Manufacturing process of hot-tubing wear-resistant pipeline and pipeline

Abstract

This application relates to the field of industrial pipeline manufacturing technology, and discloses a manufacturing process and pipeline for a hot-delivery wear-resistant pipeline. The process includes: performing three-layer surfacing welding inside the inner sleeve, consisting of a single-strip circumferential weld as the root, a transition weld, and a swing circumferential weld as the cover, while controlling the pipe wall temperature; conducting a hydrostatic pressure test independently on the outer sleeve; welding a sliding support ring and a retaining support ring on the inner wall of the outer sleeve, inserting the inner sleeve into the outer sleeve and fixing it with the retaining support ring, so that the outer wall of the inner sleeve slides against the sliding support ring; pumping lightweight heat-insulating castable into the annular gap while the outer sleeve is in a vertical state and curing it; and finally coating the surface of the outer sleeve. This invention reduces the thermal deformation of the thin-walled inner pipe through three-layer progressive surfacing welding, releases the thermal expansion stress caused by the temperature difference by using inner and outer nested sliding components, and separates the pressure-bearing boundary from the high-temperature resistant boundary, thereby improving the structural safety of the composite pipeline under harsh working conditions.

Description

Technical Field

[0001] This invention relates to the field of industrial pipeline manufacturing technology, specifically to a manufacturing process and a pipeline for hot-delivery wear-resistant pipeline. Background Technology

[0002] In modern metallurgical processes, high-temperature, high-pressure, and abrasive materials need to be transferred via pneumatic conveying systems. Existing conveying pipelines typically employ rigid composite structures, where pressure-bearing capacity and high-temperature and wear-resistant properties are often coupled. When the pipeline interior is subjected to long-term erosion by high-temperature gas-solid two-phase flow, resulting in localized wear, the high-temperature, high-pressure medium will directly act on the external pressure-bearing shell, increasing the risk of localized pipe wall failure and leakage.

[0003] Some pipelines employ a double-layer structure to cope with complex operating conditions, but the inner and outer pipes are mostly rigidly welded together. Due to the high temperature of the transported medium, the temperature of the inner pipe rises rapidly, while the temperature of the outer pipe remains relatively low, resulting in a significant temperature difference. This difference in axial expansion causes thermal expansion stress at the structural joints. Under conditions of alternating hot and cold operation, the repeated accumulation of stress can easily lead to weld tearing at the internal connections.

[0004] Furthermore, in the pipe manufacturing process, to improve the wear resistance of the inner wall, hard alloy welding is often performed inside the austenitic stainless steel inner tube. Because the stainless steel substrate has a large coefficient of linear expansion and poor thermal conductivity, the concentrated heat input from thick-walled welding can cause significant thermal deformation of the pipe. This deformation can lead to deflection of the long, thin-walled tube, reducing its straightness and making it difficult to meet the high-precision dimensional requirements for coaxiality of the inner and outer tubes during subsequent composite pipe assembly. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a manufacturing process and a pipe for hot-transport wear-resistant pipes, which solves the problems of structural damage caused by thermal expansion stress, thermal deformation of thin-walled inner pipes affecting coaxial assembly, and leakage caused by internal wear of the pressure-bearing shell when transporting high-temperature and high-pressure media.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a manufacturing process for a hot-delivery wear-resistant pipe, employing the following technical solution: A manufacturing process for a hot-carrying wear-resistant pipe includes the following steps: Austenitic heat-resistant stainless steel pipe was selected as the base material for the inner sleeve. Three layers of anti-deformation and wear-resistant surfacing were sequentially welded inside the inner sleeve. The first layer used a single-strip circumferential weld for the root pass, the second layer used a single-strip circumferential weld for the transition, and the third layer used a swing-type circumferential weld for the cover pass. Temperature control was implemented on the outer wall of the inner sleeve throughout the welding process. After welding, the outer sleeve was cooled to room temperature for later use. Seamless steel pipe was selected as the outer sleeve, with flanges welded to both ends. Before the inner sleeve and insulation material were installed, the outer sleeve underwent an independent hydrostatic pressure test. The outer sleeve was selected based on the absence of significant structural deformation and pressure drop. The outer sleeve of the elephant tube is emptied and dried; a sliding support ring and a retaining support ring are welded to the inner wall of the outer sleeve after it has passed the pressure test; the inner sleeve is inserted into the outer sleeve and the concentricity of the assembly is adjusted; then the inner sleeve is welded and fixed to the retaining support ring, and a lifting lug is welded to the outer wall of the outer sleeve; the outer sleeve is lifted vertically by the lifting lug, and lightweight heat-insulating castable is pumped into the annular gap between the inner and outer sleeves and vibrated and cured to form a lightweight heat-insulating castable layer; finally, the outer surface of the outer sleeve is sandblasted and then coated with inorganic zinc-rich primer and organic silicone heat-resistant paint in sequence.

