High-pressure-resistance butt welding elbow
By designing guide fins and biomimetic reinforcing ribs, combined with a multi-layer composite material structure, and optimizing fluid dynamics and stress distribution, the stress concentration and turbulent wear problems of traditional elbows under high pressure environments are solved, achieving an elbow design with high pressure resistance and long service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU JINCHUANGXINTIAN PIPE IND CO LTD
- Filing Date
- 2025-05-28
- Publication Date
- 2026-05-05
AI Technical Summary
Traditional butt-welded elbows are prone to stress concentration, turbulence, and erosion wear under high pressure, high temperature, and corrosive media environments, resulting in uneven structure and short service life.
It adopts a flow-guiding fin, biomimetic reinforcing ribs and multi-layer composite material structure, including an outer layer of pure 316L stainless steel, an intermediate layer with gradually decreasing silicon carbide content and an inner layer of high silicon carbide particle stainless steel, combined with the logarithmic spiral arrangement of biomimetic reinforcing ribs to optimize fluid dynamics and stress distribution.
It significantly reduces the resistance to medium flow, reduces turbulent energy loss, improves stress gradient transfer efficiency, extends service life, enhances compressive strength, reduces maximum equivalent stress by 52%, and extends the number of fatigue cycles.
Smart Images
Figure CN224201333U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of butt welded elbow technology, and in particular to a high-pressure-resistant butt welded elbow. Background Technology
[0002] In industries such as petroleum, chemical, and nuclear power, pipeline systems often need to withstand the long-term effects of high pressure, high temperature, and corrosive media. Elbows, as key components for changing the direction of fluid flow, directly affect the safety and operating efficiency of the entire system due to their structural strength, fatigue resistance, and fluid dynamic characteristics.
[0003] Traditional butt-welded elbows mainly adopt a uniform wall thickness design, which has the following technical defects:
[0004] Stress concentration problem: When the fluid turns, the elbow is subjected to centrifugal force, the inner wall is subjected to compressive stress and the outer wall is subjected to tensile stress, resulting in uneven stress distribution. Stress concentration is particularly likely to occur in the 45° and 135° areas. Long-term operation may lead to cracks or even pipe rupture accidents.
[0005] Turbulence and erosion wear: Traditional elbows lack internal flow guiding structures, and fluid is prone to turbulence and eddies when turning, which not only increases pressure drop but also accelerates erosion wear of the inner wall and reduces service life. To address this, we propose a high-pressure-resistant butt-welded elbow. Utility Model Content
[0006] This utility model is a high-pressure-resistant butt-welded elbow proposed to overcome the shortcomings of the existing technology.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A high-pressure-resistant butt-welded elbow includes an elbow body, with a plurality of flow-guiding fins disposed on the inner side of the elbow body, a stress-protecting sleeve disposed on the outer side of the elbow body, and a plurality of biomimetic reinforcing ribs disposed on the inner side of the stress-protecting sleeve.
[0009] Preferably, the height h of the biomimetic reinforcing rib satisfies h = (0.1-0.15)t0 with respect to the reference wall thickness t0 of the elbow body.
[0010] Preferably, the biomimetic reinforcing ribs are arranged in a logarithmic spiral, and the direction of the biomimetic reinforcing ribs forms an angle of 30°-45° with the tangential direction of the center line of the elbow body.
[0011] Preferably, the wall thickness of the elbow body is distributed in a sinusoidal square distribution along the tangential angle θ of the centerline.
[0012] Preferably, the biomimetic reinforcing rib has a trapezoidal cross-section with a top width to bottom width ratio of 1:1.2-1.5.
[0013] Preferably, the elbow body includes an outer layer, an intermediate transition layer, and an inner layer. The outer layer is disposed inside the stress protection sleeve, the intermediate transition layer is disposed inside the outer layer, and the inner layer is disposed inside the intermediate transition layer.
[0014] Preferably, the outer layer is made of pure 316L matrix components.
[0015] Preferably, the inner layer is made of 316L stainless steel with 20%-30% silicon carbide particles added.
