Large branch pipe streamline reducing special-shaped sleeve for repairing and plugging tee joint and forming method

Abstract

The invention discloses a large branch pipe streamline variable-diameter special-shaped sleeve for repairing and blocking a tee joint and a forming method.The large branch pipe streamline variable-diameter special-shaped sleeve for repairing and blocking the tee joint comprises a main pipe, a branch pipe is arranged on the side wall of the main pipe, and the two ends of the main pipe are symmetrically arranged relative to the axis of the branch pipe; one end, far away from the main pipe, of the branch pipe is connected with one end of the nipple; a straight pipe section is arranged at the end, away from the branch pipe, of the main pipe, and a reducing section is arranged at the position, between the straight pipe section and the branch pipe, of the main pipe. According to the special-shaped sleeve, the problems that an existing sleeve for repairing is large in welding workload, and fillet welds are prone to cracking are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of universal sleeves for repairing and plugging tees, and particularly relates to a large branch pipe streamlined diameter-changing special-shaped sleeve for repairing and plugging tees, and also relates to a molding method of the sleeve. Background Art

[0002] The plugging tee plays a great role in repairing pipeline corrosion defects and leakage. After the plugging tee is repaired, corrosion leakage will occur at the weld between the pipeline and the plugging tee, and sealing leakage will also occur at the plugging tee flange. In response to the above problems, the main idea of ​​repairing the plugging tee on site is to repair the local defects in steps: using a different-diameter sleeve suitable for repairing large-wall-thickness-difference butt-weld defects to repair the defects at the weld between the pipeline and the tee. The special-shaped sleeve has 4 welds installed on site; (2) using a special-shaped sleeve suitable for repairing the local flange of the different-diameter tee to repair the sealing leakage at the plugging tee flange. The special-shaped sleeve has 3 welds installed on site. In this way, there are 7 welds in one repair, which leads to a large workload of on-site installation welding. At present, B-type sleeves are generally used for repair sleeves, which have the characteristics of low cost, good effect and high reliability. The B-type sleeve repair method can not only withstand circumferential loads, but also axial and bending loads. However, it is mainly used for the repair of low-grade steel and small and medium-sized oil pipelines. Since there is currently no repair method suitable for X65, X70 and X80 high-grade steel materials, when high-grade steel pipelines such as the West-East Gas Pipeline, Shaanxi-Beijing Pipeline, and China-Myanmar Pipeline use B-type sleeves to repair circumferential welds, low-grade Q345R sleeves are habitually used for pipeline repair; however, high-grade steel pipelines have large diameters and high pressures. If leakage occurs, the calculated wall thickness of the Q345R sleeve used for reinforcement far exceeds the pipe wall thickness. The general wall thickness requirement is about 40mm, and the maximum wall thickness reaches 70mm, which increases the difficulty of welding and is prone to cracking of the corner welds of the B-type sleeve.

[0003] Therefore, there is an urgent need for a sleeve that can repair and seal corrosion leakage at the tee weld and seal leakage at the tee flange with as little welding workload as possible, while also preventing cracking of the fillet weld. Summary of the Invention

[0004] The purpose of the present invention is to provide a large branch pipe streamline variable diameter special-shaped sleeve for repairing and blocking a tee, which solves the problems of large welding workload and easy cracking of the corner welds in the existing repair sleeves.

[0005] Another object of the present invention is to provide a method for forming a large branch pipe streamline variable diameter special-shaped sleeve for repairing and blocking a tee.

[0006] The technical solution adopted by the present invention is a large branch pipe streamline reducing special-shaped sleeve for repairing and blocking a tee, comprising a main pipe, a branch pipe provided on the side wall of the main pipe, the two ends of the main pipe being symmetrically arranged relative to the axis of the branch pipe, the end of the branch pipe away from the main pipe being connected to one end of a short section, and the other end of the short section being connected to a pipe cap;

[0007] A straight pipe section is provided at the end of the main pipe away from the branch pipe, and a reduced diameter section is provided at the main pipe between the straight pipe section and the branch pipe.

[0008] The present invention is also characterized in that:

[0009] The connection between the main pipe and the branch pipe adopts a curved transition.

