CN110906526B

CN110906526B - Preparation method of metal tank body

Info

Publication number: CN110906526B
Application number: CN201911094932.6A
Authority: CN
Inventors: 不公告发明人
Original assignee: Foshan Zhixiao Technology Service Co ltd
Current assignee: Foshan Zhixiao Technology Service Co ltd
Priority date: 2019-11-11
Filing date: 2019-11-11
Publication date: 2021-10-19
Anticipated expiration: 2039-11-11
Also published as: CN110906526A

Abstract

The invention discloses a preparation method of a metal tank body, which comprises the following steps in sequence: adopting a carbon steel pipe, and closing up two ports; and then, treating by adopting a surface treatment process, so that at least an anti-corrosion layer is formed on the outer surface of the metal tank body to obtain the metal tank body, wherein the surface treatment process is a chromizing process, a molybdenating process, a nitriding process or a nitrocarburizing process. The invention adopts carbon steel as the base material, the processing difficulty is greatly reduced compared with stainless steel, the included angle of the shoulder part of the metal tank body can be enlarged to 150 degrees, the corrosion resistance can be comparable to and better than that of stainless steel SUS304 after surface treatment, and moreover, because the corrosion resistant layer of the invention does not fear the high temperature of flame, the copper pipe at the interface does not need to reserve a welding position of more than 5mm, so that the integral furnace-through welding can be realized when manufacturing the silencer or the liquid accumulator.

Description

Preparation method of metal tank body

Technical Field

The invention relates to the field of refrigeration or heating, in particular to a preparation method of a metal tank body.

Background

A muffler or a liquid reservoir in the conventional temperature adjusting field (e.g., air conditioner) includes a housing, and an inlet pipe and an outlet pipe welded to both ends of the housing. The shell is a tube body with a larger diameter, and then the end ports at the two ends are narrowed to be matched with the smaller tube diameters of the air inlet tube and the air outlet tube through closing processing (such as spinning).

Since the piping of the air conditioner is made of copper pipe, the shell 1a of the conventional silencer or liquid reservoir is made of all-copper material (as shown in fig. 1), but the cost of the copper material is high.

For this reason, the shell is changed to be made of iron in the industry, as shown in fig. 2, the two ends of an iron pipe are closed and cold-processed (for example, spun), the two ends of the iron pipe are welded with a copper air inlet pipe and a copper air outlet pipe 2b (so that an air conditioner manufacturer can weld with a copper air conditioner pipe in the future), then the outer surface of the shell 1b of the silencer or the liquid reservoir is painted with paint for surface treatment and corrosion prevention, and the painted area is an area in a dotted line frame in the figure. Wherein, the copper product intake pipe of muffler or reservoir, the outer oral area part of outlet duct 2b 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, therefore copper product intake pipe, outlet duct 2b expose the length of casing part and generally 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 high temperature, the strength and fatigue resistance of the copper pipe are reduced, the longer the portions of the copper material inlet pipe and outlet pipe 2b exposed out of the shell are exposed, 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 shell 1b and the copper material inlet pipe and outlet pipe 2b cannot be furnace-through welding but can be flame welding. Therefore, the structure and the manufacturing process are high in cost and complex in process, and the interior of the iron shell cannot be rusted.

Therefore, as shown in fig. 3, the shell 1c is made of stainless steel instead, and is made of a single material, so that the shell is not laminated during processing and has high corrosion resistance (the salt spray test is generally required to be more than or equal to 500 hours in the refrigeration industry). But stainless steel materials are expensive and difficult to machine. Stainless steel generally is the austenite, easily ftractures when carrying out the spinning binding off, and the rate of cracking is more than 2% (the austenite becomes extremely unstable tissue through processing back, and the very big follow-up stress release of residual stress, the later stage that does not split at that time also can split the proportion height), moreover because easily ftracture, therefore the angle alpha of casing shoulder position generally can only be about 60, leads to the volume of muffler or reservoir to be slightly littleer, can only increase the length of casing and can not adopt the great tubular product of pipe diameter for guaranteeing certain volume. In the welding and assembling process, the stainless steel is easy to discolor in the common furnace-passing welding, so a special reducing tunnel furnace is needed, and the welding and assembling process is complicated, expensive and high in operating cost. Therefore, the cost of the stainless steel shell is high, the rejection rate is high, and the length of the stainless steel shell required under the same volume is longer.

Disclosure of Invention

In order to solve the problems, the invention aims to provide a method for manufacturing a metal tank body, which has the advantages of greatly reduced cost, low rejection rate, basically eliminated risk of fracture of a copper pipe at an interface and shorter shell length under the same volume.

