Method for protecting an oversized rack for marine environment

Abstract

Combining the most severe marine service environment of the measurement and control radar and the use condition of the heavy load and the movement friction of the pitch rack, the current various organic coating, metal / ceramic spraying layer, plating layer and conversion film layer will be off or worn to lose the protection of the base, and cannot meet the use requirement. The application provides a protection method for the super large rack in marine environment, and realizes the engineering application of the nitrogen / carbon / yttrium / oxygen multi-element controllable ion penetration technology in the wear protection treatment of the super large arc-shaped rack for the first time. Through the shape-keeping tooling, the deformation of the rack is effectively and accurately controlled, the composite permeated layer with the large thickness effective hardened layer, excellent corrosion resistance and wear resistance is obtained, the wear protection problem of the super large rack in the marine environment is solved, and the environmental adaptability of the measurement and control radar is obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of structural engineering, and specifically relates to a method for protecting an ultra-large rack for marine environments. Background Technology

[0002] This radar operates in a marine atmospheric environment, enduring long-term exposure to high temperatures, high humidity, high salt spray, and strong solar radiation, with an atmospheric corrosion rating of C5-M (the highest level). The radar achieves pitch support and drive through a high-precision wheel-rail rolling pair between the pitch rail and rollers in its servo drive system, and a high-precision transmission via a pitch rack. The pitch rack is made of 40CrNi2MoA alloy steel and has an exceptionally large structural dimension (over 10m in length). During its operation, it withstands heavy loads and friction, requiring not only high rigidity and high machining precision but also high surface hardness, wear resistance, and corrosion resistance.

[0003] Given the harsh marine service environment of telemetry and control radar and the heavy load and friction of pitch racks, current organic coatings, metal / ceramic spray coatings, platings, and conversion films will peel off or wear down and lose their protective effect on the substrate, thus failing to meet the requirements. This presents a new challenge to the field of wear-resistant and corrosion-resistant technologies. Summary of the Invention

[0004] Therefore, this invention proposes a protection method for ultra-large gear racks used in marine environments. The ultra-large gear racks can pass a 500-hour neutral salt spray test and a 192-hour acidic salt spray test (protection level Rp not lower than 9), and exhibit excellent wear resistance. Specifically, the method includes the following steps:

[0005] The first step is mounting: Install the rack onto the conformal fixture and secure it securely.

[0006] The second step is degreasing: After installing the rack, place the conformal tooling in a neutral degreasing solution for 10-20 minutes at a temperature of 50℃-70℃ until all surface oil is removed.

[0007] The third step is pre-cleaning: After degreasing, clean the toothed rack mounting device in cold water for 3-5 minutes, repeating 2-3 times until it is clean.

[0008] Step 4, preheating: Place the cleaned rack-mounting device in a room temperature oven and slowly heat it to 350℃. After reaching 350℃, keep it at that temperature for 45 minutes. The heating rate is 5℃ / min.

[0009] Step 5, Nitrogen / Carbon / Yttrium Ion Co-diffusion: Quickly move the conformal tooling with the rack into the nitrogen / carbon / yttrium ion co-diffusion furnace, use a highly permeable composite infiltration agent, and treat at 440℃-450℃ for 6 hours.

[0010] Step 6, Oxygen ion stabilization treatment: Quickly move the conformal tooling with the rack installed into the oxygen ion stabilization furnace, and use oxygen ions to stabilize the nitrogen-carbon-yttrium infiltrated layer. Treat at 380℃-400℃ for 30 minutes.

[0011] Step 7, Cooling: The molded fixture with the rack installed is cooled to room temperature along with the furnace.

[0012] Step 8, post-cleaning: After cooling, clean the rack mounting device in hot water at 50℃-70℃ for 3-5 minutes, repeating 2-3 times until clean.

[0013] Step 9, Drying: After cleaning, the fixture for installing the rack is allowed to air dry naturally at room temperature.

[0014] Step 10, oil immersion: Immerse the dried mounting tool for the rack in room temperature spindle oil for 10 to 15 minutes.

[0015] Step 11, Unloading: Disassemble and separate the rack from the special conforming tool.

[0016] The conformal tooling in this invention is designed and developed based on thermal simulation technology. First, through finite element simulation analysis of the temperature field, displacement field, and stress field of the rack preheating, nitrogen / carbon / yttrium ion co-infiltration, and oxygen ion stabilization processes, it is determined that the stress concentration of the rack is located in the gear ring, while the stress concentration of the conformal tooling is located in the lifting lug and connecting rod. Then, the stress concentration areas of the conformal tooling are structurally strengthened and optimized. By connecting it to the rack with 7 to 9 pins, the weight distribution of the rack is evenly distributed, effectively controlling the deformation caused by the rack's own weight.

[0017] The beneficial effects of this invention are as follows:

[0018] 1) This invention is the first in China to realize the engineering application of nitrogen / carbon / yttrium / oxygen multi-element controllable ion infiltration technology in the wear-resistant protection treatment of ultra-large arc-shaped racks. By developing shape-preserving tooling, the deformation of the rack is effectively and precisely controlled, and a composite infiltrated layer with a large thickness of effective hardened layer, excellent corrosion resistance and wear resistance is obtained. This solves the problem of wear-resistant protection of ultra-large racks in marine environments and significantly improves the environmental adaptability of telemetry and control radar.

[0019] 2) The racks produced according to the method of the present invention have good quality consistency and the finished product qualification rate is as high as 98% or more: the finished product is black in appearance, and the surface protective layer (composite diffusion layer) is continuous, uniform and complete, without defects such as powdering, looseness and scratches.