[0007] By adopting the above technical solutions, the three-layer progressive overlay welding method combined with external forced temperature control effectively controls the heat input during the overlay welding process, limiting the thermal deformation of the austenitic stainless steel substrate caused by local overheating and ensuring the straightness of the long, thin-walled pipe. Simultaneously, conducting an independent hydrostatic pressure test on the outer casing beforehand eliminates the obstruction of internal components and casting material to the pressure medium leakage, which helps improve the reliability of the outer pipe as a pressure-bearing boundary. Furthermore, the use of reverse nesting assembly and vertical casting processes during the assembly stage reduces the eccentric gravity effect caused by conventional horizontal assembly, resulting in a uniform insulation layer thickness between the inner and outer casings. Therefore, the project achieves high structural safety, meets assembly requirements in terms of form and position tolerances, and has clearly defined quality inspection points.

[0008] Preferably, during the entire welding process, the outer wall temperature of the inner sleeve is maintained between 100℃ and 145℃. The specific parameters for the three-layer anti-deformation and wear-resistant surfacing are as follows: the first layer uses hard alloy welding wire, welding current of 220A to 250A, arc voltage of 24V to 26V, welding speed of 30cm / min to 40cm / min, and surfacing thickness controlled between 2.0mm and 3.0mm; the second layer uses welding current of 250A to 280A, arc voltage of 26V to 28V, welding speed of 25cm / min to 35cm / min, and surfacing thickness controlled between 3.5mm and 4.0mm; the third layer uses welding current of 280A to 320A, arc voltage of 28V to 32V, oscillation frequency of 40 times / min to 60 times / min, and surfacing thickness controlled between 3.5mm and 4.0mm.

[0009] By adopting the above technical solution, the welding heat input follows the physical relationship of thermal balance, that is, the heat input equals the arc voltage multiplied by the welding current divided by the welding speed. The first layer uses a lower current and a faster welding speed to keep the heat input at a low level, which is conducive to rapid fusion and reduces thermal shock to the bottom of the substrate. The second layer increases the current and decreases the welding speed to ensure sufficient fusion between layers, thereby forming a thermal stress transition zone. The third layer uses oscillating circumferential welding, increasing the current to 320A to provide the required molten heat energy. The oscillating motion spreads and levels the liquid metal in the molten pool, reducing the surface roughness of the weld overlay. Combined with maintaining the outer wall temperature of the pipe within the specified range, a stable temperature gradient is easily formed in the radial direction of the pipe wall. This helps to weaken the internal thermal stress caused by the expansion of the austenite phase at high temperatures, thereby limiting the overall thermal deformation of the inner pipe within the allowable tolerance range.

[0010] Preferably, the test pressure for the hydrostatic test is set to 1.035 MPa to 1.100 MPa, and the pressure stabilization time is controlled to 10 min to 15 min.

[0011] By adopting the above technical solution, setting a test pressure higher than the rated working pressure can verify the elastic deformation recovery ability of the outer casing material before the yield limit. When hydrostatic pressure is applied to the inner wall of the outer casing, the pipe material is subjected to circumferential and radial stresses. The pressure holding process can be used to check whether micropores or cracks have expanded and leaked under continuous fluid stress, and further confirm the structural bearing strength of the pressure-bearing shell under extreme working conditions.

[0012] Preferably, the number of sliding support rings is at least two; the inner diameter of the retaining support ring is 5mm to 10mm larger than the outer diameter of the inner sleeve; after being inserted into the inner sleeve, the concentricity of the inner sleeve and the outer sleeve is controlled within the range of ±0.5mm to ±2.0mm.

[0013] By adopting the above technical solution, the physical dimensional difference between the inner diameter of the retaining support ring and the outer diameter of the inner sleeve provides a corresponding radial clearance. This clearance not only allows for the deposition space of the bridging weld but also accommodates the radial thermal expansion of the inner tube during the initial heating stage, thus preventing the radial expansion of the inner tube from squeezing the retaining support ring and generating destructive shear forces. Controlling the concentricity error helps maintain the uniformity of the cross-sectional area of ​​the annular insulation space, reducing the risk of localized hot spots on the outer sleeve due to insufficient local insulation thickness.

