Production process of hot-dip galvanized bolt-sphere joint net rack

Abstract

The invention discloses a production process of a hot-dip galvanized bolt-sphere joint net rack, which comprises the following steps: respectively carrying out impurity pretreatment, preheating treatment, hot-dip galvanizing treatment, arrangement and passivation on a bolt sphere, a bolt, a straight rod and a conical head to finish hot-dip galvanizing: carrying out rough increase treatment on the side surfaces of the two ends of the straight rod and the side surface, close to the large diameter, of the conical head before preheating treatment; the method comprises the following steps: assembling a hot-dip galvanized bolt, a straight rod and a conical head together, carrying out spot welding on the straight rod and the conical head to form a welding seam, carrying out high-temperature burning on the welding seam to remove a zinc layer, welding the welding seam to form a rod piece, connecting the rod piece and a bolt ball through a bolt, and enabling the rod piece to form a metal structure net through a bolt ball node according to a design rule. According to the production process of the hot-dip galvanized bolt-sphere joint net rack, the bolt-sphere joint net rack has good corrosion resistance.

Description

Technical Field

[0001] The invention relates to a production process of a hot-dip galvanized bolt ball node grid, belonging to the technical field of bolt ball node grid manufacturing. Background Art

[0002] The bolt ball node grid is a metal structure grid composed of multiple rods through the bolt ball node and according to the actual design rules; the rod is composed of a straight rod and a cone head, the bolt is movably mounted between the straight rod and the cone head, and the bolt passes through the cone head to connect the bolt ball to connect the rod and the bolt ball. In order to prevent the corrosion of the metal structure grid, during production, it is necessary to perform hot-dip galvanizing on the bolt ball, bolt, straight rod, and cone head respectively, and then the straight rod, bolt, and cone head are combined to weld the straight rod and cone head. However, due to the presence of the galvanized layer, cracks and pores appear in the welding, and the welding quality is reduced. Before welding, the straight rod and cone head welding parts need to be dezincified. The dezincification method is pickling, but the straight rod and cone head need to be partially dezincified and the profile is large and heavy, which is difficult to operate, inefficient, and will also cause environmental pollution; high temperature burning, but it will cause the galvanized layer to be damaged around the dezincified parts of the straight rod and cone head, such as zinc layer detachment, cracks, bubbles and peeling, etc., the corrosion performance of the galvanized layer is reduced, and the service life of the metal structure grid is shortened. To this end, the present invention provides a hot-dip galvanized bolt ball node truss production process. During the hot-dip galvanizing process, the present invention explores how to improve the removal efficiency of the zinc layer at the welding parts on the sides of the straight rod and the cone head while reducing the loss around the welding parts, while taking into account the welding efficiency of the welding parts. Summary of the invention

[0003] Aiming at at least one problem existing in the above-mentioned prior art, the present invention provides a production process of a hot-dip galvanized bolt ball node grid.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme: a hot-dip galvanized bolt ball node grid production process, comprising the following steps: (1) The bolt ball, bolt, straight rod and cone head are pre-treated for impurities, and then the side surfaces at both ends of the straight rod and the side surface of the cone head close to the large diameter are roughened; (2) preheating the bolt ball, bolt, straight rod, and cone head processed in step (1); (3) hot-dip galvanizing the bolt ball, bolt, straight rod, and cone head preheated in step (2); (4) finishing, passivating and cooling the bolt balls, bolts, straight rods and cone heads that have been galvanized in step (3); (5) Assemble the hot-dip galvanized bolts, straight rods and cone heads in step (4) above together, and spot weld the straight rods and cone heads to form a weld with a width of 3 to 5 mm, so that the cone head is connected to the straight rod; (6) The weld of step (5) is subjected to high temperature cauterization to remove the zinc layer on the side of the straight rod and the cone head, and then cooled; (7) welding the weld from which the zinc layer was removed in step (6) to form a rod, and cooling; (8) Connect the rods and bolt balls by bolts, so that the rods form a metal structure grid through the bolt ball nodes according to the design rules.

[0005] Preferably, in step (1), the impurity pretreatment includes cleaning, degreasing, rust removal and water washing.

