CN113431014A - Ocean platform casting node with gradually-changed wall thickness and preparation method thereof - Google Patents
Ocean platform casting node with gradually-changed wall thickness and preparation method thereof Download PDFInfo
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- CN113431014A CN113431014A CN202110745462.6A CN202110745462A CN113431014A CN 113431014 A CN113431014 A CN 113431014A CN 202110745462 A CN202110745462 A CN 202110745462A CN 113431014 A CN113431014 A CN 113431014A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/085—Cooling or quenching
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
- E02B17/0004—Nodal points
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Rigid Pipes And Flexible Pipes (AREA)
Abstract
A casting node with gradually-changed wall thickness for an ocean platform comprises a main body for connecting steel structure pipe fittings, wherein the main body is integrally cast steel and comprises a central connecting pipe, 2-4 inclined pipes and 2-6 bottom pipes; the link of central connecting pipe, pipe chute and bottom tube passes through mutually and converges and form node core area in one department, and the axis of all connecting pipe fittings intersects in two central points in node core area, and two central points are apart from 250 and give first place to 300mm, set up fillet transition between the interior outer wall surface of two adjacent connected pipes. The cast joint reduces the whole weight and ensures good welding performance while reducing the weight. The casting node can be formed in one step, the process is simpler, and the manufacturing cost is greatly reduced.
Description
Technical Field
The invention belongs to the field of ocean platform equipment, and particularly relates to a corrosion-resistant high-strength high-toughness cast node in a low-temperature environment.
Background
The ocean platform is the foundation for human ocean development, and the nodes are a key component in the ocean platform. The main function of the node is to connect the key and bear the load, and because the stress state of the node is relatively complicated, the stress concentration phenomenon is easily generated, so that cracks appear, and the structure is possibly failed due to further expansion, so that serious accidents occur. Therefore, the design of the node needs to meet the overall stress strength of the platform structure and also needs to meet the local strength of each component meeting the node, including the structural strength, the static strength and the fatigue strength, so as to ensure the safety of the platform. The welding joint has high internal stress and serious low-temperature cold brittleness, and stress concentration is easy to occur under the action of external force to cause joint damage, thus the safety of the platform is damaged. The cast joint has high rigidity, stress concentration coefficient of only one half of that of a welded joint, long fatigue life, strong extreme environment resistance, isotropy of cast steel and higher toughness in the thickness direction. In addition, the cost of the casting node is lower than that of the welding node, and the casting node replaces the welding node, except for individual nodes, most casting nodes can save steel by 5-15%, and the manufacturing cost is reduced by 3-30%, so that the development of ocean platform casting nodes is a future development trend.
Disclosure of Invention
The invention aims to provide a casting node with gradually-changed wall thickness for an ocean platform, which comprises a main body for connecting steel structure pipe fittings, wherein the main body is integrally cast steel and comprises a central connecting pipe, 2-4 inclined pipes and 2-6 bottom pipes; the link of central connecting pipe, pipe chute and bottom tube passes through mutually and converges and form node core area in one department, and the axis of all connecting pipe fittings intersects in two central points in node core area, and two central points are apart from 250 and give first place to 300mm, set up fillet transition between the interior outer wall surface of two adjacent connected pipes. Preferably, the main body comprises a central connecting pipe, 2 inclined pipes and 2 bottom pipes.
In the novel gradually-changing wall thickness casting node, the wall thickness of the upper parts of the pipe fittings of the central connecting pipe and the inclined pipe is gradually increased, and the wall thickness of the lower parts of the pipe fittings is uniform; the wall thickness of the central connecting pipe is gradually increased from a position 180-220mm away from the end point of the central connecting pipe, the wall thickness of the central point at the upper part of the central connecting pipe is the largest, the minimum wall thickness at the upper part of the central connecting pipe is 25-30mm, the maximum wall thickness is 35-45mm, and the wall thickness at the lower part of the central pipe is 25-30 mm; the wall thickness of the inclined tube is gradually increased from the intersection area of the inclined tube and the central connecting tube, the minimum wall thickness of the upper part of the inclined tube is 20-25mm, the maximum wall thickness is 30-40mm, and the wall thickness of the lower part of the inclined tube is 20-25 mm; the inclined pipe is connected with the central connecting pipe at an angle of 30-45 degrees; the bottom tube is a uniform wall thickness tube with the wall thickness of 12-15mm and is connected with the central connecting tube at an angle of 60-90 degrees.
