Protection process of high-strength marine fastener

Abstract

The invention relates to the technical field of ship and sea fastener protection, in particular to a protection process of a high-strength ship and sea fastener. The protection process of the high-strength marine fastener comprises the following steps: S100, pretreating a connecting pair; s200, the gasket and the bolt cap are connected in an adhesive mode through polysulfide sealant, a sealant film is pasted to the polished rod portion of the bolt, and a gap between the bolt cap and the gasket and a gap between the sealant film and the rod portion of the bolt are sealed and coated; s300, bolts penetrate through the connecting assembly to install the bolt pair assemblies, gaps and thread parts between the bolt pair assemblies are sealed and coated with polysulfide sealant, and pre-tightening force is applied to connecting pairs; and S400, the connecting pair and the bolt pair sealed and coated with the polysulfide sealant are subjected to standing for preset time till the polysulfide sealant is solidified. The protection process of the high-strength ship-sea fastener has the advantage that the bolt is prevented from being corroded by being soaked in seawater.

Description

Technical Field

[0001] The invention relates to the technical field of ship and marine fastener protection, and in particular to a protection process for high-strength ship and marine fasteners. Background Art

[0002] High-strength marine fasteners that have been in service for a long time often suffer from fracture failure caused by corrosion and hydrogen-induced damage, which seriously threatens operational safety. Although the connection pair of high-strength marine fasteners is sealed with rubber sealing rings, after long-term use in the marine environment, as the rubber sealing ring ages, seawater or marine atmosphere can still slowly penetrate into the connection pair through the gap between the fastener and the rubber sealing ring, thereby causing galvanic corrosion and crevice corrosion at the fastener mating point, and pitting or uniform corrosion inside the gap; at the same time, under the action of the corrosive medium and potential, hydrogen gradually penetrates into the fastener matrix, which may cause hydrogen-induced damage.

[0003] At present, the protection of high-strength marine fasteners is mainly focused on the substrate and surface treatment technology. For example, the Chinese invention patent with publication number CN115747660A discloses high-strength weather-resistant bolts and their preparation process, which involves hardware accessories preparation technology, aiming to solve the problem that the existing coating method is difficult to fundamentally solve the problem that the bolts will fail in the environment due to corrosion fracture and hydrogen-induced delayed fracture. The key points of its technical solution are: including a bolt body, which is made of medium-carbon alloy steel composite micro-alloying elements to form an integrated structure, and the micro-alloying elements include: V 0.01-0.05wt%; Ti0.01-0.04wt%; B 0.01-0.07wt%; Nb 0.35-0.75wt%; Mo0.2-0.95wt%; Cu 0.2-0.35wt%; the sum of V, Ti and B is 0.03-0.12wt%, and the sum of Nb, Mo and Cu is 1.2-2.00wt%. Through the technical solution of this patent, the corrosion resistance of the bolt is improved from the material selected for manufacturing the bolt, but during long-term use, the bolt will still be gradually corroded when immersed in seawater, especially between the bolt and the connecting parts, and the parts in the fastening assembly are prone to seawater retention, which is more susceptible to corrosion. Summary of the invention

[0004] In view of this, the present invention aims to provide a protection process for high-strength marine fasteners, which adopts measures such as bonding the gaps between the components of the bolt pair, between the bolt pair and the connecting component, and between the threads of the bolt and the nut with polysulfide sealant, and protecting the peripheral side walls of the bolt cap and the nut with a film, etc., to solve the problem that the bolts will still be gradually corroded when immersed in seawater, especially between the bolts and the connecting parts, and between the components in the fastening assembly. Seawater is easily retained, making it more susceptible to corrosion.

[0005] In order to solve the above problems, the present invention provides a protection process for high-strength marine fasteners, comprising:

[0006] S100, pre-processing the connection pair;

[0007] S200, bonding the gasket to the bolt cap by polysulfide sealant, pasting a sealant film on the bare rod of the bolt, and sealing the gap between the bolt cap and the gasket and between the sealant film and the bolt rod;

[0008] S300, passing bolts through the connection assembly to install each bolt sub-assembly, sealing the gaps and threaded parts between the bolt sub-assemblies with polysulfide sealant, and applying a pre-tightening force to the connection pair;

[0009] S400, leaving the connection pair and the bolt pair coated with polysulfide sealant to stand for a preset time until the polysulfide sealant solidifies.

[0010] Furthermore, in step S100, the method for preprocessing the connection pair includes:

[0011] Clean the connection surfaces and perform protective operations on the side walls of the bolt caps and nuts.

[0012] Furthermore, the method for protecting the side walls of the bolt cap and the nut is to stick a film on the side walls.

[0013] Furthermore, in step S200, the gasket that is glued to the bolt cap is a circular gasket.

[0014] Furthermore, in step S300, it includes:

[0015] S310, passing the bolt through the connection assembly, and sealing the gap between the circular gasket and the connection assembly with polysulfide sealant;

[0016] S320, sequentially installing a square gasket and a spring gasket on the threaded portion of the bolt of the connection assembly, and sealing the gap between the connection assembly, the square gasket and the spring gasket with polysulfide sealant;

[0017] S330. Apply polysulfide sealant to the threaded portion protruding outside the spring gasket;

[0018] S340, install the nut, and seal the gap between the spring washer and the nut with polysulfide sealant;

[0019] S350, tighten the nut to apply pre-tightening force to the connection pair.