[0006] Preferably, in step (1), the roughening treatment is performed by grinding or spraying abrasives.

[0007] Preferably, in step (1), the roughness Ra of the side surfaces at both ends of the straight rod and the side surfaces of the cone head close to the large diameter is controlled to be 2-3 μm, which can not only reduce the amount of galvanized layer on the side surfaces at both ends of the straight rod and the side surfaces of the cone head close to the large diameter, but also improve the quality of subsequent welding.

[0008] Preferably, in step (2), the preheating treatment method is immersion in a low-melting-point salt melt at a temperature of 435-445° C. and an immersion time of 10-20 seconds.

[0009] Preferably, the low melting point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate.

[0010] Preferably, in step (3), the hot-dip galvanizing treatment conditions are: temperature between 435 and 445° C., and immersion time between 10 and 20 seconds.

[0011] Preferably, in step (3), the zinc plating solution is a zinc solution or a zinc-aluminum mixed solution.

[0012] Preferably, in step (6), the high-temperature cauterization adopts an all-solid-state induction heating device, which comprises a heat induction coil, a water-cooling protective sleeve 1 and a water-cooling protective sleeve 2. The heat induction coil is used for high-temperature cauterization of the weld. The water-cooling protective sleeve 1 and the water-cooling protective sleeve 2 are arranged on both sides of the heat induction coil to cool the ends of the straight rod and the cone head. The water-cooling protective sleeve 1 covers the straight rod, and the water-cooling protective sleeve 2 covers the cone head, so that the galvanized layer on the circumference of the straight rod and the end of the curved surface of the cone head close to the heat induction coil is protected, thereby reducing the loss of the galvanized layer and effectively improving the anti-corrosion effect of the metal structure grid.

[0013] Preferably, the thermal induction coil is a single coil, and the diameter of the thermal induction coil is smaller than the width of the weld.

[0014] Preferably, the cross section of the heat induction coil on the inner side near the center line is trapezoidal in structure, so that the heat of the heat induction coil can be concentrated and dissipated into the weld, and the burning of the straight line and the end of the cone head near the side by the heat induction coil can be further reduced.

[0015] Beneficial effects of the present invention: The bolt ball node grid production process of the present invention is to perform hot-dip galvanizing on the bolt ball, bolt, straight rod and cone head respectively, and then assemble them according to the design rules, so that the produced bolt ball node grid has good corrosion resistance; the bolt ball node grid production process of the present invention is to use a low-melting-point salt melt to preheat each component before hot-dip galvanizing, which can improve the cleanliness of the surface of each component and is conducive to the infiltration of zinc on the surface of each component; the bolt ball node grid production process of the present invention is to first perform roughening treatment on the side surfaces of the two ends of the straight rod and the side surfaces of the cone head close to the large diameter, and then perform hot-dip galvanizing, which is conducive to the subsequent removal of the zinc layer and also improves the welding effect between the straight rod and the cone head; the bolt ball node grid production process of the present invention is to use a water-cooling protective sleeve to cool the end of the straight rod and the cone head when the side surfaces of the straight rod and the cone head are subjected to high-temperature burning and zinc removal during the process of assembling the straight rod and the cone head, which can reduce the influence of high-temperature burning on the circumference of the straight rod and the curved surface of the cone head, reduce the loss of the galvanized layer, and improve the corrosion resistance of the metal structure grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A three-dimensional diagram of the combination of the thermal induction coil and the water-cooling protective sleeve of the present invention; Figure 2 It is a side view of the combination of the thermal induction coil and the water-cooling protective sleeve of the present invention; Figure 3 It is a front view of the combination of the thermal induction coil and the water-cooling protective sleeve of the present invention; Figure 4 A cross-sectional view along the circumferential direction of the thermal induction coil of the present invention; Figure 5 A cross-sectional view of the water-cooling protective jacket of the present invention along the circumferential direction; Figure 6 It is a radial cross-sectional view of the water-cooling protective jacket of the present invention.

