Laboratory heat treatment simulation method for thickened drill rod sample

Abstract

The invention belongs to the technical field of seamless steel pipe manufacturing in the metallurgical industry, and relates to a laboratory heat treatment simulation method for a thickened drill pipe sample, a fan-shaped through groove is longitudinally cut in one side of a steel pipe model, and the through groove is sequentially provided with a module a, a module b, a module c, a module d and a module e from inside to outside; a pipe body material of a small drill pipe sample is cut into a plurality of strip-shaped samples in the longitudinal direction, before heat treatment, the strip-shaped samples are inserted into a module c in a steel pipe model, iron sheets with matched thicknesses are inserted into a module a, a module b, a module d and a module e respectively, the materials of the iron sheets are the same as the materials of the drill pipes, and the heat treatment performance of the drill pipes with different upsetting wall thicknesses is simulated and tested. The method can simulate the heat treatment performance of drill rods with different upsetting wall thicknesses, and is simple and convenient to operate and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of seamless steel pipe manufacturing in the metallurgical industry, and relates to a method for simulating laboratory heat treatment of a thickened drill pipe sample. Background Art

[0002] With the development of oil and gas exploration towards deep wells and ultra-deep wells, oil and gas in 9000-meter or even 10000-meter deep wells are continuously developed. As an important drilling tool, drill pipes need to withstand complex mechanical loads and harsh environmental conditions during use. The development of deep wells and ultra-deep wells also poses strict requirements on the required drill pipes.

[0003] In order to meet the strict requirements for drill pipes in deep well and ultra-deep well areas, generally, upsetting and thickening treatment is carried out on the pipe ends of drill pipes. When upsetting the pipe ends, the mechanical properties after heat treatment, especially indicators such as strength and toughness, need to be considered. Since the wall thicknesses of the drill pipe body and the pipe ends are different, when conducting strength verification, the size of the thickened pipe ends needs to be adjusted, and a series of different upsetting and thickening sizes need to be designed. Moreover, the mechanical properties after heat treatment are also different. Drill pipes with different upset wall thicknesses have different performance characteristics such as torque and connection strength. The mechanical properties directly affect the use safety of drill pipes.

[0004] Therefore, when upsetting the pipe ends, the mechanical properties after heat treatment, especially indicators such as strength and toughness, need to be considered. Generally speaking, the thicker the thickness of the upset pipe ends, the slower the cooling rate during the quenching and cooling process of heat treatment, resulting in a lower final yield strength.

[0005] As drill pipe designers, they are particularly concerned about the mechanical properties of pipe end heat treatment and hope to predict in advance or know how many millimeters the pipe ends can be upset to and what the strength level of the pipe ends can reach after the final heat treatment.

[0006] During the early-stage industrial drill pipe test production process, if all types of upset drill pipes are produced, first, the large-scale production cycle is long, and second, the industrial production cost is high. To upset pipe ends with different wall thicknesses, different upsetting tools and dies are often required. This method is not only time-consuming and laborious but also costly.

[0007] Therefore, how to accurately evaluate the heat treatment performance of drill pipes with different wall thicknesses has become a major challenge in production. Summary of the Invention

[0008] In view of the current situation of long production cycle and high production cost of drill pipes with different upset wall thicknesses, in order to predict in advance the mechanical properties of drill pipes with different upset wall thicknesses after heat treatment and accelerate the process of design and research and development, the present invention provides a laboratory heat treatment simulation method for thickened drill pipe samples. By cutting the original steel pipe into strip samples and combining an adjustable modular design, it can simulate the heat treatment performance of the pipe ends of drill pipes with different upset thicknesses. This method is not only easy to operate, but also can significantly reduce the test cost, providing reliable technical support for the optimization of the heat treatment process of drill pipes and other steel pipe products.

[0009] The present invention is realized by the following technical solutions:

[0010] The present invention discloses a laboratory heat treatment simulation method for thickened drill pipe samples, including:

[0011] (1) Longitudinally cut out a sector-shaped through groove on one side of the steel pipe model. The sector-shaped through groove is successively provided with module a, module b, module c, module d, and module e from inside to outside; module a and module e have the same thickness, and module b and module d have the same thickness;

[0012] (2) Cut the pipe body material of the drill pipe sample into several strip samples longitudinally, and the strip samples are correspondingly matched with the module c;

[0013] (3) Before heat treatment, insert the strip samples into module c of the steel pipe model, and leave module c empty up and down, which represents the heat treatment performance of the drill pipe body without upset; insert iron sheets with matching thicknesses into module b and module d, and insert the strip samples into the corresponding module c of the steel pipe model at the same time, which represents the heat treatment performance of the drill pipe end with an upset thickness equal to the sum of the wall thicknesses of module b, module c, and module d; insert the strip samples into module c of the steel pipe model, and insert iron sheets with matching thicknesses into module a, module b, module d, and module e respectively, which represents the heat treatment performance of the drill pipe end with an upset thickness equal to the sum of the wall thicknesses of module a, module b, module c, module d, and module e, and so on, to simulate and evaluate the heat treatment performance of drill pipes with different upset wall thicknesses. The material of the iron sheet is the same as that of the drill pipe;

