Seamless steel pipe, preparation method and application

Abstract

The present invention provides a seamless steel pipe, a preparation method, and an application thereof. The chemical composition of the seamless steel pipe includes: C 0.18-0.26%, Si ≤ 0.35%, Mn 0.50-1.00%, Cr 0.8-1.2%, Mo 0.35-0.5%, V 0.1-0.16%, W 0.45-0.70%, Al ≤ 0.05%, Ca ≤ 0.005%, N ≤ 0.010%, S ≤ 0.005%, P ≤ 0.010%, Cu ≤ 0.15%, Ti ≤ 0.015%, Ni ≤ 0.25%, O ≤ 0.0020%, H ≤ 0.0002%, As ≤ 0.015%, Sn ≤ 0.010%, Pb ≤ 0.010%, Sb ≤ 0.010%, and Bi ≤ 0.010%. At a low cost, the pipe can have high strength, high toughness, high collapse resistance and high temperature resistance.

Description

Technical Field

[0001] The present invention relates to the field of metallurgy technology, and in particular to a seamless steel pipe, a preparation method and an application thereof. Background Art

[0002] At present, seamless steel pipes are widely used in 140Ksi perforating gun barrels and 140v casings. Among them:

[0003] (1) For perforating gun barrels

[0004] Perforating is a crucial technology in oil exploration and development systems engineering and a key means of improving oil and gas well recovery. During perforation operations, the perforating gun barrel acts as a charge carrier, positioning the perforating direction, protecting the perforating pyrotechnic components from wellbore fluid immersion, withstanding pressure, mitigating damage to downhole casing, and protecting the oil reservoir casing during blasts. Due to its harsh operating conditions, the barrel is subject to not only corrosion from the medium, well temperature, and pressure, but also the primary threat posed by the high pressure and massive shock wave generated by the perforating charge. Consequently, stringent requirements are placed on the quality, strength, and toughness of the perforating gun barrel.

[0005] Perforating gun barrels require not only high pressure resistance but also the ability to withstand the high pressures generated by deep wells and perforating charge firing, while also resisting expansion and deformation to effectively prevent well sticking. Furthermore, in addition to the strength requirements for perforating gun barrels, there is also a desire to reduce barrel wall thickness to improve perforation quality. Therefore, perforating gun barrels must possess both high strength and high toughness. High-strength perforating gun barrels with insufficient toughness, especially low transverse impact toughness, can lead to high perforation burrs and even gun body cracking, causing well sticking and other accidents. As well depth increases, the casing strength used increases, requiring greater explosive force for perforating, and thus increasing the strength requirements for the perforating gun barrel itself. Limited research has been conducted in China on ultra-deep well perforating equipment, and the material selection has focused on conventional low-alloy steels such as 32CrMo4 and 35CrMo. The primary approach is to increase barrel wall thickness to improve collapse resistance.

[0006] For example, CN 107841681 B provides a method for manufacturing a perforating gun. This method utilizes a sub-temperature quenching process between AC1 and AC3 temperatures to produce the final perforating gun steel pipe. This method is complex to control for large-scale on-site production and suffers from poor process stability. Patent CN 108118251 A provides a method for manufacturing a high-strength perforating gun. This patent specifies a Mo content of 0.3-0.7% and contains no W. The steel pipe manufactured using this method cannot simultaneously meet the room temperature yield strength requirements of >965 MPa, a tensile strength of ≥1034 MPa, and a full-size (10×10 mm) V-notch transverse (T) impact energy of ≥80 J at 0°C. Patent CN 201510234477.0 discloses a high-grade steel perforating gun barrel and forming method. This steel has a low carbon content, a Mo content of approximately 1.0%, and contains alloying elements such as W. This makes it expensive, easily bends after water quenching at 880-920°C, and presents significant production challenges. CN108251747A provides a steel pipe for a crane boom and a manufacturing method thereof. Calculated by weight, the steel pipe comprises 0.11-0.15% C, 0.28-0.76% Si, 0.92-1.20% Cr, 1.10-1.20% Mn, 0.50-0.60% Mo, 0.056-0.12% V, 0.039-0.12% Nb, 0.565-1.23% W, 0.34-1.32% Ni, and 0-0.005% N. The patent has a high W content and contains relatively high amounts of Ni and Nb, as well as a large amount of alloying elements. The alloying elements interact and interfere with each other greatly, resulting in uncontrollable performance of the final product. Furthermore, due to the relatively high alloy content, the material manufacturing cost is relatively high.