[0017] In the figure: 1. thermal induction coil, 1a. inner side, 2. water cooling protective sleeve 1, 2a. inlet, 2b. outlet, 3. water cooling protective sleeve 2. DETAILED DESCRIPTION

[0018] The technical scheme in the implementation of the present invention is clearly and completely described below in conjunction with the accompanying drawings. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the conditions recommended by the normal conditions or the manufacturers. If the manufacturers are not specified in the reagents, instruments, and components used, they are all conventional products that can be purchased commercially.

[0019] Example A hot-dip galvanized bolt ball node grid production process comprises the following steps: (1) The bolt ball, bolt, straight rod and cone head are cleaned, degreased, rusted and washed with water to remove impurities. The side surfaces at both ends of the straight rod and the side surfaces of the cone head close to the large diameter are ground or sprayed with abrasive to increase the roughness. The roughness Ra of the side surfaces at both ends of the straight rod and the side surfaces of the cone head close to the large diameter is controlled to 2~3μm. This can reduce the amount of galvanized layer on the side surfaces at both ends of the straight rod and the side surfaces of the cone head close to the large diameter, and improve the quality of subsequent welding. (2) preheating the bolt balls, bolts, straight rods, and cone heads treated in step (1) by immersing them in a low-melting-point salt melt at a temperature of 435-445° C. for a time of 10-20 seconds; the low-melting-point salt is a mixture of zinc chloride, aluminum chloride, and sodium citrate; (3) The bolt ball, bolt, straight rod and cone head preheated in step (2) are subjected to hot-dip galvanizing treatment by immersing in zinc liquid or zinc-aluminum mixed liquid at a temperature of 435-445° C. for a time of 10-20 seconds; (4) finishing, passivating and cooling the bolt balls, bolts, straight rods and cone heads that have been galvanized in step (3); (5) Assemble the hot-dip galvanized bolts, straight rods and cone heads in step (4) above together, and spot weld the straight rods and cone heads to form a weld with a width of 3 to 5 mm, so that the cone head is connected to the straight rod; (6) The weld of step (5) is subjected to high temperature cauterization to remove the zinc layer on the side of the straight rod and the cone head, and then cooled; (7) welding the weld from which the zinc layer was removed in step (6) to form a rod, and cooling; (8) Connect the rods and bolt balls by bolts, so that the rods form a metal structure grid through the bolt ball nodes according to the design rules.

[0020] Example 1 The hot-dip galvanizing production process of bolt balls is as follows: (1) Impurity pretreatment: clean, degrease, remove rust and wash the bolt ball; (2) Preheat treatment: Immerse the bolt ball that has been pretreated with impurities in a low-melting-point salt melt at a temperature of 435-440°C for 15 seconds. The low-melting-point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate in a ratio of 8:1:0.5. (3) Hot-dip galvanizing treatment: immerse the preheated bolt ball in zinc solution at a temperature of 435-440°C for 15 seconds; (4) The bolt balls that have been galvanized in step (3) are sorted, passivated, cooled, and set aside.

[0021] Example 2 The hot-dip galvanizing production process of bolts is as follows: (1) Impurity pretreatment: clean, degrease, remove rust and wash the bolts; (2) Preheat treatment: Immerse the impurity pretreated bolts in a low-melting-point salt melt at a temperature of 435-440°C for 10 seconds. The low-melting-point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate in a ratio of 8:1:0.5. (3) Hot-dip galvanizing: Immerse the preheated bolts in zinc solution at a temperature of 435-440°C for 10 seconds. (4) The bolts that have been galvanized in step (3) are sorted, passivated, cooled, and set aside.

[0022] Example 3 The hot-dip galvanizing production process of the cone head is as follows: (1) Impurity pretreatment: clean, degrease, remove rust and wash the cone head; (2) Roughening treatment: The side of the cone head close to the large diameter after impurity pretreatment is polished to control the roughness Ra of the side to 2~3μm; (3) Preheating treatment: immerse the roughened straight rod into a low-melting-point salt melt at a temperature of 440-445°C for 20 seconds. The low-melting-point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate in a ratio of 8:1:0.5. (4) Hot-dip galvanizing treatment: immerse the preheated cone head in zinc liquid at a temperature of 440-445°C for 20 minutes; (5) The cone head that has been hot-dip galvanized in step (4) is sorted, passivated, cooled, and set aside.

