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CN-118455845-B - Method for improving corrosion resistance of welded joint of stainless steel plate and application thereof

CN118455845BCN 118455845 BCN118455845 BCN 118455845BCN-118455845-B

Abstract

The invention relates to the technical field of household appliances, and provides a method for improving corrosion resistance of a welding joint of stainless steel plates and application thereof, wherein the welding joint is formed by welding two stainless steel plates with gap sizes distributed at 0-1 mm and staggered edge sizes distributed at 0-1.5 mm under the condition that the oxygen concentration is lower than 1%, an anode material is arranged in a region, within 30mm from the welding joint, of the stainless steel plates, and the pitting potential of the anode material is lower than the lowest pitting potential of the stainless steel plates, and the potential difference value of the two stainless steel plates is larger than 0.15V. The invention designs the structure of the anode material with specific material and installs the anode material at the specific welding joint position, thereby realizing the protection effect of the far super magnesium rod when passivation is not carried out, and having great application potential in a heating water tank and a heat pump water heater.

Inventors

  • WANG XINBAO
  • LI HONGWU
  • ZHANG XUDONG
  • LV YAXIN

Assignees

  • 广东美的制冷设备有限公司
  • 广东美的暖通设备有限公司
  • 美的集团股份有限公司

Dates

Publication Date
20260505
Application Date
20240515

Claims (13)

  1. 1. The method for improving corrosion resistance of the welded joint of the stainless steel plate is characterized in that the welded joint is formed by welding two stainless steel plates with gap sizes distributed at 0-1 mm and staggered edge sizes distributed at 0-1.5 mm under the condition that the oxygen concentration is lower than 1%, anode materials are arranged in the area, within 30mm from the welded joint, of the stainless steel plates, and the pitting potential of the anode materials is lower than the lowest pitting potential of the stainless steel plates, and the potential difference value of the two is larger than 0.15V; The stainless steel plate is made of austenitic stainless steel or duplex stainless steel, and the anode material is one or a combination of more than two of 430 stainless steel, 304 stainless steel, 201 stainless steel and carbon steel.
  2. 2. The method of claim 1, wherein the two stainless steel plates have different pitting potentials, the stainless steel plate having a lower pitting potential is a low potential stainless steel, and the anode material is disposed on the low potential stainless steel.
  3. 3. The method for improving corrosion resistance of a welded joint of stainless steel plates according to claim 1 or 2, wherein the stainless steel plates are made of 316L or 2205, and the anode material is 430 stainless steel.
  4. 4. A method of improving corrosion resistance at a welded joint of stainless steel sheet according to claim 3, wherein the anode material is an anode sheet.
  5. 5. A stainless steel heating water tank assembly, comprising: the barrel body is made of austenitic stainless steel or duplex stainless steel; the end socket is made of austenitic stainless steel or duplex stainless steel; The seal head and the barrel body are made of stainless steel plates; The sealing head comprises a first sealing head and a second sealing head, wherein the first sealing head is arranged at one end of the barrel body, the second sealing head is arranged at the other end of the barrel body, the sealing head and the barrel body are directly welded or welded after flaring to form an annular welding joint, when the sealing head and the barrel body are welded, the gap size between the surfaces to be welded of the sealing head and the barrel body is distributed at 0-1 mm, the staggered edge size is distributed at 0-1.5 mm, and the annular welding joint is formed by welding under the condition that the oxygen concentration is lower than 1%; The anode material is arranged on the sealing head and/or the barrel body and is located in an area within 30mm from the annular welding joint, the pitting potential of the anode material is lower than the lowest pitting potential of the stainless steel plate, the potential difference value of the pitting potential and the stainless steel plate is larger than 0.15V, and the anode material comprises one or a combination of more than two of 430 stainless steel, 304 stainless steel, 201 stainless steel and carbon steel.
  6. 6. The stainless steel heating water tank assembly according to claim 5, wherein the head and the barrel are made of stainless steel plates with different pitting potentials, and the stainless steel plate with lower pitting potential is low-potential stainless steel; The stainless steel plate is made of one or more than two of 304, 304L, 316L and 2205, and the anode material is 430 stainless steel.
  7. 7. The stainless steel heating water tank assembly of claim 5 or 6, wherein the anode material is an anode sheet; the spacing between adjacent anode plates is within 400 mm.
  8. 8. The stainless steel heating water tank assembly of claim 7, wherein the spacing between adjacent anode strips is 150-400 mm.
  9. 9. The stainless steel heating water tank assembly as claimed in any one of claims 5,6, 8, further comprising a coil pipe, which is the same as or different from the material of the tub, provided on the inner and/or outer side walls of the tub; And a clamp, at least part of the surface of the side wall of the pipeline forming the coil is tightly matched with the clamp, the pitting potential of the clamp is lower than that of the coil, and the potential difference of the pitting potential and the pitting potential of the clamp is greater than 0.15V, so that the corrosion resistance of the coil is improved.
  10. 10. The stainless steel heating water tank assembly as recited in claim 7, further comprising a coil pipe, which is made of the same or different materials as the tub, and is provided on the inner and/or outer side walls of the tub; And a clamp, at least part of the surface of the side wall of the pipeline forming the coil is tightly matched with the clamp, the pitting potential of the clamp is lower than that of the coil, and the potential difference of the pitting potential and the pitting potential of the clamp is greater than 0.15V, so that the corrosion resistance of the coil is improved.
  11. 11. The stainless steel heating water tank assembly according to claim 9, wherein the clamp is a strip-shaped structure with the width of 15-40 mm formed by bending and deforming a 430 stainless steel sheet, and the clamp comprises a plurality of concave surfaces which are used for being tightly matched with the side wall of a pipeline of the coil pipe; A gap is formed between each layer of pipelines forming the coil, a pair of clamps are positioned on the inner side and the outer side of the coil, and a fastener is adopted to penetrate through the clamps and the gap to fix the clamps and tightly match the concave surfaces of the clamps with the side walls of the pipelines.
  12. 12. The stainless steel heating water tank assembly according to claim 10, wherein the clamp is a strip-shaped structure with the width of 15-40 mm formed by bending and deforming a 430 stainless steel sheet, and the clamp comprises a plurality of concave surfaces which are used for being tightly matched with the side wall of a pipeline of a coil pipe; A gap is formed between each layer of pipelines forming the coil, a pair of clamps are positioned on the inner side and the outer side of the coil, and a fastener is adopted to penetrate through the clamps and the gap to fix the clamps and tightly match the concave surfaces of the clamps with the side walls of the pipelines.
  13. 13. A heat pump water heater comprising the stainless steel heating water tank assembly of any one of claims 5 to 12.