[0014] Preferably, the sandblasting treatment is completed to Sa2.5 grade; the dry film thickness of the inorganic zinc-rich primer is 60μm to 80μm, and the dry film thickness of the organosilicon heat-resistant paint is 35μm to 45μm; the natural environmental curing time of the castable is 20 to 30 days.

[0015] By adopting the above technical solutions, sandblasting increases the surface roughness of the substrate, thereby enhancing the adhesion of the primer. The zinc powder in the inorganic zinc-rich primer undergoes a galvanic cell oxidation reaction, consuming itself and acting as a sacrificial anode for cathodic protection. The surface silicone resin forms a stable silicon-oxygen bond cross-linking network at high temperatures, creating a corrosion-resistant and high-temperature-resistant sealing layer. Controlling the curing cycle allows the free and bound water inside the lightweight insulating castable to fully undergo hydration and volatilize, reducing the possibility of residual internal moisture vaporizing and forming high-pressure steam that damages the castable layer structure when high-temperature airflow passes through.

[0016] Secondly, the present invention provides a hot-transfer wear-resistant pipe, which adopts the following technical solution: A heat-conveying wear-resistant pipe includes an outer sleeve with flanges fixedly connected to both ends; an inner sleeve coaxially inserted inside the outer sleeve, the inner wall of the inner sleeve having a first single-ring weld layer, a second single-ring weld layer, and a third swing-ring weld layer sequentially bonded together; a support and limiting assembly disposed between the outer sleeve and the inner sleeve, including a sliding support ring and a material-stopping support ring fixed to the inner wall of the outer sleeve; the inner sleeve is fixedly connected to the material-stopping support ring, and the outer wall of the inner sleeve is in sliding fit with the sliding support ring; a lightweight heat-insulating casting layer fills the annular gap between the outer sleeve and the inner sleeve; the outer surface of the outer sleeve is sequentially coated with an inorganic zinc-rich primer and an organosilicon heat-resistant paint.

[0017] By adopting the above technical solution, the structural design of the supporting and limiting components separates the functions of the inner and outer pipes. The inner sleeve only serves as the physical boundary for high temperature resistance and corrosion resistance, and the high-pressure fluid load inside the system is transferred to the outer sleeve. When the inner sleeve transports high-temperature fluid, its thermal expansion deformation follows the material linear expansion relationship, that is, the deformation length is equal to the original length multiplied by the product of the linear expansion coefficient and the absolute temperature difference. Due to the temperature difference between the inner and outer pipes, the axial thermal expansion elongation of the inner sleeve is usually greater than that of the outer sleeve. At this time, the outer wall of the inner sleeve, which is fixed to the retaining support ring on one side, slides freely along the inner edge of the sliding support ring, converting the axial thermal expansion stress into mechanical displacement and releasing it, thus reducing the structural risk of weld tearing in the rigid connection structure during thermal expansion and contraction cycles.

[0018] Preferably, the inner sleeve is made of 310S austenitic heat-resistant stainless steel, and the total weld thickness of the first single-ring weld layer, the second single-ring weld layer and the third oscillating ring weld layer is 9.5mm to 10.5mm.

[0019] By adopting the above technical solutions, 310S austenitic heat-resistant stainless steel exhibits good high-temperature oxidation resistance and structural stability. The three-layer composite weld overlay structure of a specific thickness not only meets the requirements for resisting wear from long-term friction of high-speed solid particles, but also helps to block the physical path of surface microcracks extending to the substrate by utilizing the metallographic transition between each weld layer.

[0020] Preferably, the inner diameter of the retaining support ring is 5mm to 10mm larger than the outer diameter of the inner sleeve, and the inner sleeve and the retaining support ring are fixed together by a weld.

[0021] By adopting the above technical solution, the weld bridging fixing form creates a relatively flexible mechanical stress node. During the thermal cycle of heating and cooling, this physical gap and the bridging weld can absorb the alternating vibration and minute radial strain generated by the pipeline system, which helps to prevent fatigue fracture of the fixed joint due to stress concentration.

[0022] Preferably, the outer sleeve is made of L245 seamless steel pipe; the sliding support ring and the retaining support ring are both made of SUS304 austenitic stainless steel.

[0023] By adopting the above technical solution, the support ring is made of austenitic material with a crystal structure similar to that of the inner sleeve, which better maintains the consistency of thermal expansion at the connection point under high-temperature conduction conditions, reducing the possibility of interfacial shear failure due to differences in the expansion coefficients of dissimilar steels. The L245 seamless steel pipe provides room-temperature compressive toughness, achieving a material decoupling between pressure-bearing and high-temperature resistance functions.