[0023] Example 4 The hot-dip galvanizing production process of straight rods is as follows: (1) Impurity pretreatment: clean, degrease, remove rust and wash the straight rod; (2) Roughening treatment: The two end sides of the straight rod that has been pretreated with impurities are polished respectively to control the roughness Ra of the side to 2~3μm; (3) Preheating treatment: immerse the roughened straight rod into a low-melting-point salt melt at a temperature of 440-445°C for 20 seconds. The low-melting-point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate in a ratio of 8:1:0.5. (4) Hot dip galvanizing: immerse the preheated straight rod in zinc solution at a temperature of 440-445°C for 20 minutes; (5) The straight rods that have been hot-dip galvanized in step (4) are sorted, passivated, cooled, and set aside.

[0024] Example 5 The hot-dip galvanizing production process of the cone head is as follows: (1) Impurity pretreatment: clean, degrease, remove rust and wash the cone head; (2) Roughening treatment: The side of the cone head that has been pretreated with impurities and close to the large diameter is dry-blasted with steel grit to control the roughness Ra of the side to 2~3μm; (3) Preheating treatment: immerse the roughened straight rod into a low-melting-point salt melt at a temperature of 440-445°C for 20 seconds. The low-melting-point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate in a ratio of 8:1:0.5. (4) Hot-dip galvanizing treatment: immerse the preheated cone head in zinc liquid at a temperature of 440-445°C for 20 minutes; (5) The cone head that has been hot-dip galvanized in step (4) is sorted, passivated, cooled, and set aside.

[0025] Example 6 The hot-dip galvanizing production process of straight rods is as follows: (1) Impurity pretreatment: clean, degrease, remove rust and wash the straight rod; (2) Roughening treatment: The two end sides of the straight rod that has been pretreated with impurities are treated with dry steel grit blasting to control the roughness Ra of the side to 2~3μm; (3) Preheating treatment: immerse the roughened straight rod into a low-melting-point salt melt at a temperature of 440-445°C for 20 seconds. The low-melting-point salt is a mixture of zinc chloride, aluminum chloride and sodium citrate in a ratio of 8:1:0.5. (4) Hot dip galvanizing: immerse the preheated straight rod in zinc solution at a temperature of 440-445°C for 20 minutes; (5) The straight rods that have been hot-dip galvanized in step (4) are sorted, passivated, cooled, and set aside.

[0026] Example 7 The production process of the galvanized bolt ball node grid is as follows: (1) Spot welding: Assemble the cone head of Example 3, the straight rod of Example 4 and the bolt of Example 2 together, and then connect the cone head and the straight rod together by spot welding, so that a weld is formed between the cone head and the straight rod, and the width of the weld is 3 mm; (2) High-temperature cauterization: The weld is cauterized at high temperature using a fully solid-state induction heating device. The heat induction coil of the fully solid-state induction heating device corresponds to the weld. The water-cooling protective sleeve 1 is coated on the end of the straight rod near the weld, and the water-cooling protective sleeve 2 is coated on the end of the cone head near the weld. The fully solid-state induction heating device is started, and the heat induction coil cauterizes the weld at high temperature. The cooling circulation system of the fully solid-state induction heating device then starts the water-cooling protective sleeve 1 and the water-cooling protective sleeve 2 to perform cooling circulation control. When the heat induction coil is burned until the sides of the cone head and the straight rod are red hot, the cooling circulation of the heat induction coil is started to remove the zinc layer. Compared with the existing straight rod and cone head side without treatment and hot-dip galvanizing, under the same heating conditions, the high-temperature cauterization time for removing the zinc layer in this embodiment is shortened by 45%. After natural cooling, the zinc layer on the circumference of the straight rod and the curved surface of the cone head is not burned away by the water-cooling protective sleeves 1 and 2. There are a few slight fine lines on the edges of the circumference and the side where the curved surface connects. (3) Welding: The weld seam from which the zinc layer was removed in step (2) above is welded so that the weld seam is filled by welding, and there are no cracks, gaps, bubbles, etc. between the straight rod and the cone head. The welding effect is very good, and the rod is formed and cooled; (4) Connect the bolts on the rods with the threaded holes of the bolt balls and assemble them according to the design rules so that the rods form a metal structural grid through the bolt ball nodes.

