CN211693947U - Connecting pipe structure - Google Patents

Abstract

The utility model discloses a connecting pipe structure, the pipe body is iron base material pipe, the inside welded connection of one end mouth of pipe has the inside lining pipe of copper, and the region that this port surface is not less than 3mm from the port edge has the anti-corrosion coating that is formed by chromium plating technology, nickel plating technology, copper iron diffusion technology, chromizing technology, carbon chromium co-cementation technology, molybdenum cementation technology, carbon molybdenum co-cementation technology, nitridation technology or nitrocarburizing technology; the other end of the connecting rod is externally welded with an iron connecting base which is used for being welded with the shell. The utility model discloses an iron is the substrate, be convenient for follow-up and other copper product pipe welded connection, the flame high temperature is not feared to the anti-corrosion coating that makes its formation through surface treatment technology at the port outer wall simultaneously, therefore the copper pipe of kneck need not to reserve the welding position more than 5mm, the cracked risk of copper pipe emergence has basically been stopped, even at pipe body welded connection base this moment, also can be with the bushing pipe in the copper, the pipe body is assembled with the connection base three and is once only crossed the stove and weld, shorten preparation time and energy saving greatly.

Description

Connecting pipe structure

Technical Field

The utility model relates to an air conditioner field, especially a connecting pipe structure.

Background

As shown in fig. 1 and 2, the reservoir of the conventional air conditioner compressor includes a housing 1, an upper connection pipe 2, and a lower connection pipe 3. The compressor generally includes a housing 4 (generally composed of three parts of an upper end cap 41, a cylinder 42 and a lower end cap 43 (a three-part structure) or two parts of an upper cylinder and a lower cylinder (a two-part structure)), a connecting pipe 5, and the like. The connecting pipe 5 and the shell 4 are welded by resistance welding, and an iron connecting base 6 is required to be added between the two, as shown in fig. 3.

Because the piping of air conditioner is the copper pipe, consequently traditional connecting pipe 2, connecting pipe 5 all adopt full copper material, but the copper product price is high. Meanwhile, the shells 1 and 4 are made of iron materials, and the outer surfaces of the shells need to be painted with paint for surface treatment and corrosion prevention. Wherein, the outer oral area part of the last connecting pipe 2 of copper matter, connecting pipe 5 need reserve at least that 5mm within range can not have paint to adhere to in order to carry out follow-up and air conditioner piping flame welded connection, consequently connecting pipe 2, connecting pipe 5 in the copper matter expose the length of casing part and all can be greater than 10mm, if length is not enough, subsequent welding process can destroy the apparent paint of iron material casing and lead to being rusted in the future. However, since the grain size of the copper material is increased at a high temperature, the strength and fatigue resistance of the copper pipe are reduced, the longer the upper connecting pipe 2 and the connecting pipe 5 of the copper material are exposed out of the shell, and the higher the risk of fatigue fracture due to vibration of the pipe in the long-term operation of the compressor in the future, the welding of the iron connecting base and the upper connecting pipe 2 and the connecting pipe 5 of the copper material cannot be performed through furnace welding in batches, and only flame welding can be performed one by one. Therefore, the structure and the manufacturing process have low efficiency, high cost and complex process.

SUMMERY OF THE UTILITY MODEL

In order to solve the above problems, the present invention provides a connecting pipe structure, which simplifies the structure, reduces the cost, and greatly reduces the risk of fatigue fracture of the connecting pipe.

The purpose of the utility model is realized like this: a connecting pipe structure, includes the pipe body, its characterized in that: the pipe body is an iron-based pipe, a copper lining pipe is welded and connected in a pipe orifice at one end, and an anti-corrosion layer formed by a chromium plating process, a nickel plating process, a copper-iron diffusion process, a chromium impregnation process, a chromium-carbon co-infiltration process, a molybdenum impregnation process, a molybdenum-carbon co-infiltration process, a nitriding process or a nitrocarburizing process is arranged in a region of the outer surface of the port, which is not less than 3mm from the edge of the port; the other end of the connecting rod is externally welded with an iron connecting base which is used for being welded with the shell.