[0007] (2) For 140V bushing

[0008] Ultra-deep well casing and tubing offer significant economic benefits and market potential. Ultra-deep well construction requires not only higher strength but also toughness and corrosion resistance. 140V casing requires not only high strength but also high toughness, high collapse resistance, and excellent high-temperature resistance. The development of new steel grades focuses on resolving the conflict between high strength and toughness, and between performance and production costs.

[0009] In summary, in oil exploration and development systems, it is difficult to obtain seamless steel pipes with excellent overall performance (such as high strength, high toughness, high collapse resistance, and excellent high-temperature resistance) at a low cost using existing technologies for 140Ksi perforating gun barrels and 140V casing. Therefore, it is necessary to provide a seamless steel pipe that can combine these excellent properties at a low cost. Summary of the Invention

[0010] The main purpose of the present invention is to provide a seamless steel pipe and its preparation method and application, so as to solve the problem that the existing technology cannot obtain seamless steel pipes with excellent comprehensive performance (such as high strength, high toughness, high anti-collapse performance and excellent high temperature resistance) at a lower cost.

[0011] To achieve the above-mentioned object, according to one aspect of the present invention, a seamless steel pipe is provided. The chemical composition of the seamless steel pipe comprises, by weight percentage, C, 0.18-0.26%, Si≤0.35%, Mn, 0.50-1.00%, Cr, 0.8-1.2%, Mo, 0.35-0.5%, V, 0.1-0.16%, W, 0.45-0.70%, Al≤0.05%, Ca≤0.005%, N≤0.010%, S≤0.005%, P≤0.010%, Cu≤0.15%, Ti≤0.015%, Ni≤0.25%, O≤0.0020%, H≤0.0002%, As≤0.015%, Sn≤0.010%, Pb≤0.010%, Sb≤0.010%, Bi≤0.010%, and the balance is iron and unavoidable impurities.

[0012] Furthermore, the chemical composition of the seamless steel pipe includes, by weight percentage: C, 0.18-0.26%, Si, 0.15-0.35%, Mn, 0.65-0.85%, Cr, 0.8-1.2%, Mo, 0.35-0.5%, V, 0.1-0.16%, W, 0.45-0.70%, Al, 0.008-0.04%, Ca≤0.005%, N≤0.008%, S≤ 0.005%, P≤0.010%, Cu≤0.15%, Ti≤0.015%, Ni≤0.25%, O≤0.0020%, H≤0.0002%, As≤0.015%, Sn≤0.010%, Pb≤0.010%, Sb≤0.010%, Bi≤0.010%, and the balance is iron and unavoidable impurities; preferably, the weight ratio between W and Mo is 0.50~0.82:1.

[0013] Furthermore, the metallographic structure of the seamless steel pipe includes tempered bainite and austenite, and the volume content of austenite is ≤5%; preferably, the grain size of the seamless steel pipe is greater than grade 7.

[0014] To achieve the above object, according to one aspect of the present invention, a method for preparing the aforementioned seamless steel pipe is provided, which comprises: smelting, casting, rolling and tempering heat treatment of raw materials in sequence according to the stoichiometric ratio to obtain the seamless steel pipe.

[0015] Furthermore, the rolling ratio in the rolling process is ≥3, preferably 5-10; preferably, the rolling process includes initial rolling and final rolling, and the temperature of the initial rolling is controlled to be 1100-1250°C, and the temperature of the final rolling is controlled to be 830-950°C.

[0016] Furthermore, the tempering heat treatment includes: quenching, tempering and hot straightening the rolled tube billet in sequence to obtain a seamless steel pipe; preferably, quenching includes first subjecting the material to a heat preservation treatment at a temperature of 880-940°C for 30-90 minutes and then rapidly quenching and cooling the material to room temperature; preferably, tempering includes first subjecting the material to a heat preservation treatment at a temperature of 660-720°C for 40-100 minutes and then air cooling the material; preferably, the treatment temperature of hot straightening is 450-600°C.

[0017] Furthermore, the cooling medium used in the quenching cooling is water; preferably, during the quenching cooling process, the cooling rate of the material is 40 to 80° C. / s.

[0018] Furthermore, the smelting method is one of vacuum induction smelting, electric arc furnace smelting or converter smelting.