The purpose of the invention is realized as follows: a preparation method of a metal tank body is characterized by comprising the following steps in sequence: (1) adopting a carbon steel pipe, and closing up two ports; (2) and (2) treating the carbon steel pipe processed in the step (1) by adopting a surface treatment process to form an anti-corrosion layer on at least the outer surface of the carbon steel pipe to obtain a metal tank body, wherein the surface treatment process is a chromizing process, a molybdenum cementation process, a molybdenating process, a nitriding process or a nitrocarburizing process.

Fixedly welding copper lining pipes in the two ports of the metal tank body, and completing the welding during or after the step (2), wherein the preferable method comprises the following steps: before the step (2) is carried out, arranging copper lining pipes in the two ports with the closed ends processed, then completing the welding of the carbon steel pipe fitting and the copper lining pipes at high temperature in the surface treatment process of the step (2), and finally removing the carbon steel pipe fitting and the copper lining pipes if an anti-corrosion layer exists on the inner wall of the copper lining pipes; or after the step (2) is carried out, welding copper lining pipes in pipe orifices at two ends of the metal tank body in a brazing mode, preferably furnace welding; or, after the step (2), removing the anti-corrosion layer at least on the part matched with the copper inner bushing in the two ports, and then welding the anti-corrosion layer with the copper inner bushing, wherein the welding mode is brazing, preferably furnace welding; or, the two ports of the metal tank body are welded with extension pipes, the outer ports of the extension pipes are welded with copper lining pipes, the welding is completed during or before or after the step (2), the extension pipes are pipes with corrosion resistant surfaces or pipes with corrosion resistant layers formed on at least the outer surfaces of the extension pipes through a surface treatment process, and the preferred method is as follows: before the step (2) is carried out, extension pipes are arranged in the two ports which are processed by closing up, copper lining pipes are arranged in the outer ports of the extension pipes, then the welding of the carbon steel pipe fitting, the extension pipes and the copper lining pipes is completed in the high temperature of the surface treatment process in the step (2), and finally, if an anti-corrosion layer exists on the inner wall of the copper lining pipe, the anti-corrosion layer is removed; or, before the step (2) is carried out, arranging extension pipes in the two ports which are processed by closing up, then completing the welding of the carbon steel pipe fitting and the extension pipes in the high temperature of the surface treatment process in the step (2), and then welding a copper lining pipe in the outer port of the extension pipe, wherein the welding mode is brazing, and preferably furnace welding; or before the step (2) is carried out, arranging extension pipes in the two ports which are processed by closing up, then completing the welding of the carbon steel pipe fitting and the extension pipes at high temperature in the surface treatment process of the step (2), then removing an anti-corrosion layer at least on the part of the outer port of the extension pipe, which is matched with the copper inner lining, and then welding the extension pipe fitting and the copper inner lining, wherein the welding mode is brazing, and preferably furnace welding; or, after the step (2) is carried out, the extension pipes with the corrosion-resistant surfaces are welded in the pipe orifices at the two ends of the metal tank body, then the copper lining pipes are welded in the outer end orifices of the extension pipes by brazing, and the preferred mode of brazing is furnace welding; or after the step (2) is carried out, arranging extension pipes in pipe orifices at two ends of the metal tank body, arranging copper lining pipes in outer end orifices of the extension pipes, and completing welding of the metal tank body, the extension pipes and the copper lining pipes through furnace welding; or, respectively welding the outer end of the extension pipe with the copper lining pipe and the step (2), and then welding the extension pipe welded with the copper lining pipe with the surface-treated metal tank body.

The shell wall of the metal tank body is sequentially provided with a carbon steel layer and an anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises a mutual permeation layer; or the shell wall of the metal tank body is sequentially provided with an anti-corrosion layer, a carbon steel layer and an anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises a mutual permeation layer.

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

The metal tank body comprises a shell body and two ports, wherein a shoulder is arranged between the shell body and the ports, and the included angle of the shoulder is 30-150 degrees.

The outer pipe port flanging of the copper lining pipe covers the port edge of the metal tank body or the port edge of the outer port of the extension pipe, and the flanging thickness is 0.1mm-5 mm; or the outer pipe opening of the copper lining pipe is not provided with a flanging and directly protrudes out of the port edge of the metal tank body or the port edge of the outer port of the extension pipe 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 port of the metal tank body or the external port of the extension pipe are overlapped by at least 3mm in the length direction to form a welding area.