After the surface treatment process is carried out on the tube body, the tube wall of the area with the anti-corrosion layer sequentially comprises an iron layer and the anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises an interpenetrating layer, an interdiffusion layer or a plating layer; or the pipe wall of the area with the anti-corrosion layer is sequentially provided with the anti-corrosion layer, the iron layer and the anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises an interpenetrating layer, an interdiffusion layer or a plating layer.

The thickness of the anti-corrosion layer is not less than 1 μm.

The outer pipe orifice flanging of the copper lining pipe covers the pipe orifice edge of the pipe body, and the flanging thickness is 0.1mm-5 mm; or the outer pipe orifice of the copper lining pipe is not provided with a flanging and directly protrudes out of the edge of the pipe orifice of the pipe body by 0.1mm-5 mm.

The pipe orifice outside the copper lining pipe is provided with a 30-120-degree flanging, and the joint of the flanging and the inner diameter pipe wall of the copper lining pipe is provided with a chamfer or not; or the outer pipe orifice of the copper lining pipe is not provided with a flanging, and the edge of the outer pipe orifice is chamfered or the outer pipe orifice is flared; or the pipe orifice of the copper lining pipe is provided with a flanging or not, the inner wall of the pipe orifice is a step hole, and the small step hole and the large step hole are sequentially arranged from inside to outside; or the pipe orifice of the copper lining pipe is provided with a flange or not, the pipe orifice of the outer pipe is provided with a tapered hole, and the aperture of the tapered hole is from inside to outside and from small to large.

The copper lining pipe and the pipe body are at least overlapped by 3mm in the length direction to form a welding area; the iron connecting base and the pipe body are overlapped by at least 3mm in the length direction to form a welding area.

The copper lining pipe and the pipe body are in interference fit, at least one surface in a welding area between the copper lining pipe and the pipe body is subjected to wire drawing treatment, and/or the iron connecting base is in interference fit with the pipe body, and at least one surface in the welding area between the copper lining pipe and the pipe body is subjected to wire drawing treatment.

The iron connecting base is annular and comprises a neck part which is used for penetrating through the mounting hole of the shell and a base body which is used for propping against the periphery of the mounting hole; the outer peripheral surface of the neck part is in clearance fit with the mounting hole of the shell.

The diameter of the outer peripheral surface of the neck is at least 0.5mm smaller than the aperture of the mounting hole of the shell, the maximum diameter of the outer periphery of the seat body is at least 1mm larger than the aperture of the mounting hole, and preferably, the seat body is provided with a welding inclined plane used for welding with the shell.

The compressor for refrigeration or heating, the compressor liquid storage device, the silencer, the gas-liquid separator or the oil-gas separator comprising the connecting pipe structure.

The utility model aims at the defects of the prior structure and the prior art, improves the connecting pipe of the compressor, the silencer or the liquid storage device, adopts iron as the base material, has lower price, the copper lining pipe is additionally arranged in the pipe orifice at one end of the pipe body, so that the pipe body can be conveniently welded and connected with other copper pipes in the following process, and meanwhile, the outer wall of the port is formed into an anti-corrosion layer through a surface treatment process, the anti-corrosion layer does not fear high temperature of flame (the problem of peeling of paint coating can not occur), so the welding position of more than 5mm of the copper pipe at the interface is not required to be reserved, can high temperature resistant weld once more, stopped basically that the copper pipe of kneck takes place cracked risk, even need connect the base at the pipe body other end welding iron this moment, also can be with the equipment of copper lined pipe, pipe body and iron connection base three, once only go on the stove and weld, shorten preparation time and energy saving consumption greatly.