[0010] The reduced diameter section includes a first reduced diameter section, one end of the first reduced diameter section is connected to the branch pipe, the other end of the first reduced diameter section is connected to one end of the second reduced diameter section, the other end of the second reduced diameter section is connected to one end of the third reduced diameter section, and the other end of the third reduced diameter section is connected to the straight pipe section. The side walls of the first reduced diameter section, the second reduced diameter section and the third reduced diameter section are all arc-shaped, the curvature of the side wall of the first reduced diameter section is 1342 mm, the curvature of the side wall of the second reduced diameter section is 2119.4 mm, and the curvature of the side wall of the third reduced diameter section is 264.96 mm.

[0011] Another technical solution adopted by the present invention is a method for forming a large branch pipe streamline reducing special-shaped sleeve for repairing and blocking a tee, which is specifically implemented according to the following steps:

[0012] Step 1, preparing an equal-diameter tee by a hot extrusion molding method, wherein the equal-diameter tee includes a main pipe and a branch pipe;

[0013] Step 2: Reduce the diameters of the two ends of the main pipe of the equal-diameter tee in stages to obtain a reduced-diameter section and a straight pipe section;

[0014] Step 3, subjecting the equal-diameter tee processed in step 2 to tempering heat treatment to obtain a sleeve blank, and machining the inner diameter of the sleeve blank to obtain a semi-finished sleeve;

[0015] Step 4: welding a short section to the end of the branch pipe of the semi-finished sleeve obtained in step 3, and welding a pipe cap to the end of the short section away from the branch pipe to obtain a sleeve.

[0016] The present invention is also characterized in that:

[0017] The specific process of step 2 is as follows: heat one end of the main pipe of the equal-diameter tee to above the austenite temperature, place it on the reducing die, press the other end of the main pipe with the press, and press the heated end of the main pipe into the reducing die. During the pressing process, control the pressing amount and perform the reduction several times. Before each reduction, the reduced end of the main pipe needs to be heated to above the austenite temperature. During pressing, reserve the inner diameter machining allowance and the straight pipe section. The reduction of one end of the main pipe is completed. Repeat the above process to complete the reduction of the other end of the main pipe to obtain the reduced section and the straight pipe section.

[0018] The number of diameter reduction is 3 times, the first diameter reduction ratio is 15% to 30%, the second diameter reduction ratio is 10% to 15%, and the third diameter reduction ratio is 2% to 10%.

[0019] The inner cavity of the diameter reduction die includes a die bottom end, a die middle section is provided at the top of the die bottom end, and a die head end is provided at the top of the middle section;

[0020] The bottom of the mold is cylindrical and is used to press straight pipe sections;

[0021] The middle section of the mold is used to press the reduced diameter section. The curvature of the middle section near the bottom of the mold is 264.96mm, the curvature of the middle section near the head of the mold is 1342mm, and the curvature of the middle of the middle section is 2119.4mm.

[0022] The head end of the mold is arc-shaped and is used to press the connection between the branch pipe and the main pipe.

[0023] In step 3, the temperature of the tempering heat treatment is 500° C. to 650° C., and the holding time is 30 min to 60 min.

[0024] The sleeve is made of X65 or X70 steel grade material.

[0025] The size of the sleeve is: the size of the branch pipe, main pipe and seal of the tee is enlarged by T+g as the gap, where T is the wall thickness of the steel plate used to process the sleeve, and g is the gap between the inner wall of the sleeve and the outer contour of the butt steel pipe or tee main pipe.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention is used for repairing and plugging the large branch pipe streamline variable diameter special-shaped sleeve, which can realize the overall covering of the large diameter plugging flange branch pipe tee to achieve the purpose of in-service repair and reinforcement, and the technical workload of the special-shaped sleeve on-site installation is reduced from 7 welds to 4, reducing the risk of weld cracking and greatly reducing the on-site welding workload;

[0028] (2) The present invention is used to form a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee. The pressing amount is controlled by a stepwise reduction method to facilitate forming and geometric dimension control. The sleeve cavity is large and can cover the requirements of workpieces of different shapes, which is convenient for actual assembly application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a large branch pipe streamline variable diameter special-shaped sleeve for repairing and blocking a tee according to the present invention;

