NC30Fe high-chromium nickel-based alloy pierced billet as well as preparation method and application thereof

Abstract

The invention provides an NC30Fe high-chromium nickel-based alloy pierced billet as well as a preparation method and application of the NC30Fe high-chromium nickel-based alloy pierced billet. The preparation method comprises the following steps: firstly, heating an NC30Fe high-chromium nickel-based alloy tube blank to a specific charging temperature, and perforating by utilizing a hot cross rolling perforation process; in the punching process, it is ensured that the dimensional tolerance and eccentricity of a pierced billet meet the requirements by strictly controlling the roller distance, the top temperature and the extension coefficient; and then, quenching treatment is carried out on the pierced billet subjected to perforation, so that the grain size is controlled to be within the range of grade 3 to grade 7, and the high-temperature strength and creep resistance of the material are improved. According to the preparation method disclosed by the invention, through introduction of a hot cross piercing process, the problems of more surface defects, large eccentricity and difficulty in grain control caused by a traditional hot extrusion process are solved, the yield is increased to 93% or above, and the surface smoothness and the dimensional precision are remarkably improved. The pierced billet is suitable for preparation of high-temperature corrosion-resistant and high-precision nickel-based alloy pipes in the fields of petroleum, chemical engineering, aerospace and the like, and has high application value.

Description

Technical Field

[0001] The invention relates to the technical field of nickel-based alloy materials, and in particular to an NC30Fe high-chromium nickel-based alloy rough pipe and a preparation method and application thereof. Background Art

[0002] High chromium nickel-based alloys are widely used in petrochemical, aerospace, and nuclear industries due to their excellent high-temperature strength, corrosion resistance, and good thermal stability. Such alloys usually contain a high proportion of chromium and nickel elements, ensuring service life and stability under high temperatures and extreme environments. With the continuous improvement of modern industry's requirements for material performance, the demand for high-performance nickel-based alloy materials is increasing, especially in equipment components working under high pressure and high temperature conditions. However, due to the high hardness, high viscosity, and low plasticity of high chromium nickel-based alloys, they are prone to cracking, poor eccentricity, and high processing costs during the processing and forming process. Therefore, the preparation of high-quality nickel-based alloy rough pipes has become a technical difficulty.

[0003] NC30Fe is a high-chromium nickel-based alloy. It is a new third-generation alloy with better stress corrosion resistance and other properties under the working conditions of pressurized water reactor heat transfer tubes. This alloy is an improved alloy with increased chromium content based on Inconel 600. It has high strength, high metallurgical stability and excellent processing performance. On the other hand, the Cr in the chemical composition of the alloy makes the alloy have significant resistance to corrosion by oxidizing chemicals and high-temperature oxidizing gases, and the high nickel content gives the alloy the characteristics of stress corrosion cracking resistance in halide environments and sodium hydroxide solutions. At present, the traditional method of preparing nickel-based alloy rough pipes mostly adopts hot extrusion combined with cold rolling process. Hot extrusion technology heats the alloy material to make it form under low deformation resistance. This process reduces the difficulty of processing to a certain extent. However, in the production of high-chromium nickel-based alloy rough pipes, the traditional hot extrusion method shows a series of shortcomings:

[0004] Low yield rate: During the hot extrusion process, the high viscosity and high hardness of high chromium nickel-based alloys lead to a high friction coefficient and large material loss during the extrusion process. The yield rate is often difficult to exceed 85%, resulting in low material utilization and increased preparation costs; Many surface defects: During the hot extrusion process, due to the intense contact and friction between the extrusion die and the high-chromium nickel-based alloy, cracks, burrs and oxide scales often appear on the surface of the alloy tube, which in turn affects the adaptability of the subsequent cold processing process. These defects not only affect the surface quality of the product, but also aggravate the expansion of cracks in subsequent processing, reducing the mechanical properties and corrosion resistance of the final product;

[0005] Insufficient rolling precision: The traditional hot extrusion + cold rolling process is difficult to effectively control the dimensional tolerance and eccentricity of the rough pipe. The high chromium nickel-based alloy is very easy to cause eccentricity problems during the rolling process due to its unique hardness. The eccentricity exceeds the standard requirements, affecting the consistency and precision of the pipe, and does not meet the requirements of modern industry for high-precision pipes; Difficulty in controlling grain size: It is difficult to control the grain size of high-chromium nickel-based alloy rough pipes by hot extrusion. Especially in industrial applications with high requirements for grain size, traditional methods cannot meet the requirements of uniform and moderate grain size. Coarse or uneven grain distribution is usually prone to occur, which reduces the creep resistance of the material under high temperature conditions.

