CN115388683A

CN115388683A - Welding structure of plate-fin reactor

Info

Publication number: CN115388683A
Application number: CN202210944768.9A
Authority: CN
Inventors: 张�浩; 马骏驰; 张立伟; 张嘉; 程臣
Original assignee: 93184 Unit Of Chinese Pla; Wuhan Research Institute Of Marine Electric Propulsion No 712 Research Institute Of China Shipbuilding Corp
Current assignee: 93184 Unit Of Chinese Pla; Wuhan Research Institute Of Marine Electric Propulsion No 712 Research Institute Of China Shipbuilding Corp
Priority date: 2022-08-08
Filing date: 2022-08-08
Publication date: 2022-11-25

Abstract

The invention discloses a welding structure of a plate-fin reactor, which comprises partition plates, fins and a plurality of sealing strips which are alternately arranged, wherein each sealing strip is of a T-shaped structure with a tongue-and-groove structure formed by transverse edges and vertical edges, the left side and the right side of each transverse edge are respectively provided with a groove and a tenon, the two adjacent transverse edges are embedded and connected through the grooves and the tenons, the vertical edges on the lower sides of the transverse edges are lapped between the two adjacent partition plates, the bottoms of the vertical edges are contacted with the fins, brazing filler metal is arranged between the left side and the right side of each transverse edge and the partition plates, the transverse edges are contacted with a welding head, and a melting welding seam is formed between the welding head and the sealing strips; this patent carries out welded structure design through the T font strip of paper used for sealing of taking the tongue-and-groove structure, can effectively avoid the problem that the brazing seam ftractures along the head direction when vacuum brazing plate-fin reactor strip of paper used for sealing and head fusion welding, improves welding quality and production efficiency.

Description

Welding structure of plate-fin reactor

Technical Field

The invention relates to a welding structure, in particular to a welding structure of a seal and an end enclosure of a vacuum brazing plate-fin reactor.

Background

The plate-fin heat exchanger core is formed by sequentially stacking a partition plate, a seal and fins, wherein amorphous thin-band brazing filler metal or paste-shaped brazing filler metal is usually placed between the partition plate and the seal and between the partition plate and the fins, and the partition plate and the fins are compacted and brazed into a whole in a vacuum furnace. The heat exchanger has the advantages of compact structure, large heat exchange area, high heat exchange efficiency and the like, and is widely applied to engineering.

The plate-fin reactor based on the plate-fin heat exchanger is characterized in that catalysts are filled among fins, and heat coupling reaction is generated among different flow channels. Because the reaction temperature and the pressure are higher, the reactor material is made of austenitic stainless steel, and the brazing filler metal is high-temperature nickel-based brazing filler metal. The nickel-based brazing filler metal has the advantages of oxidation resistance, high strength of brazed joints, corrosion resistance and the like, has good high-temperature performance, and is mainly Ni-Cr-Si brazing filler metal and Ni-Cr-B-Si brazing filler metal which are common at present. The main function of Si and B is to reduce the melting point of the brazing filler metal, but the two alloy elements are easy to form brittle compounds in the brazing process, so that the toughness of a brazing seam is reduced, and the risk of generating welding cracks exists.

In the existing welding structure of the plate-fin reactor, after the core body is brazed, a fusion welding method is adopted to weld the end enclosure, the direction of the end enclosure is vertical to the direction of a brazing seam, and the fusion welding seam can damage the existing brazing seam, which is characterized in that: the fusion welding is directly contacted with the brazing, the brazing seam is locally melted due to instantaneous high temperature, and the unfused brazing seam is possibly generated after being cooled to cause medium leakage; brittle compounds formed by Si and B elements in the nickel-based brazing filler metal are easy to crack along the direction of a brazing seam under the influence of thermal stress generated by fusion welding, and meanwhile, the two elements can also cause adverse effect on the quality of the fusion welding seam.

The commonly adopted solution is to use the fusion welding repair welding along the direction of the brazing seam, and the problems are that: on one hand, in the repair welding process, the brittle cracks usually extend along with the fusion welding seam, so that the repair welding seam is prolonged, the welding workload is large, and the production and processing cost is high; on the other hand, the position of the stop point of the repair welding is also the intersection point of the fusion welding seam and the brazing seam, the original brazing seam is influenced by high temperature and can generate internal defects such as unfused, air holes and the like, the risk of further cracking exists in the running process of the reactor, and the reliability of the reactor is reduced.

Disclosure of Invention

In order to solve the technical problems in the background technology, the invention provides a welding structure of a seal and a seal head of a vacuum brazing plate-fin reactor, so as to avoid the problem that a brazing seam cracks along the seal head direction when the seal and the seal head in a core body of the vacuum brazing plate-fin reactor are melted and welded.