Drawings

FIG. 1 is a schematic diagram of a compressor according to the prior art;

fig. 2 and 3 are schematic views of a connection structure between a connection pipe and a shell in a compressor according to the prior art;

fig. 4 is a schematic structural diagram of embodiment 1 of the present invention;

fig. 5 is a schematic sectional view of a pipe body according to example 1 of the present invention, which has a corrosion-resistant layer region;

fig. 6 is a schematic structural diagram of embodiment 2 of the present invention;

figure 7 is a schematic cross-sectional view of a corrosion resistant layer region of a pipe body according to example 2 of the present invention;

fig. 8 and 9 are schematic views of copper-lined pipe structures according to embodiments 3 and 4 of the present invention;

fig. 10 to 13 are schematic structural views of tube bodies according to embodiments 5 to 8 of the present invention, respectively.

Detailed Description

The utility model relates to a connecting pipe structure 7, which comprises a pipe body 71, wherein the pipe body 71 is an iron base pipe, a copper lining pipe 73 is welded in a pipe orifice at one end, and an anti-corrosion layer 74 is arranged in a region of the outer surface of the port, which extends from the edge of the port to the direction of the other end for a distance D not less than 3 mm; and an iron connecting base 72 for resistance welding with the shell 4 is welded outside the other end.

The anti-corrosion layer 74 is formed by a surface treatment process of a chrome plating process, a nickel plating process, a copper-iron diffusion process, a chromizing process, a molybdenation process, a nitriding process, or a nitrocarburizing process. Chromizing, molybdenating, nitriding, nitrocarburizing, copper-iron diffusion or electroplating are all conventional processes. For example, chromizing is a chemical surface heat treatment process for infiltrating chromium into the surface of a metal part, and examples of the chemical surface heat treatment process include filler infiltration (also called solid method or powder method), gas method, molten salt method (also called liquid method), vacuum method, electrostatic spraying or coating thermal diffusion chromizing. The molybdenum infiltration is a chemical surface heat treatment process for infiltrating molybdenum into the surface of a metal workpiece, and has plasma infiltration. Nitriding is a chemical heat treatment process for making nitrogen atoms permeate into the surface layer of a workpiece in a certain medium at a certain temperature, and commonly includes liquid nitriding, gas nitriding, ion nitriding (glow nitriding) and the like. Carburizing is to put the workpiece into an active carburizing medium, and heat the workpiece to make the active carbon atoms decomposed from the carburizing medium permeate into the surface layer of the steel part, so as to obtain high carbon on the surface layer, and generally, gas carburizing, solid carburizing, liquid carburizing and the like can be adopted. The carbonitriding, nitrocarburizing and molybdenizing are chemical surface heat treatment processes for simultaneously infiltrating carbon and chromium or nitrogen or molybdenum into the surface of a steel part. The copper-iron diffusion process is a process of forming a copper coating on the surface of a workpiece through a copper plating process, then enabling the copper coating to be totally or partially diffused with the surface of the workpiece through a high-temperature furnace (the general condition is that the temperature is more than 600 ℃ (the temperature is the actual temperature of the surface of a product in the furnace) at a high temperature for more than 1 minute), changing the combination of van der Waals force of the coating into atomic interaction combination, greatly improving the adhesive force of copper on the surface of iron, recrystallizing the copper at the high temperature, removing the stress of copper crystal lattices during electroplating, solving the problem of peeling of the copper layer and optimizing the corrosion resistance. The electroplating or chemical plating process can form a coating on the surface of the workpiece, and the coating can prevent the peeling problem during the subsequent welding at high temperature so as not to cause the non-welding or the leakage, therefore, the utility model discloses select to form the anticorrosive coating of chromium or nickel, etc., because the expansion coefficient of the coating on the outer layer of the iron pipe adopting these materials is similar to that of iron or is less than that of iron.

The anti-corrosion layer 74 covers a region of the outer surface of the tube body 71 extending from the port edge toward the other end by a distance D of not less than 3mm, preferably not less than 5mm, and may cover the entire outer surface of the tube body 71 or the entire outer surface except for a region welded to the iron connection base 72. If partially covered, the uncovered areas would need to be painted to resist corrosion.