[0020] Furthermore, in step S300, it also includes:

[0021] S360: Fill the gap between the threaded parts of nuts and bolts with polysulfide sealant.

[0022] Furthermore, in step S400, the preset standing time is 3-4 hours.

[0023] Furthermore, in step S400, the polysulfide sealant is left for 3-5 days after solidification.

[0024] Furthermore, the protection process also includes:

[0025] S500. Filling the bolt installation holes of the connection pair with protective material, wherein the protective material includes at least one of cement and epoxy resin.

[0026] Furthermore, the protection process also includes:

[0027] S600, conduct a water pressure test. After a preset number of pressure cycles under the conditions of preset pressure and preset pressure holding time, it is visually observed that the polysulfide sealant is intact, the overall sealing of the connection pair is good, and no water ingress occurs.

[0028] Compared with the prior art, the protection process of a high-strength marine fastener described in the present invention has the following advantages:

[0029] The advantages of this technical solution are that polysulfide sealant is used to bond the gaps between the components of the bolt pair, between the bolt pair and the connecting component, and between the threads of the bolt and the nut, and the surrounding side walls of the bolt cap and the nut are protected by film, etc., so as to prevent the bolt from being corroded when immersed in seawater, and seawater is easily retained between the bolt and the connecting component and between the components in the fastening assembly, making it difficult to be corroded. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the fastener of the present invention after the protection process is applied in the installed state.

[0031] Description of reference numerals:

[0032] 1-polysulfide sealant, 2-bolt, 3-round gasket, 4-square gasket, 5-spring gasket, 6-nut, 7-connecting assembly, 8-sealing film. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] In the present invention, the descriptions involving "first", "second", "upper", "lower", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "upper", "lower" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the technical solutions between the embodiments can be combined, they are all within the protection scope required by the present invention.

[0035] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0036] like Figure 1 As shown, a protection process for high-strength marine fasteners includes:

[0037] S100, pre-treating the connection pair, the pre-treating method comprising: cleaning the connection pair surface, and performing protective operation on the side walls of the bolt cap and the nut by sticking an adhesive film to prevent the polysulfide sealant from being smeared on the side walls of the bolt cap and the nut when applying the adhesive, thereby affecting the screwing of the bolt and the nut. The adhesive film can be made of adhesive tape, adhesive paper, etc.;

[0038] S200, bonding the gasket to the bolt cap by polysulfide sealant, wherein the gasket is preferably a circular gasket, and pasting a sealant film on the bare rod of the bolt to seal the gap between the bolt cap and the gasket and between the sealant film and the bolt rod;

[0039] S300, install each bolt sub-assembly by passing the bolt through the connection assembly, seal the gaps and threaded parts between the bolt sub-assemblies with polysulfide sealant, and apply pre-tightening force to the connection pair, including:

[0040] S310, passing the bolt through the connection assembly, and sealing the gap between the circular gasket and the connection assembly with polysulfide sealant;

[0041] S320, sequentially installing a square gasket and a spring gasket on the threaded portion of the bolt of the connection assembly, and sealing the gap between the connection assembly, the square gasket and the spring gasket with polysulfide sealant;

[0042] S330. Apply polysulfide sealant to the threaded portion protruding outside the spring gasket;

[0043] S340, install the nut, and seal the gap between the spring washer and the nut with polysulfide sealant;

[0044] S350, tighten the nut to apply pre-tightening force to the connection pair.

[0045] S360, fill the gap between the threaded parts of the nut and the bolt with polysulfide sealant;

[0046] S400, leaving the connection pair and the bolt pair coated with polysulfide sealant to stand for a preset time, preferably 3-4 hours, until the polysulfide sealant solidifies, and leaving the polysulfide sealant to stand for 3-5 days after solidification. After standing for 3 days, the hardness of the polysulfide sealant reaches 80-90% of the standard state; after standing for 5 days, the polysulfide sealant reaches the target state;

[0047] S500, filling the bolt installation holes of the connection pair with protective material, wherein the protective material includes at least one of cement and epoxy resin, and the connection pair is further protected by filling the protective material;

[0048] S600, conduct a water pressure test. After a preset number of pressure cycles under the conditions of preset pressure and preset pressure holding time, it is visually observed that the polysulfide sealant is intact, the overall sealing of the connection pair is good, and no water ingress occurs.

[0049] After sealing and protecting the connection pairs and bolt pairs, the effect is tested through a water pressure test. The process requirements must be met to ensure that the bolts will not be corroded for a long time in seawater.

[0050] Through the above protection process, measures such as bonding the gaps between the components of the bolt pair, between the bolt pair and the connecting components, and between the threads of the bolt and the nut with polysulfide sealant, and applying film protection to the peripheral side walls of the bolt cap and the nut are adopted to prevent the bolts from being corroded when immersed in seawater, and prevent seawater from being easily retained between the bolts and the connecting parts, and between the components in the fastening assembly, making them less susceptible to corrosion.

