A method for manufacturing a seamless heat exchange tube of hastelloy UNS N06022

Abstract

The application discloses a manufacturing method of UNS N06022 seamless heat exchange pipe of hastelloy, and belongs to the technical field of material processing, which comprises the following steps: (1) performing incoming inspection, inner and outer surface grinding and re-inspection on a hot extrusion blank; (2) performing multi-pass intermediate product cold rolling, and performing intermediate product oil removal, intermediate product heat treatment, intermediate product straightening, intermediate product pipe cutting, pickling, intermediate product grinding and intermediate product inspection after the cold rolling; (3) performing finished product cold rolling, and performing pre-degreasing after the finished product cold rolling; (4) performing finished product oil removal; (5) performing finished product heat treatment; (6) performing finished product straightening; (7) performing finished product ultrasonic eddy current, water pressure and pipe cutting, and sampling and performing physical and chemical tests during the pipe cutting; and (8) performing finished product surface inspection, size inspection, cleaning, mark spraying and finishing processes on the obtained steel pipe, and finally performing packaging and warehousing, so that the method has high first-time inspection qualified rate and high material yield.

Description

TECHNICAL FIELD

[0001] The application relates to a manufacturing method of a seamless heat exchange pipe, in particular to a manufacturing method of a seamless heat exchange pipe made of UNS N06022 Hastelloy, and belongs to the technical field of material processing. BACKGROUND

[0002] UNS N06022 alloy is a kind of nickel-based Ni-Cr-Mo-Wu alloy, which is famous for its excellent corrosion resistance and high temperature strength, especially in strong oxidizing medium and chloride-containing organic environment. In the chemical and petrochemical production process, high temperature, high pressure and corrosive medium are often used, so higher requirements are put forward for the corrosion resistance and high temperature resistance of the material. N06022 alloy as a kind of all-purpose corrosion-resistant alloy can adapt to various harsh working environments, and has excellent oxidation resistance to water medium and resistance to reducing and oxidizing environments encountered in the process. Therefore, it is of great practical significance and market demand to research and produce UNS N06022 alloy seamless pipe, which can provide more reliable and efficient material solutions for industrial production. At present, the domestic small-bore UNS N06022 alloy seamless heat exchange pipe has the problems of low first inspection qualified rate, low yield, low size precision, poor inner and outer surface quality and the like.

[0003] The present patent CN115921573B discloses a manufacturing method of UNS N10276 hastelloy seamless heat exchange pipe, which includes (1) incoming inspection and pipe blank inner and outer surface grinding of UNS N10276 hot extrusion blank, (2) three-pass intermediate product cold rolling, after each pass, intermediate product oil removal, intermediate product heat treatment, intermediate product straightening, intermediate product cutting, pickling, intermediate product inspection and grinding are needed; (3) finished product cold rolling of the third-pass steel pipe; (4) finished product oil removal, finished product heat treatment, finished product straightening, finished product ultrasonic eddy current, water pressure, cutting, sampling and physical and chemical test during cutting; (5) finished product surface inspection, cleaning, marking and finishing process, and finally packaging and warehousing; the patent CN117696621B discloses a manufacturing method of UNS N08810 alloy seamless heat exchange pipe, which includes (1) incoming inspection and inner and outer surface grinding of steel material; (2) one-pass intermediate product cold rolling, after cold rolling, intermediate product oil removal, intermediate product heat treatment, intermediate product straightening, intermediate product cutting, pickling, intermediate product grinding and intermediate product inspection are needed; (3) finished product cold rolling; (4) finished product oil removal; (5) finished product heat treatment; (6) finished product straightening; (7) finished product ultrasonic eddy current, water pressure, cutting, sampling and physical and chemical test during cutting; (8) finished product surface inspection, size inspection, cleaning, marking and finishing process, and finally packaging and warehousing; in the above two patents, simple oil removal steps are adopted during intermediate product oil removal and finished product pipe oil removal, which completes the oil removal program to some extent, but the direct oil removal method has the problems of more surface oil, long oil removal time, prolonged soaking time, reduced production effect, large amount of required degreasing agent, rising cost and inability to meet the requirements of future clean production trend; in addition, the intermediate product inspection and grinding in the patent are only simple grinding, which is uneven and easy to cause rough polishing marks, resulting in slight polishing marks on the surface of the finished product after cold rolling; the patent CN119406965A discloses a manufacturing method of UNS N06690 alloy seamless heat exchange pipe, which discloses the finished product pipe oil removal method in the present application, which adopts one alkali tank + space oil tank soaking + two alkali tank soaking method for oil removal, but this oil removal method is only suitable for small-scale or pilot production due to the high cost of space oil, and is not suitable for mass production, and the present application can achieve the same effect through finished product cold rolling pre-degreasing + specified cold rolling, degreasing process flow time + FB degreasing unqualified cold-state inner polishing.

[0004] Therefore, it is urgent for the technical personnel in the field to develop a manufacturing method of UNS N06022 hastelloy seamless heat exchange pipe, which can overcome the above problems, has high first inspection pass rate, high material yield, high size precision, good inner and outer surface quality, and can meet the standard technical requirements in terms of physical and chemical properties. SUMMARY

[0005] The technical problem solved by the present application is to provide a manufacturing method of seamless heat exchange pipe of UNS N06022 Hastelloy, which has high first inspection pass rate, high material yield, high dimensional accuracy, good inner and outer surface quality, stable microstructure and performance, strong practicability and is beneficial to batch production.

