Seamless steel pipe, method for producing the same, and use thereof

Abstract

The present application provides a kind of seamless steel tube and its preparation method and application, the chemical composition of the seamless steel tube includes: C, 0.02~0.06%, Si, 0.12~0.17%, Mn, 27~30%, S≤0.005%, P≤0.005%, Cr, 3.5~3.7%, Cu, 0.5~0.7%, Mo≤0.15%, Ti, 0.01~0.10%, Nb, 0.015~0.03%, Al, 0.02~0.04%, V, 0.18~0.25, N≤700ppm, O≤30ppm, H≤2.0ppm, the balance is Fe and impurity.The seamless steel tube of the present application compared with existing high nickel steel and stainless steel, cost advantage is more obvious, can be applied in-110℃~-196℃ low temperature environment after subsequent heat treatment, with higher strength and better low temperature toughness simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgy, and particularly relates to a seamless steel pipe and a preparation method and application thereof. BACKGROUND

[0002] The steel pipe for ultra-low temperature pipeline mainly refers to a pipeline material which has good low-temperature toughness and high strength at ultra-low temperature (below -110 DEG C). The steel pipe is mainly applied to the production, storage and transportation pipeline of liquefied natural gas (LNG), liquefied petroleum gas, liquid oxygen and liquid nitrogen. The pipeline needs to have good low-temperature toughness, corrosion resistance, fatigue resistance, welding performance and other comprehensive properties due to the special requirements of the use environment.

[0003] At present, the low-temperature pipeline mainly has two series which are widely applied to the storage and transportation of liquid ethylene and other gases in the petroleum and chemical industry: the first series is 3.5Ni, 5Ni and 9Ni martensitic low-temperature pipeline; and the second series is 304 and 316 austenitic stainless steel series low-temperature pipeline. However, the two series of low-temperature pipelines have the following problems: the low-temperature toughness and strength of the first series of 3.5Ni, 5Ni and 9Ni martensitic low-temperature pipeline can meet the use requirements, but the pipeline is expensive due to the high Ni element content; and the low-temperature toughness of the second series of 304 and 316 austenitic stainless steel series low-temperature pipeline is good, but the strength is poor, and the alloy content is also high and the pipeline is expensive.

[0004] In summary, the prior art is difficult to obtain the seamless steel pipe with excellent comprehensive properties (such as high low-temperature toughness, high strength, etc.) at a low cost. Therefore, it is necessary to provide a seamless steel pipe which can have the excellent properties at a low cost. SUMMARY

[0005] The main purpose of the present application is to provide a seamless steel pipe and a preparation method and application thereof, so as to solve the problem that the prior art cannot obtain the seamless steel pipe with excellent comprehensive properties (such as high low-temperature toughness, high strength, etc.) at a low cost, and solve the problem that the existing high manganese steel billet is prone to cracking in the heat treatment process.

[0006] To achieve the above object, according to one aspect of the present application, there is provided a seamless steel pipe, the chemical composition of which includes, in terms of weight percentage, C: 0.02-0.06%, Si: 0.12-0.17%, Mn: 27-30%, S: ≤0.005%, P: ≤0.005%, Cr: 3.5-3.7%, Cu: 0.5-0.7%, Mo: ≤0.15%, Ti: 0.01-0.10%, Nb: 0.015-0.03%, Al: 0.02-0.04%, V: 0.18-0.25, N: ≤700ppm, O: ≤30ppm, H: ≤2.0ppm, and the balance being Fe and impurities.

[0007] Further, the chemical composition of the seamless steel pipe includes, in terms of weight percentage, C: 0.02-0.06%, Si: 0.12-0.17%, Mn: 27-30%, S: 0.001-0.005%, P: 0.001-0.005%, Cr: 3.55-3.70%, Cu: 0.55-0.65%, Mo: 0.010-0.15%, Ti: 0.01-0.10%, Nb: 0.015-0.03%, Al: 0.02-0.04%, V: 0.18-0.25, N: 300-700ppm, O: 10-30ppm, H: 0.10-2.0ppm.

[0008] Further, the seamless steel pipe has an outer diameter of 32-610mm and a wall thickness of 3-40mm.