[0024] Preferably, the outer wall of the outer sleeve is also welded with lifting lugs for vertical hoisting and pouring.

[0025] By adopting the above technical solution, the lifting lugs provide symmetrical force support points under vertical lifting conditions, so that the weight of the tube itself is distributed vertically along the axial direction. This reduces the degree of axial deflection deformation of the slender tube due to gravity bending moment during horizontal or inclined handling and casting, which is beneficial to maintaining the concentricity of the inner and outer sleeves and the molding quality of the internal heat insulation casting layer.

[0026] This invention provides a manufacturing process and a pipe for hot-delivery wear-resistant pipe. It has the following beneficial effects: 1. This invention employs a three-layer progressive welding process within the inner sleeve, consisting of a single-strip circumferential weld for the root pass, a single-strip circumferential weld for the transition pass, and a wobbling circumferential weld for the cover pass. Combined with temperature control of the outer wall of the sleeve, this regulates the heat input during the welding stage. This limits the axial bending deformation of the thin-walled austenitic stainless steel substrate under localized heating, ensuring the formed inner sleeve remains straight and meets the dimensional requirements for subsequent coaxial nesting assembly.

[0027] 2. This invention utilizes a sliding support ring and a retaining support ring on the inner wall of the outer sleeve to construct an inner and outer nested assembly. This allows the inner sleeve to be fixed only to one end of the retaining support ring, while its outer wall maintains a sliding fit along the inner edge of the sliding support ring. When conveying high-temperature media, the axial thermal expansion of the inner sleeve can be converted into mechanical displacement along the support ring, alleviating the thermal stress accumulation caused by the expansion difference between the inner and outer sleeves due to temperature differences, and reducing the risk of weld cracking under alternating hot and cold operating conditions.

[0028] 3. This invention employs a composite structure consisting of an inner sleeve, a lightweight heat-insulating cast layer, and an outer sleeve, separating the high-temperature resistance and wear resistance of the pipeline from its pressure-bearing function. The inner sleeve, acting as the working boundary in contact with high-temperature materials, has its heat conduction to the outside blocked by the insulation layer, thus maintaining the outer sleeve, which acts as the pressure-bearing boundary, at a lower temperature. Even if the inner sleeve experiences localized wear due to long-term material erosion, the working pressure inside the pipeline is still borne by the outer sleeve, reducing the possibility of direct damage to the pipe wall by the high-temperature medium and thus improving the safety of system operation. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the inner sleeve structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the outer sleeve of the present invention; Figure 3 This is a schematic diagram of the sliding support ring of the present invention; Figure 4 This is a schematic diagram of the material retaining support ring of the present invention.

[0030] Among them, 1. Inner sleeve; 2. Outer sleeve; 3. Sliding support ring; 4. Material retaining support ring; 5. Lifting lug; 6. Flange; 7. Lightweight thermal insulation casting layer. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0033] Lightweight insulating castable, brand name: Kaolite® 2200 Monolithic.

[0034] Inorganic zinc-rich primer, brand: Jotun Resist 86.

[0035] Organosilicon heat-resistant paint, brand: Jotun Solvalitt 600.

[0036] Preparation Example 1: This preparation example provides a method for preparing an inner sleeve with a deformation-resistant and wear-resistant weld overlay layer, including the following steps: (1) Select a 310S standard austenitic heat-resistant stainless steel pipe with a wall thickness of 20mm as the inner sleeve, and keep the outer wall temperature of the inner sleeve at 120℃ throughout the welding process. (2) Weld the first layer inside the inner sleeve using single-strip circumferential welding, using VAUTID-145 hard alloy welding wire, with welding current set to 235A, arc voltage set to 25V, welding speed set to 35cm / min, and weld thickness controlled at 2.5mm. (3) Weld the second layer inside the inner sleeve using single-strip circumferential welding. The welding current is set to 265A, the arc voltage is set to 27V, the welding speed is set to 30cm / min, and the weld thickness is controlled at 3.5mm. (4) Weld the third layer inside the inner sleeve by oscillating ring welding. The welding current is set to 300A, the arc voltage is set to 30V, the oscillation frequency is set to 50 times / min, and the weld thickness is controlled at 4.0mm. (5) After welding, the inner sleeve is cooled to room temperature in the air to obtain a total weld overlay thickness of 10.0 mm.

