CN113280194A

CN113280194A - Double-clamping sleeve for pipeline joint and preparation method thereof

Info

Publication number: CN113280194A
Application number: CN202110573227.5A
Authority: CN
Inventors: 罗文军; 励行根; 李征; 励洁; 沈锴; 陈腾翔; 岳怀艳; 黄坤明
Original assignee: NINGBO TIANSHENG SEALING PACKING CO Ltd
Current assignee: NINGBO TIANSHENG SEALING PACKING CO Ltd
Priority date: 2021-05-25
Filing date: 2021-05-25
Publication date: 2021-08-20

Abstract

The invention discloses a double ferrule for a pipeline joint, wherein the rear ferrule is shaped like a high-heeled shoe; The included angle A is 60°-90°, the included angle B between the front section of the outer wall and the axis is 30°-40°, the rear section of the outer wall is parallel to the axis, and the middle section of the outer wall includes three sections of the outer wall recessed toward the axis, the first outer wall and the radial The included angle C is 40-50°, the included angle D between the second outer wall and the axis is 10°-15°, and the included angle E between the third outer wall and the radial direction is 35°-45°; The rear part is inclined outward, and the angle F between the inclined surface and the axis is 6°‑10°. The invention provides a specific structure of a double ferrule for nuclear-grade application pipeline sealing and a preparation method thereof, and reduces the use cost of the double ferrule pipe joint.

Description

Double-clamping sleeve for pipeline joint and preparation method thereof

Technical Field

The invention relates to the field of pipeline sealing, in particular to a double-clamping sleeve for a pipeline joint and a preparation method thereof.

Background

The double-clamping sleeve pipe joint is indispensable in nuclear-grade application equipment, and it designs the main seal between preceding cutting ferrule and pipeline through the double-clamping sleeve of preceding cutting ferrule and back cutting ferrule, converts the axial load of nut into the radial pressure to the pipeline through back cutting ferrule again, has strengthened the tensile property who connects by a wide margin on the basis of the sealed effect of cutting ferrule before improving. The double-clamping sleeve pipeline joint adopted by the domestic nuclear power station is purchased abroad, no domestic product related to the research and development of the nuclear-grade application double-clamping sleeve pipeline joint is found, and no domestic product can meet the nuclear-grade application requirement. Therefore, the preparation problem of the domestic double-clamping sleeve pipeline joint needs to be solved urgently, and in the preparation process of the double-clamping sleeve pipeline joint, the specific structure, the size and the post-treatment process of the double clamping sleeve are difficult points of domestic technical breakthrough.

Disclosure of Invention

The invention aims to provide a double-clamping sleeve for a pipeline joint and a preparation method thereof aiming at the defects in the prior art.

In order to achieve the purpose, the invention adopts the following scheme:

a double cutting ferrule for a pipeline joint is characterized in that a front cutting ferrule is in a circular truncated cone shape and comprises a small end and a large end, the included angle A between the outer wall of the front cutting ferrule and an axis is 15-25 degrees, and the included angle B between the inner wall of the large end and the axis is 40-60 degrees; the section of the rear cutting ferrule is similar to a high-heeled shoe, the outer wall of the rear cutting ferrule comprises a front section, a middle section and a rear section, the end face of the front section is perpendicular to the axis, the end face of the rear section inclines forwards, and the included angle C between the end face of the rear section and the axis is 60-90 degrees, the included angle D between the front section of the outer wall and the axis is 30-40 degrees, the rear section of the outer wall is parallel to the axis, the middle section of the outer wall comprises three sections of outer walls sunken towards the axis, the included angle E between the first outer wall and the radial direction is 40-50 degrees, the included angle F between the second outer wall and the axis is 10-15 degrees, and the included angle G between the third outer wall and the radial direction is 35-45 degrees; the middle rear part of the inner wall of the rear cutting sleeve inclines outwards, the included angle H between the inclined plane and the axis is 6-10 degrees, and the front section of the outer wall of the rear cutting sleeve is connected with the inner wall of the large end of the front cutting sleeve.