[0006] The technical solution of the present application to solve the above technical problems is:

[0007] A manufacturing method of seamless heat exchange pipe of UNS N06022 Hastelloy, specifically comprising the following steps:

[0008] (I) The UNS N06022 hot extruded blank is subjected to incoming inspection and inner and outer surface grinding, specifically: the pipe blank is subjected to preliminary inspection + grinding + reinspection, and during reinspection, each branch is subjected to endoscopy and PT is performed on the sampled pipe;

[0009] (II) The pipe blank obtained in step (I) is subjected to multi-pass intermediate product cold rolling, and after each pass of cold rolling, the intermediate product is subjected to oil removal, intermediate product heat treatment, intermediate product straightening, intermediate product cutting, pickling, intermediate product grinding and intermediate product inspection, wherein:

[0010] During intermediate product cold rolling, the cold rolling deformation is controlled to be 45%-65%, and the rolling speed and the feed amount are controlled as follows:

[0011] The rolling mill model is LG60 or LG110, the rolling speed is ≤80 times / min, and the feed amount is ≤3 mm / turn;

[0012] The Q value of the intermediate product cold rolling is controlled to be ≥0.95, and the outer diameter deviation and the wall thickness deviation after rolling are controlled as follows:

[0013] The rolling mill model is LG60 or LG110, the outer diameter deviation is controlled to be ±0.5%D mm (generally taking a multiple of 0.05 of the calculated value), and the wall thickness deviation is controlled to be ±5%S mm (generally taking a multiple of 0.05 of the calculated value);

[0014] The specific process of intermediate product oil removal is: oil scraping by an oil scraper → alkali tank oil removal → rinsing → hot water tank soaking → acid tank oil removal → rinsing → inspection;

[0015] The intermediate product heat treatment is carried out in a roller hearth furnace, the furnace atmosphere is micro-oxidizing gas, the heat treatment temperature is 1150±10℃, and the holding time is 2.5 times the wall thickness;

[0016] (III) The steel pipe obtained in step (II) is subjected to finished product cold rolling;

[0017] The finished product is rolled with a cold rolling deformation of 50-65%, the rolling speed is controlled to be ≤120 times / min, the feed amount is ≤2mm / time, and the Q value is ≥0.9;

[0018] During the finished product cold rolling, the outer diameter deviation after rolling is controlled to be ±0.10mm, and the wall thickness deviation is controlled to be ±0.10mm;

[0019] During the finished product cold rolling, the pre-degreasing is synchronously performed, the pre-degreasing is that the outer surface of the finished product pipe after cold rolling is wiped by the cotton cloth soaked in acetone, and the inner hole of the finished product pipe after cold rolling is hit by the wool felt ball for 2-3 times;

[0020] (4) the steel pipe obtained in step (3) is subjected to finished product degreasing;

[0021] The finished product degreasing step specifically comprises: the oil scraping machine degreasing is performed within 6h after the pre-degreasing in step (3) → the alkali tank immersion is performed within 6h after the degreasing → the hot water tank immersion → the outer surface wiping → the inner wall wool felt ball hitting → the FB is checked for the inner hole degreasing quality, and the inner hole is cleaned after the cold inner hole throwing if there is a small amount of oil stain or oil film in the inner hole;

[0022] (5) the steel pipe obtained in step (4) is subjected to finished product heat treatment;

[0023] The finished product heat treatment is performed in a bright furnace, and the atmosphere in the furnace is pure hydrogen;

[0024] The finished product heat treatment temperature is controlled to be 1150±10℃, and the holding time is 2.5 times of the wall thickness (generally, the larger integer value is taken);

[0025] (6) the steel pipe obtained in step (5) is subjected to finished product straightening;

[0026] (7) the steel pipe obtained in step (6) is subjected to finished product ultrasonic eddy current, water pressure and pipe cutting, and the sampling is performed for physical and chemical tests during the pipe cutting;

[0027] (8) the steel pipe obtained in step (7) is subjected to finished product surface inspection, size inspection, cleaning, marking spraying and finishing processes, and finally is packaged and stored.

[0028] The further limited technical scheme of the application is:

[0029] Further, in the manufacturing method of the UNS N06022 seamless heat exchange pipe, in the alkali tank degreasing in the intermediate product degreasing in step (2), the solution composition in the alkali tank is controlled to be: degreasing agent: water = 1:20 (by mass), the alkali tank temperature is 50-60℃, and the alkali tank immersion time is 50-60min;

[0030] The solution composition in the acid cylinder during the acid cylinder degreasing is as follows: HF: 1%, HNO3: 10-15%, and the balance is tap water, the sum of the above components is 100%, the acid cylinder temperature is 55-60 DEG C, and the pickling time is 20-35 min.

[0031] In the manufacturing method of the foregoing Hastelloy UNS N06022 seamless heat exchange pipe, the straightening parameters are controlled as follows when the intermediate product is straightened in step (two):

[0032] If the outer diameter of the intermediate product is greater than 57 mm, the straightening control speed is less than or equal to 6 m / min, the bending degree after straightening is less than or equal to 1.5 mm / m, and the outer diameter deviation after straightening is ±0.05% D mm;

[0033] If the outer diameter of the intermediate product is less than or equal to 57 mm, the straightening control speed is less than or equal to 8 m / min, the bending degree after straightening is less than or equal to 1 mm / m, and the outer diameter deviation after straightening is ±0.05% D mm.

[0034] Technical effects, the present application can avoid the risk of straightening injury and straightening printing caused by iron straightening by regulating the straightening speed, straightness and outer diameter deviation range after straightening, guaranteeing the bending degree, ensuring the straightening quality, strictly regulating the outer diameter deviation range after straightening to effectively avoid the risk of outer diameter deviation caused by straightening, thereby improving the dimensional accuracy.

[0035] In the manufacturing method of the foregoing Hastelloy UNS N06022 seamless heat exchange pipe, the solution composition in the acid cylinder during pickling of the intermediate product in step (two) is as follows: HF: 5-8%, HNO3: 10-15%, and the balance is tap water, the sum of the above components is 100%, the acid cylinder temperature is controlled to be 50-55 DEG C, and the pickling time is 20-30 min; preferably, the acid cylinder is opened every 1 min to observe the inner and outer surface conditions after pickling for 20 min, and the pickling is stopped when the inner and outer surfaces are in a state of light and uniform oxide skin.