At least one surface of the welding area between the copper lining pipe and the port of the metal tank body or the outer port of the extension pipe is subjected to wire drawing treatment.

The metal tank body is a shell of a liquid storage device or a silencer for refrigeration or heating.

The invention aims at overcoming the defects of the existing structure and process and improving the muffler or the liquid accumulator. The carbon steel is adopted as a base material, the price is lower, and the carbon steel is ferrite, so the processing difficulty is greatly reduced (such as spinning processing) compared with that of stainless steel, the cracking condition can not occur basically, the included angle of the shoulder part of the metal tank body can be enlarged to 150 degrees, the volume is larger (or less materials are needed under the same volume) under the condition of the same length, an anti-corrosion layer is formed on the surface of the treated metal tank body, the corrosion resistance of the anti-corrosion layer can be comparable to and better than that of stainless steel SUS304, and the anti-corrosion layer of the invention is not afraid of flame high temperature, so that a copper pipe at an interface does not need to reserve a welding position of more than 5mm, high-temperature resistance re-welding can be realized, the risk of the copper pipe at the interface being broken is basically avoided, and the whole furnace-passing welding can be realized when the silencer or the liquid storage device is manufactured.

Drawings

FIGS. 1-3 are schematic diagrams of the structures of 3 types of prior art mufflers or reservoirs, respectively;

FIG. 4 is a schematic structural view of embodiment 1 of the present invention;

FIG. 5 is a schematic cross-sectional view of a housing wall of example 1 of the present invention;

FIG. 6 is a schematic structural view of embodiment 2 of the present invention;

FIG. 7 is a schematic structural view of embodiment 3 of the present invention;

FIGS. 8 and 9 are schematic diagrams of copper-lined pipe structures according to embodiments 4 and 5 of the present invention;

FIG. 10 is a schematic cross-sectional view of a housing wall of example 7 of the present invention;

FIG. 11 is a schematic structural view of examples 8, 9 and 10 of the present invention.

Detailed Description

The invention relates to a preparation method of a metal tank body, which comprises the following steps:

(1) the carbon steel pipe fitting is adopted, and two ports are closed. The necking process may generally be performed by cold working, such as spinning. Preferably, mild steel tubing is used.

(2) And (2) treating the carbon steel pipe processed in the step (1) by adopting a surface treatment process to form an anti-corrosion layer on at least the outer surface of the carbon steel pipe (at least ensuring the rust and corrosion prevention of the outer surface), so as to obtain a metal tank body, wherein the metal tank body can be used as a shell body of a liquid storage device or a silencer for refrigeration or heating, and the surface treatment process is a chromizing process, a chromizing co-cementation process, a molybdenating co-cementation process, a nitriding process or a nitrocarburizing process. The surface treatment process must be carried out after the closing-up processing step, otherwise the processing difficulty of the carbon steel pipe fitting which is firstly subjected to the surface treatment process is greatly increased.

Chromizing, molybdenating, nitrocarburizing, nitriding, nitrocarburizing, and the like 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.

According to different specific surface treatment processes, the anti-corrosion layer 12 may only cover the outer surface of the metal tank body 1, the shell wall of the metal tank body 1 is provided with the carbon steel layer 11 and the anti-corrosion layer 12 from inside to outside in sequence, and the anti-corrosion layer 12 at least comprises an interpenetrating layer; alternatively, the anti-corrosion layer 12 may cover the inner and outer surfaces of the metal can body 1, and this is most preferable, as shown in fig. 5, the shell wall of the metal can body 1 is formed with the anti-corrosion layer 12, the carbon steel layer 11, and the anti-corrosion layer 12 in this order from the inside to the outside, that is, the inner and outer surfaces of the metal can body 1 are formed with the anti-corrosion layer, and the anti-corrosion layer includes at least one interpenetrating layer. Wherein if the chromizing process, the chromizing co-cementation process, the molybdenation process or the molybdenation co-cementation process is adopted, the anti-corrosion layer comprises a mutual cementation layer and a chromium layer, a chromium carbide layer, a molybdenum layer or a molybdenum carbide layer which is formed on the surface of the mutual cementation layer and is not infiltrated into the carbon steel layer.

Preferably, the thickness of the corrosion resistant layer 12 is not less than 1 μm, preferably 1 to 100 μm, more preferably 3 to 30 μm.

Preferably, the metal tank body 1 comprises a shell body and two ports, a shoulder is arranged between the shell body and the ports, the processing difficulty is greatly reduced compared with that of stainless steel due to the fact that carbon steel is used as a base material, cracking basically cannot occur, the included angle beta range of the shoulder can be increased to 30-150 degrees, and the limit of 60 degrees of the stainless steel shell is broken through.