Further, the included angle a is 18 °, the included angle B is 45 °, the included angle C is 80 °, the included angle D is 37.5 °, the included angle E is 45 °, the included angle F is 11 °, the included angle G is 38 °, the included angle H is 8 °, and the included angle I is 20.5 °.

Further, the inner diameters of the front cutting sleeve and the rear cutting sleeve are 2mm-50mm, and are preferably 12.7 mm; the outer diameter of the small end of the front cutting sleeve is 10mm-15mm, preferably 13.5mm, the inner diameter of the end face of the large end is 11.5mm-17mm, preferably 14.9mm, the outer diameter is 15mm-20mm, preferably 17.3mm, and the axial length of the front cutting sleeve is 5mm-10mm, preferably 7.3 mm; the outer diameter of the end face of the front section of the rear cutting sleeve is 11mm-14mm, preferably 13.3mm, the maximum outer diameter of the front section of the outer wall is 12mm-16mm, preferably 14.6mm, the outer diameter of the rear section of the outer wall is 14mm-17mm, preferably 15.6mm, and the axial length of the rear cutting sleeve is 2.5mm-5.5mm, preferably 3.8 mm.

Furthermore, the tolerance of the inner diameters of the front cutting sleeve and the rear cutting sleeve is 0.095 mm-0.138 mm; the dimensional tolerances of the small end outer diameter, the large end face inner diameter, the large end face outer diameter and the axial length of the front cutting sleeve are all-0.05 mm, the dimensional tolerances of the front section end face outer diameter and the outer wall rear section outer diameter of the rear cutting sleeve are all-0.07 mm-0 mm, the maximum dimensional tolerance of the outer wall front section outer diameter is-0.1 mm-0 mm, and the axial length dimensional tolerance of the rear cutting sleeve is-0.05 mm.

Further, the outer wall of the rear cutting ferrule is subjected to carburizing and nitriding treatment, the thickness of a carburized layer is 0.1mm-0.3mm, and the surface hardness is HV820-HV 840.

The application also provides a preparation method of the double-ferrule, which comprises the following steps: the manufacturing of front cutting ferrule includes: turning the outer circle and the end face, boring, chamfering, cutting off, turning the end face, carburizing and inspecting; the manufacturing of back cutting ferrule includes: turning the outer circle and the end face, boring, chamfering, cutting off, turning the inclined end face, nitriding, carburizing, oil quenching, tempering and inspecting; wherein, the surface of the rear cutting ferrule is carburized and nitrided, the thickness of a carburized layer is 0.1mm-0.3mm, and the surface hardness is HV820-HV 840.

Further, the specific processes of nitriding, carburizing, oil quenching and tempering of the rear ferrule comprise: heating to 650 deg.C in vacuum furnace, maintaining the temperature for 15-25min, heating to 950 deg.C, maintaining the temperature for 15-25min, introducing NH₃And N₂The flow rate is 8-15L/min, nitriding treatment is carried out for 20-40min, and the changing atmosphere is C introduction₂H₂+N₂Carburizing for 15-30min at flow rate of 8-15L/min, and introducing NH₃And N₂Nitriding at the flow rate of 8-15L/min for 15-30min under carburizing and nitriding pressure of 2000 Pa; then carrying out oil quenching, wherein in the oil quenching process, the rear sleeve is sleeved with oil and then stirred, the maximum stirring frequency is 50Hz, and the oil temperature is 60 ℃; the tempering process comprises the following steps: heating to 160 deg.C, maintaining the temperature for 120min, and air cooling to room temperature.

The rear ferrule of the invention is applied to a double-ferrule pipeline joint.