[0009] To achieve the above object, according to one aspect of the present application, there is provided a method for manufacturing a seamless steel pipe, which includes sequentially subjecting raw materials to smelting, vacuum degassing furnace refining, ladle refining furnace refining, billet continuous casting, pipe billet blanking, ring furnace heating, piercing, pipe rolling, sizing, solid solution homogenizing, tempering homogenizing, straightening and finishing, to obtain the seamless steel pipe.

[0010] Further, the ring furnace heating includes a preheating stage, a heating stage and a soaking stage, which are sequentially performed.

[0011] Further, the heating stage includes a first heating stage, a second heating stage, a third heating stage and a fourth heating stage, which are sequentially performed.

[0012] Further, the first heating stage has a treatment temperature of 800℃±10℃ and a time of 5-6.5h, the second heating stage has a treatment temperature of 1080℃±10℃ and a time of 1.5-2h, the third heating stage has a treatment temperature of 1150℃±10℃ and a time of 1.5-2h, and the fourth heating stage has a treatment temperature of 1120℃±10℃ and a time of 1.5-1.8h.

[0013] Further, the temperature rising rate from the preheating stage to the first heating stage, the temperature rising rate from the second heating stage to the third heating stage, and the temperature rising rate from the third heating stage to the fourth heating stage are each independently 20-50℃ / min.

[0014] Further, the temperature of the preheating stage is raised to the first heating stage, and the treatment time is 6-10h.

[0015] Further, the treatment temperature of the soaking stage is 1120℃±10℃, and the time is 1.5-1.8h.

[0016] Further, the solution homogenization includes the following steps: first, the material is subjected to a first holding treatment at a temperature of 800-860℃, and then the material is water quenched; wherein the time of the first holding treatment is controlled according to a wall thickness coefficient of 2.0-2.5min / mm.

[0017] Further, the tempering homogenization includes the following steps: first, the material is subjected to a second holding treatment at a temperature of 600-610℃, and then the material is air cooled; wherein the time of the second holding treatment is controlled according to a wall thickness coefficient of 4.0-4.5min / mm.

[0018] Further, after the high manganese steel pipe is subjected to the solution treatment, the preparation method further includes the steps of sequentially annealing, cold drawing, and cold rolling the pipe material.

[0019] Further, the preparation method further includes the step of holding the material after cold rolling at a temperature of 650℃±10℃ for 1.5-2.5h and then water cooling.

[0020] Further, before heating in the ring furnace, the preparation method further includes the step of spraying an anti-oxidation coating on the outer surface of the pipe material.

[0021] According to another aspect of the present application, the application provides the use of the seamless steel pipe prepared by the above-mentioned preparation method of a seamless steel pipe in an ultra-low temperature environment of-110℃ to-196℃.

[0022] By using the technical solution of the present application, the seamless steel pipe of the present application has more obvious cost advantages compared with existing high nickel steel and stainless steel, can be applied in a low temperature environment of-110℃ to-196℃ after subsequent heat treatment, has higher strength and better low temperature toughness, and has greater application space in a chemical low temperature service environment (such as a pipeline for transporting a gas such as liquid ethylene). BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the application and, together with the description, serve to explain the application. In the drawings:

[0024] Figure 1 A metallographic structure test chart of the embodiment A1 of the application is shown;

[0025] Figure 2 A metallographic structure test chart of the embodiment A4 of the application is shown;

[0026] Figure 3 A metallographic structure test chart of the embodiment A5 of the application after hot rolling and air cooling during sizing is shown;

[0027] Figure 4 A scanning electron microscope chart of the embodiment A5 of the application after solution homogenization treatment is shown. DETAILED DESCRIPTION

[0028] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] As described in the background section of the present application, the prior art cannot obtain a seamless steel pipe with excellent comprehensive performance (such as high low-temperature toughness, high strength, etc.) at a lower cost requirement. In order to solve this problem, the present application provides a seamless steel pipe, the chemical composition of which includes, in terms of percentage by weight: C, 0.02-0.06%, Si, 0.12-0.17%, Mn, 27-30%, S≤0.005%, P≤0.005%, Cr, 3.5-3.7%, Cu, 0.5-0.7%, Mo≤0.15%, Ti, 0.01-0.10%, Nb, 0.015-0.03%, Al, 0.02-0.04%, V, 0.18-0.25%, N≤700ppm, O≤30ppm, H≤2.0ppm, and the balance being Fe and impurities.