The upper parts of the central connecting pipe and the inclined pipe are parts above the horizontal plane of the cross section of the pipe.
The maximum wall thickness of the inclined tube is positioned on the section which is perpendicular to the axis of the central connecting tube at the center of the node.
Preferably, in the novel gradually-changing wall thickness casting node, the wall thickness of the upper part of the pipe fitting of the central connecting pipe and the inclined pipe is gradually increased, and the wall thickness of the lower part of the pipe fitting of the central connecting pipe and the inclined pipe is uniform; the wall thickness of the central connecting pipe is gradually increased from the position 190-210mm away from the end point of the central connecting pipe, the wall thickness of the central point of the central connecting pipe is the largest, the minimum wall thickness of the upper part of the central connecting pipe is 28-30mm, the maximum wall thickness is 40-42mm, and the wall thickness of the lower part of the central connecting pipe is 28-30 mm; the wall thickness of the inclined tube is gradually increased from the intersection area of the inclined tube and the central connecting tube, the minimum wall thickness of the upper part of the inclined tube is 22-23mm, the maximum wall thickness is 32-38mm, and the wall thickness of the lower part of the inclined tube is 22-23 mm; the inclined pipe is connected with the central connecting pipe at an angle of 35-40 degrees; the bottom pipe is a pipe with uniform wall thickness of 13-14mm, and is connected with the central connecting pipe fitting at an angle of 70-80 degrees.
Preferably, the steel for the casting node may be pretreated, including the steps of:
(1) quenching treatment: heating the corrosion-resistant high-strength high-toughness casting node steel casting in the low-temperature environment to 930-;
(2) tempering treatment: and (3) heating the corrosion-resistant high-strength high-toughness casting node steel in the low-temperature environment after water quenching to 450-700 ℃, preserving the heat for 4-6h, and then cooling the steel to room temperature.
The invention adopts a quenching and tempering heat treatment process when preparing the corrosion-resistant high-strength high-toughness casting node in a low-temperature environment, thereby obtaining a microstructure of tempered sorbite with a small amount of residual austenite and ferrite. The residual austenite distributed in the structure can enhance the strength and toughness of the whole steel, and the residual austenite can effectively absorb stress in the deformation process to prevent microcracks; the tempered sorbite is a matrix tissue with better toughness; the fine ferrite structure distributed in a dispersed manner can well inhibit crack propagation, and can prevent grains from growing in the phase transformation process, and in the quenching and tempering processes, the ferrite can form some superfine sub-grains along the grain boundary of the quenched prior austenite, so that the proportion of the grain boundary is increased, the content of harmful impurity elements on the unit interface is further reduced, and the toughness of the alloy is favorably improved.
Preferably, the carbon content in the steel for casting the node satisfies that C is less than or equal to 0.12 percent, and the carbon equivalent satisfies that CeqLess than or equal to 0.56 percent, reduces the whole weight of the casting node, and ensures good welding performance while reducing the wall thickness of the casting node.
Preferably, the proportion of ferrite in the steel for casting nodes is more than or equal to 10%.
Preferably, the prepared steel for the corrosion-resistant high-strength high-toughness casting node has good corrosion resistance in a low-temperature environment at-40 ℃.
