阅读说明：本技术 一种窄环平面结构的耐磨密封性铬镀层制备方法 (Preparation method of wear-resistant sealing chromium coating with narrow ring plane structure ) 是由 薛露平 杨战争 刘兴斌 叶晖 张万欣 于 2021-06-11 设计创作，主要内容包括：本发明属于电化学表面处理技术领域,具体是在具有窄环平面结构的工具钢表面制备耐磨密封性厚铬层的工艺方法。辅助阴极不仅具有遮蔽非镀覆面的功能,同时提高镀了层厚度均匀,镀铬过程中采用阶梯给电的方式,即将镀铬电流从0逐步给定至计算值,控制槽液温度、镀铬电流密度和阴阳极之间的距离,镀层硬度值保持在HV700～HV800之间且表面无裂纹,使其具有较高的硬度、优良的耐磨性及良好的密封性。(The invention belongs to the technical field of electrochemical surface treatment, and particularly relates to a process method for preparing a wear-resistant and sealing thick chromium layer on the surface of tool steel with a narrow-ring planar structure. The auxiliary cathode has the function of shielding a non-plating surface, the thickness uniformity of a plating layer is improved, a step power supply mode is adopted in the chromium plating process, namely, the chromium plating current is gradually set to a calculated value from 0, the temperature of bath solution, the chromium plating current density and the distance between a cathode and an anode are controlled, the hardness value of the plating layer is kept between HV700 and HV800, no crack exists on the surface, and the auxiliary cathode has higher hardness, excellent wear resistance and good sealing property.)

1. A preparation method of a wear-resistant sealing chromium coating with a narrow ring plane structure is characterized by comprising the following steps:

preparing an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C, wherein the auxiliary cathode A is of a circular ring structure with steps on the inner surface, namely the inner surface of the auxiliary cathode A forms the steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of a narrow ring plane structure to be plated, the auxiliary cathode A can be sleeved outside the narrow ring plane structure to be plated, the auxiliary cathode B is a stepped solid cylinder, the outer diameter of a large cylinder is matched with the inner diameter of the narrow ring plane structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow ring plane structure to be plated;

secondly, cleaning the outer surface of the narrow ring plane structure to be plated;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on a step on the inner surface of the auxiliary cathode A to obtain a first combination during hanging, placing the auxiliary cathode C on a small cylindrical surface of the auxiliary cathode B to obtain a second combination, and then placing the second combination at the center of the first combination to obtain a hanging combination;

fifthly, activating the hanging assembly obtained in the fourth step;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 40-45A/dm²The distance between the cathode and the anode is not less than 300 mm;

the current value is from 0 to 10% S to 12% S from 0min to 1 min;

the current value is increased to 20-22% S from 1-2 min;

the current value is increased to 40 to 42 percent S from the 2 to 3 min;

the current value is increased to 70S-72% S from the 3 rd min to the 4 th min;

the current value is increased to 100 percent S from 4min to 5 min;

and seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C, and then carrying out heat treatment to obtain a narrow-ring planar structure with a chromium coating.

2. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 1, wherein the method comprises the following steps:

in the first step, the materials of the prepared auxiliary cathode A and the auxiliary cathode B are the same as those of the narrow ring plane structure to be plated, and the auxiliary cathode C is an insulating material.

3. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 1, wherein the method comprises the following steps:

and in the second step, when the outer surface of the narrow ring planar structure to be plated is cleaned, one of organic solvent degreasing and chemical degreasing is selected to degrease or a combination mode is adopted to degrease according to the oil stain condition on the surface of the part.

4. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 3, wherein the method comprises the following steps: the organic solvent deoiling solvent comprises: aviation washing gasoline, alcohol or other organic solvent.

5. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 3, wherein the method comprises the following steps:

the chemical oil removal adopts 60-90 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate.

6. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 1, wherein the method comprises the following steps:

in the third step, the heat treatment temperature is 190-210 ℃, and the treatment time is 22-26 h.

7. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 1, wherein the method comprises the following steps:

in the fifth step, the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 30-50g/L, the activating temperature is room temperature, and the activating time is 0.5-1 min.

8. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 1, wherein the method comprises the following steps:

in the sixth step, the temperature for plating the chromium layer is 59 to 61 ℃.