[0036] Technical effects, the present application regulates the pickling method of the intermediate product, including strictly controlling the proportioning, temperature and time of the acid cylinder to ensure the pickling quality, and the N06022 intermediate product pipe washed in this method has a light and uniform oxide skin on the inner and outer walls, which can reduce the inner polishing amount as much as possible under the premise of not being too pickled, and save the labor cost of inner polishing.

[0037] In the manufacturing method of the foregoing Hastelloy UNS N06022 seamless heat exchange pipe, the grinding and inspection of the intermediate product in step (two) is performed in the following manner: the grinding is performed by whole outer polishing + local point grinding, the outer polishing is performed by a thousand-leaf wheel outer polishing, and the local point grinding is performed by a grinding machine with a flower wheel;

[0038] The inspection adopts visual inspection + branch endoscope inspection, the visual grinding and polishing is re-outer polishing, the inner polishing is automatically inner polishing by using a cross polishing head made of sandpaper, and the inner polishing is re-outer polishing by using an endoscope.

[0039] In the manufacturing method of the foregoing UNS N06022 Hastelloy seamless heat exchange pipe, in step (four), the finished pipe is degreased, part of the rolling oil is removed through cold rolling and pre-degreasing to prevent the rolling oil from being condensed and adsorbed on the inner wall of the pipe, and then the cold rolling and degreasing process flow rate is accelerated, the oil scraping machine is used to scrape oil within 6 hours after the pre-degreasing, and the pipe is soaked in an alkali tank within 6 hours after the oil scraping, so that the degreasing quality of the finished pipe is greatly improved, the solution in the alkali tank is specified as follows in terms of mass ratio: degreasing agent: water = 1:6.5, alkali tank temperature: 40-60 DEG C, alkali tank soaking time: 15-25 min, hot water tank temperature: 70-80 DEG C, hot water tank soaking time: 10-20 min, after the pipe is taken out of the hot water tank, the outer surface is wiped with cotton cloth soaked in acetone, and the inner wall is cleaned with wool felt for 3-5 times, the inner hole is checked by quality personnel and technical personnel after degreasing, the inner hole is basically free of oil stains, oil spots and oil film, and the pipe can be heat treated only after being signed by the quality personnel or the technical personnel, and if a small number of inner holes have oil film and oil spots in the FB inspection, the inner holes are cleaned by cold-state inner polishing, and then the FB is performed again after being put into the original frame, and the pipe is heat treated after the FB is qualified.

[0040] Technical effects, the degreasing process of the present application is helpful to improve the final degreasing quality of the finished product, avoid some residual oil stains, oil spots and oil film, and reduce the risk of nitriding during heat treatment of the finished product, and finally reduce the risk of unqualified metallographic structure, mechanical properties and crystal corrosion performance of the finished product, the degreasing process and the heat treatment of the finished product are combined with pure hydrogen atmosphere, which is helpful to improve the final physical and chemical properties of the high value-added nickel-based alloy small-diameter heat exchange pipe.

[0041] In the manufacturing method of the foregoing UNS N06022 Hastelloy seamless heat exchange pipe, in step (six), the speed of the straightening machine is controlled to be less than or equal to 10 m / min during straightening of the finished pipe, and the bending degree is less than or equal to 0.5 mm / m after straightening, and the outer diameter deviation is ±0.01 mm after straightening.

[0042] Technical effects, by specifying the type, straightening speed, straightness and outer diameter deviation range of the straightening machine, the finished product is straightened by using a plastic roller straightening machine, the straightening speed is specified to be less than or equal to 10 m / min, the bending degree is ensured, the risk of straightening damage and straightening mark caused by iron rod straightening is avoided, and the straightening quality of the finished product is ensured. The outer diameter deviation range after the finished product straightening can effectively avoid the risk of outer diameter deviation caused by straightening, so as to improve the dimensional accuracy.

[0043] In the manufacturing method of the foregoing UNS N06022 seamless heat exchange pipe, the one-time ultrasonic qualification rate in step (seven) is greater than or equal to 95%, and the one-time eddy current qualification rate is 100%.

[0044] In the manufacturing method of the foregoing UNS N06022 seamless heat exchange pipe, the surface inspection of the finished pipe in step (eight) shows that the inner and outer surfaces of the finished pipe are smooth, and the roughness Ra of the inner and outer walls is less than or equal to 0.8.

[0045] In the manufacturing method of the foregoing UNS N06022 seamless heat exchange pipe, the finished pipe obtained has the following properties: the yield strength is greater than or equal to 330 MPa, the tensile strength is greater than or equal to 750 MPa, and the elongation after fracture is greater than or equal to 60% in a room temperature tensile test; and the yield strength is greater than or equal to 245 MPa, and the tensile strength is greater than or equal to 655 MPa in a 250 DEG C high-temperature tensile test.

[0046] The present application has the following advantages:

[0047] The present application adopts multi-pass cold rolling, the deformation amount of the intermediate product is controlled to be 45%-65%, the deformation amount of the finished product is controlled to be 50%-65%, the multi-pass rolling is used to fully break the grains, and finer grain size can be obtained after heat treatment; the intermediate product cold rolling is strictly controlled in the feed amount and rolling speed (the rolling mill model is LG60 or LG110, the rolling speed is less than or equal to 60 times / min, and the feed amount is less than or equal to 3 mm / time), so that the surface quality is ensured, the deformation is more uniform by controlling the Q value to be greater than or equal to 1, and the dimensional accuracy is improved; similarly, the finished product cold rolling is strictly controlled in the feed amount (less than or equal to 2 mm / time) and the Q value (greater than or equal to 0.95) to ensure the surface quality and the dimensional accuracy.