Has the advantages that: compared with the existing casting node, the invention has the remarkable advantages that: in the solidification process, the wall is thin and gradually changed in wall thickness, the heat storage capacity of the molten steel in unit volume is small, and the solidification speed is relatively high; the adjacent thicknesses of the products are greatly different, and the thickness is gradually transited in the process of joining; the distribution positions of the risers enable the shrinkage stress of the whole casting to be distributed basically uniformly, and the feeding distance can reach 4-5 times of the wall thickness generally; the design of the pouring system can feed liquid from a low position, and the pouring system is provided with a side riser for introduction or a gap gate for introduction, so that the mold filling process is stable, slag discharge, discharge and ingate are facilitated to be arranged uniformly as much as possible, and the shrinkage stress is uniform; the thinner the casting wall, the larger the area and the complex shape, the larger the resistance of the metal flowing in the casting mold, and at the same time, the temperature reduction is fast, the fluidity is poor, the casting is difficult to be fully poured, the casting can generate the defects of cold shut, insufficient pouring and the like, and the problem is well solved by the gradual change thickness.
Drawings
FIG. 1 is a schematic view of a progressive wall thickness cast node construction;
FIG. 2 is a schematic cross-sectional view of a cast node with a gradually varying wall thickness;
FIG. 3 is a top view of a cross-sectional structure of a progressive wall thickness cast node.
Wherein, 1 is a central connecting pipe fitting; 2 is an inclined tube; 3 is a connecting pipe fitting; 4 is the central axis of the inclined tube; 5 is a central axis of the central connecting pipe fitting; and 6 is a central point.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the embodiment.
Example 1
A casting node with gradually-changed wall thickness for an ocean platform comprises a main body used for connecting a steel structure pipe body, wherein the main body is an integrally-cast steel node and comprises a main body used for connecting a steel structure pipe fitting, the main body is integrally-cast steel, and the main body comprises a central connecting pipe, 2 inclined pipes and 2 bottom pipes; the connecting ends of the central connecting pipe, the inclined pipe and the bottom pipe are mutually intersected and converged at one position to form a node core area, the central axes of all connecting pipe fittings are intersected on two central points in the node core area, the distance between the two central points is 250mm, and circular arc transition is arranged between the inner wall surface and the outer wall surface of two adjacent connecting pipe bodies. The upper part of the novel casting node with the gradually-changed wall thickness is provided with the gradually-changed wall thickness, and the lower part of the novel casting node with the gradually-changed wall thickness is provided with the uniform wall thickness; the minimum wall thickness of the central connecting pipe body is 25mm, the minimum wall thickness gradually increases from a region 200mm away from the end point of the central connecting pipe, and the thickest part is 35 mm; the minimum wall thickness of the inclined tube is 20mm, the thickness of the inclined tube gradually increases from a 200mm area, the thickest part is 30mm, and the inclined tube is connected with the central connecting tube body at an angle of 30 degrees; the bottom tube has a uniform wall thickness of 12mm, and is connected with the central connecting rod at an angle of 60 degrees. The maximum tensile strength of the cast joint is 632 MPa.
Example 2
A casting node with gradually-changed wall thickness for an ocean platform comprises a main body used for connecting a steel structure pipe body, wherein the main body is an integrally-cast steel node and comprises a main body used for connecting a steel structure pipe fitting, the main body is integrally-cast steel, and the main body comprises a central connecting pipe, 2 inclined pipes and 2 bottom pipes; the connecting ends of the central connecting pipe, the inclined pipe and the bottom pipe are mutually intersected and converged at one position to form a node core area, the central axes of all connecting pipe fittings are intersected on two central points in the node core area, the two central points are separated by 300mm, and circular arc transition is arranged between the inner wall surface and the outer wall surface of two adjacent connecting pipe bodies.