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a welded structure of plate-fin reactor, is including baffle and the fin that sets up in turn to and the strip of paper used for sealing of being connected with the baffle, the strip of paper used for sealing have a plurality ofly, the strip of paper used for sealing be horizontal limit and erect the T font structure of taking the tongue-and-groove structure that the limit constitutes, the horizontal limit left and right sides be provided with recess and tenon respectively, two adjacent horizontal limits pass through recess and tenon scarf joint, the vertical limit overlap joint of horizontal limit downside between two adjacent baffles, erect limit bottom and fin contact, be provided with the brazing filler metal between the left and right sides of perpendicular limit and the baffle, the horizontal limit and the welding head contact of fin one side are kept away from to the strip of paper used for sealing, for melting the welding seam between welding head and the strip of paper used for sealing.

The brazing filler metal of the welding structure of the plate-fin reactor is amorphous ribbon brazing filler metal or paste brazing filler metal.

The welding structure of the plate-fin reactor is characterized in that the optimized brazing filler metal is BNi2, and the thickness of the brazing filler metal is 80-120 mu m.

The welding structure of the plate-fin reactor has the transverse edge with the preferred height range of 3-5 mm and the vertical edge with the preferred height range of 8-16 mm.

The groove of the welding structure of the plate-fin reactor is a dovetail groove and can also be a tongue-and-groove with other structures. The included angle between the vertical edge and the bevel edge in the dovetail groove is preferably 40-60 degrees, and the height of the vertical edge is preferably 1-2 mm.

According to the welding structure of the plate-fin reactor, the welding end socket and the seal are made of austenitic stainless steel, including 304 and 316, and are welded into a whole through argon arc welding or laser welding.

In the welding structure of the plate-fin reactor, the partition plate is an austenitic stainless steel flat plate with uniform thickness.

In the welding structure of the plate-fin reactor, the fins are fins with the n-shaped cross sections, the fins are usually formed by stamping through a die, small holes can be punched in the fins for enhancing heat transfer, and the fins are preferably made of austenitic stainless steel or oxygen-free copper.

The beneficial effects of the invention are:

compared with a common I-shaped structure, the 1,T-shaped structure seal strip separates a melting welding seam from a brazing seam through a transverse edge, thereby reducing the influence of high temperature on the brazing seam.

2, the tongue-and-groove structure on the left and right sides of the seal can effectively prevent the brazing filler metal from expanding to the outer surface of the seal along the contact surface, and reduce the adverse effect of the brittle compounds formed by the Si and B elements on the fusion welding and brazing seams.

3, through this patent welding structure design, the problem of brazing seam along the head orientation fracture when can effectively avoiding strip of paper used for sealing and head fusion welding improves production efficiency, reduction in production cost.

Drawings

FIG. 1 is a schematic view of a weld configuration of the present invention;

FIG. 2 is a schematic view of a T-shaped seal with a tongue and groove structure according to the present invention.

The figures are numbered: 1-welding end socket, 2-seal, 21-groove, 22-transverse edge, 23-tenon, 24-vertical edge, 3-brazing filler metal, 4-fusion welding seam, 5-partition board and 6-fin.

Detailed Description

To further illustrate the objects and technical solutions of the present invention, the present invention will be further described in detail with reference to the specific embodiments shown in the drawings. The following examples are intended to illustrate the invention and are not to be construed as limiting the invention.

Referring to fig. 1 and 2, the welding structure of a plate-fin reactor disclosed by the invention comprises alternately arranged partition plates 5 and fins 6, and seals 2 connected with the partition plates 5, wherein the partition plates 5 are arranged between the seals 2, the fins 6 are arranged between the partition plates 5 and the partition plates 5, the seals 2, the partition plates 5, the fins 6 and brazing filler metal 3 form a reactor core body through vacuum brazing, the partition plates 5 are austenitic stainless steel flat plates with uniform thickness, the seals 2 are provided with a plurality of seals, the seals 2 are T-shaped structures with tongue-and-groove structures formed by transverse edges 22 and vertical edges 24, the left side and the right side of each transverse edge 22 are respectively provided with a groove 21 and a tenon 23, two adjacent transverse edges 22 are embedded through the grooves 2 and the tenons 23, and compared with the traditional I-shaped seals, the T-shaped seals 2 with tongue-groove structures, the T-shaped sealing structure is characterized in that a transverse edge 22 and a vertical edge 24 form a T shape, the preferred height range of the transverse edge 22 is 3-5 mm, the preferred height range of the vertical edge 24 is 8-16 mm, a groove 21 is a dovetail groove or a tongue-and-groove of other structures, the included angle range of the vertical edge and a bevel edge in the preferred dovetail groove is 40-60 degrees, the height range of the vertical edge is 1-2 mm, the vertical edge 24 on the lower side of the transverse edge 22 is lapped between two adjacent partition plates 5, the bottom of the vertical edge 24 is in contact with a fin 6, the fin 6 is a fin with a cross section in a shape of a Chinese character 'ji', the sealing structure is generally formed by stamping through a die, small holes can be punched in the fin for enhancing heat transfer, the preferred material is austenitic stainless steel or oxygen-free copper, brazing filler metal 3 is arranged between the left side and the right side of the vertical edge 24 and the partition plates 5, the transverse edge 22, which is far away from one side of the fin 6, is in contact with a welding end enclosure 1, and a melting welding seam 4 is arranged between the sealing strip 2 of a core body.