[0006] In order to overcome the above shortcomings, the cold rolling + heat treatment process has also been used for improvement in recent years. However, due to the high hardness of the material during the cold rolling process, it is often necessary to undergo multiple intermediate annealing to avoid cracking of the material during the cold rolling process. Multiple intermediate annealing increases the production cycle, resulting in further cost increases. At the same time, the cold rolling process is still difficult to achieve high-dimensional precision rough pipe finished products, and the tube blank bar needs to be produced through the process of peeling + deep hole drilling + end face processing + induction heating + hole expansion + hot extrusion, and the hot perforation process is not used to produce rough pipes. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe, so as to solve the problems of low efficiency, unstable finished product quality, poor surface quality, etc. existing in the conventional preparation method in the prior art.

[0008] In order to solve the above technical problems, the present invention provides a method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe, comprising the following steps: S1: preparing NC30Fe high-chromium nickel-based alloy rods, and sequentially performing peeling treatment, cutting treatment, and centering hole treatment on the alloy rods to obtain pretreated nickel-based alloy rods; S2: after the pretreated nickel-based alloy rod obtained in step S1 is charged into a furnace, the temperature is raised to 1000-1090° C. for soaking treatment, then the pretreated nickel-based alloy rod is subjected to oblique rolling and punching, and then the nickel-based alloy rod is subjected to quenching treatment to obtain a nickel-based alloy tube blank; S3: Surface treatment is performed on the nickel-based alloy tube blank obtained in step S2 to obtain a NC30Fe high-chromium nickel-based alloy rough tube.

[0009] Compared with the prior art, the present invention discloses a method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe, and its technical principle includes: in the step S1, by removing surface impurities and oxide layer, while ensuring dimensional accuracy, subsequent processing is made more efficient, and surface defects and processing errors are reduced; in the step S2, by controlling the soaking temperature to 1000-1090°C, the resistance in the perforation process and the deformation difficulty of the alloy are further reduced, and the perforation efficiency and quality are improved. Subsequently, the perforated alloy tube blank is subjected to rapid quenching treatment to prevent excessive growth of the organization and ensure the strength and toughness of the finished product; in the step S3, by surface treatment of the tube blank to remove the surface oxide layer, residual impurities and other defects, the surface finish is further improved, and a NC30Fe high-chromium nickel-based alloy rough pipe that meets the requirements is obtained; In general, the advantages of the above preparation method compared with the prior art include: improved processing efficiency: the preparation method of the present invention achieves the effect of simplifying the processing steps and reducing the total working hours through optimized peeling, centering hole drilling, oblique rolling perforation and quenching treatment, thereby greatly improving the preparation efficiency; ensuring the uniformity and stability of the quality of the finished product: the preparation method of the present invention makes the internal structure of the NC30Fe high-chromium nickel-based alloy rough pipe uniform through heat treatment and precise perforation temperature control, reduces internal stress, and effectively reduces cracks or defects that may occur in the finished product, so that the rough pipe has excellent high-temperature corrosion resistance and resistance Stress corrosion performance; Improved surface finish and corrosion resistance: The surface quality of the alloy rough pipe is greatly improved by pickling and grinding steps, impurities and oxide layers are removed, corrosion resistance is improved, and application requirements under harsh working conditions are met; Compared with the preparation method of cold rolling + heat treatment process in the prior art, the present invention provides a preparation method of NC30Fe high chromium nickel-based alloy rough pipe, and by optimizing the quenching treatment after soaking treatment (1000-1090°C) and oblique rolling and piercing, the present invention can better control the microstructure of the alloy, eliminate internal stress, and significantly improve the mechanical properties and corrosion resistance of the material. In addition, the pickling and grinding steps in the present invention further ensure the surface quality of the alloy rough pipe, reduce oxide scale and surface defects, and improve the corrosion resistance and service life of the material; By adopting hot perforation technology instead of traditional hot extrusion process, the complex process, high equipment cost, low material utilization rate and other shortcomings of the existing process are overcome, the production process is simplified, the production cost is reduced, and the quality stability and corrosion resistance of the rough pipe are significantly improved, which has significant technical progress and economic benefits.

[0010] In a possible implementation, in step S2, the temperature at which the pretreated nickel-based alloy rod is charged into the furnace is 850-900°C.

[0011] Compared with the prior art, the above technical solution sets the charging temperature of the nickel-based alloy rods in the range of 850-900°C, which can provide a stable and uniform heating environment for the alloy and promote uniform heat distribution inside the alloy. By controlling this temperature range, the alloy can achieve a uniform heating effect during the heating process, promote the homogenization of the microstructure, and avoid the problems of grain growth or surface oxidation that may be caused by higher temperatures. For high-chromium nickel-based alloys, excessively high temperatures can easily lead to element segregation or oxidation at the grain boundaries, reducing the corrosion resistance of the material. The heating solution in this temperature range can enable the NC30Fe high-chromium nickel-based alloy rough pipe to maintain excellent comprehensive performance during the processing process.

[0012] In a possible implementation manner, in step S2, the soaking treatment time is 35 to 40 minutes.