[0048] The present application specifies the method of removing oil from intermediate products, which includes pre-scraping oil with a scraping machine before oil removal operation, strictly controlling the ratio, temperature and time of the solution in the alkali tank and acid tank to ensure the quality of oil removal and avoid the risk of carburizing during heat treatment. The present application specifies the method of removing oil from finished products, which removes part of rolling oil through cold rolling pre-degreasing to prevent rolling oil from condensing and adsorbing on the inner wall of the pipe, and then accelerates the cold rolling and oil removal process flow rate. The present application specifies that the scraping machine scraping is performed within 6 hours after cold rolling pre-degreasing, and the alkali tank immersion is performed within 6 hours after scraping, which can greatly improve the oil removal quality of the finished pipe. The present application specifies that the solution in the alkali tank is in a mass ratio of degreasing agent: water = 1:6.5, the alkali tank temperature is 40-60℃, the alkali tank immersion time is 15-25min, the hot water tank temperature is 70-80℃, the hot water tank immersion time is 10-20min, after the hot water tank is taken out of the tank, the outer surface is wiped with acetone-soaked cotton cloth, and the inner wall is cleaned with wool felt, 3-5 times. After oil removal, the inner hole is checked by FB by quality personnel and technical personnel, and the inner hole is basically free of oil stains, oil spots and oil film. After signing by the quality personnel or technical personnel, the heat treatment can be performed. If a few inner holes exist oil film, oil spots and other phenomena during FB inspection, cold-state inner cleaning is performed, and then FB is performed again after being put into the original frame. After FB is qualified, heat treatment is performed.

[0049] The present application specifies that the intermediate product solid solution heat treatment is performed by using a roller hearth furnace, the furnace atmosphere is slightly oxidizing, the heat treatment temperature is 1150±10℃, the cold rolling work hardening is eliminated, and the seamless pipe has good plasticity, which is convenient for subsequent cold rolling forming. The intermediate product holding time is 2.5 times of the wall thickness, generally taking an integer greater than the numerical value, and the holding time is slightly longer, the scale is more uniform and loose, and the scale is easy to remove by pickling. The finished product solid solution heat treatment is performed by using a bright furnace, the furnace atmosphere is pure hydrogen, the heat treatment temperature is 1150±10℃, and the finished product holding time is 2.5 times of the wall thickness. The purpose is to obtain good organization and comprehensive mechanical properties while ensuring the surface color state of the heat exchange tube to be bright and the consistency of the overall color state.

[0050] The present application specifies the method of grinding and repairing the hot extrusion billet and the intermediate product pipe. The PT of the hot extrusion billet is detected for avoiding the residual of the outer surface without hot extrusion defects, and the endoscope of the hot extrusion billet is used for more accurate and efficient inner wall defect treatment, avoiding the inner wall defects flowing to the next cold rolling process to cause defect extension. The endoscope of the intermediate product grinding and repairing is used for ensuring the inner wall quality of each cold rolling process, reducing the risk of the final product pipe ultrasonic inner damage batch alarm, and improving the one-time pass rate of the final product pipe endoscope inspection, thereby improving the final ultrasonic pass rate, surface inspection pass rate and final yield.

[0051] The method solves the problems of low first inspection qualified rate, low material yield, low size precision, and poor inner and outer surface quality, and the like, and the product produced by the method has high first inspection qualified rate, high material yield, high size precision, good inner and outer surface quality, stable mechanical properties, and strong practicability, and is beneficial to batch production.

[0052] The seamless heat exchange pipe of the UNS N06022 alloy prepared by the method has a first ultrasonic qualified rate of 95% or more, a first eddy current qualified rate of 100%, a first surface inspection (visual + size inspection) qualified rate of 95% or more, and a comprehensive first inspection qualified rate (ultrasonic qualified rate x eddy current qualified rate x surface inspection qualified rate) of 90% or more.

[0053] The seamless heat exchange pipe of the UNS N06022 alloy prepared by the method has a material yield (hot extrusion blank to finished pipe) of 76% or more, can meet the following size precision: outer diameter ±0.10mm, wall thickness ±0.10mm, has smooth inner and outer surfaces, and consistent color state, and the inner and outer wall roughness Ra is 0.8 or less, the finished pipe has a yield strength of 330Mpa or more, a tensile strength of 750MPa or more, and an elongation of 60% or more in a room temperature tensile test, and a yield strength of 245Mpa or more, a tensile strength of 655MPa or more in a 250℃ high temperature tensile test. DETAILED DESCRIPTION

[0054] The application will be described in detail below with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0055] Embodiment 1

[0056] The embodiment provides a manufacturing method of a seamless heat exchange pipe of UNS N06022 alloy, and the finished product specification is φ28x2x5000mm, and the technical requirements meet the ASTM B163-2022 standard, the NB / T 47019.1-2021 standard, the NB / T 47019.9-2021 standard, and the requirements of a technical agreement, and specifically include the following steps.

[0057] (1) The UNS N06022 hot extrusion blank is subjected to incoming inspection and inner and outer surface grinding, specifically: the pipe blank is subjected to preliminary inspection + grinding + reinspection, the reinspection is performed by using an endoscope, and PT is performed on the inspection sample;

[0058] (ii) the pipe blank obtained in step (i) is subjected to multi-pass intermediate product cold rolling, after each pass, the intermediate product is subjected to intermediate product oil removal, intermediate product heat treatment, intermediate product straightening, intermediate product cutting, pickling, intermediate product grinding and intermediate product inspection, wherein:

[0059] During intermediate product cold rolling, the cold rolling deformation is controlled at 45%-65%, the rolling speed and the feed amount are controlled as follows:

[0060] The rolling mill model is LG60 or LG110, the rolling speed is ≤80 times / min, and the feed amount is ≤3 mm / turn;