[0051] The above process is described below with reference to specific embodiments.

[0052] Wipe the surface of the connection pair and use organic solvent to remove stains and grease. Use adhesive tape to tape the six side walls of the hexagonal bolt. Use M56 bolts.

[0053] Apply polysulfide sealant to the surface of the bolt cap close to the screw rod, and stick the round gasket on the bolt cap. Stick the sealant film on the bare rod part of the bolt, and seal the gap between the bolt cap and the round gasket with polysulfide sealant. Use polysulfide sealant to seal the gap between the sealant film and the bolt rod.

[0054] Pass the bolt through the connection assembly and use polysulfide sealant to seal the gap between the bolt and the component. Apply polysulfide sealant on both sides of the square gasket, and put the square gasket on the threaded part of the bolt, close to the surface of the connection assembly. Put the spring gasket on the threaded part, close to the square gasket, apply polysulfide sealant on the side of the spring gasket away from the square gasket, and screw the nut into the threaded part of the screw until it contacts the spring gasket. Use polysulfide sealant to seal the gap between the components. Continue to screw the nut and apply a preload to the connection pair, the preload is 70% of the yield strength (0.7Rp0.2). Fill the gap between the threaded part of the nut and the bolt with polysulfide sealant.

[0055] The connection pair and bolt pair coated with polysulfide sealant are left to stand for a preset time, preferably 3.5 hours, until the polysulfide sealant solidifies. After the polysulfide sealant solidifies and is left for 5 days, the polysulfide sealant reaches the target state.

[0056] The connection pair was subjected to a water pressure test, and a pump and valve test bench was used to perform a 0-4.5 MPa pressure cycle with a pressure holding time of 5 minutes, completing a total of 10 pressure cycles.

[0057] After the water pressure test, there was no obvious change in the appearance of the bolted joint, no cracks or defects in the polysulfide sealant, the overall sealing of the joint was still good, and no water entered the internal gap. The high-strength marine fastener protection process and material have excellent sealing effects, which can better meet the use requirements of high-strength marine fasteners that are in long-term service in special key parts and are inconvenient to replace midway.

[0058] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A protection process for high-strength marine fasteners, characterized in that: include: S100, pre-processing the connection pair; S200, bonding the gasket to the bolt cap by polysulfide sealant, pasting a sealant film on the bare rod of the bolt, and sealing the gap between the bolt cap and the gasket and between the sealant film and the bolt rod; S300, passing bolts through the connection assembly to install each bolt sub-assembly, sealing the gaps and threaded parts between the bolt sub-assemblies with polysulfide sealant, and applying a pre-tightening force to the connection pair; S400, leaving the connection pair and the bolt pair coated with polysulfide sealant to stand for a preset time until the polysulfide sealant solidifies.

2. The protection process for high-strength marine fasteners according to claim 1 is characterized in that: In step S100, the method for preprocessing the connection pair includes: Clean the connection surfaces and perform protective operations on the side walls of the bolt caps and nuts.

3. The protection process for high-strength marine fasteners according to claim 2 is characterized in that: The method for protecting the side walls of the bolt cap and the nut is to stick a film on the side walls.

4. The protection process for high-strength marine fasteners according to claim 1 is characterized in that: In step S200, the gasket that is glued to the bolt cap is a circular gasket.

5. The protection process for high-strength marine fasteners according to claim 4 is characterized in that: In step S300, it includes: S310, passing the bolt through the connection assembly, and sealing the gap between the circular gasket and the connection assembly with polysulfide sealant; S320, sequentially installing a square gasket and a spring gasket on the threaded portion of the bolt of the connection assembly, and sealing the gap between the connection assembly, the square gasket and the spring gasket with polysulfide sealant; S330. Apply polysulfide sealant to the threaded portion protruding outside the spring gasket; S340, install the nut, and seal the gap between the spring washer and the nut with polysulfide sealant; S350, tighten the nut to apply pre-tightening force to the connection pair.

6. The protection process of high-strength marine fasteners according to claim 5 is characterized in that: In step S300, it also includes: S360: Fill the gap between the threaded parts of nuts and bolts with polysulfide sealant.

7. The protection process for high-strength marine fasteners according to claim 1 is characterized in that: In step S400, the preset standing time is 3-4 hours.

8. The protection process for high-strength marine fasteners according to claim 7 is characterized in that: In step S400, the polysulfide sealant is left for 3-5 days after solidification.

9. The protection process for high-strength marine fasteners according to claim 1, characterized in that: The protection process also includes: S500. Filling the bolt installation holes of the connection pair with protective material, wherein the protective material includes at least one of cement and epoxy resin.

10. The protection process of high-strength marine fasteners according to claim 1, characterized in that: The protection process also includes: S600, conduct a water pressure test. After a preset number of pressure cycles under the conditions of preset pressure and preset pressure holding time, it is visually observed that the polysulfide sealant is intact, the overall sealing of the connection pair is good, and no water ingress occurs.

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