[0014] (4) Perform small sample heat treatment on the entire steel pipe model in the laboratory. After quenching and tempering heat treatment, disassemble the module, take out the strip samples, and inspect the mechanical properties. The performance test results are used to approximately simulate the mechanical properties of the upset drill pipes with different wall thicknesses after heat treatment.

[0015] Further, the wall thickness of the steel pipe model is the same as the sum of the thicknesses of module a, module b, module c, module d, and module e.

[0016] Further, the arc lengths of module a, module b, module c, module d, and module e increase successively.

[0017] Further, the outer diameter of the steel pipe model is 130 mm to 500 mm, and the wall thickness is 10 mm to 80 mm.

[0018] Further, the thicknesses of the a module and the b module are 5 mm, 10 mm or 15 mm.

[0019] Further, the laboratory heat treatment simulation method for the thickened drill pipe sample includes:

[0020] (1) Cut a sector-shaped through groove longitudinally on one side of a steel pipe model with a specification of Φ139.7×10.54 mm. The sector-shaped through groove is successively provided with an a module, a b module, a c module, a d module, and an e module from the inside to the outside;

[0021] (2) Cut a strip-shaped sample with a width of 25.4 mm and a length of 300 mm longitudinally from a drill pipe sample with a specification of Φ139.7×10.54 mm. The strip-shaped sample matches the c module;

[0022] (3) Before heat treatment, insert the strip-shaped sample into the c module of the steel pipe model, which represents the heat treatment performance of the drill pipe body with a wall thickness of 10.54 mm; insert the strip-shaped sample into the c module of the steel pipe model, insert 5-mm iron sheets into the b module and the d module, and the material of the iron sheet is the same as that of the drill pipe, which represents the heat treatment performance of the drill pipe end with a upsetting thickness of 20.54 mm; insert the strip-shaped sample into the c module of the steel pipe model, insert 5-mm iron sheets into the a module, the b module, the d module, and the e module, and the material of the iron sheet is the same as that of the drill pipe, which represents the heat treatment performance of the drill pipe end with a upsetting thickness of 30.54 mm;

[0023] (4) Perform small sample heat treatment on the entire steel pipe model in the laboratory. After quenching and tempering heat treatment, disassemble the module, take out the strip-shaped sample, and inspect the mechanical properties.

[0024] Further, the process of the heat treatment is to hold at 850 to 950 °C for 20 to 40 minutes, take out and water-cool quench; then enter a tempering furnace, hold at 600 to 650 °C for 50 to 80 minutes, and take out and air-cool.

[0025] The advantages and beneficial effects of the present invention are:

[0026] (1) The method of the present invention has simple tools and is easy to operate. It can quickly perform heat treatment simulation to evaluate the heat treatment mechanical properties of the drill pipe body and the drill pipe ends with different upsetting wall thicknesses, and can provide evaluation and scientific research references for the hardenability, strength, toughness and other indicators of the drill pipe under different upsetting wall thickness conditions. It has certain guiding and reference significance for the development of drill pipes and the research of heat treatment processes in large-scale production.

[0027] (2) The method for laboratory simulation of heat treatment of the thickened drill pipe sample provided by the present invention can simulate the heat treatment performance of drill pipes with different wall thicknesses, and has a high degree of coincidence with the mechanical properties of large-scale production heat treatment, greatly reducing the cost. Description of the Drawings

[0028] Figure 1 It is a schematic cross-sectional view of a steel pipe model. Detailed Embodiments

[0029] The present invention will be further described in detail below through specific embodiments. The following embodiments are only descriptive and not restrictive, and the protection scope of the present invention cannot be limited thereby.

[0030] Embodiment 1:

[0031] The laboratory heat treatment simulation method for the Φ139.7×10.54mm drill pipe body and the upsetting wall thickness pipe ends with different thicknesses includes:

[0032] A sector-shaped through groove is longitudinally cut out on one side of the Φ139.7×10.54mm steel pipe model. The sector-shaped through groove is successively provided with module a, module b, module c, module d, and module e from inside to outside; module a and module e have the same thickness, and module b and module d have the same thickness; the wall thickness of the steel pipe model is the same as the sum of the wall thicknesses of module a, module b, module c, module d, and module e, and the arc lengths of module a, module b, module c, module d, and module e increase successively.