Preferably, the metal tank further comprises a copper lining pipe 2 welded and fixed in the two ports so as to be welded with a copper material pipe or a composite pipe with a copper material welding part. The subsequent welding with the copper air-conditioning tubing generally uses phosphorus-copper solder, the welding temperature is above 720 ℃, so the welding of the copper lining pipe 2 and the metal tank body 1 preferably uses solder with the temperature of not lower than 800 ℃. The welding of the copper lining pipe 2 can be carried out during or after the step (2), and when the temperature range of the surface treatment process is within the welding temperature range (800-. The preferred welding method is as follows: if a surface treatment process with the treatment temperature not lower than 800 ℃ is adopted, before the step (2) is carried out, the copper lining pipe 2 and the welding flux are arranged in the two ports with the processed closing-up, then the welding of the carbon steel pipe fitting and the copper lining pipe 2 is completed in the high temperature of the surface treatment process of the step (2) (namely, the copper lining pipe is welded by the high temperature enough for melting the welding flux in the surface treatment process), and finally the anti-corrosion layer of the copper lining pipe 2 is removed. Or, after the step (2) is carried out, welding the copper lining pipe 2 in the pipe orifices at the two ends of the metal tank body 1 in a brazing mode, adopting a brazing material with the temperature of the brazing material not lower than 800 ℃, preferably performing furnace welding, and more preferably, the welding parameter of the furnace welding is more than 1 minute and preferably more than 3 minutes in the temperature of 800-1082 ℃ (the temperature is the actual temperature of the surface of the product in the furnace). Or, after the step (2), removing the anti-corrosion layer at least at the part matching with the copper inner bushing in the two ports, and then welding with the copper inner bushing 2, wherein the welding mode is brazing, preferably furnace welding, and more preferably, the welding parameter of the furnace welding is more than 1 minute, preferably more than 3 minutes in the temperature of 800-1082 ℃ (the temperature is the actual temperature of the surface of the product in the furnace).

Or, in order to meet the requirements of air conditioner manufacturers, the extension pipes 3 can be welded at the two ports of the metal tank body, and the copper lining pipes 2 are welded in the outer ports 31 of the extension pipes 3. Similarly, the copper-lined pipe 2 and the extension pipe 3 are preferably welded with a solder having a solder temperature of not less than 800 ℃. The extension pipe 3 is a pipe member having a corrosion resistant surface itself or a pipe member having a surface treatment process for forming a corrosion resistant layer on at least an outer surface thereof. The assembly sequence of the metal tank body 1, the extension pipe 3 and the copper lining pipe 2 is various, the welding can be completed in the step (2) or before or after the step (2), and according to the actual design, the preferable method can be as follows: before the step (2) is carried out, arranging an extension tube 3 and a solder in two ports which are processed by closing up, arranging a copper lining tube 2 and a solder in an outer port 31 of the extension tube, then completing the welding of the carbon steel tube, the extension tube 3 and the copper lining tube 2 in the high temperature of the surface treatment process in the step (2), and finally removing the anti-corrosion layer if the inner wall of the copper lining tube 2 exists; or before the step (2) is carried out, arranging extension pipes 3 and welding fluxes in the two ports which are processed by closing up, then completing the welding of the carbon steel pipe fitting and the extension pipes 3 at high temperature in the surface treatment process of the step (2), and then welding the copper lining pipe 2 in the outer port 31 of the extension pipe, wherein the welding mode is brazing, and preferably furnace welding; or before the step (2) is carried out, arranging an extension tube 3 and a solder in the two ports which are processed by closing up, then completing the welding of the carbon steel tube and the extension tube 3 at high temperature in the surface treatment process of the step (2), then removing an anti-corrosion layer at least on the part of the outer port 31 of the extension tube matched with the copper inner bushing 2, and then welding with the copper inner bushing 2, wherein the welding mode is brazing, preferably furnace welding; or, after the step (2) is carried out, the extension pipes 3 with the corrosion-resistant surfaces are welded in the pipe orifices at the two ends of the metal tank body 1, then the copper lining pipes 2 are welded in the pipe orifices 31 outside the extension pipes by brazing, and the preferred mode of brazing is furnace welding; or after the step (2) is carried out, arranging extension pipes 3 and solder in pipe openings at two ends of the metal tank body 1, arranging copper lining pipes 2 and solder in an outer port 31 of the extension pipes, and completing welding of the metal tank body 1, the extension pipes 3 and the copper lining pipes 2 through furnace welding; or, the welding of the extension pipe 3 and the copper lining pipe 2 and the step (2) are respectively carried out, and then the extension pipe 3 welded with the copper lining pipe 2 and the metal tank body 1 with the surface treated are welded.