[0030] The present application can make the seamless steel pipe have excellent comprehensive performance (such as high low-temperature toughness, high strength, etc.) at a lower cost through specific raw material composition design. In order to further illustrate the beneficial effects of the present application, the main elements in the above steel pipe are described as follows:

[0031] The content of Mn is controlled at 27-30%, the content of S and the content of P are both controlled at ≤0.005%. Mn is an austenite stabilizing element and also a matrix strengthening element, which can improve the strength through subsequent solid solution homogenization treatment step (precipitation strengthening), meanwhile, Mn can also improve the hardenability of the material, the Mn content in this range can make the steel have good low temperature toughness and strength. But when the content of Mn is less than 27%, the strength does not meet the use requirement, and when the content of Mn is higher than 30%, the low temperature toughness of the material is affected. The application controls the content of Mn at 27-30%, and also coordinates the content of S and P, and makes them controlled at the minimum limit (≤0.005%), because S is easy to form precipitates MnS with metal element Mn, which can reduce the low temperature toughness of the material, and P is easy to segregate at the grain boundary, which can reduce the crack propagation resistance of the grain boundary, and also can reduce the low temperature toughness of the material. The application uses the combination of the specific content of Mn and the minimum content of S and P, especially, the application does not contain Ni element, and under the condition of lower manufacturing cost, the seamless steel pipe can have excellent low temperature toughness and strength, and also can have good corrosion resistance and welding performance. The content of C is controlled at 0.02-0.06%: C can effectively improve the strength of the steel, but C can also deteriorate the low temperature impact toughness, therefore, it should be controlled in a lower range. The content of Si is controlled at 0.12-0.17%: Si is a high temperature steel martensite decomposition control element, in order to coordinate with other elements to make the material have low temperature performance and low temperature toughness performance, therefore, it should be controlled at 0.12-0.17%. The content of Cr is controlled at 3.5-3.7%: controlling Cr at 3.5-3.7% can not only improve the strength of the material, but also improve the tempering stability. The content of Cu is controlled at 0.5-0.7%: adding 0.5-0.7% Cu element can improve the strength and plasticity product of the material, Cu enrichment in austenite makes more austenite remain, and due to the strengthening effect of Cu precipitates, the strength of the material can be improved without reducing the toughness. The content of Mo is controlled at 0.01-0.15%: Mo can improve the strength of the steel, but the Mo precipitated carbide particles are coarse, which can affect the impact when it aggregates and grows, therefore, it is controlled at 0.01-0.15%. The content of Ti is controlled at 0.01-0.10%: Ti can fix nitrogen element to prevent billet cracking. The content of Nb is controlled at 0.015-0.03%: in order to coordinate with other elements to improve the strength of the material without reducing the low temperature impact toughness, therefore, it is controlled at.015-0.03%. The content of Al is controlled at 0.02-0.04%: Al can refine the austenite grain. The content of V is controlled at 0.18-0.25%: strong carbonitride forming element, the carbide of V precipitated in the steel improves the strength and hardness of the material. In the smelting process, the most important thing is to control the content of impurity elements such as S, P, N and O, which are limited in the minimum range, which is the key to improve the low temperature toughness of the low temperature steel.

[0032] It should be noted that high strength and low temperature high toughness are a contradictory relationship. The present application is based on the synergistic effect of the above elements in a specific amount, on the basis of controlling the content of manganese element at 27-30%, by adding a specific amount of Al, Ti, Nb, and V elements in the raw material to form stable nitride or carbide dispersed particles in the steel to refine the austenite grain, and controlling the content of impurity elements such as S, P, N and O within the minimum limit, and in addition to the synergistic effect of other elements (Si, Cr, Cu, Mo), the steel pipe can simultaneously consider the better strength and low temperature high toughness at a lower cost.

[0033] The above seamless steel pipe of the present application has more obvious cost advantage compared with existing high nickel steel and stainless steel, and can be applied in low temperature environment of-110℃ to-196℃ after subsequent heat treatment, while having higher strength and better low temperature toughness, and has larger application space in chemical low temperature service environment (such as transportation pipeline of liquid ethylene gas).