[0061] The Q value of the intermediate product cold rolling is controlled to be ≥0.95, and the outer diameter deviation and the wall thickness deviation after rolling are controlled as follows:

[0062] The rolling mill model is LG60 or LG110, the outer diameter deviation is controlled at ±0.5%Dmm (generally taking a multiple of 0.05 greater than or equal to the calculated value), and the wall thickness deviation is controlled at ±5%Smm (generally taking a multiple of 0.05 greater than or equal to the calculated value);

[0063] The specific process of intermediate product oil removal is: oil scraping with an oil scraper → alkali tank oil removal → rinsing → hot water tank soaking → acid tank oil removal → rinsing → inspection;

[0064] The intermediate product heat treatment is carried out in a roller hearth furnace, the furnace atmosphere is micro-oxidizing gas, the heat treatment temperature is 1150±10℃, and the holding time is 2.5 times the wall thickness;

[0065] (iii) the steel pipe obtained in step (ii) is subjected to finished product cold rolling;

[0066] The cold rolling deformation during finished product rolling is 50%-65%, the rolling speed is controlled at ≤120 times / min, the feed amount is ≤2 mm / turn, and the Q value is ≥0.9;

[0067] During finished product cold rolling, the outer diameter deviation after rolling is controlled at ±0.10 mm, and the wall thickness deviation is controlled at ±0.10 mm;

[0068] Pre-degreasing is carried out simultaneously during finished product cold rolling, the pre-degreasing is wiping the outer surface of the finished product pipe after cold rolling with acetone-soaked cotton cloth, and the finished product pipe after cold rolling is first hit 2-3 times in the hole with a wool felt ball, to remove part of the rolling oil through cold rolling pre-degreasing, to prevent rolling oil from condensing and adsorbing on the inner wall of the pipe, and then to speed up the cold rolling and oil removal process flow rate;

[0069] (iv) the steel pipe obtained in step (iii) is subjected to finished product oil removal;

[0070] The product pipe deoiling step is specifically as follows: step (three) oil scraping machine scraping within 6 hours after pre-degreasing → alkali tank soaking within 6 hours after scraping → hot water tank soaking → outer surface wiping → inner wall woolen felt balling → FB by branch for checking inner hole deoiling quality, cold-state inner hole cleaning after inner hole exists a small amount of oil stain or oil film;

[0071] (five) the steel pipe obtained in step (four) is subjected to product heat treatment;

[0072] The product heat treatment is carried out in a bright furnace, and the atmosphere in the furnace is pure hydrogen;

[0073] The heat treatment temperature is controlled to be 1150±10℃ during the product heat treatment, and the holding time is 2.5 times of the wall thickness (generally, the larger integer value is taken);

[0074] (six) the steel pipe obtained in step (five) is subjected to product straightening;

[0075] (seven) the steel pipe obtained in step (six) is subjected to product ultrasonic eddy current, water pressure, and pipe cutting, and sampling is performed for physical and chemical tests during pipe cutting;

[0076] (eight) the steel pipe obtained in step (seven) is subjected to product surface inspection, size inspection, cleaning, marking spraying, and finishing processes, and finally, packaging and warehousing are performed.

[0077] In the embodiment, the cold rolling process of the UNS N06022 alloy seamless heat exchange pipe is strictly controlled in terms of the intermediate product and product cold rolling deformation, reasonable rolling speed and relatively small feed amount are selected to ensure the inner and outer surface quality, the Q value is controlled to ensure the uniformity of the microstructure in the wall thickness direction, thereby improving the size accuracy and improving the inner wall quality. The specific cold rolling parameters are shown in Table 1, and the size accuracy and actual size are shown in Table 2;

[0078] Table 1 UNS N06022 cold rolling parameters

[0079]

[0080] Table 2 UNS N06022 technical requirement size accuracy and actual measurement size

[0081]

[0082] As can be seen from Table 2, the size accuracy of the intermediate product pipe and the product pipe in each pass meets the internal control requirements, and the size accuracy of the product pipe is higher than the requirements of the ASME SB729-2023 standard and the NB / T 47019.1-2021 standard.

[0083] The specific process for removing oil from the intermediate product of the UNS N06022 alloy seamless heat exchange pipe is as follows: scraping oil by using an oil scraper → removing oil in an alkali tank → washing → soaking in a hot water tank → removing oil in an acid tank → washing → inspection, and the main control requirements for removing oil from the intermediate product are shown in Table 3; the specific steps for removing oil from the finished pipe are as follows: scraping oil by using an oil scraper within 6 hours after cold rolling and pre-degreasing → soaking in an alkali tank within 6 hours after scraping oil → soaking in a hot water tank → wiping the outer surface → hitting the inner wall with a wool felt ball → inspection, and the main control requirements for removing oil from the finished pipe are shown in Table 4; the inner and outer surfaces of the pipe obtained by removing oil according to the above method are clean and free of oil stains, and there is no risk of nitriding during heat treatment.

[0084] Table 3 Main control requirements for removing oil from the intermediate product of UNS N06022

[0085]

[0086] Table 4 Main control requirements for removing oil from the finished pipe of UNS N06022

[0087]

[0088] Table 4 is the main control requirement for removing oil from the finished pipe of the UNS N06022 alloy heat exchange pipe, and after removing oil, the inner hole is inspected by quality personnel and technical personnel, and the inner hole is basically free of oil stains, oil spots and oil film, etc., and the heat treatment can be carried out only after the signature of the quality personnel or technical personnel, and if a small number of inner holes exist oil film, oil spots and other phenomena in the FB inspection, the inner hole is cleaned in a cold state and then re-performed FB after being put into the original frame, and the heat treatment is carried out after the FB is qualified;

[0089] The degreasing agent alkali powder in Table 3 and Table 4 includes the following components in terms of mass percentage: disodium silicate: 20-30%, sodium carbonate: 20-30%, ethylenediaminetetraacetic acid tetrasodium salt: 3-10%, ethoxylated cocoalkyl amine: 1-2.5%, and the balance is sodium hydroxide, the sum of the above components is 100%, and the above components are made by using the existing conventional degreasing agent process.