[0013] Compared with the prior art, the above technical scheme is used to control the soaking treatment time to 35 to 40 minutes. The control of the soaking time is a key factor in the heat treatment process. Too short a soaking time will lead to uneven temperature inside the bar, thereby causing uneven distribution of the microstructure and even causing fluctuations in mechanical properties. Too long a soaking time will cause problems such as grain coarsening and reduced strength in the material. In the above possible implementation method, the soaking time is set within the range of 35 to 40 minutes, which can ensure that the alloy material reaches a uniform and stable temperature before oblique rolling and piercing, avoiding stress concentration and performance degradation caused by uneven heating.

[0014] In a possible implementation, in step S2, the ovality of the oblique rolling and piercing die is 1.08-1.15, the plug diameter is 66-70 mm, the elongation coefficient is 2.4-2.6, the plug position is 48-56 mm, and the preheating temperature of the plug is 880-900°C.

[0015] Compared with the prior art, the parameters of the above technical solution are adopted to set the die ovality to 1.08-1.15, which can accurately control the fluidity of the alloy material during the punching process, so that the material can distribute the pressure more evenly during plastic deformation, thereby reducing the stress concentration on the hole wall surface and ensuring the roundness and dimensional accuracy of the hole; the control of the plug diameter (66-70mm) and the elongation coefficient (2.4-2.6) ensures the effective extension of the material during punching, prevents the plug from over-extruding the material to cause cracking, and maintains the stability of the punching process; the control of the plug position (48-56mm) can achieve precise plug advancement, thereby ensuring that the punching depth and hole diameter meet the design requirements and prevent dimensional errors caused by too deep or too shallow punching; the plug preheating temperature (880-900℃) By moderately heating the plug, the heat exchange between the material and the plug is made more uniform, reducing the risk of material adhesion to the plug and effectively preventing the plug from causing surface defects in the material during the piercing process. Through the precise setting of the above parameters, the oblique rolling piercing process achieves the following technical effects: Enhance the dimensional stability of the finished product: Accurate piercing control and hole wall uniformity improve the dimensional consistency of the finished rough pipe, which helps to meet more stringent processing requirements; Improve the mechanical properties of the rough pipe: Optimized ovality, elongation coefficient and plug control prevent stress concentration, reduce microstructural damage, and thereby improve the mechanical strength and durability of the material; Improve processing efficiency and yield rate: By reducing surface defects and reducing scrap rate, the improved piercing process not only improves the overall processing efficiency, but also effectively reduces production costs.

[0016] In a possible implementation, in step S2, the roller spacing of the oblique rolling and perforation is 70-80 mm, and the guide plate spacing is 80-90 mm.

[0017] Compared with the existing technology, the above technical solution ensures that the material is subjected to uniform radial pressure during the perforation process by controlling the roller spacing (70-80mm), making the alloy material flow more evenly along the perforation direction, avoiding the inner and outer wall defects caused by excessive pressure in the early stage of perforation; the optimization of the guide plate spacing (80-90mm) provides appropriate support and guidance for the alloy material, making the material extend more smoothly along the predetermined direction during the oblique rolling perforation process. This design effectively reduces the uneven local deformation of the material and prevents eccentricity of the hole wall and irregular perforation.

[0018] In a possible implementation, in step S2, the quenching treatment conditions are: quenching the nickel-based alloy rod within 30 to 50 seconds, and the quenching medium is water at ≤50°C.

[0019] Compared with the prior art, the above technical solution can quickly dissipate the heat by controlling the cooling time after high-temperature treatment of the alloy material, thereby avoiding uneven growth and precipitation of grains. Rapid cooling can inhibit austenite transformation and maintain the toughness and strength of the material; by using low-temperature water ≤50°C as a cooling medium, heat can be effectively and evenly removed to avoid local overcooling, thereby reducing thermal stress and strain concentration that may occur during the cooling process. At the same time, low-temperature water reduces the thermal stress inside the material and reduces the risk of cracking due to uneven cooling speed.

[0020] In a possible implementation, in step S3, the surface treatment includes pickling and grinding.

[0021] Compared with the existing technology, the above technical scheme can effectively remove surface oxide scale, impurities and surface defects through a combination of pickling and grinding treatments, and provide a high-quality surface state for the NC30Fe high-chromium nickel-based alloy rough pipe to ensure its performance in high temperature and high-corrosion environments, and ensure safety and stability under long-term service conditions.

[0022] Another technical problem to be solved by the present invention is to provide a NC30Fe high chromium nickel-based alloy rough pipe to overcome the shortcomings of conventional NC30Fe high chromium nickel-based alloy rough pipes in the prior art, such as high eccentricity, uneven grain size, and easy failure in high temperature and high stress environments.

[0023] In order to solve the above technical problems, the present invention provides a NC30Fe high chromium nickel-based alloy rough pipe prepared by the preparation method, the eccentricity of the same section of the NC30Fe high chromium nickel-based alloy rough pipe is less than 1.5mm, and the grain size is level 3 to level 7.