[0037] Preparation Example 2: This preparation example provides a method for preparing an inner sleeve with a deformation-resistant and wear-resistant weld overlay layer, including the following steps: (1) Select a 310S standard austenitic heat-resistant stainless steel pipe with a wall thickness of 20mm as the inner sleeve, and keep the outer wall temperature of the inner sleeve at 100℃ throughout the welding process. (2) Weld the first layer inside the inner sleeve using single-strip circumferential welding with Böhler A45 hard alloy welding wire. The welding current is set to 220A, the arc voltage is set to 24V, the welding speed is set to 40cm / min, and the weld thickness is controlled at 2.0mm. (3) Weld the second layer inside the inner sleeve using single-strip circumferential welding. The welding current is set to 250A, the arc voltage is set to 26V, the welding speed is set to 35cm / min, and the weld thickness is controlled at 3.5mm. (4) Weld the third layer inside the inner sleeve by oscillating ring welding. The welding current is set to 280A, the arc voltage is set to 28V, the oscillation frequency is set to 40 times / min, and the weld thickness is controlled at 4.0mm. (5) After welding, the inner sleeve is cooled to room temperature in the air to obtain a total weld overlay thickness of 9.5 mm.

[0038] Preparation Example 3: This preparation example provides a method for preparing an inner sleeve with a deformation-resistant and wear-resistant weld overlay layer, including the following steps: (1) Select a 310S standard austenitic heat-resistant stainless steel pipe with a wall thickness of 20mm as the inner sleeve, and keep the outer wall temperature of the inner sleeve at 145℃ throughout the welding process. (2) Weld the first layer inside the inner sleeve using single-strip circumferential welding, using VAUTID-145 hard alloy welding wire, with welding current set to 250A, arc voltage set to 26V, welding speed set to 30cm / min, and weld thickness controlled at 3.0mm. (3) Weld the second layer inside the inner sleeve using single-strip circumferential welding. The welding current is set to 280A, the arc voltage is set to 28V, the welding speed is set to 25cm / min, and the weld thickness is controlled at 4.0mm. (4) Weld the third layer inside the inner sleeve by oscillating ring welding. The welding current is set to 320A, the arc voltage is set to 32V, the oscillation frequency is set to 60 times / min, and the weld thickness is controlled at 3.5mm. (5) After welding, the inner sleeve is cooled to room temperature in the air to obtain a total weld overlay thickness of 10.5 mm.

[0039] Example 1:

[0040] This embodiment provides a manufacturing process and a pipe for hot-delivery wear-resistant pipe, including the following steps: (1) Select L245 seamless steel pipe with a diameter of D630×10mm as the outer sleeve, and fully weld DN600-PN25 SUS304 flanges at both ends; before installing the inner sleeve and lightweight heat insulation castable, conduct a hydrostatic pressure test on the outer sleeve independently. The test pressure is set at 1.05MPa, and the pressure stabilization time is controlled at 12min. Select the outer sleeve with no obvious structural deformation and no pressure drop as the outer sleeve that passes the pressure test. Then drain the water and dry it. (2) Weld two sliding support rings of SUS304 material to the inner wall of the outer sleeve after the pressure test is passed. Weld a retaining support ring of SUS304 standard austenitic stainless steel to one side of the inner wall of the outer sleeve. Insert the inner sleeve prepared in Preparation Example 1 into the outer sleeve so that the concentricity of the two tubes is controlled within ±1.0 mm. The inner diameter of the retaining support ring is 10 mm larger than the outer diameter of the inner sleeve. Then weld the inner sleeve and the retaining support ring together and weld lifting lugs on both sides of the outer wall of the outer sleeve.

[0041] (3) Lift the outer tube with the lifting lugs to make it vertical, pump lightweight heat insulation castable into the annular gap formed between the inner and outer tubes on the same axis, and compact it while pouring; cure it in the natural environment for 25 days to form a lightweight heat insulation castable layer. (4) The outer surface of the outer casing is sandblasted to Sa2.5 grade, and then an inorganic zinc-rich primer with a dry film thickness of 70μm and an organic silicone heat-resistant paint with a dry film thickness of 40μm are sprayed in sequence. After curing, the hot-carrying wear-resistant pipe is obtained.