[0019] According to another aspect of the present invention, a 140Ksi perforating gun barrel is provided. The tube material of the 140Ksi perforating gun barrel is the aforementioned seamless steel tube, or the seamless steel tube prepared by the aforementioned preparation method.

[0020] According to another aspect of the present invention, a 140V bushing is provided. The pipe material of the 140V bushing is the aforementioned seamless steel pipe, or the seamless steel pipe prepared by the aforementioned preparation method.

[0021] By applying the technical solution of the present invention, the seamless steel pipe can have excellent comprehensive performance (such as high strength, high toughness, high collapse resistance and excellent high temperature resistance) at a relatively low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 The metallographic structure test diagram of the steel pipe in Example 3 of the present invention is shown. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0025] As described in the background technology section of this application, the existing technology cannot obtain seamless steel pipes with excellent comprehensive properties (such as high strength, high toughness, high anti-collapse performance and excellent high temperature resistance) at a lower cost. In order to solve this problem, the present application provides a seamless steel pipe, the chemical composition of the seamless steel pipe including: C, 0.18-0.26%, Si≤0.35%, Mn, 0.50-1.00%, Cr, 0.8-1.2%, Mo, 0.35-0.5%, V, 0.1-0.16%, W, 0.45-0.70%, Al≤0.05%, Ca≤0.005%, N≤0.010%, S≤0.005%, P≤0.010%, Cu≤0.15%, Ti≤0.015%, Ni≤0.25%, O≤0.0020%, H≤0.0002%, As≤0.015%, Sn≤0.010%, Pb≤0.010%, Sb≤0.010%, Bi≤0.010%, and the balance is iron and unavoidable impurities.

[0026] The present invention, through the design of specific raw material components, can achieve seamless steel pipes with excellent comprehensive properties (such as high strength, high toughness, high collapse resistance and excellent high temperature resistance) at a relatively low cost. To further illustrate the beneficial effects of the present invention, the main elements in the above pipes are described below:

[0027] The W content is controlled between 0.45% and 0.70%, the Cr content is controlled between 0.8% and 1.2%, and the Mo content is controlled between 0.35% and 0.5%. The rational combination of Cr, Mo, and W within this range not only effectively improves the toughness of the steel but also enables the material to achieve higher strength properties at subsequent higher tempering temperatures. Furthermore, the aforementioned components of this application do not contain Ni and Nb. By utilizing a rational formulation of small amounts of Cr, Mo, and W, a high-performance seamless steel pipe can be produced at low cost, resulting in a low material manufacturing cost. The C content is controlled between 0.18% and 0.26%, thereby reducing the sensitivity to water quenching cracking while maintaining the material's high strength properties. Si: Solid dissolves in ferrite to increase the yield strength of the steel, but this also results in a loss of ductility and toughness. To achieve a synergistic effect with other elements to achieve both high strength and high toughness, the Si content is ≤ 0.35% by weight. Mn: Mainly dissolved in ferrite to strengthen the steel, it is used to improve the hardenability of the steel. However, if the Mn content is too high, segregation is severe, significantly impacting the material's lateral impact. In order to cooperate with other elements to make the material have excellent hardenability and less lateral impact, the Mn content is controlled at 0.50-1.00% by weight. Cr: It is an element that can strongly improve hardenability and is a strong carbide-forming element. During tempering, carbides are precipitated to increase the strength of steel, which is beneficial to improving the high temperature strength and anti-collapse performance of the material. However, if the content is too high, coarse Mn will precipitate. 23 C6 carbides lose their beneficial effects. To balance the material's high-temperature strength and collapse resistance, the Cr content is controlled at 0.8-1.2% by weight. V: A strong carbonitride-forming element. Vanadium carbonitrides precipitate in fine dispersions within the ferrite, further achieving precipitation strengthening during tempering. They effectively pin dislocation movement and delay the crushing instability process, thereby effectively improving the material's high-temperature strength and collapse resistance. However, V carbides only readily precipitate when tempered above 500°C. Therefore, under current conventional tempering temperature conditions, to fully utilize the V effect, the V content is controlled at 0.1-0.16% by weight. Al: A traditional deoxidizing and nitrogen-fixing element. The AlN formed can refine austenite grains, which helps delay the crushing instability process. Al is ≤0.05% by weight. Ca: It can purify molten steel, promote the spheroidization of MnS, and improve the anti-extrusion performance of the material. However, when the content is too high, it is easy to form coarse non-metallic inclusions. Therefore, in order to balance the comprehensive performance of the material, Ca is ≤ 0.005% by weight.