[0020] 3) The production process of the method of the present invention is green and environmentally friendly, achieving zero emissions. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention.

[0022] Figure 2 This is a partial outline of the rack.

[0023] Figure 3 Outline drawing of the clamping plate for shape retention tooling.

[0024] Figure 4 Outline drawing of the hook for shape-preserving tooling.

[0025] Figure 5 This is a schematic diagram of a rack (including shape-maintaining fixture) in a seepage furnace. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Taking a section (approximately 5m in length) of a super-large rack (material 40CrNi2MoA) for a certain type of telemetry and control radar as an example, the detailed process of its protective treatment is as follows: Five test pieces (made of the same material as the rack and processed using the same method) are prepared for the rack's protective treatment. Specifically, this includes:

[0028] (1) Mounting: Install the rack into the conformal fixture.

[0029] (2) Degreasing: Use HJ-105 neutral degreasing solution for chemical degreasing, temperature 50℃-70℃, time: 10-15min, until the oil stains are completely removed.

[0030] (3) Pre-washing: Place in cold water and wash for 3-5 minutes, wash 2-3 times until clean.

[0031] (4) Preheating: Place in a room temperature oven and slowly heat to 350℃ (heating rate 5℃ / min), and keep warm for 45 minutes after reaching 350℃.

[0032] (5) Nitrogen / carbon / yttrium ion co-infiltration: The nitrogen / carbon / yttrium ion co-infiltration furnace is rapidly transferred to a high-permeability composite infiltration agent and treated at 440℃-450℃ for 6 hours.

[0033] (6) Oxygen ion stabilization: Quickly transfer the oxygen ion stabilization furnace and treat it at 380℃-400℃ for 30 min.

[0034] (7) Cooling: Cool to room temperature with the furnace.

[0035] (8) Post-washing: Place in hot water at 50℃-70℃ for 3-5 minutes, wash 2-3 times until clean.

[0036] (9) Drying: air dry naturally at room temperature.

[0037] (10) Oil immersion: Soak in spindle oil at room temperature for 10 to 15 minutes.

[0038] (11) Unloading: Disassemble and separate the rack from the special conforming tool.

[0039] test:

[0040] (1) The treated rack has a black appearance, and the surface protective layer (composite diffusion layer) is continuous, uniform, and complete, without defects such as powdering, looseness, or scratches. The flatness change value of the treated rack is 0.1-0.15mm, and the curvature change value is 0.1mm, both of which meet the design requirements.

[0041] (2) After 500 hours of neutral salt spray testing, the protection level Rp of the furnace-bearing test specimens reached level 10 (no corrosion); after 800 hours of neutral salt spray testing, the protection level Rp reached level 9; after 192 hours of acidic salt spray testing, the protection level Rp reached level 9; the effective hardened layer depth of the furnace-bearing test specimens was 0.43-0.5 mm, and the wear rate was 1×10⁻⁶. -15 m 3 / mN(GB / T 12444 Test Ring-Block Sliding Wear Test).

[0042] Inspection conclusion: Quality is qualified.

[0043] This invention is not limited to the specific embodiments described above, and various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made to the above embodiments based on the technical essence of this invention should be included within the scope of protection of this invention.

Claims

1. A method of protecting an ultra-large rack for marine environment, characterized in that: It comprises the following steps: First step, hanging: install the rack to the shape-retaining tool and reliably fix it; Second step, oil removal: place the shape-retaining tool with the installed rack in a neutral oil removal solution for 10-20 min at a temperature of 50-70℃ until the surface oil is completely removed; Third step, pre-washing: place the shape-retaining tool with the installed rack in cold water for 3-5 min for 2-3 times until it is completely washed; Fourth step, preheating: place the shape-retaining tool with the installed rack in a normal temperature oven, slowly heat it to 350℃, and keep it at 350℃ for 45 min; Fifth step, nitrogen / carbon / yttrium ion co-permeation: quickly move the shape-retaining tool with the installed rack into a nitrogen / carbon / yttrium ion co-permeation furnace, use a high-permeability composite penetrant, and treat it at 440-450℃ for 6 h; Sixth step, oxygen ion stabilization treatment: quickly move the shape-retaining tool with the installed rack into an oxygen ion stabilization furnace, use oxygen ions to stabilize the nitrogen / carbon / yttrium permeated layer, and treat it at 380-400℃ for 30 min; Seventh step, cooling: cool the shape-retaining tool with the installed rack to room temperature with the furnace; Eighth step, post-washing: place the shape-retaining tool with the installed rack in hot water at 50-70℃ for 3-5 min for 2-3 times until it is completely washed; Ninth step, drying: naturally dry the shape-retaining tool with the installed rack at room temperature after washing; Tenth step, oil immersion: soak the dried shape-retaining tool with the installed rack in spindle oil at room temperature for 10-15 min; Eleventh step, unloading: detach and separate the rack from the special shape-retaining tool. The shape-retaining tool is designed based on thermal simulation technology. Firstly, through finite element simulation analysis of the temperature field, displacement field, and stress field of the rack preheating, nitrogen / carbon / yttrium ion co-permeation, and oxygen ion stabilization process, it is determined that the stress concentration of the rack is distributed in the gear ring part, and the stress concentration of the shape-retaining tool is distributed in the lug and connecting rod parts. Then, the stress concentration parts of the shape-retaining tool are structurally reinforced and optimized, connected with the rack through 7-9 pins, evenly distribute the gravity of the rack, and effectively control the deformation of the rack caused by its own weight.

2. A method of protecting an ultra-large rack for marine environment according to claim 1, characterized in that: In the fourth step of preheating, the heating rate is 5℃ / min.

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