[0042] Example 2:

[0043] This embodiment provides a manufacturing process and a pipe for hot-delivery wear-resistant pipe, including the following steps: (1) Select L245 seamless steel pipe with a diameter of D630×10mm as the outer sleeve, and fully weld DN600-PN25 SUS304 flanges at both ends; before installing the inner sleeve and lightweight heat insulation castable, conduct a hydrostatic pressure test on the outer sleeve independently. The test pressure is set at 1.035MPa, and the pressure stabilization time is controlled at 10min. Select the outer sleeve with no obvious structural deformation and no pressure drop as the outer sleeve that passes the pressure test. Then drain the water and dry it. (2) Weld two sliding support rings of SUS304 material to the inner wall of the outer sleeve after the pressure test is passed. Weld a retaining support ring of SUS304 standard austenitic stainless steel to one side of the inner wall of the outer sleeve. Insert the inner sleeve prepared in Preparation Example 2 into the outer sleeve so that the concentricity of the two tubes is controlled within ±0.5mm. The inner diameter of the retaining support ring is 5mm larger than the outer diameter of the inner sleeve. Then weld the inner sleeve and the retaining support ring together and weld lifting lugs on both sides of the outer wall of the outer sleeve.

[0044] (3) Lift the outer tube with the lifting lugs to make it vertical, pump lightweight heat insulation castable into the annular gap formed between the inner and outer tubes on the same axis, and compact it while pouring; cure it in the natural environment for 20 days to form a lightweight heat insulation castable layer. (4) The outer surface of the outer casing is sandblasted to Sa2.5 grade, and then an inorganic zinc-rich primer with a dry film thickness of 60μm and an organic silicone heat-resistant paint with a dry film thickness of 35μm are sprayed in sequence. After curing, the hot-carrying wear-resistant pipe is obtained.

[0045] Example 3:

[0046] This embodiment provides a manufacturing process and a pipe for hot-delivery wear-resistant pipe, including the following steps: (1) Select L245 seamless steel pipe with a diameter of D630×10mm as the outer sleeve, and fully weld DN600-PN25 SUS304 flanges at both ends; before installing the inner sleeve and lightweight heat insulation castable, conduct a hydrostatic pressure test on the outer sleeve independently. The test pressure is set at 1.100MPa, and the pressure stabilization time is controlled at 15min. Select the outer sleeve with no obvious structural deformation and no pressure drop as the outer sleeve that passes the pressure test. Then drain the water and dry it. (2) Weld two sliding support rings of SUS304 material to the inner wall of the outer sleeve after the pressure test is passed. Weld a retaining support ring of SUS304 standard austenitic stainless steel to one side of the inner wall of the outer sleeve. Insert the inner sleeve prepared in Preparation Example 3 into the outer sleeve so that the concentricity of the two tubes is controlled within ±2.0 mm. The inner diameter of the retaining support ring is 6 mm larger than the outer diameter of the inner sleeve. Then weld the inner sleeve and the retaining support ring together and weld lifting lugs on both sides of the outer wall of the outer sleeve.

[0047] (3) Lift the outer tube with the lifting lugs to make it vertical, pump lightweight heat insulation castable into the annular gap formed between the inner and outer tubes on the same axis, and compact it while pouring; cure it in the natural environment for 30 days to form a lightweight heat insulation castable layer. (4) The outer surface of the outer casing is sandblasted to Sa2.5 grade, and then an inorganic zinc-rich primer with a dry film thickness of 80μm and an organic silicone heat-resistant paint with a dry film thickness of 45μm are sprayed in sequence. After curing, the hot-transport wear-resistant pipe is obtained.

[0048] Example 4:

[0049] This embodiment provides a manufacturing process and a pipe for hot-delivery wear-resistant pipe, including the following steps: (1) Select L245 seamless steel pipe with a diameter of D630×10mm as the outer sleeve, and fully weld DN600-PN25 SUS304 flanges at both ends; before installing the inner sleeve and lightweight heat insulation castable, conduct a hydrostatic pressure test on the outer sleeve independently. The test pressure is set at 1.08MPa, and the pressure stabilization time is controlled at 14min. Select the outer sleeve with no obvious structural deformation and no pressure drop as the outer sleeve that passes the pressure test. Then drain the water and dry it. (2) Weld two sliding support rings of SUS304 material to the inner wall of the outer sleeve after the pressure test is passed. Weld a retaining support ring of SUS304 standard austenitic stainless steel to one side of the inner wall of the outer sleeve. Insert the inner sleeve prepared in Preparation Example 1 into the outer sleeve so that the concentricity of the two tubes is controlled within ±1.5mm. The inner diameter of the retaining support ring is 8mm larger than the outer diameter of the inner sleeve. Then weld the inner sleeve and the retaining support ring together and weld lifting lugs on both sides of the outer wall of the outer sleeve.

[0050] (3) Lift the outer tube with the lifting lugs to make it vertical, pump lightweight heat insulation castable into the annular gap formed between the inner and outer tubes on the same axis, and compact it while pouring; cure it in the natural environment for 28 days to form a lightweight heat insulation castable layer. (4) The outer surface of the outer casing is sandblasted to Sa2.5 grade, and then an inorganic zinc-rich primer with a dry film thickness of 65μm and an organic silicone heat-resistant paint with a dry film thickness of 42μm are sprayed in sequence. After curing, the hot-transport wear-resistant pipe is obtained.

