Welding joint for inner hole welding of heat exchange pipe
By setting a step-shaped reserved groove and limit ring on the pipe plate, the inner hole full-fusion welding head of the small-diameter heat exchange tube is realized, which solves the problem of welding difficulties of small-diameter heat exchange tubes and improves welding reliability and stress resistance Corrosion performance ensures high-quality connection and sealing of the welds.
Patent Information
- Application Number
- CN202420873136.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-25
- Publication Date
- 2025-01-10
- Estimated Expiration
- 2034-04-25
AI Technical Summary
Due to space limitations, small-diameter heat exchange pipes are difficult to weld the inner holes of the wire. The conventional forms of strength expansion, welding, and expansion welding have problems such as three-way stress fatigue, plastic deformation residual stress, gap corrosion and difficulty in detection.
By setting a step-shaped reserved groove and limit ring on the pipe plate, a fully fusion welding joint in the inner hole of the heat exchange tube is achieved, ensuring the sealing and firm connection of the welds, avoiding gap corrosion and stress corrosion, and facilitating radiation detection.
It improves welding reliability, enhances stress corrosion resistance, reduces crack risks, and achieves high-quality connection and sealing of welds.
Smart Images
Figure CN222336169U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of heat exchangers, and in particular to a welded joint for inner hole welding of a heat exchange tube. Background Art
[0002] Shell and tube heat exchanger is also called shell and tube heat exchanger. It is a wall heat exchanger that uses the wall of the tube bundle enclosed in the shell as the heat transfer surface. The connection structure between the heat exchange tube and the tube sheet: strength expansion, strength welding, expansion welding and internal hole welding.
[0003] Large diameter heat exchange tubes can be welded with inner hole filled with wire. However, due to space limitations, small diameter heat exchange tubes are difficult to fill with wire and inner hole welding cannot be achieved. Therefore, conventional small diameter heat exchange tubes still use strength expansion, strength welding, and expansion welding. The following problems exist in the use of strength expansion, strength welding, and expansion welding: (1) The end face sealing weld belongs to (including) the fillet joint form, which has a three-dimensional stress state and poor fatigue life. (2) During expansion, the tube undergoes large plastic deformation and forms large residual stress, which may cause stress corrosion during operation. (3) There is a gap between the heat exchange tube and the tube hole of the tube sheet, which is easy to accumulate scale and may cause gap corrosion during operation. (4) It is impossible to use non-destructive testing methods such as X-ray detection and ultrasonic detection to inspect the internal quality of the weld. Summary of the invention
[0004] The purpose of the present application is to provide a welded joint for inner hole welding of a heat exchange tube in order to solve the above-mentioned problem. A stepped weld is set through the tube hole on the tube plate. When the heat exchange tube is in the tube hole, the reserved weld can be welded by full fusion welding of the inner hole. Therefore, it has high reliability, does not produce gap corrosion, has good stress corrosion resistance, is convenient for weld radiographic detection, and is not prone to cracks during operation.
[0005] This application achieves the above objectives through the following technical solutions:
[0006] A welded joint for inner hole welding of a heat exchange tube comprises a tube sheet and a heat exchange tube. The tube sheet is provided with a tube hole. A reserved groove is arranged on the inner side of the orifice of the tube hole, and the diameter of the reserved groove is larger than the outer diameter of the heat exchange tube. A limiting ring is fixedly arranged on the outer side of the end of the heat exchange tube along the circumferential direction, and the limiting ring is adapted to the diameter of the reserved groove.
[0007] Preferably, the diameter of the reserved groove is 0.4 mm-0.7 mm larger than the diameter of the tube hole, and the depth of the reserved groove is 0.9 mm-1.2 mm.
[0008] Compared with the prior art, the present application sets a stepped reserved groove through the tube hole on the tube plate so that a weld can be formed between it and the heat exchange tube. When the heat exchange tube is in the tube hole, the reserved weld can be welded by full fusion welding of the inner hole. Therefore, it has high reliability, does not produce gap corrosion, has good stress corrosion resistance, is convenient for weld radiographic detection, and is not prone to cracks during operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present application but do not constitute a limitation to the present application. In the accompanying drawings:
[0010] Figure 1 It is a schematic diagram of the structure of this application.
[0011] The following are the descriptions of the reference numerals:
[0012] 1. Tube sheet; 2. Tube hole; 3. Reserved groove; 4. Limiting ring; 5. Heat exchange tube. DETAILED DESCRIPTION
[0013] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.
[0014] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the attached Figure 1 , and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application.
[0015] like Figure 1 As shown, a welded joint for inner hole welding of a heat exchange tube comprises a tube sheet 1 and a heat exchange tube 5, wherein the tube sheet 1 has a tube hole 2, a reserved groove 3 is arranged on the inner side of the hole mouth of the tube hole 2, and the diameter of the reserved groove 3 is larger than the outer diameter of the heat exchange tube 5, and a limiting ring 4 is fixedly arranged on the outer side of the end of the heat exchange tube 5 along the circumferential direction, and the limiting ring 4 is adapted to the diameter of the reserved groove 3.
[0016] Specifically, a reserved groove 3 is provided on the inner side of the orifice of the tube hole 2, and the diameter of the reserved groove 3 is larger than the outer diameter of the heat exchange tube 5 so that the heat exchange tube 5 can be inserted, and at the same time, a gap can be provided between the heat exchange tube 5 and the reserved groove 3 to facilitate full fusion welding of the inner hole. When the heat exchange tube 5 is inserted into the inner side of the reserved groove 3, the limiting ring 4 follows and is inserted into the reserved groove 3. At this time, the limiting ring 4 contacts the reserved groove 3, and the limiting ring 4 limits the heat exchange tube 5 to make the gap between the heat exchange tube 5 and the reserved groove 3 more uniform, thereby improving the welding quality.
[0017] Preferably, the diameter of the reserved groove 3 is 0.4 mm-0.7 mm larger than the diameter of the tube hole 2, and the depth of the reserved groove 3 is 0.9 mm-1.2 mm.
[0018] Specifically, the inner hole is fully fused welded, and a weld is formed by melting the parent material to fill the reserved groove 3, thereby ensuring a firm connection between the heat exchange tube 5 and the tube sheet 1, and ensuring the sealing between the tube hole 2 and the heat exchange tube 5.
[0019] In the above structure, the heat exchange tube 5 is inserted into the tube hole 2, and the end of the heat exchange tube 5 contacts the reserved groove 3. At the same time, the limiting ring 4 allows a pre-melted weld to be provided between the reserved groove 3 and the heat exchange tube 5, and then the heat exchange tube 5 is sealed and connected to the tube hole 2 through full fusion welding of the inner hole.
[0020] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, which fall within the scope of the present application to be protected. The scope of protection claimed in the present application is defined by the attached claims and their equivalents.
Claims
1. A welded joint for inner hole welding of a heat exchange tube, characterized in that: A tube sheet (1) and a heat exchange tube (5), wherein the tube sheet (1) is provided with a tube hole (2), a reserved groove (3) is provided on the inner side of the hole opening of the tube hole (2), and the diameter of the reserved groove (3) is larger than the outer diameter of the heat exchange tube (5), and a limiting ring (4) is fixedly provided on the outer side of the end of the heat exchange tube (5) along the circumferential direction, and the limiting ring (4) is adapted to the diameter of the reserved groove (3).
2. A welded joint for inner hole welding of a heat exchange tube, characterized in that: The diameter of the reserved groove (3) is 0.4 mm to 0.7 mm larger than the diameter of the tube hole (2), and the depth of the reserved groove (3) is 0.9 mm to 1.2 mm.