[0033] A strip-shaped sample with a width of 25.4mm and a length of 300mm is longitudinally cut out from the sample of the Φ139.7×10.54mm drill pipe. Before heat treatment, the strip-shaped sample is inserted into module c of the steel pipe model. Experiments A, B, and C are respectively carried out.

[0034] Experiment A: The strip-shaped sample is inserted at the position of module c, and module c is left empty above and below. The steel pipe model is subjected to heat treatment of quenching and tempering of the sample in the laboratory. The heat treatment process is to keep the temperature at 900°C for 30 minutes, and then water-cooled quenching when taken out of the furnace; then put it into the tempering furnace and keep the temperature at 630°C for 60 minutes, and then air-cooled when taken out of the furnace. After cooling to room temperature, the module is disassembled, and the strip-shaped sample with a width of 25.4mm and a length of 300mm at the position of module c is taken out, and the mechanical properties of the strip-shaped sample are inspected, representing the mechanical properties of the drill pipe body with a wall thickness of 10.54mm.

[0035] Experiment B: Insert the strip-shaped specimen at the c module, and then insert 5-mm iron sheets at the upper and lower b modules and d modules of the c module for clamping. The material of the iron sheets is the same as that of the drill pipe. Heat-treat the steel pipe model with a small sample of quenching and tempering in the laboratory. The heat treatment process is to hold at 900 °C for 30 minutes, take out of the furnace and quench with water; then put it into the tempering furnace, hold at 630 °C for 60 minutes, and take out of the furnace and air-cool. After cooling to room temperature, disassemble the module and take out the strip-shaped specimen with a width of 25.4 mm and a length of 300 mm at the c module, and test the mechanical properties of the strip-shaped specimen, representing the mechanical properties of the drill pipe end upset to 20.54 mm.

[0036] Experiment C: Insert the strip at the c module, and then insert 5-mm iron sheets at the a module, b module, d module, and e module respectively for clamping. The material of the iron sheets is the same as that of the drill pipe. Heat-treat the steel pipe model with a small sample of quenching and tempering in the laboratory. The heat treatment process is to hold at 900 °C for 30 minutes, take out of the furnace and quench with water; then put it into the tempering furnace, hold at 630 °C for 60 minutes, and take out of the furnace and air-cool. After cooling to room temperature, disassemble the module and take out the strip-shaped specimen with a width of 25.4 mm and a length of 300 mm at the c module, and test the mechanical properties of the strip-shaped specimen, representing the mechanical properties of the drill pipe end upset to 30.54 mm.

[0037] The mechanical property test results of Experiment A, Experiment B, and Experiment C are shown in Table 1.

[0038] Table 1 Mechanical property test results of strip-shaped specimens

[0039]

[0040] It can be seen from the experiments in Table 1 that the strength of Experiment A is the highest, and the strength of the third experiment is the lowest. This is because in the first experiment, the specimen was inserted at the c module, leaving the upper and lower parts of the c module empty, representing the heat treatment performance of a 10.54-mm thin-wall drill pipe specimen. The quenching and cooling effect is better, and the yield strength and tensile strength are higher. In Experiment C, 5-mm iron sheets were inserted at the a module, b module, d module, and e module for clamping, which is equivalent to heat-treating the drill pipe end with a upset thickness of 30.54 mm. The quenching and cooling effect is the worst, so the strength of the specimen test result is also the lowest.

[0041] To verify the accuracy of the heat treatment simulation method in the laboratory, large-scale production upset heat treatment verification was carried out: The drill pipe body materials of Φ139.7×10.54 mm and the pipe ends were respectively upset to 20.54 mm and 30.54 mm, and large-scale production heat treatment was carried out. The heat treatment process is to hold at 900 °C for 30 minutes, take out of the furnace and quench with water; then put it into the tempering furnace, hold at 630 °C for 60 minutes, and take out of the furnace and air-cool. After cooling to room temperature, test the mechanical properties. The test results of the average mechanical properties of the drill pipes subjected to large-scale production upset heat treatment are shown in Table 2.

[0042] Table 2 Mechanical Properties of Upsetting Heat Treatment in Large-scale Production

[0043] Wall thickness mm Yield strength MPa Tensile strength MPa Elongation after fracture % 10.54 1212 1273 24 20.54 1186 1242 25 30.54 1159 1210 24

[0044] Comparing the data results in Table 1 and Table 2, it can be seen that the test results of the upsetting heat treatment performance in large-scale production are relatively close to the test results of the heat treatment simulation in the laboratory using the present invention. This shows that the test results of the heat treatment simulation method in the laboratory of the present invention have good reference value and can be used to simulate the mechanical properties of the heat treatment of drill pipes with different wall thicknesses during upsetting.