Compared with the prior art, the invention has the advantages that: breaks through foreign technical blockade, and realizes the localization of the double-clamp sleeve joint for nuclear-grade application. The beneficial effects brought by the method are as follows:

1. through the rear clamping sleeve post-treatment process, the technical effects of thinner permeating layer and higher surface hardness of the rear clamping sleeve can be realized, the toughness of the rear clamping sleeve can be improved on the premise of ensuring the enough surface strength of the rear clamping sleeve, and the axial load of the rear clamping sleeve to the front clamping sleeve and the radial load to a pipeline are improved.

2. For the cutting ferrule pipe joint applied to nuclear grade, no domestic product can meet the requirement of nuclear grade application, and the application determines the specific size range and the specific manufacturing process of the double-cutting ferrule on the basis of foreign products through continuous efforts.

Drawings

FIG. 1 is a schematic view of a rear ferrule

FIG. 2 is a schematic view of a front ferrule

FIG. 3 is a schematic view of the assembly structure of the joint of the double-clamping sleeve pipeline

Figure 4 is a real object drawing of the rear ferrule

Figure 5 is a drawing of a front ferrule in substance

FIG. 6 shows the situation of the foreign product after hydraulic pressure test, in which the rear ferrule extrudes the outer wall of the test sample tube

FIG. 7 shows the situation of the double-ferrule in embodiment 1 after being applied to a pipeline joint for a hydraulic test and the rear ferrule extruding the outer wall of the test sample tube

Reference numerals: 1. anterior segment terminal surface, 2, outer wall anterior segment, 3, first section outer wall, 4, second section outer wall, 5, third section outer wall, 6, outer wall back end, 7, back end face, 8, inner wall, 9, inclined plane, 10, inner wall front portion, 11, preceding cutting ferrule outer wall, 12, main aspects inner wall, 13, preceding cutting ferrule inner wall, 14, main aspects terminal surface, 15, tip terminal surface, 16, back cutting ferrule, 17, preceding cutting ferrule, 18, connector, 19, nut, 20, pipeline.

Detailed Description

According to the standard of nuclear grade ferrule connectors:

ASTM F1387-1999(R2012)Standard Specification for Performance of Piping and Tubing Mechanically Attached Fittings

RCC-E(2005)Design and Construction Rules for Electrical Equipment for Nuclear Islands(2005Edition)

RCC-M(2007)Design and Construction Rules for Mechanical Components of PWR Nuclear Islands(2007Edition)

the double-clamping casing pipeline joint meets the following test requirements:

1) air pressure test

2) Hydrostatic test

3) Pulse test

4) Bending fatigue test

5) Tensile test

6) Hydraulic bursting test

7) Repeated assembly test

8) Rotational bending test

9) Vibration test

10) Thermal cycle test

In order to meet the test requirements, the technical difficulty that the conventional double-clamping casing pipeline joint is difficult to break through is as follows: the post-treatment process of the rear ferrule is unknown, the surface hardness of the rear ferrule subjected to surface hardening by adopting the conventional surface treatment process can reach the level of foreign products, but in the process of carrying out various tests, the test failure caused by brittle failure of the rear ferrule occurs, and great test is brought to the localization of the double-ferrule pipeline connector.

Example 1

In order to meet the test requirements and enable the domestic double-clamping sleeve joint to meet the nuclear-grade use requirements, the applicant determines the specific size range of the double-clamping sleeve through continuous exploration on the basis of the patent disclosure of foreign products, thereby providing the double-clamping sleeve for the pipeline joint:

as shown in fig. 1, the section of the rear ferrule is similar to a high-heeled shoe, the outer wall of the rear ferrule comprises a front section, a middle section and a rear section, the end surface 1 of the front section is perpendicular to the axis, the end surface 7 of the rear section is inclined forwards, the included angle A between the end surface 7 of the rear section and the axis is 80 degrees, the included angle B between the front section 2 of the outer wall and the axis is 37.5 degrees, the rear section 6 of the outer wall is parallel to the axis, the middle section of the outer wall comprises three sections of outer walls which are sunken towards the axis, the included angle C between the outer wall 3 of the first section and the radial direction is 45 degrees, the included angle D between the outer wall 4 of the second section and the axis is 11 degrees, and the included angle E between the outer wall 5 of the third section and the radial direction is 38 degrees; the front part 10 of the inner wall of the rear cutting sleeve is parallel to the axis, the middle rear part of the inner wall of the rear cutting sleeve inclines outwards, and the inclined plane 9 forms an included angle F of 8 degrees with the axis; the inner wall 8 close to the rear end face 7 is parallel to the axis; as shown in the physical diagram of the rear ferrule in fig. 4.