The preparation method of the connecting tube structure 7 comprises the following steps: the welding of the copper-lined pipe 73, the iron connection base 72 and the pipe body 71 may be performed during the aforementioned surface treatment process or before or after. When the temperature range of the surface treatment process is within the range of the welding temperature (800-. The copper-lined pipe 73 is welded for subsequent welding with a copper piping or with a composite pipe having a copper weld. Since the solder of phosphorus and copper is generally used for the subsequent welding with the copper air-conditioning pipe, the welding temperature is above 720 ℃, and the solder (for example, tin bronze solder) with the solder temperature not lower than 800 ℃ is preferably used for the welding of the copper lining pipe 73 and the pipe body 71. Preferably, the welding condition of the copper lining pipe 73 and the pipe body 71 is that the copper lining pipe is passed through a high temperature furnace at the temperature of 800-1082 ℃ (the temperature is the actual temperature of the surface of the product in the furnace) for more than 1 minute, preferably more than 3 minutes; when welding and surface treatment are performed simultaneously, the process conditions of welding are generally adopted. The welding condition of the iron connecting base 72 and the tube body 71 can also adopt a welding flux (such as tin bronze welding flux) with the temperature of the welding flux not lower than 800 ℃, and the welding of the copper lining tube 73 and the tube body 71 is carried out synchronously, and the three are integrally welded in a furnace, which is the optimal scheme; alternatively, the welding may be performed separately from the copper-lined pipe 73 and the pipe body 71, and in this case, silver solder may be used, and the welding temperature may be 650 ℃.

The pipe wall of the area of the pipe body 71 which forms the anti-corrosion layer 74 after the surface treatment process sequentially comprises an iron layer and an anti-corrosion layer from inside to outside, wherein the anti-corrosion layer at least comprises one of an interpenetrating layer, an interdiffusion layer or a plating layer; or the pipe wall is sequentially provided with an anti-corrosion layer, an iron layer and an anti-corrosion layer from inside to outside, wherein the anti-corrosion layer at least comprises one of an interpenetrating layer, an interdiffusion layer or a plating layer. If the chromizing process, the chromizing co-infiltration process, the molybdenating co-infiltration process or the copper-iron diffusion process is adopted, the anti-corrosion layer can comprise a chromium layer, a chromium carbide layer, a molybdenum layer, a molybdenating layer or a copper layer which is not mutually infiltrated or mutually diffused with the iron layer and is formed on the surface of the mutual infiltration layer or the mutual diffusion layer.

The thickness of the corrosion resistant layer 74 is not less than 1 μm. The thickness of the mutual permeation layer formed on the surface of the pipe body 71 by the chromizing process, the molybdenating process, the nitriding process or the nitrocarburizing process is not less than 1 μm, preferably 1-100 μm, and more preferably 3-30 μm. The thickness of the interdiffusion layer formed on the surface of the tube body 71 by the copper-iron diffusion process is not less than 0.5 μm, preferably 1-100 μm, and more preferably 2-30 μm.

Preferably, in order to facilitate the subsequent flame welding connection with the copper air-conditioning piping by an air-conditioning manufacturer, the position welded with the copper air-conditioning piping cannot be made of iron as much as possible, so that the outer pipe opening of the copper lining pipe 73 is provided with a flange 731 covering the port edge of the pipe body 71, and the thickness of the flange is 0.1mm-5 mm; or the outer pipe opening of the copper lining pipe 74 is not provided with a flanging and directly protrudes out of the edge of the end opening of the pipe body 71, and the protruding length A is 0.1mm-5 mm. The thinner the thickness of the aforesaid flange or the shorter the length of the external pipe orifice protrusion, the lower the risk of fatigue fracture, as the process allows.