[0027] Example 8 The production process of the galvanized bolt ball node grid is as follows: (1) Spot welding: Assemble the cone head of Example 5, the straight rod of Example 6 and the bolt of Example 2 together, and then connect the cone head and the straight rod together by spot welding, so that a weld is formed between the cone head and the straight rod, and the width of the weld is 3 mm; (2) High-temperature cauterization: The weld is cauterized at high temperature using a fully solid-state induction heating device. The heat induction coil of the fully solid-state induction heating device corresponds to the weld. The water-cooling protective sleeve 1 is coated on the end of the straight rod near the weld, and the water-cooling protective sleeve 2 is coated on the end of the cone head near the weld. The fully solid-state induction heating device is started, and the heat induction coil cauterizes the weld at high temperature. The cooling circulation system of the fully solid-state induction heating device then starts the water-cooling protective sleeve 1 and the water-cooling protective sleeve 2 to perform cooling circulation control. When the heat induction coil is burned until the sides of the cone head and the straight rod are red hot, the cooling circulation of the heat induction coil is started to remove the zinc layer. Compared with the existing straight rod and cone head side without treatment and hot-dip galvanizing, under the same heating conditions, the high-temperature cauterization time for removing the zinc layer in this embodiment is shortened by 38%. After natural cooling, the zinc layer on the circumference of the straight rod and the curved surface of the cone head is not burned and removed by the water-cooling protective sleeves 1 and 2. There are a few slight fine lines on the edges of the circumference and the curved surface connecting the sides, and occasionally slight cracks. (3) Welding: The weld seam from which the zinc layer was removed in step (2) above is welded so that the weld seam is filled by welding, and there are no cracks, gaps, bubbles, etc. in the welding between the straight rod and the cone head. The welding effect is very good, and the rod is formed and cooled; (4) Connect the bolts on the rods in step (3) above to the threaded holes of the bolt balls in Example 1, and assemble them according to the design rules so that the rods form a metal structure grid through the bolt ball nodes.

[0028] Example 9 The production process of the galvanized bolt ball node grid is as follows: (1) Spot welding: Assemble the cone head of Example 5, the straight rod of Example 6 and the bolt of Example 2 together, and then connect the cone head and the straight rod together by spot welding, so that a weld is formed between the cone head and the straight rod, and the width of the weld is 4 mm; The remaining steps are the same as those in Example 7. Compared with the existing straight rod and cone head that are hot-dip galvanized without any treatment on the side surfaces, under the same heating conditions, the time for removing the zinc layer by high-temperature burning in this embodiment is shortened by 43%, and there are a few slight fine lines on the edges of the peripheral surface and the side surfaces connecting the curved surface. The welding between the straight rod and the cone head has no cracks, gaps, bubbles, etc., and the welding effect is better.

[0029] Example 10 The production process of the galvanized bolt ball node grid is as follows: (1) Spot welding: Assemble the cone head of Example 5, the straight rod of Example 6 and the bolt of Example 2 together, and then connect the cone head and the straight rod together by spot welding, so that a weld is formed between the cone head and the straight rod, and the width of the weld is 5 mm; The remaining steps are the same as those in Example 7. Compared with the existing straight rod and cone head that are hot-dip galvanized without any treatment on the side surfaces, under the same heating conditions, the time for removing the zinc layer by high-temperature burning in this embodiment is shortened by 41%, and there are a few slight fine lines and occasional slight cracks on the edges of the peripheral surface and the curved surface connecting the side surfaces. The welding between the straight rod and the cone head has no cracks, gaps, bubbles, etc., and the welding effect is better.