9. The method for preparing the wear-resistant and sealing chromium coating of the narrow-ring planar structure according to claim 1, wherein the method comprises the following steps:

in the seventh step, the temperature for carrying out heat treatment on the narrow-ring planar structure with the chromium coating is 190-210 ℃, and the treatment time is 22-26 h.

Technical Field

The invention belongs to the technical field of electrochemical surface treatment, and particularly relates to a process method for preparing a wear-resistant and sealing thick chromium layer on the surface of tool steel with a narrow-ring planar structure. The thickness of the prepared chromium plating layer is more than 200 mu m, the thickness dispersion difference is not more than 10 percent, the requirement of wear-resistant sealing under the working conditions of high pressure, high speed and high temperature difference can be met, the plating layer does not have any unfavorable phenomena of falling, peeling, cracking and the like, the narrow ring plane structure is a circular ring structure, and the width of the circular ring is generally 18-22 mm.

Background

The turbo pump of a liquid rocket engine of a certain model can stably run under the severe working conditions of high pressure, high speed, high temperature difference and the like, and the sealing structure adopts end surface contact type mechanical sealing and mainly depends on the sealing surface formed by high-precision end surface matching and sliding friction on the surface of a friction pair. The moving ring is used as a main friction pair of the sealing structure, the base material of the moving ring is tool steel, and chromium is plated on the surface of the moving ring so as to meet the requirements of wear-resistant sealing under high speed, high pressure and high temperature difference.

In the electrochemical field, the chrome plating process of steel parts is common, but the chrome plating process is often applied to the cylindrical surface hard chrome plating layer, and microcracks exist on the surface. After a large amount of data are checked and read, a simulation piece is utilized to carry out a verification test, when a chromium plating layer is deposited on a narrow-ring plane in the conventional steel piece hard chromium plating process, the distribution of power lines is extremely uneven, so that the uniformity of the thickness of the plating layer is poor, the plating layer is U-shaped, the sealing requirements under high pressure, high speed and high temperature difference cannot be met, and the normal delivery and use of products are seriously influenced.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method combines the product shape, utilizes a finite element analysis method to design and manufacture an auxiliary cathode, and utilizes a proper chromium plating process specification to electrodeposit a chromium plating layer which is well combined with a matrix and meets the requirements on hardness and wear resistance, wherein the electroplating time is given according to the thickness requirement of the plating layer and the deposition rate of the plating layer.

The technical solution of the invention is as follows:

a method for preparing a wear-resistant sealing chromium coating with a narrow-ring planar structure comprises the following steps:

the method comprises the following steps that firstly, an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C are prepared, the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material and is of a circular ring structure with steps on the inner surface, namely, the inner surface of the auxiliary cathode A forms steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of the narrow-ring planar structure to be plated, the auxiliary cathode A can be sleeved outside the narrow-ring planar structure to be plated, the auxiliary cathode B is a solid cylinder in a step shape, the outer diameter of a large cylinder is matched with the inner diameter of the narrow-ring planar structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow-ring planar structure to be plated;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60-90 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 190-210 ℃, the treatment time is 22-26h, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on a step on the inner surface of the auxiliary cathode A to obtain a first combination during hanging, placing the auxiliary cathode C on a small cylindrical surface of the auxiliary cathode B to obtain a second combination, then placing the second combination at the center of the first combination to obtain a hanging combination, and confirming that the electric conductivity of the hanging combination is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 30-50g/L, the activating temperature is room temperature, and the activating time is 0.5-1min, and the activating treatment aims to remove an oxide film naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 59-61 ℃;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 40-45A/dm²The distance between the cathode and the anode is not less than 300 mm;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

and seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring plane structure with a chromium coating.

And step eight, carrying out heat treatment on the narrow-ring plane structure with the chromium coating to eliminate hydrogen embrittlement, wherein the heat treatment temperature is 190-210 ℃, and the treatment time is 22-26 h.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention designs the auxiliary cathode according to the structural characteristics of the product, and solves the technical difficulty of the uniformity of the narrow-ring plane chromium plating;

(2) the adopted step power supply mode can obtain a chromium coating with good conclusion, and suitable chromium plating process parameters can ensure that the hardness value of the coating is HV700-HV800 and the surface has no cracks;

(3) by adopting the chromium-plated product, the plating quality can meet the wear-resistant sealing requirement of the moving ring under the working conditions of high pressure, high speed and high temperature difference after a plurality of times of hot trial tests and examinations of the liquid rocket engine.