[0034] In order to further balance the manufacturing cost of the seamless steel pipe and the strength and low temperature toughness, in a preferred embodiment, the chemical composition of the seamless steel pipe includes, by weight percentage: C, 0.02-0.06%, Si, 0.12-0.17%, Mn, 27-30%, S, 0.001-0.005%, P, 0.001-0.005%, Cr, 3.55-3.70%, Cu, 0.55-0.65%, Mo, 0.010-0.15%, Ti, 0.01-0.10%, Nb, 0.015-0.03%, Al, 0.02-0.04%, V, 0.18-0.25, N, 300-700ppm, O, 10-30ppm, H, 0.10-2.0ppm.

[0035] In an alternative embodiment, the outer diameter of the seamless steel pipe is 32-610mm, and the wall thickness is 3-40mm. Based on the synergistic effect of the above components, the present application can obtain a thin-walled steel pipe with better strength and low temperature high toughness without multiple drawing (compared with high nickel steel and stainless steel), and the process is simpler and more convenient, and batch production can be realized.

[0036] The present application also provides a preparation method of the above-mentioned seamless steel pipe, comprising: sequentially smelting, vacuum degassing furnace refining (VD treatment), ladle refining furnace refining (LF treatment), billet continuous casting, pipe blank cutting, ring furnace heating, piercing, pipe rolling, sizing, solid solution homogenization, tempering homogenization, straightening and finishing of raw materials in stoichiometric ratio, to obtain the seamless steel pipe. Based on the above reasons, the present application can make the comprehensive performance of the seamless steel pipe excellent (such as high low temperature toughness, high strength, etc.) at a lower cost.

[0037] In order to further balance the low-temperature toughness and strength of the seamless steel pipe, control the uniformity of material heating, and avoid defects of the product caused by improper heating, in some preferred embodiments, the ring furnace heating comprises a preheating stage, a heating stage and a soaking stage which are sequentially performed. Preferably, the temperature of the preheating stage is raised to a processing temperature of a first heating stage by the furnace temperature, and the processing time is 6-10 h. Preferably, the processing temperature of the soaking stage is 1120℃±10℃, and the time is 1.5-1.8 h. Based on the composition of the seamless steel pipe, the application further optimizes the process of the heating stage, which comprises a first heating stage, a second heating stage, a third heating stage and a fourth heating stage which are sequentially performed. Preferably, the processing temperature of the first heating stage is 800℃±10℃, and the time is 1-1.5 h; the processing temperature of the second heating stage is 1080℃±10℃, and the time is 1.5-2 h; the processing temperature of the third heating stage is 1150℃±10℃, and the time is 1.5-2 h; the processing temperature of the fourth heating stage is 1120℃±10℃, and the time is 1.5-1.8 h. Further preferably, the heating rate for raising the temperature from the processing temperature of the first heating stage to the processing temperature of the second heating stage, the heating rate for raising the temperature from the processing temperature of the second heating stage to the processing temperature of the third heating stage, and the heating rate for raising the temperature from the processing temperature of the third heating stage to the processing temperature of the fourth heating stage are each independently 20-50℃ / min.

[0038] The application adopts a low-temperature slow preheating stage, a four-stage high-temperature rapid heating stage and a ring furnace heating process with a lower soaking temperature, can control the uniformity of the temperature of the material, and reduce the crack occurrence rate. In the initial stage, the billet is slowly heated at a lower heating rate, and the internal temperature is homogenized for a relatively long holding time to eliminate internal stress and reduce the crack occurrence rate. As the temperature rises, the thermal conductivity improves, the cracking risk decreases, the heating rate can be appropriately increased and the holding time can be reduced, while ensuring the uniformity of the temperature, the heating efficiency is improved.

[0039] The application adopts a four-stage heating process: the first heating stage is 5-6.5 hours from room temperature to 800℃, the slow heating rate prevents the billet from cracking due to volume expansion during austenite transformation; the second heating stage completes the uniform transformation of austenitization; the third heating stage completely heats and homogenizes the billet; the fourth heating stage adjusts to the best deformation temperature (1120℃±10℃) of the billet, which is convenient for subsequent processing.

[0040] In a preferred embodiment, the solution homogenization comprises the following steps: first, subjecting the material to a first holding treatment at a temperature of 800-860℃, and then water quenching the material out of the furnace; wherein the time of the first holding treatment is controlled according to a wall thickness coefficient of 2.0-2.5 min / mm. According to the present application, the treatment conditions of the solution homogenization are specially designed according to the chemical composition of the seamless steel pipe, and the temperature is preferably within the range of 800-860℃, so as to dissolve the excessively coarse carbides formed by Al, Ti, Nb and V in the steel, and further improve the impact toughness of the steel plate. In the present application, the time of the first holding treatment is controlled according to a wall thickness coefficient of 2.0-2.5 min / mm, which is based on the following considerations: when the time of the first holding treatment is too long, the surface of the steel pipe will be seriously oxidized, and the energy consumption will increase; when the time is too short, the austenitization transformation of the steel material cannot be completed.