[0051] Reference Figures 1 to 4 This invention provides a heat-conveying wear-resistant pipe, comprising: The outer sleeve 2 is fixedly connected to flanges 6 at both ends; The inner sleeve 1 is coaxially inserted inside the outer sleeve 2. The inner wall of the inner sleeve 1 has a first single ring weld layer, a second single ring weld layer and a third swing ring weld layer connected in sequence. A support and limiting assembly is provided between the outer sleeve 2 and the inner sleeve 1, including a sliding support ring 3 and a material-stopping support ring 4 fixed to the inner wall of the outer sleeve 2; the inner sleeve 1 is fixedly connected to the material-stopping support ring 4, and the outer wall of the inner sleeve 1 is in sliding fit with the sliding support ring 3; A lightweight heat-insulating casting layer 7 is filled in the annular gap between the outer sleeve 2 and the inner sleeve 1; The outer surface of the outer tube 2 is coated with inorganic zinc-rich primer and organosilicon heat-resistant paint in sequence.

[0052] The inner sleeve 1 is made of 310S austenitic heat-resistant stainless steel. The total weld thickness of the first single ring weld layer, the second single ring weld layer, and the third oscillating ring weld layer is 9.5mm to 10.5mm.

[0053] The inner diameter of the retaining support ring 4 is 5mm to 10mm larger than the outer diameter of the inner sleeve 1. The inner sleeve 1 and the retaining support ring 4 are fixed together by a weld. The outer sleeve 2 is made of L245 seamless steel pipe; the sliding support ring 3 and the retaining support ring 4 are both made of SUS304 austenitic stainless steel. Lifting lugs 5 for vertical hoisting and pouring are also welded to the outer wall of the outer sleeve 2.

[0054] Specifically, when transporting high-temperature gas-solid two-phase materials through a pipeline, the high-temperature material flows inside the inner sleeve 1, where the three-layer weld overlay on the inner wall can resist high-speed friction from solid particles. The lightweight insulating casting layer 7 blocks heat transfer outward, keeping the outer sleeve 2 at a lower temperature. The outer sleeve 2 does not bear the direct thermal shock of the high-temperature material and is mainly responsible for bearing the fluid pressure inside the system.

[0055] During equipment operation, a significant temperature difference exists between the inner and outer tubes, causing the axial thermal expansion elongation of the inner sleeve 1 to be greater than that of the outer sleeve 2. The inner sleeve 1 is fixed to the retaining support ring 4 via a bridging weld, serving as a relatively static connection reference. As the temperature rises, the inner sleeve 1 can slide axially along the inner edge of the sliding support ring 3. This support arrangement, with one end fixed and the other sliding, converts the thermal expansion elongation of the inner sleeve 1 into mechanical displacement for release, mitigating the accumulation of thermal expansion stress inside the enclosed shell and reducing the possibility of weld tearing at the rigid connection under thermal cycling conditions.

[0056] The lifting lugs 5 installed on the outer side of the outer casing 2 are used to keep the pipe vertically suspended during the manufacturing stage. They rely on the symmetrical distribution of gravity to limit the bending deformation of the slender pipe body, ensuring that the lightweight insulating castable is uniformly and densely filled in the annular gap. The inorganic zinc-rich primer and organosilicon heat-resistant paint system coated on the outermost part of the pipe body can provide external anti-corrosion protection for the outer wall of the outer casing 2.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process for a hot-transport wear-resistant pipe, characterized in that, Includes the following steps: S1. Select austenitic heat-resistant stainless steel pipe as the base material of inner sleeve (1), and perform three layers of anti-deformation and wear-resistant overlay welding in sequence inside the inner sleeve (1); wherein, the first layer adopts single ring welding for the root, the second layer adopts single ring welding for the transition, and the third layer adopts swing ring welding for the cover; during the entire welding process, the temperature of the outer wall of the inner sleeve (1) is controlled; after welding, cool to room temperature for later use; S2. Select seamless steel pipe as outer sleeve (2) and weld flanges (6) at both ends; before installing inner sleeve (1) and insulation material, conduct hydrostatic pressure test on outer sleeve (2) independently, select outer sleeve (2) without obvious structural deformation and without pressure drop, drain and dry it; S3. Weld a sliding support ring (3) and a baffle support ring (4) to the inner wall of the outer sleeve (2) after it has passed the pressure test; insert the inner sleeve (1) obtained in step (1) into the outer sleeve (2) and adjust the concentricity of the assembly; then weld the inner sleeve (1) to the baffle support ring (4) and weld the lifting lug (5) to the outer wall of the outer sleeve (2). S4. Lift the outer tube (2) vertically using the lifting lug (5), pump lightweight heat-insulating castable into the annular gap between the inner and outer tubes, and vibrate and cure it to form a lightweight heat-insulating castable layer (7); finally, sandblast the outer surface of the outer tube (2) and spray inorganic zinc-rich primer and organic silicone heat-resistant paint in sequence.