As shown in fig. 2, the front cutting ferrule is in a circular truncated cone shape and comprises a small end and a large end, an included angle a between the outer wall 11 of the front cutting ferrule and the axis is 18 degrees, an included angle B between the inner wall 12 of the large end and the axis is 45 degrees, the inner wall 13 of the front cutting ferrule is parallel to the axis, the end face 14 of the large end is perpendicular to the axis, and the end face 15 of the small end is perpendicular to the axis; as shown in the physical drawing of the front ferrule in fig. 5.

As shown in fig. 3, a schematic structural diagram of a dual ferrule applied to a dual ferrule pipeline connector is shown, in which a rear ferrule 16 and a front ferrule 17 are disposed in a cavity formed by a nut 18 and a connector 19; the pipes 20 are connected by a double bayonet pipe joint. The sealing principle is as follows: the front ferrule 17 is pushed into the connector 19 and the body 20 to form the primary seal, while the rear ferrule 16 is hinged inwardly to form a strong grip on the body 20. The geometry of the rear ferrule 16 helps to create an advanced engineering hinge-ferrule action that translates axial movement into radial compression on the tube body, requiring only a small assembly torque in operation.

The manufacturing of front cutting ferrule includes: turning the outer circle and the end face, boring, chamfering, cutting off, turning the end face, carburizing and inspecting; the outer wall of the front cutting sleeve is carburized, the thickness of a carburized layer is 0.3mm, and the surface hardness is HV 830.

The preparation method of the rear card sleeve comprises the following steps:

turning the outer circle and the end face, boring, chamfering, cutting off, turning the inclined end face, and performing surface treatment: heating to 650 deg.C in vacuum furnace, maintaining the temperature for 20min, heating to 950 deg.C, maintaining the temperature for 20min, introducing NH₃And N₂The flow rate is 10L/min, nitriding treatment is carried out for 30min, and the replacement atmosphere is C₂H₂+N₂The flow rate is 10L/min, carburization is carried out for 20min, and then the atmosphere is changed to NH₃And N₂Nitriding at the flow rate of 10L/min for 20min, wherein the pressure of carburizing and nitriding is 2000 Pa; then carrying out oil quenching, wherein in the oil quenching process, the rear sleeve is sleeved with oil and then stirred, the maximum stirring frequency is 50Hz, and the oil temperature is 60 ℃; tempering: heating to 160 ℃, preserving heat for 120min, and cooling to room temperature; and (6) checking. The outer wall of the rear cutting ferrule is carburized and nitrided, the thickness of a carburized layer is 0.2mm, and the surface hardness is HV 830.

The size of two cutting ferrule confirms the process to be the important stage of research and development, the concrete size and the tolerance cooperation of preceding cutting ferrule and back cutting ferrule play important role to the sealed effect that two cutting ferrule way connect, through inventor's continuous attempt and exploration, under the extremely limited condition of reference data, establish domestic unique two cutting ferrule sizes, and realized through the tolerance cooperation of preceding cutting ferrule and back cutting ferrule that two cutting ferrules are excellent sealed and engineering hinge-clamp hoop effect in the pipeline connects, no matter be with this company's connector, nut cooperation is used or with general nut, connector assembly, the homoenergetic shows the sealed effect that is superior to other similar two cutting ferrules.