[0016] Preferably, the intermediate transition layer is made of 316L stainless steel with a gradually decreasing silicon carbide content (5%-15%).
[0017] In summary, this invention optimizes fluid dynamics by using guide fins in conjunction with biomimetic reinforcing ribs arranged in a logarithmic spiral to form a composite flow field, reducing the flow resistance of the medium by 15%-20% and effectively suppressing eddy current generation. The tangential angle design of the ribs at 30°-45° ensures optimal mechanical coupling between the fluid shear force and the direction of the reinforcing ribs, reducing turbulent energy loss.
[0018] This utility model reconstructs the stress field: by precisely matching the trapezoidal cross section (top width to bottom width ratio 1:1.2-1.5) of the biomimetic reinforcing rib with the height h = (0.1-0.15)t0, the stress gradient transmission efficiency is improved by more than 30%. The logarithmic spiral arrangement of the ribs simulates the growth lines of seashells, reducing the circumferential stress concentration factor to below 1.2.
[0019] This utility model has a multi-layer composite protection system: the outer layer is a pure 316L matrix that provides basic toughness; the middle transition layer has a gradually decreasing silicon carbide content (5%-15%) that forms a continuous transition zone for the coefficient of thermal expansion, which reduces the peak thermal stress by 40%; and the inner layer is a 316L stainless steel component reinforced with 20%-30% silicon carbide particles, which extends the wear resistance life by 3 to 5 times.
[0020] This invention features intelligent wall thickness distribution: the wall thickness of the elbow body varies with the centerline angle θ according to the square function of a sine wave, forming thickness enhancement peaks in the key stress areas of 45° and 135°, which reduces the overall weight by 12% while increasing the burst pressure by 25%.
[0021] This utility model features a biomimetic mechanical adaptation: the stress protection sleeve and the biomimetic reinforcing rib form a composite protective structure that is rigid on the outside and flexible on the inside. Under an internal pressure of 10MPa, the maximum equivalent stress is reduced by 52% compared to the traditional elbow, and the fatigue cycle count reaches 2×10^6 without failure. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the front axial side of this utility model;
[0023] Figure 2 This is a side-section structural diagram of the present invention.
[0024] In the diagram: 1. Elbow body; 11. Outer layer; 12. Intermediate transition layer; 13. Inner layer; 2. Guide fins; 3. Stress protection sleeve; 4. Bionic reinforcing ribs. Detailed Implementation
[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.
[0026] like Figures 1-2 As shown, a high-compression welded elbow includes an elbow body 1, with several guide fins 2 on its inner side and a stress protection sleeve 3 on its outer side. The stress protection sleeve 3 has several biomimetic reinforcing ribs 4 on its inner side.
[0027] The guide fins 2 are evenly distributed along the circumference of the inner wall of the elbow, with a height of 5%-8% of the inner diameter of the elbow and a fin spacing of 1 / 10-1 / 8 of the radius of curvature of the elbow. They are used to guide the fluid to turn smoothly and reduce turbulence and pressure drop.
[0028] The stress protection sleeve 3 is made of high-strength alloy steel (such as 42CrMo) and is fitted on the outside of the elbow body 1. Its thickness is 0.3-0.5 times the elbow reference wall thickness t0. It is used to bear external loads and inhibit crack propagation.
[0029] The biomimetic reinforcing rib 4 is set between the stress protection sleeve 3 and the elbow body 1, and is integrally formed by precision casting or 3D printing. The relationship between the rib height h and the elbow reference wall thickness t0 is h=(0.1-0.15)t0, so as to optimize the stress transmission path.
[0030] The biomimetic reinforcing rib 4 is arranged in a logarithmic spiral. The ribs of the biomimetic reinforcing rib 4 are arranged in a logarithmic spiral (r=a·e^(bθ)) with a spiral coefficient b=0.05-0.1, so that its direction is at an angle of 30°-45° with the tangential of the elbow centerline to match the direction of fluid shear force and reduce stress concentration.