[0024] Compared with the prior art, the NC30Fe high chromium nickel-based alloy rough pipe of the present application has the following advantages: the NC30Fe high chromium nickel-based alloy rough pipe of the present invention achieves the excellent effect of the eccentricity of the alloy rough pipe in the same section being less than 1.5 mm through precise control in the perforation and heat treatment steps. Through this high-precision eccentricity control, the stress concentration phenomenon of the rough pipe when subjected to external stress is reduced, thereby improving the uniformity and fatigue resistance of the structure; and the grain size of the alloy rough pipe is controlled between level 3 and level 7, ensuring that the alloy has both mechanical strength and toughness, and at the same time has good creep resistance under high temperature and high pressure, solving the problems of poor eccentricity and grain size in the prior art, and significantly improving the quality and application performance of the alloy rough pipe.

[0025] Another technical problem to be solved by the present invention is to provide a solution to the problem of the deficiencies in the oxidation resistance and high-temperature oxidizing gas corrosion resistance of the conventional NC30Fe high-chromium nickel-based alloy rough pipe in the prior art, so that it has better corrosion resistance and oxidation resistance in harsh chemical environments.

[0026] In order to solve the above technical problems, the present invention provides an application of the NC30Fe high-chromium nickel-based alloy rough pipe, which includes the application of the alloy rough pipe in an environment with oxidation resistance and high-temperature oxidizing gas corrosion, and specifically includes the application of the alloy rough pipe in equipment in contact with nitric acid or nitric acid / hydrofluoric acid solution.

[0027] Compared with the prior art, the application of the NC30Fe high-chromium nickel-based alloy rough pipe of the present application has the following advantages: the NC30Fe high-chromium nickel-based alloy rough pipe of the present invention can effectively resist oxidation and corrosion of corrosive gases in environments containing nitric acid, nitric acid / hydrofluoric acid and other corrosive gases or liquids, extend the service life of the equipment, and reduce maintenance frequency and costs. This feature is particularly important in highly corrosive chemical process equipment, improving overall safety and operating efficiency; conventional alloy materials are prone to oxidation and corrosion in harsh environments, resulting in shortened equipment life and safety hazards. The NC30Fe high-chromium nickel-based alloy rough pipe of the present invention significantly improves the tolerance of the material in corrosive environments such as oxidizing gases, nitric acid and nitric acid / hydrofluoric acid through the optimization of high chromium and high nickel components, meets the performance requirements of high-standard equipment for materials, and effectively solves the shortcomings of the prior art.

[0028] As a preferred solution, the applications include the use of the alloy rough pipe in tail gas heaters in nitric acid production, stainless steel pickling equipment, and containers and heating coils for nitric acid / hydrofluoric acid solutions in nuclear fuel recovery, and in coal gasification equipment, burners and furnace tubes for processing sulfuric acid, petrochemical furnaces, heat exchangers, incinerators, and glass solidification equipment for disposing of radioactive waste.

[0029] Compared with the prior art, the alloy rough pipe of the present invention can extend the service life of equipment in highly corrosive and high temperature environments, reduce equipment maintenance costs, and ensure the safety and stability of equipment under extreme working conditions. In addition, the durability and corrosion resistance of the alloy rough pipe make it suitable for a variety of high-standard equipment, meeting the dual requirements of high-temperature oxidation resistance and chemical tolerance, and solving the technical problem that existing materials are prone to corrosion and failure in such harsh environments. DETAILED DESCRIPTION

[0030] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0031] The NC30Fe nickel-based alloy in the present invention belongs to a high-chromium nickel-based alloy, and the preparation of its rough pipe has the following technical difficulties: 1) The second bite of the tube is difficult. After the tube contacts the head, it slips and gets stuck in the rolling belt area of ​​the roll; 2) The alloy is highly sensitive to thermal deformation temperature, and the rough pipe is prone to cracking and breaking during perforation. In mild cases, cracks are found all over the inner and outer surfaces of the rough pipe, and in severe cases, the rough pipe is broken. For thin-walled rough pipes (D / S>9), there will also be a "chain belt" phenomenon.

[0032] In view of the above-mentioned difficulties in the preparation of NC30Fe high-chromium nickel-based alloy rough pipes, the present invention provides a method for preparing NC30Fe high-chromium nickel-based alloy rough pipes. The preparation method ensures that the size and surface of the rough pipes have good effects and a high yield rate by introducing hot oblique rolling and perforation.

[0033] The present invention provides a method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe, comprising the following steps: S1: Prepare NC30Fe high-chromium nickel-based alloy rods, and sequentially perform peeling, cutting and centering hole processing on the alloy rods to obtain pretreated nickel-based alloy rods; in the process of preparing NC30Fe nickel-based alloy rough pipes, firstly pretreat the NC30Fe nickel-based alloy rods, and the preparation of the NC30Fe nickel-based alloy rods is carried out according to technical means well known to those skilled in the art, and the present application has no special restrictions on this. Specifically, the operation is as mentioned in S1 above, and the pretreatment specifically comprises sequentially peeling, cutting and centering hole processing on the NC30Fe nickel-based alloy rods, and the peeling, cutting and centering hole processing are technical means well known to those skilled in the art, and the present application does not impose any special restrictions on this.