[0041] In a preferred embodiment, the tempering homogenization comprises the following steps: first, subjecting the material to a second holding treatment at a temperature of 600-610℃, and then air cooling the material out of the furnace; wherein the time of the first holding treatment is controlled according to a wall thickness coefficient of 4.0-4.5 min / mm. According to the present application, the treatment conditions of the tempering homogenization are specially designed according to the chemical composition of the seamless steel pipe, and the holding time is increased according to the increase of the C content and the Mn content. In the present application, the time of the second holding treatment is controlled according to a wall thickness coefficient of 4.0-4.5 min / mm, which is based on the following considerations: when the time of the first holding treatment is too long, the strength will decrease; when the time is too short, the carbide precipitation will be insufficient, which will affect the low-temperature impact toughness.

[0042] In order to further balance the low-temperature toughness and strength of the seamless steel pipe, after the solution treatment of the steel pipe, the preparation method further comprises the steps of sequentially annealing, cold drawing and cold rolling the pipe material. Preferably, the method further comprises the step of subjecting the material after cold rolling to a holding treatment at a temperature of 650℃±10 for 1.5-2.5h, and then water cooling the material out of the furnace. Preferably, when the wall thickness of the prepared seamless steel pipe increases, the pipe material will adopt multiple annealing and multiple cold drawing steps.

[0043] In order to prevent the formation of iron oxide scale on the pipe blank during the heating process in the ring furnace, which will cause the performance of the seamless steel pipe to deteriorate, the preparation method further comprises the step of spraying an anti-oxidation coating on the outer surface of the pipe material before heating in the ring furnace.

[0044] The present application also provides a seamless steel pipe prepared by the above-mentioned preparation method, or the application of the seamless steel pipe prepared by the above-mentioned preparation method in a super-low temperature environment of-110℃ to-196℃. Based on the above reasons, the present application can achieve excellent comprehensive performance (such as high low-temperature toughness, high strength, etc.) of the seamless steel pipe at a lower cost, and the application performance is more excellent.

[0045] The application will be described in further detail below with reference to specific embodiments, which are not to be understood as limiting the scope of the application as claimed.

[0046] Five examples A1-A5 and five comparative examples B1-B5 were prepared according to the formulations in Table 1.

[0047] Table 1

[0048]

[0049]

[0050] The process parameters of examples A1-A5 are shown in Table 2 and Table 3, and the process parameters of comparative examples B1-B5 refer to those of example A2.

[0051] Table 2

[0052]

[0053] Table 3

[0054]

[0055]

[0056] Performance test:

[0057] The material performance was tested according to the test method of ASME A370.

[0058] The performance test results are shown in Table 3.

[0059] The seamless steel pipe of the above examples and comparative examples has a specification of Φ168x7.11.

[0060] Table 3

[0061]

[0062] Figure 1 The metallographic structure test figure of example A1 of the application is shown, and it can be seen that the steel pipe after solution homogenization treatment contains a large number of dendrites, which indicates that it has good impact toughness.

[0063] Figure 2 The metallographic structure test figure of example A4 of the application is shown, compared with example A1, the increase of Mn content and the increase of solution temperature make the grain size slightly grow, but still maintain good low temperature toughness and strength.

[0064] Figure 3 and Figure 4The microstructure test chart of the hot-rolled and air-cooled embodiment A5 and the scanning electron microscope chart of the solid solution homogenization treatment of the embodiment A5 are shown respectively, from which Figure 3 It can be seen that a large number of coarse Mn and Cr carbides are precipitated at the grain boundaries in the rolled state of the steel plate after hot-rolling and air-cooling, which greatly damages the low-temperature impact toughness of the steel pipe. But from the microstructure test chart of the embodiment A5 after the solid solution heat treatment at 850°C, it can be seen that the coarse carbides are dissolved, and the impact toughness of the steel pipe is improved. Figure 4 It can be seen that by the solid solution heat treatment at 850°C, the coarse carbides are dissolved, and the impact toughness of the steel pipe is improved.