[0028] It should be noted that high strength and high toughness are in a contradictory relationship. However, this application is based on the synergistic effect of the above elements in specific dosages, resulting in a low dislocation density sorbite structure and a high density of nano-sized precipitates. The two complement each other, allowing the material to simultaneously achieve high strength, high toughness, high collapse resistance, and excellent high-temperature resistance.

[0029] The above steel materials in this application can achieve the following excellent effects:

[0030] (1) Yield strength at room temperature ≥965MPa, tensile strength ≥1034MPa; full-size (10×10mm) V-notch impact energy at 0℃ transverse (T) ≥80J, longitudinal (L) ≥100J.

[0031] (2) When the temperature rises to 400℃, the strength decreases by no more than 15%, and it can be used in an environment with a maximum temperature of 250℃.

[0032] (3) When subsequently used in a perforating gun barrel, the expansion of the barrel after perforation is ≤4.5 mm, which can ensure that the barrel does not crack during perforation.

[0033] In order to further balance the manufacturing cost, rigidity and high temperature resistance of the material, in a preferred embodiment, the chemical composition of the seamless steel pipe includes, by weight percentage: C, 0.18-0.26%, Si, 0.15-0.35%, Mn, 0.65-0.85%, Cr, 0.8-1.2%, Mo, 0.35-0.5%, V, 0.1-0.16%, W, 0.45-0.70%, Al, 0.00 8~0.04%,Ca≤0.005%,N≤0.008%,S≤0.005%,P≤0.010%,Cu≤0.15%,Ti≤0.015%,Ni≤0.25%,O≤0.0020%,H≤0.0002%,As≤0.015%,Sn≤0.010%,Pb≤0.010%,Sb≤0.010%,Bi≤0.010%,the balance is iron and unavoidable impurities. Further preferably, the weight ratio between W and Mo is 0.50~0:82:1.

[0034] To further enhance the material's excellent overall performance, in a preferred embodiment, the seamless steel pipe's metallographic structure includes tempered sorbite and austenite, with the austenite content being ≤5% by volume. Preferably, the seamless steel pipe has a grain size greater than grade 7.

[0035] This application also provides a method for preparing the aforementioned seamless steel pipe, comprising: smelting, casting, rolling, and quenching and tempering raw materials in a sequential manner according to stoichiometric ratios to produce a seamless steel pipe. Based on the aforementioned reasons, the present invention can achieve seamless steel pipes with excellent overall performance (such as high strength, high toughness, high collapse resistance, and excellent high-temperature resistance) at a relatively low cost.

[0036] To further promote uniform and dense metallographic structure of the material, in a preferred embodiment, the rolling ratio during the rolling process (defined as the ratio of the cross-sectional areas of the workpiece before and after rolling deformation, rolling ratio for hot rolling of steel pipes = cross-sectional area of the tube blank used for rolling / cross-sectional area of the steel pipe after rolling) is ≥ 3, preferably 5 to 10. To further improve the mechanical properties of the material, in a preferred embodiment, the rolling process includes initial rolling and final rolling, with the initial rolling temperature controlled at 1100-1250°C and the final rolling temperature controlled at 830-950°C.

[0037] To further balance the toughness and strength properties of the material, in a preferred embodiment, the tempering heat treatment includes sequentially quenching, tempering, and heat straightening the rolled material to produce a seamless steel pipe. Based on the composition of the steel, this application further optimizes the tempering heat treatment process. This process effectively controls the composition of the material's metallographic structure, thereby reducing dislocation density and significantly improving the toughness of the material while maintaining high strength. Preferably, the heat straightening treatment temperature is 450-600°C.

[0038] In a preferred embodiment, quenching includes first subjecting the material to a heat treatment at 880-940°C for 30-90 minutes, then rapidly quenching the material (rapid quenching cooling refers to a speed greater than air cooling, typically a cooling rate of 20°C / s or more) to room temperature, and then cooling the material to room temperature (15-50°C) by internal and external water spraying. In order to obtain more than 95% martensite in the material, in a preferred embodiment, the cooling medium used for quenching is water. Preferably, during the cooling process, the cooling rate of the material is 40-80°C / s.