[0030] Embodiment 11 The high-temperature cauterization of Examples 7 to 10 uses an all-solid-state induction heating device, which is also equipped with a cooling circulation system. The all-solid-state induction heating device is a prior art that can achieve the purpose of high-temperature heating and cooling circulation, and will not be emphasized. The present invention will focus on the thermal induction coil 1 on the all-solid-state induction heating device. The thermal induction coil 1 is installed on the body of the all-solid-state induction heating device through a bracket. The thermal induction coil 1 is a single coil, and the pipe diameter of the thermal induction coil 1 is smaller than the width of the weld. The thermal induction coil 1 is connected to the cooling circulation system, and the water flow cooling path inside the thermal induction coil 1 is a prior art that can achieve water flow circulation cooling, and will not be emphasized. Explanation; in addition, a water-cooling protective sleeve 1 2 and a water-cooling protective sleeve 2 3 are connected to the bracket, and the water-cooling protective sleeve 1 2 and the water-cooling protective sleeve 2 3 are arranged on both sides of the thermal induction coil 1. The thermal induction coil 1, the water-cooling protective sleeve 1 2 and the water-cooling protective sleeve 2 3 are coaxially arranged. The water-cooling protective sleeve 1 2 can cover the end of the side of the straight rod circumference close to the zinc layer to be removed, and the water-cooling protective sleeve 2 can cover the end of the side of the cone head curved surface close to the zinc layer to be removed. In this way, the galvanized layer on the end of the straight rod circumference and the cone head curved surface close to the thermal induction coil 1 is protected, the loss of the galvanized layer is reduced, and the anti-corrosion effect of the metal structure grid is effectively improved. The water-cooling protective sleeve 1 2 and the water-cooling protective sleeve 2 3 are also connected to the cooling circulation system.

[0031] Furthermore, in order to concentrate the heat of the thermal induction coil into the weld, the cross-section of the inner side 1a of the thermal induction coil near the center line is set to a trapezoidal structure, which can also further reduce the burning of the straight line and the end of the cone head near the side by the thermal induction coil.

[0032] The water cooling paths inside the water-cooling protective jacket 1 2 and the water-cooling protective jacket 2 3 are the same, and the water circulation path is a double-ring cavity design. A ring baffle is arranged inside the water-cooling protective jacket 2, and the ring baffle forms a coaxially arranged inner ring cavity and outer ring cavity inside the water-cooling protective jacket 2. The inlet 2a is connected to the inner ring cavity, and the outlet 2b is connected to the outer ring cavity. The inlet 2a and the outlet 2b are both arranged at the top of the water-cooling protective jacket 1 2, and a connecting port 2c is arranged at the bottom of the ring baffle. The connecting port 2c connects the inner ring cavity and the outer ring cavity. The initial cooling water inlet 2a enters, so that the inner ring cavity and the outer ring cavity are filled with water, and the water overflows and flows out from the outlet 2b, and the cooling water continues to be introduced into the inner ring cavity, and the cooling water flows out from the outlet to form a water cooling path of the water-cooling protective jacket 2.

[0033] Comparative Example 1 According to step Example 3, the roughness Ra of the side of the cone head is controlled to be less than 2μm and greater than 1.6; according to step Example 4, the roughness Ra of the side of the straight rod is controlled to be less than 2μm and greater than 1.6; then according to Example 7, the cone head and the straight rod of this comparative example are subjected to high-temperature calcination. Compared with the existing straight rod and cone head side surfaces that are not treated and then hot-dip galvanized, under the same heating conditions, the high-temperature calcination time for removing the zinc layer in this comparative example is shortened by 8.5%, and there are some slight fine lines and cracks on the edges of the peripheral surface and the curved surface connecting the side surfaces, and there are some cracks, and there are no cracks, gaps, bubbles or other problems in the welding between the straight rod and the cone head.

[0034] Comparative Example 2 According to step Example 3, the roughness Ra of the side of the cone head is controlled to be greater than 3μm; according to step Example 4, the roughness Ra of the side of the straight rod is controlled to be greater than 3μm; and then according to Example 7, the cone head and the straight rod of this comparative example are subjected to high-temperature calcination. Compared with the existing straight rod and cone head side being hot-dip galvanized without treatment, under the same heating conditions, the high-temperature calcination time for removing the zinc layer in this comparative example is shortened by 50%, and there are only a few slight fine lines on the edges of the peripheral surface and the side connecting the curved surface. There are no cracks in the welding between the straight rod and the cone head, but there are gaps and occasional bubbles.