The aforementioned pipe element having a corrosion resistant surface may be: stainless steel pipe, stainless iron pipe, Bundy pipe, steel pipe with copper coating, steel pipe with nickel coating, or carbon steel pipe or iron pipe with surface coated with copper-infiltrated layer, chromium-infiltrated layer, molybdenum-infiltrated layer, nitriding layer or nitrocarburizing layer, which can be welded with the metal tank body 1 before or after or during the surface treatment process of step (2).

The pipe fitting which needs to form the anti-corrosion layer on at least the outer surface thereof through the surface treatment process can be an iron pipe, a carbon steel pipe and the like, and is placed in pipe orifices at two ends of the carbon steel pipe fitting, and the surface treatment process in the step (2) and the carbon steel pipe fitting form the anti-corrosion layer together.

Preferably, in order to facilitate the subsequent flame welding connection with the copper air-conditioning piping, the position welded with the copper air-conditioning piping cannot be made of carbon steel as much as possible, so that the outer pipe opening of the copper lining pipe 2 is provided with a flange 21 covering the port edge of the metal tank body 1 or the port edge of the outer port of the extension pipe, and the thickness of the flange is 0.1mm-5 mm; or the outer pipe opening of the copper lining pipe 2 is not provided with a flanging and directly protrudes out of the port edge of the metal tank body 1 or the port edge of the outer port of the extension pipe, 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, the outer pipe opening of the copper lining pipe 2 is provided with a 30-120-degree flanging 21, the angle of the flanging is matched with the angle of the port edge of the metal tank body 1 or the port edge of the outer port of the extension pipe and can cover the port edge, and the joint of the flanging 21 and the inner diameter pipe wall of the copper lining pipe 2 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.

Preferably, the length B of the copper lining pipe 2 at least overlapping with the port of the metal tank body 1 or the external port of the extension pipe 3 in the length direction is 3mm, so as to form a welding area, and ensure the welding strength of the copper lining pipe 2 and the port of the metal tank body 1 or the external port of the extension pipe 3.

Preferably, at least one surface of a welding area between the copper lining pipe 2 and the outer port of the metal tank body 1 or the extension pipe 3 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 metal tank body 1 or the port of the outer port of the extension pipe 3, and molten solder is uniformly filled in the whole welding area through capillary action during high-temperature welding. The copper lining pipe 2 is preferably in interference fit with the port of the metal tank body 1 or the outer port of the extension pipe 3.

The metal tank body prepared by the preparation method is applied to a liquid storage device or a silencer in the field of air conditioners.

Example 1

As shown in fig. 4, a carbon steel pipe is adopted, two ports are closed up through spinning to form a shell body and two ports, a shoulder is arranged between the shell body and the ports, and the included angle beta of the shoulder is 120 degrees; arranging a copper lining pipe 2 and a solder with the temperature of not lower than 800 ℃ in two ports with processed closing-up, and then adopting a conventional salt bath chromizing process to form an anti-corrosion layer 12 on the inner surface and the outer surface of the carbon steel pipe fitting integrally, wherein the anti-corrosion layer 12 is a chromium-carbon steel interpenetrating layer (as shown in figure 5), and the thickness of the anti-corrosion layer 12 is not less than 1 mu m. In the high temperature of the salt bath chromizing process, the copper lining pipe 2 is welded with the port of the carbon steel pipe fitting 1. If the inner wall of the copper lining pipe also forms an anti-corrosion layer after chromizing, the inner wall needs to be scraped. The manufactured metal tank body can be used for a liquid storage device or a silencer.

In this embodiment, the outer port of the copper lining pipe 2 is provided with a flange 21 of about 90 degrees, which covers the port edge of the metal tank body 1, and the thickness of the flange 21 is 1 mm. The copper lining pipe 2 and the port of the metal tank body 1 are overlapped for at least 3mm in the length direction to form a welding area. The copper lining pipe 2 is in interference fit with the port of the metal tank body, and the area where the outer surface of the copper lining pipe 2 is welded with the port of the metal tank body is subjected to wire drawing treatment.