[0090] The oil scraping machine equipment used for removing oil from the intermediate product and the finished product of the pipe is a commercially available KH-60 full-automatic oil scraping cutting machine, and the oil scraping parameters are as follows: the speed of the oil scraping machine is 15 m / min, and the oil scraping machine time = (the average length of each pipe × the number of pipes per frame) / the speed of the oil scraping machine.

[0091] Compared with the simple oil removal process without adding an oil scraping machine and pre-degreasing, the finished product oil removal process of the present application has the following advantages:

[0092] The simple oil removal process is as follows: soaking in an alkali tank → soaking in a hot water tank → wiping the outer surface → hitting the inner wall with a wool felt ball → inspection, and the oil removal time is 1 hour, the oil removal effect is poor, the roughness Ra is 1.0-1.6, the crystal corrosion qualified rate is 90%, the one-time inspection qualified rate is 95% with white spots, and the economic efficiency is poor;

[0093] The oil removal process of the present application is that the oil scraping machine scrapes oil within 6h after cold rolling pre-degreasing, then the oil is soaked in alkali tank within 6h after scraping, then hot water tank soaking, then outer surface wiping, then inner wall woolen ball beating, and then inspection. The oil removal time includes alkali tank soaking for 20min, hot water tank soaking for 10min, and the overall time is controlled within 30min. The oil removal effect is good, the roughness Ra is 0.3-0.8, the crystal corrosion qualified rate is 100%, the one-time inspection qualified rate is 99% without white spot phenomenon, and the economy is good to save the rolling and oil removal cost.

[0094] The intermediate product heat treatment of the UNS N06022 alloy seamless heat exchange pipe in this embodiment is placed in a roller hearth furnace, and the furnace atmosphere is oxidizing. The finished pipe heat treatment is placed in a bright furnace, and the furnace atmosphere is pure hydrogen. The heat treatment system is shown in Table 5.

[0095] Table 5 UNS N06022 heat treatment system

[0096]

[0097] As shown in Table 5, the intermediate product solid solution heat treatment is carried out in a roller hearth furnace, and the furnace atmosphere is slightly oxidizing. The furnace has a total of 6 temperature zones. The first three temperature zones T01-T03 are the heating zones, and the last three temperature zones T04-T06 are the holding zones. The heat treatment temperature is 1150℃, the holding time is 24min, 15min and 9min respectively, and the cooling method is water cooling. The finished product heat treatment is bright heat treatment, and the furnace atmosphere is pure hydrogen. The furnace has a total of 5 temperature zones. The first two temperature zones T01-T02 are the heating zones, and the last three temperature zones T03-T05 are the holding zones. The heat treatment temperature is 1150℃, the holding time is 6min, and the cooling method is water jacket cooling.

[0098] The intermediate product straightening and finished product straightening parameters of the UNS N06022 alloy seamless heat exchange pipe in this embodiment are shown in Table 6. By specifying the straightening machine type, straightening speed, straightness and straightening outer diameter deviation range requirements, especially the finished product straightening, using a plastic roller straightening machine, specifying the straightening speed, ensuring the bending degree while avoiding the risk of straightening damage and straightening marks, and ensuring the finished product straightening quality. Strictly regulating the straightening, especially the outer diameter deviation range after the finished product straightening, can effectively avoid the risk of outer diameter deviation caused by straightening, thereby improving the dimensional accuracy.

[0099] Table 6 UNS N06022 straightening parameters

[0100]

[0101] The requirements for cutting the intermediate product and finished product of the UNS N06022 alloy seamless heat exchange pipe in this embodiment are shown in Table 7. By strictly controlling the flat head amount and strictly following the middle cutting method, manual measurement is required to mark the intermediate position before cutting, and visual inspection is not allowed. This can reduce the risk of undersize of the intermediate product and finished product, and improve the final product inspection pass rate and final material yield.

[0102] Table 7 UNS N06022 pipe cutting requirements

[0103]

[0104] The main control requirements for pickling the UNS N06022 alloy seamless heat exchange pipe intermediate product in this embodiment are shown in Table 8, including strictly controlling the ratio, temperature and time of the acid cylinder to ensure the quality of pickling. The N06022 intermediate product washed in this method has a slight and uniform oxide skin on the inner and outer walls. Under the premise of not being too acidic, the amount of oxide skin is minimized to save the cost of inner polishing labor.

[0105] Table 8 Main control requirements for UNS N06022 intermediate product pickling process

[0106]

[0107] The inspection and grinding operation requirements for the UNS N06022 alloy hot extruded pipe blank and intermediate product are shown in Table 9. The PT of the hot extruded blank is for avoiding defects on the outer surface, and the endoscope for the hot extruded blank is for more accurate and efficient inner wall defect treatment to avoid the extension of defects to the next cold rolling process. The endoscope for the intermediate product grinding is for ensuring the inner wall quality of the finished cold rolling product, reducing the risk of unqualified endoscope caused by ultrasonic internal injury and inner wall defects, thereby improving the final ultrasonic pass rate, surface inspection pass rate and final material yield.

[0108] Table 9 UNS N06022 grinding operation requirements

[0109]

[0110] In Table 9 above, during the intermediate product grinding and inspection, the grinding adopts the whole inner and outer polishing + local point grinding method. The outer polishing adopts a thousand-leaf outer polishing, the inner polishing adopts a cross-shaped polishing head automatic inner polishing machine, the local point grinding adopts a grinding machine with a flower-shaped wheel, and the local point grinding with a large amount is re-polished. The inspection adopts the visual + branch endoscope method, and the unqualified endoscope is re-polished.