The upper part of the novel casting node with the gradually-changed wall thickness is provided with the gradually-changed wall thickness, and the lower part of the novel casting node with the gradually-changed wall thickness is provided with the uniform wall thickness; the minimum wall thickness of the central connecting pipe body is 30mm, the area 220mm away from the end point of the central connecting pipe begins to increase gradually, and the thickest part is 45 mm; the minimum wall thickness of the inclined tube is 25mm, the thickness of the inclined tube gradually increases from a 220mm area, the thickest part is 40mm, and the inclined tube is connected with the central connecting tube body at an angle of 45 degrees; the bottom tube is uniform in wall thickness, the wall thickness is 15mm, and the bottom tube is connected with the central connecting tube body at an angle of 90 degrees. The maximum tensile strength of the cast node is 627 MPa.
Comparative example 1
An ocean platform gradual wall thickness casting node is the same as that in embodiment 1 in structure, but all pipes are pipes with the same wall thickness, and the thickness of each pipe is 35 mm. The maximum tensile strength of the cast joint is 520 MPa.
Comparative example 2
An ocean platform gradual wall thickness casting node is the same as the structure of the ocean platform gradual wall thickness casting node in the embodiment 1, but all pipes are pipes with the same wall thickness, and the thickness of each pipe is 25 mm. The maximum tensile strength of the cast joint was 504 MPa.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention, and any modifications, equivalent alterations and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. A casting node with gradually-changed wall thickness for an ocean platform is characterized by comprising a main body for connecting steel structure pipe fittings, wherein the main body is integrally cast steel and comprises a central connecting pipe, 2-4 inclined pipes and 2-6 bottom pipes; the link of central connecting pipe, pipe chute and bottom tube passes through mutually and converges and form node core area in one department, and the axis of all connecting pipe fittings intersects in two central points in node core area, and two central points are apart from 250 and give first place to 300mm, set up fillet transition between the interior outer wall surface of two adjacent connected pipes.
2. The casting joint of claim 1, wherein the upper portion of the central connecting tube and the tube member of the down tube have a gradually increasing wall thickness and the lower portion has a uniform wall thickness; the wall thickness of the central connecting pipe is gradually increased from a position 180-220mm away from the end point of the central connecting pipe, the wall thickness of the central point at the upper part of the central connecting pipe is the largest, the minimum wall thickness at the upper part of the central connecting pipe is 25-30mm, the maximum wall thickness is 35-45mm, and the wall thickness at the lower part of the central pipe is 25-30 mm; the wall thickness of the inclined tube is gradually increased from the intersection area of the inclined tube and the central connecting tube, the minimum wall thickness of the upper part of the inclined tube is 20-25mm, the maximum wall thickness is 30-40mm, and the wall thickness of the lower part of the inclined tube is 20-25 mm; the inclined pipe is connected with the central connecting pipe at an angle of 30-45 degrees; the bottom tube is a uniform wall thickness tube with the wall thickness of 12-15mm and is connected with the central connecting tube at an angle of 60-90 degrees.
3. The casting joint of claim 1, wherein the upper portion of the central connecting tube and the tube member of the down tube have a gradually increasing wall thickness and the lower portion has a uniform wall thickness; the wall thickness of the central connecting pipe is gradually increased from the position 190-210mm away from the end point of the central connecting pipe, the wall thickness of the central point of the central connecting pipe is the largest, the minimum wall thickness of the upper part of the central connecting pipe is 28-30mm, the maximum wall thickness is 40-42mm, and the wall thickness of the lower part of the central connecting pipe is 28-30 mm; the wall thickness of the inclined tube is gradually increased from the intersection area of the inclined tube and the central connecting tube, the minimum wall thickness of the upper part of the inclined tube is 22-23mm, the maximum wall thickness is 32-38mm, and the wall thickness of the lower part of the inclined tube is 22-23 mm; the inclined pipe is connected with the central connecting pipe at an angle of 35-40 degrees; the bottom pipe is a pipe with uniform wall thickness of 13-14mm, and is connected with the central connecting pipe fitting at an angle of 70-80 degrees.
4. A casting joint as claimed in claim 1, wherein the upper part of the pipe elements of the central connecting pipe and the down tube is the part above the horizontal plane of the cross-section of the pipe elements.