Example 2

As shown in fig. 6, a carbon steel pipe is adopted, and two ports are closed by spinning; the existing glow nitriding process is adopted to form an anti-corrosion layer 12 on the outer surface of the carbon steel pipe, the anti-corrosion layer 12 is a nitrogen-carbon steel mutual-permeation layer, and the thickness of the anti-corrosion layer 12 is not less than 1 mu m.

After nitriding, welding the copper lining pipes 2 in pipe orifices at two ends of the metal tank body 1, adopting welding flux with the welding flux temperature not lower than 800 ℃, wherein the welding mode is furnace welding, and the welding parameter of the furnace welding is more than 1 minute at the temperature of 800-.

In this embodiment, the outer opening of the copper lining pipe 2 is not provided with a flange, and protrudes 1.5mm directly from the edge of the opening of the metal tank body 1, and the outer opening is provided with a flared opening 22. The area of the flare 22 may be greater than 0.5mm from the edge of the outer tube mouth inwards.

The rest is the same as example 1.

Example 3

The carbon steel pipe fitting is adopted, two ports are closed through spinning, and then the chromizing process is adopted, so that the anti-corrosion layers 12 are formed on the inner surface and the outer surface of the carbon steel pipe fitting. Then arranging a copper lining pipe 2 and a solder with the solder temperature not lower than 800 ℃ in two ports of the carbon steel pipe with the finished surface treatment for welding, wherein the welding mode is furnace-passing welding, and the welding parameters of the furnace-passing welding are more than 3 minutes at the temperature of 800-1082 ℃.

As shown in fig. 7, in the present embodiment, the outer pipe opening of the copper lining pipe 2 is not provided with a flange, and directly protrudes 2mm from the edge of the end opening of the metal can body 1, and the outer pipe opening is provided with a flaring 22. The area of the flared opening 22 is from the position corresponding to the edge of the port of the metal tank body 1 to the edge of the outer port, and at this time, the flared opening 22 can play a limiting role to limit the depth of the copper lining pipe 2 inserted into the port of the metal tank body 1.

The rest is the same as example 1.

Example 4

The surface treatment process adopts the existing double glow plasma molybdenum cementation process, the outer pipe opening of the copper lining pipe 2 is not provided with a flanging, but the inner edge of the outer pipe opening is provided with a chamfer 23, as shown in figure 8.

The rest is the same as example 2.

Example 5

Adopting a carbon steel pipe, closing up two ports by spinning to form a shell body and two ports, wherein a shoulder part is arranged between the shell body and the ports, and the included angle alpha of the shoulder part is 120 degrees; and then, forming an anti-corrosion layer 12 on the outer surface of the carbon steel pipe by adopting the existing gas nitrocarburizing process, wherein the anti-corrosion layer 12 is a nitrogen and carbon-carbon steel mutual permeation layer, and the thickness of the anti-corrosion layer 12 is not less than 1 mu m. If the inner wall of the copper lining pipe also forms an anti-corrosion layer, it needs to be scraped. After nitrocarburizing, welding the copper lining pipes 2 in the pipe orifices at the two ends of the metal tank body 1, adopting welding flux with the temperature of not lower than 800 ℃, wherein the welding mode is furnace-through welding, and the welding parameters of the furnace-through welding are more than 3 minutes at the temperature of 1082 ℃ of 800-.

In this embodiment, the outer pipe opening of the copper lining pipe 2 is not provided with a flange, and directly protrudes 1mm from the edge of the port of the metal can body 1, the inner wall of the outer pipe opening is a step hole 24, and the small step hole and the large step 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 copper lining pipe 2 and the port of the metal tank body 1 are overlapped for at least 3mm in the length direction to form a welding area. And (3) carrying out wire drawing treatment on the area welded between the outer surface of the copper lining pipe 2 and the port of the metal tank body.

Example 6

In this embodiment, the outer pipe orifice of the copper lining pipe is not provided with a flange, the inner part of the outer pipe orifice is provided with a tapered hole, and the diameter of the tapered hole is from inside to outside.

The rest is the same as example 3.

Example 7

Adopting a carbon steel pipe, closing up two ports by spinning to form a shell body and two ports, wherein a shoulder part is arranged between the shell body and the ports, and the included angle alpha of the shoulder part is 120 degrees; and then, forming the anti-corrosion layer 12 on the outer surface of the carbon steel pipe by adopting a carbon-chromium co-cementation process, wherein the anti-corrosion layer 12 is a carbon, chromium-carbon steel mutual cementation layer 121 and a chromium carbide layer 122 (shown in figure 10), and the thickness of the anti-corrosion layer 12 is not less than 1 mu m. After the carbon and chromium co-permeation, the anti-corrosion layer 12 is removed from the pipe orifices at the two ends of the metal tank body 1, then the copper lining pipe 2 is welded, the solder with the solder temperature not lower than 800 ℃ is adopted, the welding mode is through-furnace welding, and the welding parameter of the through-furnace welding is more than 3 minutes at the temperature of 800-1082 ℃.