[0031] The cross-section of the biomimetic reinforcing rib 4 is trapezoidal, with the ratio of the top width W1 to the bottom width W2 being 1:1.2-1.5, and the rib spacing being 3h-5h, in order to enhance bending strength and avoid sudden stress changes;
[0032] The wall thickness of the elbow body 1 follows a sinusoidal square distribution along the tangential angle θ of the centerline, as expressed in the following expression:
[0033] t(θ) = t0 + Δt·sin 2(2θ)
[0034] Where t0 is the reference wall thickness and Δt is the maximum thickness increase (usually taken as 0.2t0-0.3t0), local reinforcement zones are formed at 45° and 135° to balance the circumferential stress under internal pressure load;
[0035] The elbow body 1 adopts a three-layer composite structure, from the outside to the inside: the outer layer 1 is a pure 316L stainless steel substrate, accounting for 40%-50% of the thickness, providing basic toughness and weldability; the middle transition layer 2 is a 316L composite material with a gradually decreasing silicon carbide (SiC) content (5%-15%), accounting for 20%-30% of the thickness, formed by powder metallurgy layer-by-layer sintering to ensure a smooth transition in the coefficient of thermal expansion.
[0036] The inner layer 13 is a 316L composite material containing 20%-30% silicon carbide particles, with a thickness of 30%-40%. It is prepared by laser cladding process, with a hardness ≥HRC45 and wear resistance more than 3 times that of pure 316L.
[0037] Manufacturing process of this embodiment
[0038] Bionic reinforcing rib forming: Precision casting or selective laser melting (SLM) technology is used to form a metallurgical bond between the rib and the stress protection sleeve 3.
[0039] Multi-layer composite elbow body manufacturing: the outer layer 11 is formed by conventional forging;
[0040] The intermediate transition layer 12 is sintered by gradient powder hot isostatic pressing (HIP);
[0041] The inner layer 13 adopts a plasma spraying + hot rolling composite process.
[0042] Overall assembly: After heating the stress protection sleeve 3 to 300-400℃, it is heat-fitted onto the elbow body 1. After cooling, an interference fit is formed. Finally, the inner surface is polished to Ra≤0.8μm.
[0043] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.
Claims
1. A high-compression-resistant butt-welded elbow, characterized in that, The elbow body (1) includes a plurality of guide fins (2) on the inner side of the elbow body (1), a stress protection sleeve (3) on the outer side of the elbow body (1), and a plurality of biomimetic reinforcing ribs (4) on the inner side of the stress protection sleeve (3).
2. The high-compression weld elbow according to claim 1, characterized in that, The height h of the biomimetic reinforcing rib (4) satisfies h = (0.1-0.15)t0 with respect to the reference wall thickness t0 of the elbow body (1).
3. The high-compression weld elbow according to claim 1, characterized in that, The ribs of the bionic reinforcing rib (4) are arranged in a logarithmic spiral, and the direction of the bionic reinforcing rib (4) forms an angle of 30°-45° with the tangential direction of the center line of the elbow body (1).
4. A high-compression weld elbow according to claim 1, characterized in that, The wall thickness of the elbow body (1) is sinusoidally squared along the tangential angle θ of the centerline.
5. A high-compression weld elbow according to claim 1, characterized in that, The cross-section of the biomimetic reinforcing rib (4) is trapezoidal, with a top width to bottom width ratio of 1:1.2-1.
5.
6. A high-compression weld elbow according to claim 1, characterized in that, The elbow body (1) includes an outer layer (11), an intermediate transition layer (12) and an inner layer (13). The outer layer (11) is disposed inside the stress protection sleeve (3), the intermediate transition layer (12) is disposed inside the outer layer (11), and the inner layer (13) is disposed inside the intermediate transition layer (12).
7. A high-compression weld elbow according to claim 6, characterized in that, The outer layer (11) is made of pure 316L matrix components.
8. A high-compression weld elbow according to claim 6, characterized in that, The inner layer (13) is made of 316L stainless steel with 20%-30% silicon carbide particles added.
9. A high-compression weld elbow according to claim 6, characterized in that, The intermediate transition layer (12) is made of 316L stainless steel with a gradually decreasing silicon carbide content (5%-15%).