[0039] In a preferred embodiment, tempering includes first subjecting the material to heat preservation treatment at a temperature of 660 to 720°C for 40 to 100 minutes and then air cooling the material. Depending on the chemical composition of the raw materials, the amount of carbide precipitation phase generated during the tempering process of the heat treatment will be affected by different temperature conditions. In order to meet the high strength and toughness requirements, the tempering temperature of the heat treatment is also adjusted accordingly. In order to make the material have excellent toughness and strength properties at the same time, the present application is tempered at 660 to 720°C. This is based on the moderate carbon content in the material composition of the present application and the presence of more alloys. Tempering at this temperature can allow carbon to fully react with elements such as Mo, W, and V to form corresponding carbides, which play a sufficient precipitation strengthening role. Through high-temperature tempering, the dislocation density under high carbon content is reduced, and the martensitic plate structure after tempering is restored, merged with widening and polygonization, so that the high-angle grain boundaries (≥15 degrees) increase, the energy required for crack propagation during the impact process increases, and the impact performance increases.

[0040] The present application does not specifically limit the above-mentioned smelting method, and the smelting methods commonly used in the art can be applied to the present invention. In order to further improve the comprehensive performance of the material, in a preferred embodiment, the above-mentioned smelting method includes but is not limited to one of vacuum induction smelting, electric arc furnace smelting or converter smelting. It is further explained that when the converter smelting method is adopted, the raw materials are firstly smelted in an electric furnace, then refined outside the furnace, and then calcium treated, and then vacuum degassing treated. This is well known to those skilled in the art and will not be described in detail here.

[0041] The present application does not specifically limit the above-mentioned casting method, and any commonly used casting method in the art can be applied to the present invention. In order to further improve the comprehensive performance of the material, in a preferred embodiment, the present application further casts or continuously casts (such as arc continuous casting) the material after smelting to obtain a tube blank, and then cools and finishes the tube blank before use.

[0042] This application does not make any special limitation on the above-mentioned rolling method, and the rolling methods commonly used in the field can be applied to the present invention. In order to further optimize the structural properties of the material, in a preferred embodiment, the rolling includes: billet inspection and grinding → sawing and blanking → ring furnace heating → conical roller perforation → tube rolling → online normalization → step furnace reheating → sizing → cooling on a cooling bed. Among them, online normalization is to refine the hot-rolled grains, and other methods can also be used to make the hot-rolled grain size ≥7 levels, and the grains are uniform. Online normalization: also known as online normalizing process, usually refers to using an online heating furnace to reheat the steel to a temperature above the Ac3 or Acm line, keeping it warm for a period of time, so that the structure of the steel is transformed into austenite, and then air-cooling, sometimes blowing or spray cooling can be used as needed to transform the supercooled austenite structure into pearlite. The cooling rate for normalizing is faster than the cooling rate of conventional normalizing, so the pearlite structure obtained is also correspondingly finer.

[0043] The present application also provides a 140Ksi perforating gun barrel. The tube material of the 140Ksi perforating gun barrel is the aforementioned seamless steel tube, or the seamless steel tube prepared by the aforementioned preparation method.

[0044] Based on the reasons mentioned above, this application can make the seamless steel pipe have excellent comprehensive performance (such as high strength, high toughness, high anti-collapse performance and excellent high temperature resistance) at a lower cost, and the application performance is better.

[0045] The present application also provides a 140v sleeve, the pipe material of the 140v sleeve is the aforementioned seamless steel pipe, or the seamless steel pipe prepared by the aforementioned preparation method.

[0046] Based on the reasons mentioned above, this application can make the seamless steel pipe have excellent comprehensive performance (such as high strength, high toughness, high anti-collapse performance and excellent high temperature resistance) at a lower cost, and the application performance is better.

[0047] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0048] According to the composition formula in Table 1, 12 embodiments A1 to A12 and 9 comparative examples B1 to B9 were obtained.

[0049] Table 1

[0050]

[0051]

[0052]

[0053] The process parameters in the examples are shown in Table 2.

[0054] Table 2

[0055]

[0056]

[0057] Performance characterization:

[0058] The mechanical properties of the material are tested with reference to GB / T 228 Tensile test for metal materials.

[0059] The transverse impact energy test of the material is carried out according to GB / T 229 Charpy pendulum impact test method for metallic materials.