[0030] Figure 2 A side view of a large branch pipe streamline reducing special-shaped sleeve for repairing and blocking a tee according to the present invention;

[0031] Figure 3 A schematic diagram of the first diameter reduction in the molding method of the streamlined variable-diameter special-shaped sleeve for repairing and blocking a tee according to the present invention;

[0032] Figure 4 It is a schematic diagram of the second diameter reduction in the molding method of the streamlined variable diameter special-shaped sleeve of the large branch pipe used for repairing and blocking the tee according to the present invention;

[0033] Figure 5 A schematic diagram of the third diameter reduction in the molding method of the streamlined variable-diameter special-shaped sleeve for repairing and blocking a tee according to the present invention;

[0034] Figure 6 A schematic diagram of the diameter reduction of the other end of the main pipe in the molding method of the streamlined reduced-diameter special-shaped sleeve for repairing and blocking a tee according to the present invention;

[0035] Figure 7 It is a structural schematic diagram of the diameter reducing die in the molding method of the streamlined variable diameter special-shaped sleeve of the large branch pipe used for repairing and blocking the tee according to the present invention.

[0036] In the figure, 1. pipe cap, 2. branch pipe, 3. main pipe, 4. short section, 5. reduced diameter section, 6. straight pipe section, 7. press, 8. bottom end of mold, 9. head end of mold, 10. middle section of mold. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] The present invention is used to repair the large branch pipe streamline variable diameter special-shaped sleeve of the tee, the structure is as follows Figure 1 and Figure 2As shown, it includes a main pipe 3, a branch pipe 2 is provided on the side wall of the main pipe 3, the connection between the main pipe 3 and the branch pipe 2 adopts a curved transition, the two ends of the main pipe 3 are symmetrically arranged relative to the axis of the branch pipe 2, the end of the branch pipe 2 away from the main pipe 3 is connected to one end of a short section 4, and the other end of the short section 4 is connected to the pipe cap 1; a straight pipe section 6 is provided at the end of the main pipe 3 away from the branch pipe 2, and a reduced diameter section 5 is provided between the straight pipe section 6 and the branch pipe 2.

[0039] The reduced diameter section 5 includes a first reduced diameter section, one end of the first reduced diameter section is connected to the branch pipe 2, the other end of the first reduced diameter section is connected to one end of the second reduced diameter section, the other end of the second reduced diameter section is connected to one end of the third reduced diameter section, and the other end of the third reduced diameter section is connected to the straight pipe section 6. The side walls of the first reduced diameter section, the second reduced diameter section and the third reduced diameter section are all arc-shaped, the curvature R1 of the side wall of the first reduced diameter section is 1342 mm, the curvature R2 of the side wall of the second reduced diameter section is 2119.4 mm, and the curvature R3 of the side wall of the third reduced diameter section is 264.96 mm. The length of the straight pipe section is 50 mm to 80 mm.

[0040] The method for forming a large branch pipe streamline variable diameter special-shaped sleeve for repairing and blocking a tee according to the present invention is specifically implemented according to the following steps:

[0041] Step 1: Prepare an equal-diameter tee by hot extrusion, wherein the equal-diameter tee includes a main pipe 3 and a branch pipe 2;

[0042] The specific process of preparing the equal-diameter tee is as follows: the steel plate is rolled and welded into a blank tube, the blank tube is heated in a furnace to 800℃~950℃ and kept warm until the heating is uniform, and then taken out of the furnace and flattened, and the weld is ensured to be at the bottom of the equal-diameter tee during flattening, and then the blank tube is put into the furnace and heated to 800℃~950℃ and kept warm until the heating is uniform, and then the bottom is quenched after being taken out of the furnace, and then put into a mold for bulging and pressing into a branch pipe, and then the end is removed, shaped and rounded, and then heat treated at a heat treatment temperature of 500℃~700℃ to obtain the equal-diameter tee;

[0043] Step 2: Reduce the diameters of the two ends of the main pipe 3 of the equal-diameter tee in stages to obtain a reduced-diameter section 5 and a straight pipe section 6;