[0065] The above only is the preferred embodiment of the present application, and is not used to limit the present application, and for the person skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A seamless steel pipe characterized by, The seamless steel pipe has a chemical composition by weight percentage including C, 0.02-0.06%, Si, 0.12-0.17%, Mn, 27-30%, S, ≤0.005%, P, ≤0.005%, Cr, 3.5-3.7%, Cu, 0.5-0.7%, Mo, ≤0.15%, Ti, 0.01-0.10%, Nb, 0.015-0.03%, Al, 0.02-0.04%, V, 0.18-0.25, N, ≤700ppm, O, ≤30ppm, H, ≤2.0ppm, and the balance of Fe and impurities. The preparation method of the seamless steel pipe includes sequentially performing smelting, vacuum degassing furnace refining, ladle refining furnace refining, billet continuous casting, pipe blank cutting, ring furnace heating, piercing, pipe rolling, sizing, solid solution homogenization, tempering homogenization, straightening and finishing on raw materials in a stoichiometric ratio to obtain the seamless steel pipe. The ring furnace heating includes sequentially performing a preheating stage, a heating stage and a soaking stage. The heating stage includes sequentially performing a first heating stage, a second heating stage, a third heating stage and a fourth heating stage; the first heating stage has a processing temperature of 800℃±10℃ and a time of 5-6.5h; the second heating stage has a processing temperature of 1080℃±10℃ and a time of 1.5-2h; the third heating stage has a processing temperature of 1150℃±10℃ and a time of 1.5-2h; the fourth heating stage has a processing temperature of 1120℃±10℃ and a time of 1.5-1.8h; and the soaking stage has a processing temperature of 1120℃±10℃ and a time of 1.5-1.8h. The solid solution homogenization includes the following steps: first, performing first holding treatment on the material at a temperature of 800-860℃, and then water quenching the material out of the furnace; wherein the time of the first holding treatment is controlled according to a wall thickness coefficient of 2.0-2.5min / mm. The tempering homogenization includes the following steps: first, performing second holding treatment on the material at a temperature of 600-610℃, and then air cooling the material out of the furnace; wherein the time of the second holding treatment is controlled according to a wall thickness coefficient of 4.0-4.5min / mm.

2. The seamless steel tube according to claim 1, characterized in that, The seamless steel pipe has a chemical composition by weight percentage including C, 0.02-0.06%, Si, 0.12-0.17%, Mn, 27-30%, S, 0.001-0.005%, P, 0.001-0.005%, Cr, 3.55-3.70%, Cu, 0.55-0.65%, Mo, 0.010-0.15%, Ti, 0.01-0.10%, Nb, 0.015-0.03%, Al, 0.02-0.04%, V, 0.18-0.25, N, 300-700ppm, O, 10-30ppm, H, 0.10-2.0ppm.

3. The seamless steel tube according to claim 1 or 2, characterized in that, The seamless steel pipe has an outer diameter of 32-610mm and a wall thickness of 3-40mm.

4. The seamless steel tube according to claim 1 or 2, characterized by The temperature rising rate from the processing temperature of the first heating section to the processing temperature of the second heating section, the temperature rising rate from the processing temperature of the second heating section to the processing temperature of the third heating section, and the temperature rising rate from the processing temperature of the third heating section to the processing temperature of the fourth heating section are each independently 20-50℃ / min.

5. The seamless steel pipe according to claim 1 or 2, characterized by The temperature of the preheating section is raised to the processing temperature of the first heating section at a furnace temperature, and the processing time is 6-10h.

6. The seamless steel pipe according to claim 1 or 2, characterized by After the high manganese steel pipe is subjected to the solid solution treatment, the preparation method further comprises the steps of sequentially annealing, cold drawing and cold rolling the pipe material.

7. The seamless steel tube according to claim 6, characterized in that, The preparation method further comprises the step of keeping the cold-rolled material at a temperature of 650℃±10 for 1.5-2.5h and then taking it out of the furnace for water cooling.

8. The seamless steel pipe according to claim 1 or 2, characterized by Before the pipe material is heated in the ring furnace, the preparation method further comprises the step of spraying an anti-oxidation coating on the outer surface of the pipe material.

9. Application of the seamless steel pipe according to any one of claims 1-8 in an ultra-low temperature environment of-110℃ to-196℃.

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