The brazing filler metal 3 is an amorphous thin strip brazing filler metal or a paste brazing filler metal, the preferred material is BNi2, the thickness is 80-120 um, the welding seal head 1 and the seal 2 are made of austenitic stainless steel, including 304 and 316, the welding is integrated through argon arc welding or laser welding, a flow channel is provided for a medium, and a melting welding line traverses the upper side of the transverse edge 22.

The assembly and welding sequence was as follows:

the method comprises the steps of uniformly placing a BNi2 amorphous thin strip brazing filler metal 3 or a paste brazing filler metal 3 on a partition plate 5, placing a fin 6 and a T-shaped seal 2 on the brazing filler metal 3, and continuously and uniformly placing the brazing filler metal 3 on the vertical edge 24 of the T-shaped seal 2 and the side of the fin 6 to form a basic unit, and sequentially stacking a plurality of basic units according to design requirements to form a plate-fin reactor core.

Applying 5-8 MPa pressure on the core body by using a special fixture, placing the core body and the fixture into a vacuum brazing furnace for brazing after clamping, adopting a step-by-step heating mode, leading the maximum welding temperature to be about 1040 ℃, then discharging the core body from the furnace after cooling along with the furnace at the temperature of 30-50 ℃, and finishing the brazing of the core body.

The welding head 1 and the core body are welded into a whole by argon arc welding or laser welding and a proper welding process, a fusion welding seam 4 is formed on the contact surface of the T-shaped head 2 and the welding head 1, the brazing seam is kept intact without cracking after welding, and the brazing seam and the fusion welding seam meet the use requirement of the reactor through pressure resistance and air tightness detection.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the invention, and is not intended to limit the invention to the particular forms disclosed, since various modifications, equivalents and improvements may be made within the spirit and scope of the invention.

Claims

1. The utility model provides a welded structure of plate-fin reactor, includes baffle (5) and fin (6) of setting up in turn to and seal (2) of being connected with baffle (5), its characterized in that: strip of paper used for sealing (2) have a plurality ofly, strip of paper used for sealing (2) are the T font structure that horizontal limit (22) and perpendicular limit (24) constitute, horizontal limit (22) about the side be provided with recess (21) and tenon (23) respectively, two adjacent horizontal limits (22) are through recess (21) and tenon (23) scarf joint, perpendicular limit (24) overlap joint between two adjacent baffles (5), erect limit (24) bottom and fin (6) contact, be provided with brazing filler metal (3) between perpendicular limit (24) left and right sides and baffle (5), horizontal limit (22) and welding head (1) contact, be between welding head (1) and the strip of paper used for sealing (2) and melt welding seam (4).

2. A welded structure of plate-fin reactor according to claim 1, characterized in that the filler metal (3) is an amorphous ribbon filler metal or a paste filler metal.

3. The welding structure of a plate-fin reactor as claimed in claim 2, wherein the brazing filler metal (3) is BNi2 and has a thickness of 80-120 um.

4. A welded structure of plate-fin reactor according to claim 1, wherein the height of the transverse side (22) is 3-5 mm, and the height of the vertical side (24) is 8-16 mm.

5. The welding structure of the plate-fin reactor as claimed in claim 4, wherein the groove (21) is a dovetail groove, the included angle between the vertical edge and the bevel edge in the dovetail groove is 40-60 degrees, and the height of the vertical edge is 1-2 mm.

6. The welding structure of a plate-fin reactor according to any one of claims 1 to 5, wherein the welding head (1) and the seal (2) are austenitic stainless steel and are welded integrally by argon arc welding or laser welding.

7. A welded structure of plate-fin reactor according to any one of claims 1 to 5, characterized in that the partition plates (5) are flat plates of austenitic stainless steel of uniform thickness.

8. A welded structure of plate-fin reactor according to any one of claims 1 to 5, wherein the fins (6) have a cross-section of a shape of a Chinese character 'ji', and are made of austenitic stainless steel or oxygen-free copper.