[0044] The specific process of step 2 is as follows: one end of the main pipe 3 of the equal-diameter tee is heated to above the austenite temperature, and is placed on the reducing die. The press 7 presses the other end of the main pipe 3, and the heated end of the main pipe 3 is pressed into the reducing die. During the pressing process, since it is impossible to form the large diameter to the small diameter in one step, the pressing amount is controlled and the diameter is reduced in several times. Before each reduction, the reduced end of the main pipe 3 needs to be heated to above the austenite temperature. During the pressing, the inner diameter machining allowance and the straight pipe section 6 need to be reserved. The straight pipe section 6 can be left with 50mm to 80mm. The reduction of one end of the main pipe 3 is completed. The above process is repeated to complete the reduction of the other end of the main pipe 3 to obtain the reduced diameter section 5 and the straight pipe section 6.

[0045] The number of times of diameter reduction is 3 times, such as Figure 3 As shown, the first reduction ratio is 15% to 30%. Figure 4 As shown, the second reduction ratio is 10% to 15%. Figure 5 As shown, the third reduction ratio is 2% to 10%; Figure 6 As shown, both ends of the main pipe 3 are reduced in diameter;

[0046] like Figure 7 As shown, the inner cavity of the diameter reduction die includes a die bottom end 8, a die middle section 10 is provided at the top of the die bottom end 8, and a die head end 9 is provided at the top of the middle section 10;

[0047] The bottom end 8 of the mold is cylindrical and is used to press the straight pipe section 6;

[0048] The middle section 10 of the mold is used to press the reduced diameter section 5. The curvature of the end of the middle section 10 close to the mold bottom end 8 is 264.96 mm, the curvature of the end of the middle section 10 close to the mold head end 9 is 1342 mm, and the curvature of the middle part of the middle section 10 is 2119.4 mm.

[0049] The die head 9 is arc-shaped and is used to press the connection between the branch pipe 2 and the main pipe 3;

[0050] Step 3: Tempering the equal-diameter tee after the treatment in step 2 at a temperature of 500° C. to 650° C. for a holding time of 30 min to 60 min to obtain a sleeve blank, and machining the inner diameter of the sleeve blank to obtain a semi-finished sleeve;

[0051] Step 4: Weld a short section 4 to the end of the branch pipe 2 of the semi-finished sleeve obtained in step 3, and weld a pipe cap 1 to the end of the short section 4 away from the branch pipe 2 to obtain a sleeve. The sleeve is made of X65 or X70 steel grade material, which is not prone to cracking when repairing high-grade steel pipelines. The branch pipe 2, short section 4, and pipe cap 1 are prefabricated and welded in the factory to reduce on-site installation workload;

[0052] The size of the sleeve is as follows: Use a 3D scanner to perform a 3D scan on the shoulder, main pipe, branch pipe and seal of the tee to be blocked to obtain the external contour map and contour parameters of the shoulder, main pipe, branch pipe and seal of the tee. The obtained external contours of the branch pipe, main pipe and seal of the tee are enlarged so that the gap between the external contours before and after enlargement is T+g, where T is the wall thickness of the steel plate used to process the sleeve, and g is the gap between the inner wall of the sleeve and the external contour of the butted steel pipe or the tee main pipe. The enlarged size is the final size of the sleeve.

[0053] The reduced diameter section 5 obtained by reducing the diameter using a reducing die includes a first reduced diameter section, one end of the first reduced diameter section is connected to the branch pipe 2, the other end of the first reduced diameter section is connected to one end of the second reduced diameter section, the other end of the second reduced diameter section is connected to one end of the third reduced diameter section, and the other end of the third reduced diameter section is connected to the straight pipe section 6. The side walls of the first reduced diameter section, the second reduced diameter section and the third reduced diameter section are all arc-shaped, the curvature R1 of the side wall of the first reduced diameter section is 1342 mm, the curvature R2 of the side wall of the second reduced diameter section is 2119.4 mm, and the curvature R3 of the side wall of the third reduced diameter section is 264.96 mm. By setting the curvatures R1, R2, and R3, a smooth transition is achieved, which facilitates metal rheology during the hot working process.