Preferably, in order to facilitate the subsequent assembly with the copper air-conditioning tubing, a 30-120-degree turn-up 731 is arranged at the outer pipe opening of the copper lining pipe 733, the angle of the turn-up 731 is matched with that of the port edge of the pipe body 71 to cover the port edge, and a chamfer or no chamfer is arranged at the joint of the turn-up 731 and the inner diameter pipe wall of the copper lining pipe 73; or, the outer pipe orifice of the copper lining pipe 73 is not provided with a flanging, and the edge of the outer pipe orifice is chamfered or is flared 732; or, the outer pipe mouth of the copper lining pipe 73 is provided with a flanging or not, the inner wall of the outer pipe mouth is a stepped hole, and the small stepped hole and the large stepped hole are sequentially arranged from inside to outside; or the outer pipe opening of the copper lining pipe 73 is provided with a flanging or not, the inner part of the outer pipe opening is provided with a tapered hole, and the diameter of the tapered hole is from inside to outside and is from small to large.

Preferably, the length B of the overlap between the copper lining pipe 73 and the end of the pipe body 71 in the longitudinal direction is at least 3mm, and a welding region is formed to secure the welding strength between the copper lining pipe 73 and the end of the pipe body 71. Preferably, the iron connecting base 72 and the pipe body 71 are overlapped by at least 3mm in the length direction to form a welding area, so as to ensure the welding strength of the iron connecting base 72 and the pipe body 71.

Preferably, at least one surface of the welding area between the copper lining pipe 73 and the pipe body 71 is subjected to wire drawing treatment, so that uniformly distributed grooves are formed on the outer surface of the copper lining pipe and/or the inner surface of the port of the pipe body 71, and molten solder is uniformly filled in the whole welding area through capillary action during high-temperature welding. The copper lining pipe 73 is preferably in interference fit with the end of the pipe body 71. Similarly, at least one of the surfaces in the weld region between the ferrous connection mount 72 and the tube body 71 may be brushed. The iron connecting base 72 and the pipe body 71 are preferably in interference fit.

Preferably, the iron connecting base 72 is ring-shaped, and includes a neck portion 721 for penetrating the mounting hole of the housing 4, and a seat body 722 for abutting against the periphery of the mounting hole; the outer peripheral surface of the neck portion 721 is in clearance fit with the mounting hole of the housing 4.

Preferably, the diameter Φ a of the outer peripheral surface of the neck portion 721 is at least 0.5mm smaller than the aperture Φ C of the mounting hole of the housing 4, and the maximum diameter Φ D of the outer peripheral surface of the seat body 722 is at least 1mm larger than the aperture Φ C of the mounting hole. Preferably, the seat body 722 is provided with a welding inclined surface 723 for welding with the shell 4, so as to facilitate resistance welding, and more preferably, the angle alpha between the welding inclined surface 723 and the central axis of the pipe body is 10-89 degrees.

In order to facilitate the positioning and the arrangement of the solder of the copper lining pipe 73, the pipe body 71 is welded with one end port of the copper lining pipe 73 as a stepped hole or a flared hole or provided with an inward protruding notch.

A compressor for cooling or heating, a compressor reservoir, a muffler, a gas-liquid separator (for a central air conditioner or an automobile air conditioner), or an oil-gas separator (for an automobile air conditioner), which includes the above-described connecting pipe structure. The pipe body 71 may be a straight pipe or a bent pipe, and is designed according to an application scenario. Preferably, the connecting pipe structure is welded with a shell of a compressor, a compressor liquid storage device, a silencer, a gas-liquid separator or an oil-gas separator through resistance welding.

Example 1 (chromizing)

As shown in fig. 4, the connection tube structure 7 in this embodiment includes a tube body 71, the tube body 71 is an iron-based straight tube, a copper lining tube 73 is welded in a tube opening at one end, and an anti-corrosion layer 74 is provided on a region (about 10mm) of the outer surface of the port extending from the port edge to the other end by a distance D of not less than 5 mm; and an iron connecting base 72 for resistance welding connection with the shell is fixedly sleeved outside the other end of the shell.

