Heat spraying process for double-layer roll-welded pipe

Abstract

The invention belongs to the technical field of hot-dip plating, and discloses a double-layer roll-welded pipe hot-dip plating process, which comprises the following steps of: arranging a wave-soldering heating furnace at the downstream of a brazing furnace in a double-layer roll-welded pipe production line to carry out hot-dip plating on a double-layer roll-welded pipe just discharged from the brazing furnace, in the hot dipping process, waste heat in the pipe manufacturing and welding step and high surface cleanliness after hydrogen reduction are utilized; the wave-soldering heating furnace is provided with turbulent waves, the wave crest of the turbulent waves is higher than the pipe body of the double-layer roll-welded pipe, and the turbulent waves form showering on the pipe body when falling. The design is reasonable, hot dipping is carried out on the production line of the double-layer coiled welded pipe, a whole set of hot dipping production line does not need to be additionally arranged, product turnover is reduced, the production period is shortened, the production cost is reduced, and environmental damage is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-dip galvanizing, and in particular relates to a hot-dip galvanizing process for a double-layer rolled welded pipe. Background Art

[0002] Double-layer welded pipe is a kind of precision metal hard pipe material, which is widely used in the oil and gas systems of automobiles, refrigeration, and machine tools. Since the surface of double-layer welded pipe is not corrosion-resistant, the surface needs to be treated with corrosion resistance in actual use; At present, the treatment methods can be divided into three categories: 1. Electroplating, 2. Surface coating with organic materials, and 3. Hot-dip galvanizing. Electroplating is generally processed by professional manufacturers, which increases transportation costs, causes greater pollution, and is not conducive to environmental protection. The cost of surface coating with organic materials is relatively high, and it is generally used for high-end products. The coating machine also needs electroplating or hot-dip galvanizing in the previous process of materials. Hot-dip galvanizing has strong covering ability, dense coating, no organic impurities, and excellent corrosion resistance.

[0003] At present, the hot-dip galvanizing of the surface of double-layer coiled welded pipes is generally carried out using a professional hot-dip galvanizing production line. The dedicated production line needs to go through multiple processes such as unwinding, preliminary treatment, preheating, hot-dip galvanizing, cooling and winding to complete. The cost is relatively high, and the preliminary treatment also has certain pollution. Summary of the invention

[0004] In order to overcome the above technical problems, the present invention provides a hot-dip galvanizing process for double-layer welded pipes, which performs hot-dip galvanizing on the production line of double-layer welded pipes without the need to set up an additional complete hot-dip galvanizing production line, thereby reducing costs, improving efficiency, and being environmentally friendly.

[0005] The present invention adopts the following technical solutions: The hot-dip coating process for double-layer welded pipes includes the following steps: a wave soldering heating furnace is arranged downstream of the brazing furnace in the double-layer welded pipe production line to perform hot-dip coating on the double-layer welded pipes that have just come out of the brazing furnace. The hot-dip coating process utilizes the residual heat of the pipe making and welding steps and the high surface cleanliness after hydrogen reduction. The wave soldering heating furnace is provided with turbulent waves, the crest of the turbulent waves is higher than the double-layer welded pipe body, and the turbulent waves form a shower on the pipe body when falling.

[0006] Preferably, the wave soldering heating furnace is provided with two wave crests in succession, the turbulent wave being the first wave and the smooth wave being the second wave, the wave crest of the smooth wave being higher than the central axis of the tube body but not exceeding the tube body, and the smooth wave infiltrates and corrects the defects of the metal coating sprayed in the previous step.

[0007] Preferably, the flow direction of the two wave crests is opposite to the moving direction of the tube body.

[0008] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention performs hot-dip galvanizing on the production line of double-layer rolled welded pipes, and does not require an additional set of hot-dip galvanizing production lines, thereby reducing product turnover, shortening production cycles, reducing production costs, and reducing environmental damage; 2. The present invention arranges a wave peak heating furnace downstream of the brazing furnace to perform hot-dip coating on the double-layer coiled welded pipe just out of the brazing furnace. The hot-dip coating process utilizes the residual heat of the pipe making welding step and the high surface cleanliness after hydrogen reduction, thereby eliminating the preliminary treatment and preheating work of the special hot-dip coating production line, rationally utilizing energy, and saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the process flow of the present invention; Figure 2 It is a schematic diagram of two waves of a wave soldering heating furnace. DETAILED DESCRIPTION

[0010] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. Unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the embodiments are conventional methods in the art unless otherwise specified. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0011] The double-layer coiled welded pipe production line includes, from front to back, a single-belt unwinder, a forming machine, a brazing furnace, a cooling pipe, a traction machine and a coiler.

[0012] like Figure 1 As shown, the hot-dip galvanizing process for double-layer coiled welded pipes is to directly set a double wave soldering heating furnace downstream of the brazing furnace and upstream of the cooling pipe in the double-layer coiled welded pipe production line. The double wave soldering heating furnace uses a pump to press the hot-melt liquid metal out of two narrow gaps to form two successive upwardly arched wave peaks. The double-layer coiled welded pipe coming out of the brazing furnace passes through the two wave peaks in sequence. The wave soldering heating furnace performs hot-dip galvanizing on the double-layer coiled welded pipe just out of the brazing furnace. The hot-dip galvanizing process utilizes the residual heat of the pipe making welding step and the high surface cleanliness after hydrogen reduction, thereby eliminating the preliminary treatment and preheating work of the special hot-dip galvanizing production line, rationally utilizing energy, and saving energy. The flow direction of the two wave peaks is opposite to the traveling direction of the pipe body, as shown in FIG. Figure 2 As shown, the crest of the first turbulent wave is higher than the double-layer rolled welded pipe body. The turbulent wave forms a shower on the pipe body when falling, forming an all-round coverage of the pipe body from top to bottom. The crest of the second smooth wave is slightly higher than the center axis of the pipe body. The smooth wave infiltrates and corrects the defects of the metal coating caused by the previous spraying.

[0013] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the above embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. Double-layer coiled welded pipe hot-dip coating process, characterized in that: Includes the following: A wave soldering heating furnace is set downstream of the brazing furnace in the double-layer coiled welded pipe production line to perform hot-dip galvanizing on the double-layer coiled welded pipe just out of the brazing furnace. The hot-dip galvanizing process utilizes the residual heat of the pipe making and welding steps and the high surface cleanliness after hydrogen reduction. The wave soldering heating furnace is provided with a turbulent wave, the crest of which is higher than the tube body of the double-layer coiled welded tube, and the turbulent wave forms a shower on the tube body when falling.

2. The hot-dip galvanizing process for double-layer coiled welded pipe according to claim 1, characterized in that: The wave soldering heating furnace is set with two wave crests in succession. The turbulent wave is the first wave and the second wave is the smooth wave. The crest of the smooth wave is higher than the center axis of the tube body but does not exceed the tube body. The smooth wave infiltrates and corrects the defects of the metal coating sprayed in the previous step.

3. The hot-dip galvanizing process for double-layer coiled welded pipe according to claim 2, characterized in that: The flow direction of the two wave crests is opposite to the traveling direction of the tube body.

Images