[0034] S2: After the pretreated nickel-based alloy rod obtained in step S1 is loaded into the furnace, the temperature is raised to 1000-1090°C for uniform heat treatment, and then the pretreated nickel-based alloy rod is subjected to oblique rolling and punching, and then the nickel-based alloy rod is subjected to quenching treatment to obtain a nickel-based alloy tube blank; after the pretreatment of step S1 is completed, the pretreated nickel-based alloy rod obtained above is subjected to the treatment of step S2, and the NC30Fe nickel-based alloy tube blank is obtained by first heating and then oblique rolling and punching; in order to improve the yield rate of NC30Fe nickel-based alloy rough tube, before formal punching, the rod can be tested first, and the formal punching can be performed after adjustment. After the test is completed, hot oblique rolling and punching can be performed; S3: Surface treatment is performed on the nickel-based alloy tube blank obtained in step S2 to obtain a NC30Fe high-chromium nickel-based alloy rough tube.

[0035] The preparation method of the NC30Fe nickel-based alloy rough tube provided by the present invention introduces a specific hot oblique rolling and perforation process, thereby realizing the preparation of a nickel-based alloy rough tube with better size and surface; compared with the hot extruded rough tube of the conventional method, the metal yield rate is high, and the average rough tube yield rate can reach 93%, which is 7 to 9% higher than that of the hot extruded rough tube; the perforated rough tube is not prone to defects such as straight lines, orange peel, and wrinkles that are easy to occur in the extruded rough tube, and the inner surface quality of the perforated rough tube is better than that of the extruded tube.

[0036] As a preferred solution, in step S2, the temperature at which the pretreated nickel-based alloy rods are charged into the furnace is 850-900°C.

[0037] As a preferred solution, in step S2, the time of the heat treatment is 35 to 40 minutes.

[0038] As a preferred solution, in step S2, the ovality of the oblique rolling and piercing die is 1.08-1.15, the plug diameter is 66-70 mm, the elongation coefficient is 2.4-2.6, the plug position is 48-56 mm, and the preheating temperature of the plug is 880-900°C. The adjustment of the die mainly involves the ovality and plug position formed by the guide plate spacing and the roller spacing, which will affect the preparation of the rough pipe; if the ovality is too large, the torsional deformation is large, the rough pipe is easy to delaminate, and the ovality is small, which is not conducive to the biting of the rough pipe; if the plug position is far back, the rough pipe is prone to inward folding defects, and if the plug position is far forward, the rough pipe is not easy to bite, and the secondary biting is also more difficult.

[0039] As a preferred solution, in step S2, the roller spacing of the oblique rolling and perforation is 70-80 mm, and the guide plate spacing is 80-90 mm.

[0040] As a preferred solution, in step S2, the quenching treatment conditions are: quenching the nickel-based alloy rod within 30 to 50 seconds, and the quenching medium is water at ≤50°C.

[0041] As a preferred solution, in step S3, the surface treatment includes pickling and grinding.

[0042] The present invention also provides an NC30Fe high chromium nickel-based alloy rough pipe prepared by the preparation method, characterized in that the eccentricity of the same cross-section of the NC30Fe high chromium nickel-based alloy rough pipe is less than 1.5 mm, and the grain size is level 3 to level 7.

[0043] The present invention also provides an application of the NC30Fe high-chromium nickel-based alloy rough pipe, which includes the application of the alloy rough pipe in an environment with oxidation resistance and high-temperature oxidizing gas corrosion, and specifically includes the application of the alloy rough pipe on equipment in contact with nitric acid or nitric acid / hydrofluoric acid solution.

[0044] As a preferred solution, the applications include the use of the alloy rough pipe in tail gas heaters in nitric acid production, stainless steel pickling equipment, and containers and heating coils for nitric acid / hydrofluoric acid solutions in nuclear fuel recovery, and in coal gasification equipment, burners and furnace tubes for processing sulfuric acid, petrochemical furnaces, heat exchangers, incinerators, and glass solidification equipment for disposing of radioactive waste.

[0045] The following is an explanation of the technical solution of the present invention by combining embodiments within the above data range: Embodiment 1: Example 1 provides a NC30Fe high-chromium nickel-based alloy rough pipe and its preparation method and application. The alloy rough pipe is prepared by the preparation method, and the eccentricity of the same section of the alloy rough pipe is less than 1.5 mm, and the grain size is level 3 to level 7. The application includes the application of the alloy rough pipe in an environment with oxidation resistance and high-temperature oxidizing gas corrosion, specifically including the application of the alloy rough pipe on equipment in contact with nitric acid or nitric acid / hydrofluoric acid solution. More specifically, the application includes the application of the alloy rough pipe on tail gas heaters in nitric acid production, stainless steel pickling equipment, and containers and heating coils for nitric acid / hydrofluoric acid solutions in nuclear fuel recovery, and in coal gasification equipment, burners and furnace tubes for treating sulfuric acid, petrochemical furnaces, heat exchangers, incinerators, and glass solidification equipment for disposing of radioactive waste.