[0060] The collapse strength calculation was performed with reference to SY / T6328 Performance Calculation of Casing, Tubing, Drill Pipe and Line Pipe in the Petroleum and Natural Gas Industry and formula (3) in clause 3.1.2 of API 5C3 standard.

[0061]

[0062] A=3.297

[0063] B=0.0971

[0064] C=3751

[0065] The production steel pipe specification is 139.7×9.17.

[0066] Grain size: GB / T 6394.

[0067] The test results are shown in Table 3.

[0068] Table 3

[0069]

[0070]

[0071] As can be seen from Table 3, the seamless steel pipe provided by the present invention has a small decrease in strength at high temperatures, with a decrease of no more than 14% at 400°C, which can better meet its safety requirements for use in high-temperature wells. Metallographic observation of the seamless steel pipe of Example 3 shows that the microstructure obtained by the steel of the present invention is tempered bainite + 3% retained austenite. Figure 1 .

[0072] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A seamless steel pipe, characterized in that: The chemical composition of the seamless steel pipe includes, by weight percentage, C, 0.18-0.26%, Si≤0.35%, Mn, 0.50-1.00%, Cr, 0.8-1.2%, Mo, 0.35-0.5%, V, 0.1-0.16%, W, 0.45-0.70%, Al≤0.05%, Ca≤0.005%, N≤0.010%, S≤0.005%, P≤0.010%, Cu≤0.15%, Ti≤0.015%, Ni≤0.25%, O≤0.0020%, H≤0.0002%, As≤0.015%, Sn≤0.010%, Pb≤0.010%, Sb≤0.010%, Bi≤0.010%, and the balance is iron and unavoidable impurities; The weight ratio of Mo to W is 0.50-0.82:1; the metallographic structure of the seamless steel pipe includes tempered bainite and austenite, and the volume content of the austenite is ≤5%; The method for preparing the seamless steel pipe comprises: smelting, casting, rolling and quenching and tempering heat treatment of raw materials in sequence according to the stoichiometric ratio to obtain the seamless steel pipe; The rolling ratio in the rolling process is ≥3; the rolling process includes initial rolling and final rolling, the temperature of the initial rolling is controlled to be 1100-1250°C, and the temperature of the final rolling is controlled to be 830-950°C; The quenching and tempering heat treatment includes: quenching, tempering and hot straightening the rolled tube billet in sequence to obtain the seamless steel pipe; the quenching includes first subjecting the material to a heat preservation treatment at a temperature of 880-940°C for 30-90 minutes and then rapidly quenching and cooling the material to room temperature; the tempering includes first subjecting the material to a heat preservation treatment at a temperature of 660-720°C for 40-100 minutes and then air cooling the material; the hot straightening treatment temperature is 450-600°C.

2. The seamless steel pipe according to claim 1, characterized in that: The chemical composition of the seamless steel pipe includes, by weight percentage, C, 0.18-0.26%, Si, 0.15-0.35%, Mn, 0.65-0.85%, Cr, 0.8-1.2%, Mo, 0.35-0.5%, V, 0.1-0.16%, W, 0.45-0.70%, Al, 0.008-0.04%, Ca≤0.005%, N≤0.008%, S≤0.005%, P≤0.010%, Cu≤0.15%, Ti≤0.015%, Ni≤0.25%, O≤0.0020%, H≤0.0002%, As≤0.015%, Sn≤0.010%, Pb≤0.010%, Sb≤0.010%, Bi≤0.010%, and the balance is iron and unavoidable impurities.

3. The seamless steel pipe according to claim 1 or 2, characterized in that: The grain size of the seamless steel pipe is greater than grade 7.

4. The seamless steel pipe according to claim 1, characterized in that The rolling ratio during the rolling process is 5-10.

5. The seamless steel pipe according to claim 1, characterized in that The cooling medium used in the quenching cooling is water.

6. The seamless steel pipe according to claim 1, characterized in that: During the quenching cooling process, the cooling rate of the material is 40-80°C / s.

7. The seamless steel pipe according to claim 1, characterized in that The smelting method is one of vacuum induction smelting, electric arc furnace smelting or converter smelting.

8. A 140Ksi perforating gun barrel, characterized in that: The tube material of the 140Ksi perforating gun barrel is the seamless steel tube material according to any one of claims 1 to 7.

9. A 140V bushing, characterized in that: The pipe material of the 140v casing is the seamless steel pipe material described in any one of claims 1 to 7.

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