[0111] The ultrasonic, eddy current, water pressure, visual and dimensional inspection conditions of the finished UNS N06022 alloy seamless heat exchange pipe of this embodiment are shown in Table 10. As can be seen from Table 10, the ultrasonic inspection of the N06022 alloy seamless heat exchange pipe produced by this production method is as high as 96.28%, the eddy current and water pressure qualified rates are both 100.00%, the dimensional inspection qualified rate is also 100.00%, the dimensional accuracy is much higher than the dimensional accuracy specified in the ASTM B163-2022 standard and the NB / T 47019.1-2021 standard, the visual inspection qualified rate is as high as 96.49%, and the one-time inspection qualified rate is as high as 92.90%.

[0112] Table 10 Ultrasonic, eddy current, water pressure, visual and dimensional inspection conditions of UNS N06022 finished pipe

[0113]

[0114] The finished pipe yield rate of UNS N06022 alloy seamless heat exchange pipe of this embodiment is shown in Table 11. The total amount of φ139x18 hot extruded blank is 7.208 tons, and the final finished product φ28x2x5000mm is 825 pieces, the actual weight is 5.731 tons, and the yield rate is as high as 79.51%.

[0115] Table 11 Yield rate of UNS N06022

[0116]

[0117] The test method for the room temperature tensile properties of the finished pipe is ASTM E8-2024, and the test results are shown in Table 12. As can be seen from Table 12, the mechanical properties of the UNS N06022 seamless heat exchange pipe manufactured by this method are excellent, the yield strength of the 4 furnace batches is 337-347Mpa, which is higher than the required ≥310Mpa, the tensile strength is stable at 755-786Mpa, which is higher than the required ≥690Mpa, and the elongation after fracture is 63.5-65.5%, which is much higher than the required ≥45%.

[0118] Table 12 Room temperature tensile properties of UNS N06022 finished pipe

[0119]

[0120] According to the requirements, high temperature tensile test was carried out, the test method for the high temperature tensile properties of the finished pipe is ASTM E21-2020, the test temperature is 250℃, and the test results are shown in Table 13. As can be seen from Table 13, the mechanical properties of the UNS N06022 seamless heat exchange pipe manufactured by this method are excellent, the high temperature tensile yield strength of the 4 furnace batches is 245-262Mpa, which is higher than the required ≥224Mpa, the tensile strength is stable at 655-670Mpa, which is higher than the required ≥643Mpa.

[0121] Table 13 UNS N06022 finished pipe tensile properties at 250°C

[0122]

[0123] Non-metallic inclusion testing was performed as required, test method: ASTM E45-18a Method A, test results are shown in Table 14 below.

[0124] Table 14 UNS N06022 finished pipe non-metallic inclusion test results

[0125]

[0126] Grain size analysis was performed as required, test method: ASTM E112-13 comparative method, etching method: acid pickling potassium permanganate solution etching, test results are shown in Table 15 below.

[0127] Table 15 UNS N06022 finished pipe grain size

[0128]

[0129] Crystal corrosion tests were performed on all 4 batches of UNS N06022 finished pipe in the non-sensitized state according to ASTM G28-2022 B method, test time 24h, crystal corrosion test results are shown in Table 16 below.

[0130] Table 16 UNS N06022 finished pipe crystal corrosion test results

[0131]

[0132] The present application strictly limits the process optimization of UNS N06022 alloy seamless heat exchange pipe, solves the problems of low first inspection pass rate, low yield, low size precision and poor inner and outer surface quality, etc. As can be seen from Tables 10-16, the product produced by the method has high first inspection pass rate, high yield, high size precision, good inner and outer surface quality, stable physicochemical properties and strong practicality, and is beneficial to batch production.

[0133] In addition to the above embodiments, the present application can also have other implementation manners. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present application.