[0046] The preparation method comprises the following steps: A method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe comprises the following steps: S1: preparing NC30Fe high-chromium nickel-based alloy rods, and sequentially performing peeling treatment, cutting treatment, and centering hole treatment on the alloy rods to obtain pretreated nickel-based alloy rods; S2: Controlling the charging temperature of the furnace to be 875°C, charging the pretreated nickel-based alloy rod obtained in step S1 to the furnace, heating it to 1045°C for soaking treatment for 38 minutes, and then performing oblique rolling and punching on the pretreated nickel-based alloy rod, wherein the ovality of the oblique rolling and punching die is 1.11, the plug diameter is 68 mm, the elongation coefficient is 2.5, the plug position is 54 mm, and the preheating temperature of the plug is 89°C, the roller spacing of the oblique rolling and punching is 75 mm, and the guide plate spacing is 85 mm; Then, the nickel-based alloy rod is subjected to quenching treatment, and the quenching treatment conditions are: the nickel-based alloy rod is quenched within 40 seconds, and the quenching medium is 40° C. water, to obtain a nickel-based alloy tube blank; S3: The nickel-based alloy tube blank obtained in step S2 is pickled and ground to obtain a NC30Fe high-chromium nickel-based alloy rough tube.

[0047] Embodiment 2: Example 2 provides a NC30Fe high-chromium nickel-based alloy rough pipe and its preparation method and application. The alloy rough pipe is prepared by the preparation method, and the eccentricity of the same section of the alloy rough pipe is less than 1.5 mm, and the grain size is level 3 to level 7. The application includes the application of the alloy rough pipe in an environment with oxidation resistance and high-temperature oxidizing gas corrosion, specifically including the application of the alloy rough pipe on equipment in contact with nitric acid or nitric acid / hydrofluoric acid solution. More specifically, the application includes the application of the alloy rough pipe on tail gas heaters in nitric acid production, stainless steel pickling equipment, and containers and heating coils for nitric acid / hydrofluoric acid solutions in nuclear fuel recovery, and in coal gasification equipment, burners and furnace tubes for treating sulfuric acid, petrochemical furnaces, heat exchangers, incinerators, and glass solidification equipment for disposing of radioactive waste.

[0048] The preparation method comprises the following steps: A method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe comprises the following steps: S1: preparing NC30Fe high-chromium nickel-based alloy rods, and sequentially performing peeling treatment, cutting treatment, and centering hole treatment on the alloy rods to obtain pretreated nickel-based alloy rods; S2: Controlling the charging temperature of the furnace to be 850°C, charging the pretreated nickel-based alloy rod obtained in step S1 to the furnace, heating it to 1000°C for soaking treatment for 35 minutes, and then performing oblique rolling and punching on the pretreated nickel-based alloy rod, wherein the ovality of the oblique rolling and punching die is 1.08-1.15, the plug diameter is 66 mm, the elongation coefficient is 2.4, the plug position is 48-56 mm, and the preheating temperature of the plug is 880°C, the roller spacing of the oblique rolling and punching is 70 mm, and the guide plate spacing is 80 mm; Then, the nickel-based alloy rod is subjected to quenching treatment, and the quenching treatment conditions are: the nickel-based alloy rod is quenched within 30 seconds, and the quenching medium is 30° C. water, to obtain a nickel-based alloy tube blank; S3: The nickel-based alloy tube blank obtained in step S2 is pickled and ground to obtain a NC30Fe high-chromium nickel-based alloy rough tube.

[0049] Embodiment 3: Example 3 provides a NC30Fe high-chromium nickel-based alloy rough pipe and its preparation method and application. The alloy rough pipe is prepared by the preparation method, and the eccentricity of the same section of the alloy rough pipe is less than 1.5 mm, and the grain size is level 3 to level 7. The application includes the application of the alloy rough pipe in an environment with oxidation resistance and high-temperature oxidizing gas corrosion, specifically including the application of the alloy rough pipe on equipment in contact with nitric acid or nitric acid / hydrofluoric acid solution. More specifically, the application includes the application of the alloy rough pipe on tail gas heaters in nitric acid production, stainless steel pickling equipment, and containers and heating coils for nitric acid / hydrofluoric acid solutions in nuclear fuel recovery, and in coal gasification equipment, burners and furnace tubes for treating sulfuric acid, petrochemical furnaces, heat exchangers, incinerators, and glass solidification equipment for disposing of radioactive waste.