[0054] The repair method using the sleeve of the present invention is as follows: the sleeve of the present invention is cut in half along the horizontal axis, wrapped around the tee to be repaired, and welded with longitudinal and circumferential welds. This can repair leaks at the seal between the tee branch and the flange, as well as defects at the weld between the pipe and the tee. The sleeve has a large cavity, which can accommodate various workpiece shapes. Furthermore, the sleeve's ends have a defined length where they fit the steel pipe, allowing for inner and outer diameter cutting to suit the actual dimensions of the pipe to be repaired, facilitating assembly and application. Only three welds are required on-site to complete the repair.

[0055] Example 1

[0056] The forming method of the large branch pipe streamline reducing special-shaped sleeve used for repairing and blocking the tee is specifically implemented according to the following steps:

[0057] Step 1: Prepare an equal-diameter tee by hot extrusion, the equal-diameter tee comprising a main pipe 3 and a branch pipe 2, and the size of the equal-diameter tee is: T(S)DN900mm×900mm×900mm;

[0058] The specific process of preparing the equal-diameter tee is as follows: the steel plate is rolled and welded into a blank tube with a diameter of about 960mm, the blank tube is heated in a furnace to 800℃ and kept warm until the heating is uniform, and then flattened after being taken out of the furnace. During the flattening process, the weld is ensured to be at the bottom of the equal-diameter tee, and then the blank tube is heated in a furnace again to 800℃ and kept warm until the heating is uniform. After being taken out of the furnace, the bottom is quenched, and after quenching, it is placed in a mold and bulged to form a branch pipe, and then heat treated at 500℃ after the end is removed and rounded.

[0059] Step 2: Reduce the diameters of the two ends of the main pipe 3 of the equal-diameter tee in stages to obtain a reduced-diameter section 5 and a straight pipe section 6;

[0060] The specific process of step 2 is as follows: one end of the main pipe 3 of the equal-diameter tee is heated to above the austenite temperature, and is placed on the reducing die. The press 7 presses the other end of the main pipe 3, and the heated end of the main pipe 3 is pressed into the reducing die. During the pressing process, since it is impossible to form the large diameter to the small diameter in one step, the pressing amount is controlled and the diameter is reduced in several times. Before each reduction, the reduced end of the main pipe 3 needs to be heated to above the austenite temperature. During the pressing, the inner diameter machining allowance and the straight pipe section 6 need to be reserved. The straight pipe section 6 only needs to leave 50mm. The reduction of one end of the main pipe 3 is completed. The above process is repeated to complete the reduction of the other end of the main pipe 3 to obtain the reduced diameter section 5 and the straight pipe section 6.

[0061] The number of diameter reduction is 3 times, the first reduction ratio is 15%, the second reduction ratio is 10%, and the third reduction ratio is 2%;

[0062] The inner cavity of the diameter reduction die includes a die bottom end 8, a die middle section 10 is provided at the top of the die bottom end 8, and a die head end 9 is provided at the top of the middle section 10;

[0063] The bottom end 8 of the mold is cylindrical and is used to press the straight pipe section 6;

[0064] The middle section 10 of the mold is used to press the reduced diameter section 5. The curvature of the end of the middle section 10 close to the mold bottom end 8 is 264.96 mm, the curvature of the end of the middle section 10 close to the mold head end 9 is 1342 mm, and the curvature of the middle part of the middle section 10 is 2119.4 mm.

[0065] The die head 9 is arc-shaped and is used to press the connection between the branch pipe 2 and the main pipe 3;

[0066] Step 3, subjecting the equal diameter tee processed in step 2 to a tempering heat treatment at a temperature of 500° C. and a holding time of 60 minutes to obtain a sleeve blank, and machining the inner diameter of the sleeve blank to obtain a semi-finished sleeve;

[0067] Step 4: Weld a short section 4 to the end of the branch pipe 2 of the semi-finished sleeve obtained in step 3, and weld a pipe cap 1 to the end of the short section 4 away from the branch pipe 2 to obtain a sleeve. The sleeve is made of X65 steel grade material.