[0035] Comparative Example 3 According to Example 7, the cone head and the straight rod of this comparative example are subjected to high-temperature cauterization using existing all-solid-state induction heating equipment. Water-cooling protective sleeves 1 2 and 3 are not provided on both sides of the thermal induction coil 1. Large pieces of zinc layer are removed from the circumferential surface and the ends of the curved surface connecting the side surfaces.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0037] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A hot-dip galvanized bolt ball node grid production process, characterized in that: The following steps are involved: (1) The bolt ball, bolt, straight rod and cone head are pre-treated for impurities, and then the side surfaces at both ends of the straight rod and the side surface of the cone head close to the large diameter are roughened; (2) preheating the bolt ball, bolt, straight rod, and cone head processed in step (1); (3) hot-dip galvanizing the bolt ball, bolt, straight rod, and cone head preheated in step (2); (4) finishing, passivating and cooling the bolt balls, bolts, straight rods and cone heads that have been galvanized in step (3); (5) Assemble the hot-dip galvanized bolts, straight rods and cone heads in step (4) above together, and spot weld the straight rods and cone heads to form a weld with a width of 3 to 5 mm, so that the cone head is connected to the straight rod; (6) The weld of step (5) is subjected to high temperature cauterization to remove the zinc layer on the side of the straight rod and the cone head, and then cooled; (7) welding the weld from which the zinc layer was removed in step (6) to form a rod, and cooling; (8) Connect the rods and bolt balls by bolts, so that the rods form a metal structure grid through the bolt ball nodes according to the design rules.

2. A hot dip galvanized bolt ball node grid production process according to claim 1, characterized in that: In step (1), the impurity pretreatment includes cleaning, degreasing, rust removal and water washing.

3. A hot dip galvanized bolt ball node grid production process according to claim 1, characterized in that: In step (1), the roughening treatment is performed by grinding or spraying abrasives.

4. A hot dip galvanized bolt ball node grid production process according to claim 1 or 3, characterized in that: In step (1), the roughness Ra of the side surfaces at both ends of the straight rod and the side surface of the cone head close to the large diameter is controlled to be 2~3μm.

5. A hot dip galvanized bolt ball node grid production process according to claim 1, characterized in that: In step (2), the preheating treatment method is immersion in a low-melting-point salt melt at a temperature of 435-445° C. and an immersion time of 10-20 seconds.

6. A hot dip galvanized bolt ball node grid production process according to claim 5, characterized in that: The low melting point salt is prepared by mixing zinc chloride, aluminum chloride and sodium citrate.

7. A hot dip galvanized bolt ball node grid production process according to claim 1, characterized in that: In step (3), the hot-dip galvanizing treatment conditions are: temperature between 435 and 445° C., and immersion time between 10 and 20 seconds.

8. A hot dip galvanized bolt ball node grid production process according to claim 1 or 7, characterized in that: In step (3), the zinc plating solution is a zinc solution or a zinc-aluminum mixed solution.

9. A hot dip galvanized bolt ball node grid production process according to claim 1, characterized in that: In step (6), the high-temperature cauterization is performed using a fully solid-state induction heating device, which comprises a heat induction coil, a water-cooling protective sleeve 1 and a water-cooling protective sleeve 2. The heat induction coil is used for high-temperature cauterization of the weld. The water-cooling protective sleeve 1 and the water-cooling protective sleeve 2 are arranged on both sides of the heat induction coil to cool the ends of the straight rod and the cone head. The water-cooling protective sleeve 1 covers the straight rod, and the water-cooling protective sleeve 2 covers the cone head.

10. A hot dip galvanized bolt ball node grid production process according to claim 9, characterized in that: The thermal induction coil is a single coil, and the diameter of the thermal induction coil is smaller than the width of the weld; the cross section of the thermal induction coil on the inner side close to the center line is a trapezoidal structure.

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