An anti-corrosion layer 74 (shown in fig. 5) is formed at one end of the tube body 71 by a chromizing process, then the copper lining tube 73, the iron connecting base 72 and the tube body 71 are integrally assembled and filled with solder, and the assembly is sent into a high temperature furnace for welding under the condition that the welding temperature is 800-1082 ℃ (the temperature is the actual temperature of the surface of the product in the furnace) for more than 3 minutes. The anti-corrosion layer 74 is a chromium-iron interpenetration layer with the thickness not less than 1 μm. For example, the corrosion-resistant layer 74 is formed on both the inner and outer surfaces of the port by chromizing, and the corrosion-resistant layer 74 on the inner surface may be removed before welding the copper-lined tube 73.

The outer opening of the copper lining pipe 73 is provided with a flanging 731 with an angle of about 90 degrees, which covers the edge of the opening of the pipe body 71, and the thickness of the flanging is 1. The copper lining pipe 73 and the end of the pipe body 71 overlap at least 3mm in the longitudinal direction, and constitute a welding region. The outer surface of the copper lining pipe 73 is subjected to wire drawing treatment in the area welded with the pipe body 71, so that grooves are uniformly distributed on the outer surface of the copper lining pipe, and molten solder is uniformly filled in the whole welding area through capillary action during high-temperature welding. The copper lining pipe 73 is in interference fit with the end of the pipe body 71.

The connecting tube arrangement 7 in this embodiment can be used in a compressor. The iron connecting base 72 is ring-shaped and includes a neck portion 721 for penetrating through the mounting hole of the compressor housing 4 and a seat body 722 for abutting against the periphery of the mounting hole; the outer peripheral surface of the neck portion 721 is in clearance fit with the mounting hole of the housing 4, and the inner peripheral surface of the neck portion 721 is in interference fit with the pipe body 71. The diameter phi A of the outer peripheral surface of the neck portion 721 is at least 0.5mm smaller than the aperture phi C of the mounting hole of the shell 4, and the maximum diameter phi D of the outer peripheral surface of the seat body 722 is at least 1mm larger than the aperture phi C of the mounting hole. The seat body 722 has a welding inclined surface 723 for welding with the shell 4, and in this embodiment, the angle α between the welding inclined surface 723 and the central axis of the pipe body is 45 °. The inner surface of the iron connecting base 72 is also subjected to wire drawing treatment, so that grooves which are uniformly distributed are formed on the inner surface of the iron connecting base 72, and molten solder is uniformly filled in the whole welding area through capillary action when the iron connecting base is welded with the pipe body 71 at high temperature.

Example 2 (copper iron diffusion)

As shown in fig. 6, in the present embodiment, an anti-corrosion layer 74 is formed on one end of the tube body 71 by a cu-fe diffusion process. The copper-iron diffusion process is to form a copper plating layer by copper plating, and then to heat at a high temperature to diffuse the copper and the surface of the iron pipe fitting, so in this embodiment, the copper lining pipe 73, the iron connecting base 72, and the pipe body 71 can be assembled and filled with solder after copper plating, and then the assembly and the soldering can be performed in a high temperature furnace to diffuse the copper and the iron mutually and weld the copper and the iron together at the same time, under the condition that the temperature is 800-. The anti-corrosion layer 74 is a copper-iron interdiffusion layer 741 and a copper layer 742 from inside to outside (as shown in fig. 7), and has a thickness of not less than 1 μm. Of course, the copper lining pipe 73, the iron connection base 72, and the pipe body 71 may be welded after the interdiffusion of copper and iron is completed.

In this embodiment, the outer orifice of the copper lining tube 73 is not provided with a flange, and directly protrudes 1.5mm from the edge of the orifice of the tube body 71, and the outer orifice is provided with a flaring 732. The area of the flare 732 may be greater than 0.5mm inward from the edge of the outer tube port.

The rest is the same as example 1.

Example 3 (molybdenum impregnation)

In this embodiment, the surface treatment process adopts the conventional double glow plasma molybdenum cementation process, the formed anti-corrosion layer 74 is a molybdenum-iron mutual cementation layer and a molybdenum layer from the inside to the outside, and the thickness of the anti-corrosion layer 12 is not less than 1 μm. The outer nozzle of the copper inner liner tube 73 is not flanged, but a chamfer 733 is provided on the inner edge of the outer nozzle, as shown in fig. 8.