[0068] The reduced diameter section 5 of the sleeve includes a first reduced diameter section, one end of the first reduced diameter section is connected to the branch pipe 2, the other end of the first reduced diameter section is connected to one end of the second reduced diameter section, the other end of the second reduced diameter section is connected to one end of the third reduced diameter section, and the other end of the third reduced diameter section is connected to the straight pipe section 6. The curvature R1 of the side wall of the first reduced diameter section is 1342 mm, the curvature R2 of the side wall of the second reduced diameter section is 2119.4 mm, and the curvature R3 of the side wall of the third reduced diameter section is 264.96 mm.

[0069] Example 2

[0070] The forming method of the large branch pipe streamline reducing special-shaped sleeve used for repairing and blocking the tee is specifically implemented according to the following steps:

[0071] Step 1: Prepare an equal-diameter tee by hot extrusion, the equal-diameter tee comprising a main pipe 3 and a branch pipe 2, and the size of the equal-diameter tee is: T(S)DN900mm×900mm×900mm;

[0072] The specific process of preparing the equal-diameter tee is as follows: the steel plate is rolled and welded into a blank tube with a diameter of about 960mm, the blank tube is heated to 900℃ in a furnace and kept warm until the heating is uniform, and then flattened after being taken out of the furnace. During the flattening process, the weld is ensured to be at the bottom of the equal-diameter tee, and then the blank tube is heated to 900℃ in a furnace and kept warm until the heating is uniform. After being taken out of the furnace, the bottom is quenched, and after quenching, it is placed in a mold and bulged to form a branch pipe, and then heat-treated at 600℃ after the end is removed and rounded.

[0073] Step 2: Reduce the diameters of the two ends of the main pipe 3 of the equal-diameter tee in stages to obtain a reduced-diameter section 5 and a straight pipe section 6;

[0074] The specific process of step 2 is as follows: one end of the main pipe 3 of the equal-diameter tee is heated to above the austenite temperature, and is placed on the reducing die. The press 7 presses the other end of the main pipe 3, and the heated end of the main pipe 3 is pressed into the reducing die. During the pressing process, since it is impossible to form the large diameter to the small diameter in one step, the pressing amount is controlled and the diameter is reduced in several times. Before each reduction, the reduced end of the main pipe 3 needs to be heated to above the austenite temperature. During the pressing, the inner diameter machining allowance and the straight pipe section 6 need to be reserved. The straight pipe section 6 only needs to be 65mm. The reduction of one end of the main pipe 3 is completed. The above process is repeated to complete the reduction of the other end of the main pipe 3 to obtain the reduced diameter section 5 and the straight pipe section 6.

[0075] The number of diameter reduction is 3 times, the first reduction ratio is 20%, the second reduction ratio is 12%, and the third reduction ratio is 5%;

[0076] The diameter reduction die is the same as that in Example 1;

[0077] Step 3: Tempering the equal-diameter tee after the treatment in step 2 at a temperature of 600° C. for 45 minutes to obtain a sleeve blank, and machining the inner diameter of the sleeve blank to obtain a semi-finished sleeve;

[0078] Step 4: weld a short section 4 to the end of the branch pipe 2 of the semi-finished sleeve obtained in step 3, and weld a pipe cap 1 to the end of the short section 4 away from the branch pipe 2 to obtain a sleeve. The sleeve is made of X65 steel grade material, and the reduced diameter section 5 of the sleeve is the same as that in the embodiment.

[0079] Example 3

[0080] The forming method of the large branch pipe streamline reducing special-shaped sleeve used for repairing and blocking the tee is specifically implemented according to the following steps:

[0081] Step 1: Prepare an equal-diameter tee by hot extrusion, the equal-diameter tee comprising a main pipe 3 and a branch pipe 2, and the size of the equal-diameter tee is: T(S)DN900mm×900mm×900mm;

[0082] The specific process of preparing the equal-diameter tee is as follows: the steel plate is rolled and welded into a blank tube with a diameter of about 960mm, the blank tube is heated in a furnace to 950℃ and kept warm until it is evenly heated, and then flattened after being taken out of the furnace. During the flattening process, the weld is ensured to be at the bottom of the equal-diameter tee, and then the blank tube is heated in a furnace to 950℃ and kept warm until it is evenly heated. After being taken out of the furnace, the bottom is quenched, and after quenching, it is placed in a mold and bulged to form a branch pipe. After the end is removed, shaped and rounded, it is heat treated at a heat treatment temperature of 700℃ to obtain the equal-diameter tee.