[0050] The preparation method comprises the following steps: A method for preparing a NC30Fe high-chromium nickel-based alloy rough pipe comprises the following steps: S1: preparing NC30Fe high-chromium nickel-based alloy rods, and sequentially performing peeling treatment, cutting treatment, and centering hole treatment on the alloy rods to obtain pretreated nickel-based alloy rods; S2: Controlling the charging temperature of the furnace to be 900° C. After charging the pretreated nickel-based alloy rod obtained in step S1, the temperature is raised to 1090° C. for soaking treatment for 40 min, and then the pretreated nickel-based alloy rod is subjected to oblique rolling and punching. The ovality of the oblique rolling and punching die is 1.15, the plug diameter is 70 mm, the elongation coefficient is 2.6, the plug position is 56 mm, and the preheating temperature of the plug is 900° C. The roller spacing of the oblique rolling and punching is 80 mm, and the guide plate spacing is 90 mm. Then, the nickel-based alloy rod is subjected to quenching treatment, and the quenching treatment conditions are: the nickel-based alloy rod is quenched within 50 seconds, and the quenching medium is 50° C. water, to obtain a nickel-based alloy tube blank; S3: The nickel-based alloy tube blank obtained in step S2 is pickled and ground to obtain a NC30Fe high-chromium nickel-based alloy rough tube.

[0051] In order to further understand the present invention, the preparation method of the NC30Fe nickel-based alloy rough pipe provided by the present invention is described in detail below in combination with the above embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0052] Embodiment 4: Example 4 provides a specific industrial method for preparing NC30Fe nickel-based alloy rough pipe and alloy rough pipe, the alloy rough pipe is prepared by the above method, and the specific raw materials and preparation method used include: Specifications of rough pipe: φ90×(9~10)mm; Dimensional tolerance of rough pipe: outer diameter ±1.0mm, wall thickness ±0.5mm; Granularity of rough pipe: Grain size test shall be carried out according to GB / T6394 standard, requiring grade 3.0 to 7.0; The specific pipe making process is as follows: Bar Specifications Bar specification: φ88 (+0 / -1) mm Tool and die optimization design and processing According to the thermal deformation characteristics of NC30Fe alloy, the φ85mm, φ90mm guide plates and φ67mm plugs were optimized, the rolling section size of the guide plates and the arc radius of the plug piercing cone were optimized, and the φ85mm, φ90mm guide plates and φ67mm plugs were remade.

[0053] The process flow of the wasteland control technology solution includes: S1: tube billet bar peeling → cutting → centering → S2: heating → oblique rolling and piercing → S3: flat head → grain size detection → surface and size detection, including the following points: S1: Main points of rough pipe pipe making process: acceptance of incoming materials and peeling, cutting and centering of tube blank bars. Check that the incoming NC30Feφ88mm bars have no surface defects. After long materials are polished and peeled, they are cut and cut, and centering holes are punched; S2: Oblique rolling and piercing unit rolling rough pipe (rough pipe specification: Φ90×9-10mm): NC30Fe bar heating, furnace temperature control 880℃, heating to 1080℃, heating time 150min, soaking temperature 1080℃, soaking section holding time 35min, every 3 bars out of the furnace, the bars in the furnace are turned over once to ensure that no positive and negative sides are produced during the heating process; Before normal piercing, use 3 rods for trial piercing. After adjustment, formal piercing can be carried out. The following requirements must be met during the trial piercing process:

[0054] ①The tube blank bites smoothly and smoothly; ② The rolling mill should not exceed the specified load; ③During perforation, the ejector rod has small jump and can be retracted smoothly; ④ The inner and outer surfaces of the perforated rough pipe shall be smooth and flat, without any foreign matter or serious cracks, and the inner wall shall not have folds, cracks or interlayer defects; Tolerance control of capillary tube size: outer diameter: D +2mm, -1mm; wall thickness: ±10%, eccentricity: no more than 1.5mm for the same cross section; During the hot rolling piercing process, the temperature of the plug is strictly controlled and preheated to 880°C before use. After piercing each rough pipe, the surface of the plug should be evenly rolled with glass powder in time, and no white smoke is allowed to come out of the plug. After the rod is pierced, it is quenched within 30 to 50 seconds, and the water temperature is controlled at ≤50°C. The specific adjustment parameter data of the hot rolling piercing in Example 4 are shown in Table 1: Table 1 Hot rolling piercing adjustment parameter data table Billet diameter (mm) Perforation specification (mm) Roller spacing (mm) Guide plate spacing (mm) Ellipticity Head diameter (mm) Elongation coefficient Head position (mm) Front pressure of the head 85 90×9-10 74±1 86±1 1.162 67 2.47 58±2 6.41 S3: After the nickel-based alloy tube blank obtained in step S2 is subjected to surface treatment, a NC30Fe high-chromium nickel-based alloy rough tube is obtained, and subsequent testing is performed.

[0055] Granularity inspection of rough pipe (Specification: Φ90×10mm) The grain size of the perforated rough pipe samples was tested according to GB / T6394 standard. The grain size of the rough pipe was 5.0 / 6.5, which met the requirements for rough pipes. Dimensional tolerance inspection of rough pipes: The outer diameter deviation requirement of the rough pipe is ±1.0mm, and the actual outer diameter is φ91mm; the wall thickness deviation is ±0.5mm, and the actual average wall thickness is 10mm. The eccentricity of the same section is <1.5mm, which meets the requirements of subsequent cold processing; The following indicators can be achieved by using the steel of the present invention: The oblique rolling and perforating process can be used to perforate high-chromium, difficult-to-deform NC30Fe nickel-based alloy rough pipes that meet the requirements of cold processing; The tolerance of the rough pipe size is: outer diameter ±1.0mm, wall thickness ±0.5mm, and eccentricity of the same section is less than 1.5mm.