The rest is the same as example 1.

Example 4 (nitrocarburizing)

In this embodiment, the existing gaseous nitrocarburizing process is used to form the anti-corrosion layer 74 as a nitrogen, carbon-iron inter-penetrating layer, and the thickness of the anti-corrosion layer 12 is not less than 1 μm.

In this embodiment, the outer nozzle of the copper-lined pipe 73 is not provided with a flange, and directly protrudes 1mm from the edge of the port of the pipe body 71, the inner wall of the outer nozzle is a stepped hole 734, and the small stepped hole and the large stepped hole are sequentially arranged from inside to outside, as shown in fig. 9. The depth C of the small stepped hole is preferably not less than 0.5 mm.

The rest is the same as example 1.

Example 5 (Nickel plating)

In this embodiment, the anti-corrosion layer 74 is formed as a nickel plating layer by using the conventional nickel electroplating process.

The tube body 71 is an iron-based tube, a copper lining tube 73 is welded in a tube opening at one end, and a stepped hole 711 (shown in fig. 10) is formed in the inner wall of the end opening of the tube body 71, so that the positioning and the arrangement of the solder on the copper lining tube 73 are facilitated.

The rest is the same as example 3.

Example 6 (Co-cementation of molybdenum and carbon)

In this embodiment, the corrosion resistant layer 74 is formed by a conventional co-infiltration process of molybdenum and carbon.

The tube body 71 is an iron-based tube, a copper lining tube 73 is welded in a tube opening at one end, and the end opening of the tube body 71 is flared to form a flaring section 712 (as shown in fig. 11), so that the positioning and the arrangement of the solder of the copper lining tube 73 are facilitated.

The rest is the same as example 3.

Example 7 (nitriding)

In this embodiment, the anti-corrosion layer 74 formed by the conventional nitriding process is a nitrogen-iron inter-diffusion layer.

The tube body 71 is an iron-based tube, a copper lining tube 73 is welded in a tube opening at one end, and a notch 713 (shown in fig. 12) protruding inwards is formed at the position of the end opening of the tube body 71, which corresponds to the edge of an inner port of the copper lining tube 73, through cold working, so that the positioning and the arrangement of the solder of the copper lining tube 73 are facilitated.

The rest is the same as example 3.

Example 8 (Co-cementation of carbon and chromium)

In this embodiment, the corrosion-resistant layer 74 formed by the conventional co-carburization process is a carbon, chromium-iron co-carburized layer.

The tube body 71 is an iron-based tube, a copper lining tube 73 is welded in a tube opening at one end, the end opening of the tube body 71 is flared to form a flared section 712, so that the positioning and the arrangement of welding materials of the copper lining tube 73 are facilitated, and a second flared section 714 is formed at one end of the tube body 71 connected with the iron connecting base 72 in a flared mode (as shown in fig. 13). The pipe body 71 may be narrowed at the middle thereof, and a flared section 712 and a second flared section 714 having an increased diameter may be formed at both ends.

The rest is the same as example 3.

Example 9 (chromizing)

In this embodiment, the copper lining pipe 73 and the solder are placed at one end of the pipe body 71, and then the whole is put into a high temperature furnace, and the chromizing process forms the anti-corrosion layer 74, and the welding of the copper lining pipe 73 and the pipe body 71 is completed synchronously. Then, the iron connection base 72 and the pipe body 71 are welded.

The rest is the same as example 1.

Example 10 (copper iron diffusion)

In this embodiment, the copper lining pipe 73 and one end of the pipe body 7 are welded in a furnace, then one end of the welded copper lining pipe 73 is plated with copper to form a copper plating layer, then the high temperature heating is performed to enable the surfaces of the copper and the iron pipe to diffuse and infiltrate into each other (the temperature is greater than 600 ℃ (the temperature is the actual temperature of the surface of the product in the furnace), the high temperature furnace is used for over 1 minute to form the anti-corrosion layer 74, then the iron connecting base 72 and the pipe body 71 are welded, and the connecting pipe structure manufactured in the embodiment is used as an upper connecting pipe of the liquid storage device and is welded with a shell of the liquid storage device.