[0083] Step 2: Reduce the diameters of the two ends of the main pipe 3 of the equal-diameter tee in stages to obtain a reduced-diameter section 5 and a straight pipe section 6;

[0084] The specific process of step 2 is as follows: one end of the main pipe 3 of the equal-diameter tee is heated to above the austenite temperature, and is placed on the reducing die. The press 7 presses the other end of the main pipe 3, and the heated end of the main pipe 3 is pressed into the reducing die. During the pressing process, since it is impossible to form the large diameter to the small diameter in one step, the pressing amount is controlled and the diameter is reduced in several times. Before each reduction, the reduced end of the main pipe 3 needs to be heated to above the austenite temperature. During the pressing, the inner diameter machining allowance and the straight pipe section 6 need to be reserved. The straight pipe section 6 only needs to be 80 mm. The reduction of one end of the main pipe 3 is completed. The above process is repeated to complete the reduction of the other end of the main pipe 3 to obtain the reduced diameter section 5 and the straight pipe section 6.

[0085] The number of diameter reduction is 3 times, the first reduction ratio is 30%, the second reduction ratio is 15%, and the third reduction ratio is 10%;

[0086] The diameter reduction die is the same as that in Example 1;

[0087] Step 3: Tempering the equal-diameter tee after the treatment in step 2 at a temperature of 650° C. for 60 minutes to obtain a sleeve blank. The inner diameter of the sleeve blank is machined to obtain a semi-finished sleeve;

[0088] Step 4: weld a short section 4 to the end of the branch pipe 2 of the semi-finished sleeve obtained in step 3, and weld a pipe cap 1 to the end of the short section 4 away from the branch pipe 2 to obtain a sleeve. The sleeve is made of X65 steel grade material, and the reduced diameter section 5 of the sleeve is the same as that in the embodiment.

[0089] The special-shaped sleeve of the present invention can realize the overall covering of the tee of the large-diameter sealing flange branch pipe to achieve the purpose of in-service repair and reinforcement, and the technical workload of on-site installation of the special-shaped sleeve is reduced from 7 welds to 4, reducing the risk of weld cracking; and curves are set at the connection between the main pipe 3 and the branch pipe 2 and the reduced diameter section for smooth transition, which is convenient for metal rheology during the hot working process. The main pipe 3 has a certain length, which is used to control the outer diameter size of the sealing tee main pipe and the branch pipe flange and has a certain processing margin; the main pipe 3 of the special-shaped sleeve of the present invention is provided with a straight pipe section of a certain length, which plays a role in the stability of the circumferential seam welding.

[0090] The special-shaped sleeve of the present invention adopts an overall covering sealing tee structure, which can meet the requirements of the oil and gas transmission medium in the pipeline, and complete the in-service repair and reinforcement of the sealing defects between the main pipe and branch pipe of different shapes of sealing tees without stopping the transmission. It not only overcomes the problem of not being able to directly perform welding repairs, but also uses this structure to achieve the reinforcement of the weak areas of the sealing tee branch structure, and can realize the non-stop welding repair of the sealing defects between the branch pipe and the connecting piece in the in-service tee and the circumferential weld defects at the weld between the pipeline and the tee.

Claims

1. A large branch pipe streamline reducing sleeve for repairing and blocking a tee, characterized in that: The invention comprises a main pipe (3), a branch pipe (2) is provided on the side wall of the main pipe (3), two ends of the main pipe (3) are symmetrically arranged relative to the axis of the branch pipe (2), one end of the branch pipe (2) away from the main pipe (3) is connected to one end of a short section (4), and the other end of the short section (4) is connected to a pipe cap (1); The main pipe (3) is provided with a straight pipe section (6) at the end away from the branch pipe (2), and the main pipe (3) is provided with a reduced diameter section (5) between the straight pipe section (6) and the branch pipe (2).