2. The manufacturing process of a hot-transport wear-resistant pipe according to claim 1, characterized in that, In step S1, the temperature of the outer wall of the inner sleeve (1) is maintained between 100°C and 145°C throughout the welding process. The specific parameters for the three-layer anti-deformation and wear-resistant weld overlay are as follows: First layer: Use carbide welding wire, welding current 220A~250A, arc voltage 24V~26V, welding speed 30cm / min~40cm / min, and control the weld thickness to 2.0mm~3.0mm; Second layer: Welding current 250A~280A, arc voltage 26V~28V, welding speed 25cm / min~35cm / min, and weld thickness controlled at 3.5mm~4.0mm; Third layer: Welding current 280A~320A, arc voltage 28V~32V, oscillation frequency 40 times / min~60 times / min, and weld thickness controlled at 3.5mm~4.0mm.

3. The manufacturing process of a hot-transport wear-resistant pipe according to claim 1, characterized in that, In step S2, the test pressure of the hydrostatic test is set to 1.035MPa to 1.100MPa, and the pressure stabilization time is controlled to 10min to 15min.

4. The manufacturing process of a hot-transport wear-resistant pipe according to claim 1, characterized in that, In step S3, the number of sliding support rings (3) is at least two; The inner diameter of the retaining support ring (4) is 5mm to 10mm larger than the outer diameter of the inner sleeve (1); After inserting the inner sleeve (1), the concentricity of the inner sleeve (1) and the outer sleeve (2) is controlled within the range of ±0.5mm to ±2.0mm.

5. The manufacturing process of a hot-transport wear-resistant pipe according to claim 1, characterized in that, In step S4, the sandblasting treatment is carried out to Sa2.5 grade; the dry film thickness of the inorganic zinc-rich primer is 60μm~80μm, and the dry film thickness of the organosilicon heat-resistant paint is 35μm~45μm; The natural curing time for the castable is 20 to 30 days.

6. A hot-transport wear-resistant pipe manufactured by the process described in any one of claims 1-5, characterized in that, include: The outer sleeve (2) is fixedly connected to flanges (6) at both ends; The inner sleeve (1) is coaxially inserted inside the outer sleeve (2). The inner wall of the inner sleeve (1) has a first single ring weld layer, a second single ring weld layer and a third swing ring weld layer connected in sequence. A support limiting component is provided between the outer sleeve (2) and the inner sleeve (1), including a sliding support ring (3) and a material blocking support ring (4) fixed to the inner wall of the outer sleeve (2); the inner sleeve (1) is fixedly connected to the material blocking support ring (4), and the outer wall of the inner sleeve (1) is in sliding fit with the sliding support ring (3); A lightweight heat-insulating casting layer (7) is filled in the annular gap between the outer sleeve (2) and the inner sleeve (1); The outer surface of the outer sleeve (2) is coated with inorganic zinc-rich primer and organic silicone heat-resistant paint in sequence.

7. The hot-transfer wear-resistant pipe according to claim 6, characterized in that, The inner sleeve (1) is a 310S austenitic heat-resistant stainless steel pipe, and the total weld thickness of the first single ring weld layer, the second single ring weld layer and the third swing ring weld layer is 9.5mm to 10.5mm.

8. The hot-transfer wear-resistant pipe according to claim 6, characterized in that, The inner diameter of the retaining support ring (4) is 5mm to 10mm larger than the outer diameter of the inner sleeve (1), and the inner sleeve (1) and the retaining support ring (4) are fixed together by a weld.

9. The hot-transfer wear-resistant pipe according to claim 6, characterized in that, The outer sleeve (2) is an L245 seamless steel pipe; the sliding support ring (3) and the retaining support ring (4) are both made of SUS304 austenitic stainless steel.

10. The hot-transfer wear-resistant pipe according to claim 6, characterized in that, The outer wall of the outer sleeve (2) is also welded with lifting lugs (5) for vertical hoisting and pouring.

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