The rest is the same as example 2.

Claims (11)

1. A connecting pipe structure, includes the pipe body, its characterized in that: the pipe body is an iron-based pipe, a copper lining pipe is welded and connected in a pipe orifice at one end, and an anti-corrosion layer formed by a chromium plating process, a nickel plating process, a copper-iron diffusion process, a chromium impregnation process, a chromium-carbon co-infiltration process, a molybdenum impregnation process, a molybdenum-carbon co-infiltration process, a nitriding process or a nitrocarburizing process is arranged in a region of the outer surface of the port, which is not less than 3mm from the edge of the port; the other end of the connecting rod is externally welded with an iron connecting base which is used for being welded with the shell.

2. The connecting tube structure according to claim 1, wherein: the pipe wall of the area of the pipe body with the anti-corrosion layer is sequentially provided with an iron layer and an anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises a mutual permeation layer, a mutual diffusion layer or a plating layer; or the pipe wall of the area with the anti-corrosion layer is sequentially provided with the anti-corrosion layer, the iron layer and the anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises an interpenetrating layer, an interdiffusion layer or a plating layer.

3. The connecting tube structure according to claim 1, wherein: the thickness of the anti-corrosion layer is not less than 1 μm.

4. The connecting tube structure according to claim 1, wherein: the outer pipe orifice flanging of the copper lining pipe covers the pipe orifice edge of the pipe body, and the flanging thickness is 0.1mm-5 mm; or the outer pipe orifice of the copper lining pipe is not provided with a flanging and directly protrudes out of the edge of the pipe orifice of the pipe body by 0.1mm-5 mm.

5. The connecting tube structure according to claim 1, wherein: the pipe orifice outside the copper lining pipe is provided with a 30-120-degree flanging, and the joint of the flanging and the inner diameter pipe wall of the copper lining pipe is provided with a chamfer or not; or the outer pipe orifice of the copper lining pipe is not provided with a flanging, and the edge of the outer pipe orifice is chamfered or the outer pipe orifice is flared; or the pipe orifice of the copper lining pipe is provided with a flanging or not, the inner wall of the pipe orifice is a step hole, and the small step hole and the large step hole are sequentially arranged from inside to outside; or the pipe orifice of the copper lining pipe is provided with a flange or not, the pipe orifice of the outer pipe is provided with a tapered hole, and the aperture of the tapered hole is from inside to outside and from small to large.

6. The connecting tube structure according to claim 1, wherein: the copper lining pipe and the pipe body are at least overlapped by 3mm in the length direction to form a welding area; the iron connecting base and the pipe body are overlapped by at least 3mm in the length direction to form a welding area.

7. The connecting tube structure according to claim 1, wherein: the copper lining pipe and the pipe body are in interference fit, at least one surface in a welding area between the copper lining pipe and the pipe body is subjected to wire drawing treatment, and/or the iron connecting base is in interference fit with the pipe body, and at least one surface in the welding area between the copper lining pipe and the pipe body is subjected to wire drawing treatment.

8. A connection tube structure according to any of claims 1-7, characterized in that: the iron connecting base is annular and comprises a neck part which is used for penetrating through the mounting hole of the shell and a base body which is used for propping against the periphery of the mounting hole; the outer peripheral surface of the neck part is in clearance fit with the mounting hole of the shell.

9. The connection tube structure of claim 8, wherein: the diameter of the outer peripheral surface of the neck is at least 0.5mm smaller than the aperture of the mounting hole of the shell, and the maximum diameter of the outer periphery of the seat body is at least 1mm larger than the aperture of the mounting hole.

10. The connection tube structure of claim 8, wherein: the base body is provided with a welding inclined plane used for welding with the shell.

11. A compressor, a compressor accumulator, a muffler, a gas-liquid separator or an oil-gas separator for refrigeration or heating, comprising a connecting pipe structure according to any one of claims 1 to 9.

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