2. The large branch pipe streamline reducing special-shaped sleeve for repairing and blocking a tee according to claim 1 is characterized in that: The connection between the main pipe (3) and the branch pipe (2) adopts a curved transition.

3. The large branch pipe streamline variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 1 is characterized in that: The reduced diameter section (5) comprises a first reduced diameter section, one end of the first reduced diameter section is connected to the branch pipe (2), the other end of the first reduced diameter section is connected to one end of the second reduced diameter section, the other end of the second reduced diameter section is connected to one end of the third reduced diameter section, and the other end of the third reduced diameter section is connected to the straight pipe section (6), the side walls of the first reduced diameter section, the second reduced diameter section and the third reduced diameter section are all arc-shaped, the curvature of the side wall of the first reduced diameter section is 1342 mm, the curvature of the side wall of the second reduced diameter section is 2119.4 mm, and the curvature of the side wall of the third reduced diameter section is 264.96 mm.

4. A method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee, characterized in that: Please follow the steps below to implement: Step 1, preparing an equal-diameter tee by a hot extrusion molding method, wherein the equal-diameter tee comprises a main pipe (3) and a branch pipe (2); Step 2, reducing the diameters of the two ends of the main pipe (3) of the equal-diameter tee in stages to obtain a reduced-diameter section (5) and a straight pipe section (6); Step 3, subjecting the equal-diameter tee processed in step 2 to tempering heat treatment to obtain a sleeve blank, and machining the inner diameter of the sleeve blank to obtain a semi-finished sleeve; Step 4, welding a short section (4) to the end of the branch pipe (2) of the semi-finished sleeve obtained in step 3, and welding a pipe cap (1) to the end of the short section (4) away from the branch pipe (2) to obtain a sleeve.

5. The method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 4, characterized in that: The specific process of step 2 is as follows: one end of the main pipe (3) of the equal-diameter tee is heated to above the austenite temperature, placed on the diameter reduction die, the press (7) presses the other end of the main pipe (3), and the heated end of the main pipe (3) is pressed into the diameter reduction die. During the pressing process, the pressing amount is controlled and the diameter is reduced several times. Before each reduction, the reduced end of the main pipe (3) needs to be heated to above the austenite temperature. During the pressing, the inner diameter machining margin and the straight pipe section (6) need to be reserved. Then, the diameter reduction of one end of the main pipe (3) is completed. The above process is repeated to complete the diameter reduction of the other end of the main pipe (3), and the diameter reduction section (5) and the straight pipe section (6) are obtained.

6. The method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 5, characterized in that: The number of times of the diameter reduction is 3 times, the first diameter reduction ratio is 15% to 30%, the second diameter reduction ratio is 10% to 15%, and the third diameter reduction ratio is 2% to 10%.

7. The method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 5, characterized in that: The inner cavity of the reducing die includes a die bottom end (8), a die middle section (10) is provided at the top of the die bottom end (8), and a die head end (9) is provided at the top of the die middle section (10); The bottom end (8) of the mold is cylindrical and is used to press the straight pipe section (6); The middle section (10) of the mold is used to press the reduced diameter section (5), the curvature of one end of the middle section (10) of the mold close to the bottom end (8) of the mold is 264.96 mm, the curvature of one end of the middle section (10) of the mold close to the head end (9) of the mold is 1342 mm, and the curvature of the middle part of the middle section (10) of the mold is 2119.4 mm; The die head end (9) is arc-shaped and is used to press the connection between the branch pipe (2) and the main pipe (3).

8. The method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 4, characterized in that: In step 3, the temperature of the tempering heat treatment is 500° C. to 650° C., and the holding time is 30 min to 60 min.

9. The method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 4, characterized in that: The sleeve is made of X65 or X70 steel grade material.

10. The method for forming a large branch pipe streamlined variable diameter special-shaped sleeve for repairing and blocking a tee according to claim 4, characterized in that: The size of the sleeve is: the size of the branch pipe, main pipe and seal of the tee is enlarged by T+g as the gap, where T is the wall thickness of the steel plate used to process the sleeve, and g is the gap between the inner wall of the sleeve and the outer contour of the docking steel pipe or the tee main pipe.

Images