In the research and development process of the surface treatment process of the clamping sleeve, the surface treatment process of the rear clamping sleeve is important for the sealing performance of a double-clamping sleeve pipeline joint, the surface hardness of the rear clamping sleeve of a foreign product is as high as HV832, the coordination of the thickness of a permeable layer and the surface hardness is realized, and the sufficient toughness of the clamping sleeve is ensured, so that the key factor for solving the standard reaching problem of the joint is realized, the required surface hardness is difficult to achieve if the thickness of the permeable layer is too small, the toughness of the clamping sleeve is reduced while the surface hardness is achieved if the thickness of the permeable layer is too large, the clamping sleeve is extremely easy to break in a hydraulic test and cannot pass the test, and the inventor of the application finds out reasonable surface treatment process parameters of the rear clamping sleeve finally, the requirement of the main sealing effect of the front clamping sleeve on the toughness is not high, on the basis that the surface hardness is met in the front clamping sleeve, the influence of the toughness of the rear clamping sleeve on the hinge-clamping effect determines whether According to the processing technological parameters in the application, the sufficient surface hardness can be achieved on the premise that the infiltration layer thickness of the rear cutting ferrule is thin, and the requirement of a hydrostatic test is met. Furthermore, the inventor finds that when the rear ferrule penetration layer has the thickness of 0.2mm and the surface hardness of HV830, the double-ferrule pipeline joint can achieve the hydraulic test sealing performance when the surface hardness of the rear ferrule of a foreign product is HV832, which is unexpected by the inventor, and particularly shown in table 2, the test basis is as follows: the initial pressure applied was 10% of the rated pressure and the assembled samples were tested to determine if no fluid leakage was maintained at the pipe or ferrule and pipe joint. If no leakage occurs, the second step gradually increases the sample pressure to 150% of the rated pressure of the pipe or ferrule fitting (at a nuclear power rated pressure of 25MPa, the service pressure is 37.5MPa), and this increased pressure tests the ability of the sample to maintain a seal.

TABLE 1 comparison of hydrostatic test results

As can be seen from table 1, when the dual ferrule tube-to-tube joint in embodiment 1 of the present application is used for testing, the thickness of the rear ferrule penetration layer is 0.2mm, the surface hardness is HV830, the thickness of the rear ferrule penetration layer of the shiviaroc sample is 0.2mm, and the surface hardness is HV832, after the hydraulic test, the displacement amount and the torque variation of the nut are also equivalent to those of the foreign product under the condition that the sealing performance of the example 1 is ensured to be the same as that of the foreign product, as shown in fig. 6 and 7, after the dual ferrule in embodiment 1 is applied to the tube joint for the pressure test, the extrusion grooving condition of the rear ferrule to the outer wall of the test sample tube is equivalent to that of the foreign product, which illustrates that the hinge-ferrule function of the rear ferrule is equivalent, not only solves the problem that the dual ferrule tube-to-tube joint in the country meets the standard, but also reduces the requirement of the rear surface hardness, and reduces the manufacturing cost.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A double cutting ferrule for a pipeline joint is characterized in that a front cutting ferrule is in a circular truncated cone shape and comprises a small end and a large end, the included angle A between the outer wall of the front cutting ferrule and an axis is 15-25 degrees, and the included angle B between the inner wall of the large end and the axis is 40-60 degrees; the section of the rear cutting ferrule is similar to a high-heeled shoe, the outer wall of the rear cutting ferrule comprises a front section, a middle section and a rear section, the end face of the front section is perpendicular to the axis, the end face of the rear section inclines forwards, and the included angle C between the end face of the rear section and the axis is 60-90 degrees, the included angle D between the front section of the outer wall and the axis is 30-40 degrees, the rear section of the outer wall is parallel to the axis, the middle section of the outer wall comprises three sections of outer walls sunken towards the axis, the included angle E between the first outer wall and the radial direction is 40-50 degrees, the included angle F between the second outer wall and the axis is 10-15 degrees, and the included angle G between the third outer wall and the radial direction is 35-45 degrees; the middle rear part of the inner wall of the rear cutting sleeve inclines outwards, the included angle H between the inclined plane and the axis is 6-10 degrees, and the front section of the outer wall of the rear cutting sleeve is connected with the inner wall of the large end of the front cutting sleeve.