Claims

1. A method of manufacturing a seamless heat exchange tube of UNS N06022 Hastelloy, characterized by, Specifically comprising the following steps: (I) the UNS N06022 hot extrusion billet is subjected to incoming inspection and inner and outer surface grinding, specifically: the pipe billet is subjected to preliminary inspection + grinding + reinspection, and during reinspection, each pipe is subjected to endoscopic examination, and PT is performed for sampling inspection; (II) the pipe billet obtained in step (I) is subjected to multi-pass intermediate product cold rolling, and after each pass of cold rolling, the intermediate product is subjected to intermediate product oil removal, intermediate product heat treatment, intermediate product straightening, intermediate product pipe cutting, pickling, intermediate product grinding and intermediate product inspection, wherein: during intermediate product cold rolling, the cold rolling deformation is controlled to be 45%-65%, and the rolling speed and the feed amount are controlled as follows: the rolling mill model is LG60 or LG110, the rolling speed is ≤80 times / min, and the feed amount is ≤3 mm / time; the Q value of intermediate product cold rolling is controlled to be ≥0.95, and the outer diameter deviation and the wall thickness deviation after rolling are controlled as follows: the rolling mill model is LG60 or LG110, the outer diameter deviation is controlled to be ±0.5%D mm, and the wall thickness deviation is controlled to be ±5%S mm; the intermediate product oil removal specifically comprises the following procedures: oil scraping by using an oil scraper → alkali tank oil removal → rinsing → hot water tank soaking → acid tank oil removal → rinsing → inspection; the intermediate product heat treatment is performed in a roller hearth furnace, the furnace atmosphere is micro-oxidizing gas, the heat treatment temperature is 1150±10℃, and the holding time is 2.5 times the wall thickness value in millimeters, and the unit of the holding time is minute; during intermediate product straightening, the straightening parameters are controlled as follows: if the outer diameter of the steel pipe intermediate product is >57 mm, the straightening control speed is ≤6 m / min, the bending degree after straightening is ≤1.5 mm / m, and the outer diameter deviation after straightening is ±0.05%D mm; if the outer diameter of the steel pipe intermediate product is ≤57 mm, the straightening control speed is ≤8 m / min, the bending degree after straightening is ≤1 mm / m, and the outer diameter deviation after straightening is ±0.05%D mm; (III) the steel pipe obtained in step (II) is subjected to finished product cold rolling; the cold rolling deformation during finished product rolling is 50%-65%, the rolling speed is controlled to be ≤120 times / min, the feed amount is ≤2 mm / time, and the Q value is ≥0.9; during finished product cold rolling, the outer diameter deviation after rolling is controlled to be ±0.10 mm, and the wall thickness deviation is controlled to be ±0.10 mm; during finished product cold rolling, pre-degreasing is simultaneously performed, the pre-degreasing is wiping the outer surface of the finished product pipe after cold rolling with cotton cloth soaked in acetone, and the finished product pipe after cold rolling is hit in the inner hole with wool felt balls for 2-3 times; (IV) the steel pipe obtained in step (III) is subjected to finished product oil removal; the finished product pipe oil removal step specifically comprises the following procedures: oil scraping by using an oil scraper within 6 hours after pre-degreasing in step (III) → alkali tank soaking within 6 hours after oil scraping → hot water tank soaking → outer surface wiping → inner wall wool felt ball hitting → FB inspection of the inner hole oil removal quality of each pipe, and the inner hole is cleaned after cold-state inner wall throwing if there is a small amount of oil stain or oil film in the inner hole; (V) the steel pipe obtained in step (IV) is subjected to finished product heat treatment; the finished product heat treatment is performed in a bright furnace, and the furnace atmosphere is pure hydrogen; during finished product heat treatment, the heat treatment temperature is controlled to be 1150±10℃, and the holding time is 2.5 times the wall thickness value in millimeters, and the unit of the holding time is minute; (VI) the steel pipe obtained in step (V) is subjected to finished product straightening; (Seven) the steel pipe obtained in step (six) is subjected to product ultrasonic eddy current, water pressure, pipe cutting, and sampling for physical and chemical tests during pipe cutting; (Eight) the steel pipe obtained in step (seven) is subjected to product surface inspection, size inspection, cleaning, marking spraying and finishing processes, and finally is packaged and stored.

2. The manufacturing method of Hastelloy UNS N06022 seamless heat exchange tube according to claim 1, characterized in that: In the step (two), the solution in the alkali tank is controlled to have a mass ratio of degreasing agent to water of 1:20, an alkali tank temperature of 50-60°C, and an alkali tank soaking time of 50-60 min. In the step (two), the solution in the acid tank is controlled to have a mass percentage of HF of 1%, HNO3 of 10-15%, and tap water as the balance, a total of 100%, an acid tank temperature of 55-60°C, and an acid pickling time of 20-35 min.

3. The method of manufacturing a seamless heat exchange tube of Hastelloy UNS N06022 according to claim 1, characterized in that: In the step (two), the solution in the acid tank is controlled to have a mass ratio of HF of 5-8%, HNO3 of 10-15%, and tap water as the balance, a total of 100%, an acid tank temperature of 50-55°C, and an acid pickling time of 20-30 min.

4. The method of manufacturing Hastelloy UNS N06022 seamless heat exchange tube as claimed in claim 1, wherein: In the step (two), the grinding and inspection of the intermediate product are performed by adopting a whole external polishing plus local point grinding mode, the external polishing is performed by using a thousand-leaf external polishing machine, and the local point grinding is performed by using a grinding machine with a flower-shaped wheel. The inspection is performed by adopting a visual inspection plus individual endoscopic inspection mode, the visual inspection is performed on the grinding marks, and the endoscopic inspection is performed after internal polishing.

5. The method of manufacturing Hastelloy UNS N06022 seamless heat exchange tube as claimed in claim 1, wherein: In the step (four), the solution in the alkali tank is controlled to have a mass ratio of degreasing agent to water of 1:6.5, an alkali tank temperature of 40-60°C, an alkali tank soaking time of 15-25 min, a hot water tank temperature of 70-80°C, a hot water tank soaking time of 10-20 min, and the outer surface is wiped with cotton cloth soaked in acetone and the inner wall is cleaned with wool felt for 3-5 times after the hot water tank, and the FB inspection is performed on the inner hole after the oil removal, and if there is no oil stain or film in the inner hole, the heat treatment is performed, and if there is oil film or stain, the cold internal polishing is performed, and the FB is performed again after the inner hole is cleaned and returned to the original frame, and the heat treatment is performed after the FB is qualified.

6. The method of manufacturing Hastelloy UNS N06022 seamless heat exchange tube as claimed in claim 1, wherein: In the step (six), the speed of the straightening machine is controlled to be less than or equal to 10 m / min, the bending degree after straightening is less than or equal to 0.5 mm / m, and the outer diameter deviation after straightening is ±0.01 mm.

7. The method of manufacturing a seamless heat exchange tube of Hastelloy UNS N06022 according to claim 1, characterized in that: In the step (seven), the one-time ultrasonic qualified rate is greater than or equal to 95%, and the one-time eddy current qualified rate is 100%.

8. The method of manufacturing Hastelloy UNS N06022 seamless heat exchange tube as claimed in claim 1, wherein: In the step (eight), the inner and outer surfaces of the product pipe are smooth, and the inner and outer wall roughness Ra is less than or equal to 0.

8.

9. The method of manufacturing Hastelloy UNS N06022 seamless heat exchange tube as claimed in claim 1, wherein: The product pipe obtained by the method has a yield strength of greater than or equal to 330 MPa, a tensile strength of greater than or equal to 750 MPa, and an elongation of greater than or equal to 60% in a room temperature tensile test, and a yield strength of greater than or equal to 245 MPa and a tensile strength of greater than or equal to 655 MPa in a 250°C high temperature tensile test.

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