blanking by electro-hydraulic hammer.

[0010] Figure 2 This is a schematic diagram of the deformation of the blank during precision forging.

[0011] Figure 3 Schematic diagram of slope deformation during forging with an electro-hydraulic hammer.

[0012] Figure 4 This is a schematic diagram of forging deformation using an electro-hydraulic hammer in conjunction with a hammer.

[0013] Figure 5 This is a schematic diagram of cutting. DETAILED DESCRIPTION

[0014] To fully clarify the objectives, technical solutions, and advantages of the present invention, the following, in conjunction with the accompanying drawings and specific embodiments, further describes in detail the forging process for a large-scale, ultra-short-table, high-performance, non-magnetic stabilizer blank proposed by the present invention. It should be noted that the drawings are highly simplified and not to exact scale, and are intended solely for the purpose of assisting in the description of the embodiments of the present invention.

[0015] Example 1: Taking a 15-inch non-magnetic stabilizer as an example, a large-scale ultra-short-table high-performance non-magnetic stabilizer blank forging process is carried out as follows: The diameter of the large platform of the 15-inch stabilizer forging billet is φ425mm, the diameter of the small platforms at both ends is φ295mm, the length of the large platform is 550mm, the lengths of the small platforms at both ends are 420mm and 65mm respectively, the weight of the forging is 890Kg, and round bar forgings of the same steel grade and equivalent specifications are matched at both ends. The weight of the electroslag ingot is 3800Kg, and the diameters at both ends of the electroslag ingot are φ600mm and φ640mm respectively.

[0016] Step 1) Heat the electroslag ingot, preheat at 350℃~400℃ for 5h, then increase the temperature to 1180℃~1210℃ at a rate of less than 60℃ / h, and keep it warm for 6h; Step 2) Use an electro-hydraulic hammer to upset the electroslag ingot to H = 900mm, and then stretch it to a diameter of φ680mm; Step 3), return to the furnace and heat at a temperature of 1150°C to 1180°C for 2h to 3h; Step 4) Use a precision forging machine to forge the billet to a diameter of φ440mm; Step 5), return to the furnace and heat at a temperature of 1150°C to 1180°C for 1h to 2h; Step 6) Use a precision forging machine to forge small platforms at both ends, and the small platforms are forged to φ315mm; Step 7) Use electro-hydraulic hammer forging machine to forge the step root ramp; Step 8), return to the furnace and heat, the furnace temperature is 1080℃~1100℃, keep warm for 2h~3h; Step 9), cooling in water, water cooling time 500s; Step 10) Use an electro-hydraulic hammer with a hammer to perform enhanced forging, with an enhanced deformation of 15%; Step 11), water cooling of forgings; Step 12) Cutting and physical and chemical testing. Testing revealed that samples taken from the base of the non-magnetic stabilizer step had a yield strength of 1055 MPa, a tensile strength of 1186 MPa, an elongation of 24%, a reduction of area of ​​69%, and an impact energy (AK(V)) of 230 / 222 / 234 J. Intergranular corrosion resistance (Method A) testing indicated a step structure, while both Method E and weldability testing showed no intergranular cracks.

[0017] The above embodiment only expresses one embodiment of the present invention. Its description is relatively specific and detailed, but it should not be understood as limiting the scope of the invention patent. The scope of protection of the patent of the present invention shall be based on the appended claims.

Claims

1. A large-scale ultra-short platform high-performance non-magnetic stabilizer blank forging process, characterized in that: The following steps are involved: Step 1), using a non-magnetic stainless steel electroslag ingot as a blank; heating the non-magnetic stainless steel electroslag ingot, and the heating temperature is 1150°C to 1220°C; Step 2), the non-magnetic electroslag ingot is upset and drawn by an electro-hydraulic hammer to a diameter of φ600mm-φ750mm, which is convenient for forging by a precision forging machine; Step 3), returning to the furnace for heating, heating the blank to a temperature of 1150° C. to 1180° C.; Step 4), using the precision forging machine to continue to open the blank to the forging blank shape, the diameter of the large table and the small table are forged to 1.1 to 1.3 times the diameter of the forging blank; Step 5) Use an electro-hydraulic hammer to forge the slope left by the precision forging machine to the size of the small intermediate billet; Step 6), the intermediate billet is returned to the furnace for heating, and the billet is heated to 1050°C~1150°C, and the heat preservation time is 1h~3h; Step 7), water cooling after leaving the furnace, the water temperature is 20℃~35℃, the water cooling time is determined according to the diameter of the intermediate billet, and is controlled within the range of 1.2s / mm~1.5s / mm; Step 8), after water cooling, the residual heat in the core of the billet is conducted to the surface of the forging to increase the temperature of the forging. When the surface temperature reaches 450℃~480℃, an electro-hydraulic hammer is used in combination with a hammer to perform strengthening forging, and the electro-hydraulic hammer is used in combination with a hammer to forge the intermediate billet to the forging billet size; Step 9), water cool the finished forging to room temperature and unload.

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