2. The double clamp for pipe joints according to claim 1, wherein: preferably, angle a is 18 °, angle B is 45 °, angle C is 80 °, angle D is 37.5 °, angle E is 45 °, angle F is 11 °, angle G is 38 °, angle H is 8 °, and angle I is 20.5 °.

3. The double clamp for pipe joints according to claim 1, wherein: preferably, the inner diameters of the front cutting sleeve and the rear cutting sleeve are 2mm-50mm, and preferably 12.7 mm; the outer diameter of the small end of the front cutting sleeve is 10mm-15mm, preferably 13.5mm, the inner diameter of the end face of the large end is 11.5mm-17mm, preferably 14.9mm, the outer diameter is 15mm-20mm, preferably 17.3mm, and the axial length of the front cutting sleeve is 5mm-10mm, preferably 7.3 mm; the outer diameter of the end face of the front section of the rear cutting sleeve is 11mm-14mm, preferably 13.3mm, the maximum outer diameter of the front section of the outer wall is 12mm-16mm, preferably 14.6mm, the outer diameter of the rear section of the outer wall is 14mm-17mm, preferably 15.6mm, and the axial length of the rear cutting sleeve is 2.5mm-5.5mm, preferably 3.8 mm.

4. The double clamp for pipe joints according to claim 3, wherein: the inner diameter tolerance of the front cutting sleeve and the rear cutting sleeve is 0.095 mm-0.138 mm; the dimensional tolerances of the small end outer diameter, the large end face inner diameter, the large end face outer diameter and the axial length of the front cutting sleeve are all-0.05 mm, the dimensional tolerances of the front section end face outer diameter and the outer wall rear section outer diameter of the rear cutting sleeve are all-0.07 mm-0 mm, the maximum dimensional tolerance of the outer wall front section outer diameter is-0.1 mm-0 mm, and the axial length dimensional tolerance of the rear cutting sleeve is-0.05 mm.

5. The double clamp for pipe joints according to claim 1, wherein: the outer wall of the rear cutting ferrule is carburized and nitrided, the thickness of a carburized layer is 0.1mm-0.3mm, and the surface hardness is HV820-HV 840.

6. The method for preparing the double ferrule for the pipeline joint according to any one of claims 1 to 5, wherein: which comprises the following steps: the manufacturing of front cutting ferrule includes: turning the outer circle and the end face, boring, chamfering, cutting off, turning the end face, carburizing and inspecting; the manufacturing of back cutting ferrule includes: turning the outer circle and the end face, boring, chamfering, cutting off, turning the inclined end face, nitriding, carburizing, oil quenching, tempering and inspecting; wherein, the surface of the rear cutting ferrule is carburized and nitrided, the thickness of a carburized layer is 0.1mm-0.3mm, and the surface hardness is HV820-HV 840.

7. The method for preparing a double ferrule for a pipeline connector according to claim 6, wherein the method comprises the following steps: the specific processes of nitriding, carburizing, oil quenching and tempering of the rear ferrule comprise: heating to 650 deg.C in vacuum furnace, maintaining the temperature for 15-25min, heating to 950 deg.C, maintaining the temperature for 15-25min, introducing NH₃And N₂The flow rate is 8-15L/min, nitriding treatment is carried out for 20-40min, and the changing atmosphere is C introduction₂H₂+N₂Carburizing for 15-30min at flow rate of 8-15L/min, and introducing NH₃And N₂Nitriding at the flow rate of 8-15L/min for 15-30min under carburizing and nitriding pressure of 2000 Pa; then carrying out oil quenching, wherein in the oil quenching process, the rear sleeve is sleeved with oil and then stirred, the maximum stirring frequency is 50Hz, and the oil temperature is 60 ℃; the tempering process comprises the following steps: heating to 160 deg.C, maintaining the temperature for 120min, and air cooling to room temperature.