[0045] From the experimental results, it can be seen that the method of the present invention has strong feasibility and good actual operation effect. Moreover, this method has simple tools, is conducive to operation, and has low cost. Although this method cannot fully simulate the hot working process of the deformation of the drill pipe upsetting into different wall thicknesses and the simulation of the grain size of the microstructure in the upsetting section, it can preliminarily simulate the cooling rate of water-cooled quenching during heat treatment under different wall thickness conditions of this steel type, as well as the corresponding mechanical properties such as material tensile impact. It can provide evaluation and scientific research reference for the hardenability, strength, toughness and other indicators of the drill pipe under different wall thickness conditions during upsetting, and has certain guiding and referential significance for the development of drill pipes and the research of heat treatment processes in large-scale production.

[0046] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A laboratory heat treatment simulation method for a thickened drill pipe sample, characterized in that Comprising: (1) A sector-shaped through groove is longitudinally cut on one side of the steel pipe model. The sector-shaped through groove is successively provided with module a, module b, module c, module d, and module e from inside to outside; module a and module e have the same thickness, and module b and module d have the same thickness; (2) The pipe body material of the drill pipe sample is longitudinally cut into several strip-shaped specimens, and the strip-shaped specimens are correspondingly matched with the c module; (3) Before heat treatment, insert the strip-shaped specimen into the c module of the steel pipe model, and leave the c module empty up and down, which represents the heat treatment performance of the drill pipe body without upsetting; insert iron sheets with matching thicknesses in the b module and the d module, and insert the strip-shaped specimen into the corresponding c module of the steel pipe model at the same time, which represents the heat treatment performance of the drill pipe end with an upsetting thickness equal to the sum of the wall thicknesses of the b module, c module, and d module; insert the strip-shaped specimen into the c module of the steel pipe model, and insert iron sheets with matching thicknesses in the a module, b module, d module, and e module respectively, which represents the heat treatment performance of the drill pipe end with an upsetting thickness equal to the sum of the wall thicknesses of the a module, b module, c module, d module, and e module. And so on, to simulate and evaluate the heat treatment performance of drill pipes with different upsetting wall thicknesses; and the material of the iron sheet is the same as that of the drill pipe; (4) Perform small sample heat treatment on the entire steel pipe model in the laboratory. After quenching and tempering heat treatment, disassemble the module, take out the strip-shaped specimen, and test the mechanical properties. The performance test results are used to approximately simulate the mechanical properties of the upset drill pipes with different wall thicknesses after heat treatment.

2. The laboratory heat treatment simulation method according to claim 1, characterized in that, The wall thickness of the steel pipe model is the same as the sum of the wall thicknesses of module a, module b, module c, module d, and module e.

3. The laboratory heat treatment simulation method according to claim 1, wherein The arc lengths of module a, module b, module c, module d, and module e gradually increase.

4. The laboratory heat treatment simulation method according to claim 1, characterized in that, The outer diameter of the steel pipe model is 130 mm to 500 mm, and the wall thickness is 10 mm to 80 mm.

5. The laboratory heat treatment simulation method according to claim 1, characterized in that, The thicknesses of module a and module b are 5 mm, 10 mm, or 15 mm.

6. The laboratory heat treatment simulation method according to claim 1, characterized in that Comprising: (1) A sector-shaped through groove is longitudinally cut on one side of the steel pipe model with a specification of Φ139.7×10.54 mm. The sector-shaped through groove is successively provided with module a, module b, module c, module d, and module e from inside to outside; (2) Cut a strip-shaped specimen with a width of 25.4 mm and a length of 300 mm longitudinally from the drill pipe with a specification of Φ139.7×10.54 mm, and the strip-shaped specimen is matched and installed with the c module; (3) Before heat treatment, insert the strip-shaped specimen into the c module of the steel pipe model, which represents the heat treatment performance of the drill pipe body with a wall thickness of 10.54 mm; insert the strip-shaped specimen into the c module of the steel pipe model, and insert 5 mm iron sheets into the b module and the d module respectively, which represents the heat treatment performance of the drill pipe end with an upsetting thickness of 20.54 mm; insert the strip-shaped specimen into the c module of the steel pipe model, and insert 5 mm iron sheets into the a module, b module, d module, and e module, which represents the heat treatment performance of the drill pipe end with an upsetting thickness of 30.54 mm; the material of the iron sheet is the same as that of the drill pipe; (4) Perform small sample heat treatment on the entire steel pipe model in the laboratory. After quenching and tempering heat treatment, disassemble the module, take out the strip-shaped specimen, and test the mechanical properties.

7. The laboratory heat treatment simulation method according to claim 6, wherein The heat treatment process is to hold at 850 - 950°C for 20 - 40 minutes, then take out of the furnace and quench with water cooling; then put it into a tempering furnace, hold at 600 - 650°C for 50 - 80 minutes, and take out of the furnace for air cooling.

Images