5. A cast joint according to claim 1, wherein the maximum wall thickness of the down tube is in a cross section perpendicular to the axis of the central connecting tube at the centre of the joint.
6. The cast node of claim 1, wherein the cast node steel is pretreated comprising the steps of:
(1) quenching treatment: heating the corrosion-resistant high-strength high-toughness casting node steel casting in the low-temperature environment to 930-;
(2) tempering treatment: and (3) heating the corrosion-resistant high-strength high-toughness casting node steel in the low-temperature environment after water quenching to 450-700 ℃, preserving the heat for 4-6h, and then cooling the steel to room temperature.
7. The cast joint according to claim 6, wherein the steel for cast joints has a ferrite content of 10% or more.
8. The cast joint according to claim 6, wherein the steel for cast joint has a carbon content satisfying C.ltoreq.0.12% and a carbon equivalent satisfying Ceq≤0.56％。
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110745462.6A CN113431014B (en) | 2021-07-01 | 2021-07-01 | Ocean platform casting node with gradually-changed wall thickness and preparation method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110745462.6A CN113431014B (en) | 2021-07-01 | 2021-07-01 | Ocean platform casting node with gradually-changed wall thickness and preparation method thereof |
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| CN113431014B CN113431014B (en) | 2022-11-29 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4790172A (en) * | 1984-09-21 | 1988-12-13 | Saga Petroleum A.S. | Method for providing a tubular node in a framework truss structure such as offshore platforms for oil drilling and production |
| CN103993244A (en) * | 2014-05-28 | 2014-08-20 | 北京机电院高技术股份有限公司 | Low-alloy cast steel joint as well as smelting and pouring control method and heat treatment process thereof |
| CN205173062U (en) * | 2015-11-12 | 2016-04-20 | 浙江林家昌隆阀门铸造有限公司 | Self priming pump foundry goods |
| CN208309836U (en) * | 2018-06-06 | 2019-01-01 | 中国航空规划设计研究总院有限公司 | A kind of three-dimensional mutually passes through cast steel node construction |
| CN110106445A (en) * | 2019-06-05 | 2019-08-09 | 上海大学 | One kind is for ocean platform cast node high intensity high/low temperature toughness steel and preparation method thereof |
| CN110939198A (en) * | 2019-11-06 | 2020-03-31 | 海洋石油工程（青岛）有限公司 | Prefabricated horizontal sheet of jacket and installation process |
-
2021
- 2021-07-01 CN CN202110745462.6A patent/CN113431014B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4790172A (en) * | 1984-09-21 | 1988-12-13 | Saga Petroleum A.S. | Method for providing a tubular node in a framework truss structure such as offshore platforms for oil drilling and production |
| CN103993244A (en) * | 2014-05-28 | 2014-08-20 | 北京机电院高技术股份有限公司 | Low-alloy cast steel joint as well as smelting and pouring control method and heat treatment process thereof |
| CN205173062U (en) * | 2015-11-12 | 2016-04-20 | 浙江林家昌隆阀门铸造有限公司 | Self priming pump foundry goods |
| CN208309836U (en) * | 2018-06-06 | 2019-01-01 | 中国航空规划设计研究总院有限公司 | A kind of three-dimensional mutually passes through cast steel node construction |
| CN110106445A (en) * | 2019-06-05 | 2019-08-09 | 上海大学 | One kind is for ocean platform cast node high intensity high/low temperature toughness steel and preparation method thereof |
| CN110939198A (en) * | 2019-11-06 | 2020-03-31 | 海洋石油工程（青岛）有限公司 | Prefabricated horizontal sheet of jacket and installation process |
Non-Patent Citations (2)
| Title |
|---|
| 孙方策: "海洋平台管结构铸钢节点展望", 《钢结构》 * |
| 赵宪忠等: "建筑用铸钢节点设计的若干关键问题", 《结构工程师》 * |
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