[0056] The grain size of the rough pipe is required to be level 3 to level 7. The measured grain size of the rough pipe in Example 4 is: level 5.0 / level 6.5.

[0057] According to the above method of the present invention, a number of NC30Fe nickel-based alloy rough pipes were produced. The experimental results show that the yield rate of the nickel-based alloy rough pipes produced in Examples 1-4 can reach more than 93%.

[0058] The above examples further prove that the present invention provides a NC30Fe high-chromium nickel-based alloy rough pipe and its preparation method and application, which successfully solves the deficiencies of the conventional preparation method in the background technology in terms of high-temperature oxidation resistance, chemical corrosion resistance and mechanical stability, especially the problem of easy corrosion and failure in harsh environments such as nitric acid and hydrofluoric acid. The present invention provides an optimized NC30Fe high-chromium nickel-based alloy rough pipe, which has excellent resistance to high-temperature oxidation and stress corrosion, prolongs the service life of the equipment in extreme environments, reduces maintenance costs, and improves safety and stability in industrial applications, thereby achieving a more efficient and economical application solution.

[0059] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0060] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a NC30Fe high chromium nickel-based alloy rough pipe, characterized in that: The following steps are involved: S1: preparing NC30Fe high-chromium nickel-based alloy rods, and sequentially performing peeling treatment, cutting treatment, and centering hole treatment on the alloy rods to obtain pretreated nickel-based alloy rods; S2: after the pretreated nickel-based alloy rod obtained in step S1 is charged into a furnace, the temperature is raised to 1000-1090° C. for soaking treatment, then the pretreated nickel-based alloy rod is subjected to oblique rolling and punching, and then the nickel-based alloy rod is subjected to quenching treatment to obtain a nickel-based alloy tube blank; S3: Surface treatment is performed on the nickel-based alloy tube blank obtained in step S2 to obtain a NC30Fe high-chromium nickel-based alloy rough tube.

2. The method for preparing the NC30Fe high chromium nickel-based alloy rough pipe according to claim 1, characterized in that: In the step S2, the temperature of the pretreated nickel-based alloy rods charged into the furnace is 850-900°C.

3. The method for preparing the NC30Fe high chromium nickel-based alloy rough pipe according to claim 1, characterized in that: In the step S2, the time of the heat treatment is 35 to 40 minutes.

4. The method for preparing the NC30Fe high chromium nickel-based alloy rough pipe according to claim 1, characterized in that: In step S2, the ovality of the oblique rolling and piercing die is 1.08-1.15, the plug diameter is 66-70 mm, the elongation coefficient is 2.4-2.6, the plug position is 48-56 mm, and the preheating temperature of the plug is 880-900°C.

5. The method for preparing the NC30Fe high chromium nickel-based alloy rough pipe according to claim 1, characterized in that: In the step S2, the roller spacing of the oblique rolling and perforation is 70-80 mm, and the guide plate spacing is 80-90 mm.

6. The method for preparing the NC30Fe high chromium nickel-based alloy rough pipe according to claim 1, characterized in that: In the step S2, the quenching treatment conditions are: quenching the nickel-based alloy rod within 30 to 50 seconds, and the quenching medium is water at ≤50°C.

7. The method for preparing the NC30Fe high chromium nickel-based alloy rough pipe according to claim 1, characterized in that: In the step S3, the surface treatment includes pickling and grinding.

8. A NC30Fe high chromium nickel-based alloy rough pipe prepared by any one of the preparation methods of claims 1 to 7, characterized in that: The eccentricity of the same cross section of the NC30Fe high-chromium nickel-based alloy rough pipe is less than 1.5 mm, and the grain size is 3-7 levels.

9. An application of the NC30Fe high chromium nickel-based alloy rough pipe according to claim 8, characterized in that: The applications include the use of the alloy rough pipe in environments requiring oxidation resistance and high-temperature oxidizing gas corrosion, and specifically include the use of the alloy rough pipe in equipment in contact with nitric acid or nitric acid / hydrofluoric acid solution.

10. The use of the NC30Fe high chromium nickel-based alloy rough pipe according to claim 9, characterized in that: The applications include the use of the alloy rough pipe in tail gas heaters in nitric acid production, stainless steel pickling equipment, and containers and heating coils for nitric acid / hydrofluoric acid solutions in nuclear fuel recovery, and in coal gasification devices, burners and furnace tubes for handling sulfuric acid, petrochemical furnaces, heat exchangers, incinerators, and glass solidification equipment for disposing of radioactive waste.