In this embodiment, the outer pipe opening of the copper lining pipe 2 is provided with a flange which directly protrudes 2mm from the edge of the end opening of the metal tank body 1, the inner wall of the outer pipe opening is a step hole 24, and the small step hole and the large step hole are sequentially arranged from inside to outside. The copper lining pipe 2 and the port of the metal tank body 1 are overlapped for at least 3mm in the length direction to form a welding area. And (3) carrying out wire drawing treatment on the area welded between the inner surface of the port of the metal tank body and the copper lining pipe 2.

Example 8

The carbon steel pipe fitting is adopted, two ports are closed through spinning, and then the chromizing process is adopted, so that the anti-corrosion layers 12 are formed on the inner surface and the outer surface of the carbon steel pipe fitting. Then placing an extension tube 3 and solder (in the embodiment, a tube with a corrosion-resistant surface: a stainless steel tube) in two ports of the metal tank body 1 which is subjected to surface treatment, placing a copper lining tube 2 and solder with the temperature of not lower than 800 ℃ in the outer port 31 of the extension tube for welding, and completing the welding of the metal tank body 1, the extension tube 3 and the copper lining tube 2 through furnace welding, wherein the welding parameters of the furnace welding are more than 3 minutes at the temperature of 800-. The resulting product structure is shown in fig. 11.

The length of the extension pipe 3 is set according to actual needs. In this embodiment, the outer port of the copper-lined pipe 2 is provided with a flange 21 of about 90 °, and the flange 21 covers the port edge of the outer port 31 of the extension pipe, and the thickness of the flange 21 is 1 mm. The copper-lined pipe 2 and the outer end 31 of the extension pipe overlap at least 3mm in the longitudinal direction to form a welded region. The copper-lined pipe 2 is in interference fit with the outer port 31 of the extension pipe, and the area where the outer surface of the copper-lined pipe 2 is welded with the outer port 31 of the extension pipe is subjected to wire drawing treatment. The other end of the extension pipe is connected with the port of the metal tank body 1 in a welding way, and one surface of the area where the extension pipe and the port are welded can be subjected to wire drawing treatment. Preferably, the extension pipe 3 has a flared structure, and the inner diameter of the outer port 31 is larger than that of the other end welded to the metal can body 1.

Example 9

An extension pipe 3 with a corrosion resistant surface is welded in the two ports of the metal tank body 1 which is subjected to surface treatment, and then a copper lining pipe 2 and a solder with the solder temperature not lower than 800 ℃ are placed in the outer port 31 of the extension pipe for braze welding. The resulting product structure is shown in fig. 11.

The rest is the same as example 8.

Example 10

Adopting a carbon steel pipe fitting, closing up two ports by spinning, arranging a carbon steel extension pipe 3 and a solder in the two ports processed by closing up, arranging a copper lining pipe 2 and a solder in an outer port 31 of the extension pipe, and then adopting a conventional salt bath chromizing process as a whole to form an anti-corrosion layer 12 on the inner surface and the outer surface of the whole, wherein the anti-corrosion layer 12 is a chromium-carbon steel mutual-infiltration layer (as shown in figure 5), and the thickness of the anti-corrosion layer 12 is not less than 1 mu m. In the high temperature of the salt bath chromizing process, the welding of the copper lining pipe 2, the extension pipe 3 and the carbon steel pipe fitting 1 is also completed.

The rest is the same as example 8.

Claims

1. A preparation method of a metal tank body is characterized by comprising the following steps in sequence: (1) adopting a carbon steel pipe, and closing up two ports; (2) treating the carbon steel pipe processed in the step (1) by adopting a surface treatment process to form an anti-corrosion layer on at least the outer surface of the carbon steel pipe to obtain a metal tank body, wherein the surface treatment process is a chromizing process, a molybdenum cementation process, a molybdenating process, a nitriding process or a nitrocarburizing process; fixedly welding copper lining pipes in two ports of the metal tank body, wherein the welding is completed in the middle or after the step (2), or the welding is completed in the middle or before or after the step (2), wherein the two ports of the metal tank body are welded with extension pipes, the outer ports of the extension pipes are welded with the copper lining pipes, and the extension pipes are pipes with corrosion resistant surfaces or pipes with corrosion resistant layers formed on at least the outer surfaces of the extension pipes by a surface treatment process; the outer pipe port flanging of the copper lining pipe covers the port edge of the metal tank body or the port edge of the outer port of the extension pipe, and the flanging thickness is 0.1mm-5 mm; or the outer pipe opening of the copper lining pipe is not provided with a flanging and directly protrudes out of the port edge of the metal tank body or the port edge of the outer port of the extension pipe by 0.1mm-5 mm.