Description

Method for improving corrosion resistance of welded joint of stainless steel plate and application thereof Technical Field The invention relates to the technical field of household appliances, in particular to a method for improving corrosion resistance of a welding joint of a stainless steel plate and application thereof. Background Electrochemical corrosion is always a key reason for influencing the service life of equipment, currently, a common method for solving potential corrosion is to adopt a passivation process and a sacrificial anode method, the passivation process can integrally improve the corrosion resistance of the equipment, but the cost is extremely high, a magnesium rod is used as a sacrificial anode, the activity of the magnesium rod is high, the protection range is large, however, the consumption of the magnesium rod is too fast, the magnesium rod is consumed about half a year, and the replacement frequency is high. Therefore, the method for improving the corrosion resistance of the metal material to improve the service life of equipment, which has low cost, is researched and has very important significance. Disclosure of Invention The invention provides a method for improving corrosion resistance of a welded joint of a stainless steel plate and application thereof, which are used for solving the defects that in the prior art, stainless steel products such as a stainless steel heating water tank and the like are required to be subjected to subsequent pickling passivation treatment, high in cost, the anode is required to be replaced frequently and the protection effect is limited when the potential corrosion problem is solved. Taking a heat pump water heater taking a stainless steel box body as a heating water tank as an example, the heat pump water heater comprises main components such as an end socket, a barrel body and a coil pipe, wherein the end socket is obtained by stamping a stainless steel plate, the barrel body is obtained by directly welding after coiling the stainless steel plate, the end socket is directly welded with the barrel body or is welded after flaring to obtain a water tank body, the coil pipe can be positioned in the barrel body or outside the barrel body and mainly comprises a coil pipe body and a clamp. In the process of researching the heating water tank with the specific structure, the invention discovers that the key factors influencing the service life of the heat pump water heater and improving the user experience mainly comprise the problems of potential corrosion of the welding joint, the flaring position and the coil pipe. The thickness of the coil body is generally low and is 0.6 mm-1.2 mm in order to achieve the heating efficiency, so that the corrosion channel of the coil is small. And the welding position is more easy to corrode, how to realize the protection of the welding position is always a difficult point in the field, and the welding working conditions in different fields are different, so that the technical problems are different. For example, in the development of the stainless steel heating water tank assembly, a plurality of welding positions of the heating water tank are found, but the corrosion resistance of an annular welding joint formed by the end socket of the stainless steel plate and the barrel body of the stainless steel plate is obviously lower than that of other welding positions. This causes a great technical obstacle in developing a heat pump water heater with a long service life comprising the stainless steel heating water tank. Based on the above, the technical problem that potential corrosion is more likely to occur at the specific welding joint and the flaring position is studied in depth, and the processing working conditions of different welding joints are monitored, so that the difference between the processing working conditions of the end socket of the stainless steel plate and the barrel body of the stainless steel plate is obvious, and the fact that the welding is realized is that the oxygen content required by conventional welding is less than 0.2% and even reaches 1% is difficult to realize in the ventilation protection of welding in the process of welding the end socket and the barrel body, the gap and the misalignment of a piece to be welded are large, the gap size is distributed at 0-1 mm, the misalignment size is distributed at 0-1.5 mm is presumed to be the most easily corroded area at the welding joint of the end socket and the barrel body, and the service life of the water tank is greatly reduced. The oxygen concentration of the invention is obtained by monitoring the atmosphere at the welding joint through a monitoring device in the welding joint forming process. The space dislocation exists between two stainless steel plates to be welded, the to-be-welded points of the two stainless steel plates are placed in a space rectangular coordinate system, the dislocation of the to-be-welded points comprises a space in