2. The method of making a metal can body of claim 1, wherein: before the step (2) is carried out, arranging copper lining pipes in the two ports with the closed ends processed, then completing the welding of the carbon steel pipe fitting and the copper lining pipes at high temperature in the surface treatment process of the step (2), and finally removing the carbon steel pipe fitting and the copper lining pipes if an anti-corrosion layer exists on the inner wall of the copper lining pipes; or after the step (2) is carried out, welding copper lining pipes in pipe orifices at two ends of the metal tank body in a brazing mode; or, after the step (2), removing the anti-corrosion layer at least on the part matched with the copper lining pipe in the two ports, and then welding the anti-corrosion layer with the copper lining pipe, wherein the welding mode is brazing;

or before the step (2) is carried out, arranging extension pipes in the two ports with the closed ends processed, arranging copper lining pipes in the outer ports of the extension pipes, then completing the welding of the carbon steel pipe fitting, the extension pipes and the copper lining pipes at high temperature in the surface treatment process of the step (2), and finally removing the carbon steel pipe fitting, the extension pipes and the copper lining pipes if an anti-corrosion layer exists on the inner wall of the copper lining pipes; or, before the step (2) is carried out, arranging extension pipes in the two ports which are processed by closing up, then completing the welding of the carbon steel pipe fitting and the extension pipes in the high temperature of the surface treatment process in the step (2), and then welding a copper lining pipe in the outer port of the extension pipe, wherein the welding mode is brazing; or, before the step (2) is carried out, arranging extension pipes in the two ports which are processed by closing up, then completing the welding of the carbon steel pipe fitting and the extension pipes at high temperature in the surface treatment process of the step (2), then removing an anti-corrosion layer at least on the part of the outer port of the extension pipe matched with the copper lining pipe, and then welding the extension pipe fitting and the copper lining pipe, wherein the welding mode is brazing; or, after the step (2) is carried out, welding extension pipes with corrosion-resistant surfaces in pipe openings at two ends of the metal tank body, and then welding copper lining pipes in outer end openings of the extension pipes by brazing; or after the step (2) is carried out, arranging extension pipes in pipe orifices at two ends of the metal tank body, arranging copper lining pipes in outer end orifices of the extension pipes, and completing welding of the metal tank body, the extension pipes and the copper lining pipes through furnace welding; or, respectively welding the outer end of the extension pipe with the copper lining pipe and the step (2), and then welding the extension pipe welded with the copper lining pipe with the surface-treated metal tank body.

3. A method of making a metal can body according to claim 2, characterized in that: the brazing is furnace welding.

4. The method of making a metal can body of claim 1, wherein: the shell wall of the metal tank body is sequentially provided with a carbon steel layer and an anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises a mutual permeation layer; or the shell wall of the metal tank body is sequentially provided with an anti-corrosion layer, a carbon steel layer and an anti-corrosion layer from inside to outside, and the anti-corrosion layer at least comprises a mutual permeation layer.

5. A method of making a metal can body according to claim 1, 2, 3 or 4, characterized in that: the thickness of the anti-corrosion layer is not less than 1 μm.

6. The method of making a metal can body of claim 1, wherein: the metal tank body comprises a shell body and two ports, wherein a shoulder is arranged between the shell body and the ports, and the included angle of the shoulder is 30-150 degrees.

7. The method of making a metal can body of 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.

8. The method of making a metal can body of claim 1, wherein: the copper lining pipe and the port of the metal tank body or the external port of the extension pipe are overlapped by at least 3mm in the length direction to form a welding area.

9. The method of making a metal can body of claim 1, wherein: at least one surface of the welding area between the copper lining pipe and the port of the metal tank body or the outer port of the extension pipe is subjected to wire drawing treatment.

10. A method of manufacturing a metal can body according to any one of claims 1-4 and 6-9, characterized in that: the metal tank body is a shell of a liquid storage device or a silencer for refrigeration or heating.

11. The method of making a metal can body of claim 5, wherein: the metal tank body is a shell of a liquid storage device or a silencer for refrigeration or heating.