(4) The invention discloses a preparation method of a wear-resistant and sealing thick chromium layer with a narrow ring plane structure. Including the design of the auxiliary cathode and the setting of the chrome plating parameters. Designing and manufacturing an auxiliary cathode, adopting a proper chromium plating process and process parameters, electroplating on a narrow ring plane to generate a wear-resistant and sealing thick chromium metal layer, and then performing stress relief heat treatment. The thickness of the prepared chromium plating layer is more than 200 mu m, and the thickness dispersion is not more than 10 percent, so that the requirement of wear-resistant sealing of the moving ring under the working conditions of high pressure, high speed and high temperature difference can be met. The method develops a new process for plating chromium on the surface of a narrow-ring planar structure.

(5) The auxiliary cathode has the function of shielding a non-plating surface, the thickness uniformity of a plating layer is improved, a step power supply mode is adopted in the chromium plating process, namely, the chromium plating current is gradually set to a calculated value from 0, the temperature of bath solution, the chromium plating current density and the distance between a cathode and an anode are controlled, the hardness value of the plating layer is kept between HV700 and HV800, no crack exists on the surface, and the auxiliary cathode has higher hardness, excellent wear resistance and good sealing property.

Drawings

FIG. 1 is a schematic structural diagram of an auxiliary cathode A;

FIG. 2 is a schematic structural view of an auxiliary cathode B;

FIG. 3 is a schematic structural view of an auxiliary cathode C;

FIG. 4 is a schematic diagram of a product structure;

fig. 5 is a schematic view of the assembly structure of the product with an auxiliary cathode a, an auxiliary cathode B and an auxiliary cathode C.

Detailed Description

The following examples are provided to better illustrate the efficacy of the formulations and processes of the present invention, but the present invention is not limited to the following examples.

The chrome plating parameters adopted by the invention are as follows:

in a given manner: 1min increased from 0 by 10% of the calculated value.

Min 2 increased from 10% of calculated value to 20% of calculated value.

Min 3 increased from 20% of calculated value by 40% of calculated value.

The 4 th min increased from 40% of calculated value by 70% of calculated value.

The 5 th min increased the calculated value from 70% to 100%.

Cathode-anode distance: not less than 300mm

As shown in fig. 1-5, a method for preparing wear-resistant and sealing chromium coating with narrow ring plane structure comprises the following steps:

firstly, preparing an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C, wherein the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as that of a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material, the auxiliary cathode A is in a circular ring structure with steps on the inner surface, and the auxiliary cathode A is in a circular ring structure with steps on the inner surface and has the step diameterMinor diameter ofThat is, the inner surface of the auxiliary cathode A forms a step, and the inner diameter of the auxiliary cathode AWith the outer diameter of the narrow ring planar structure to be platedThe auxiliary cathode A can be sleeved outside a narrow ring plane structure to be plated, the auxiliary cathode B is a stepped solid cylinder, and the outer diameter of the large cylinderWith the inner diameter of the narrow ring planar structure to be coatedMatched, small cylinder outside diameterThe inner diameter of the auxiliary cathode C is matched with that of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the inner diameter of the auxiliary cathode C isThe auxiliary cathode C has an outer diameter ofAuxiliary cathode C outer diameterWith the inner diameter of the narrow ring planar structure to be coatedMatching;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60-90 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 190-210 ℃, the treatment time is 22-26h, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on the step on the inner surface of the auxiliary cathode A to obtain a first combination body when hanging, placing the auxiliary cathode C on the step on the outer surface of the auxiliary cathode B to obtain a second combination body, then placing the second combination body in the center of the first combination body to obtain a hanging combination body, and confirming that the electric conductivity of the hanging combination body is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 30-50g/L, the activating temperature is room temperature, and the activating time is 0.5-1min, and the activating treatment aims to remove an oxide film and grease dirt naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 59-61 ℃;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 40-45A/dm²The distance between the cathode and the anode is not less than 300 mm;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring planar structure with a chromium coating, wherein the thickness of the chromium coating is more than 200 mu m, and the thickness variation is not more than 10%;

and eighthly, performing heat treatment on the hanging assembly of the chromium layer to eliminate hydrogen embrittlement, wherein the temperature of the heat treatment is 190-210 ℃, and the treatment time is 22-26 h.

Example 1

A method for preparing a wear-resistant sealing chromium coating with a narrow-ring planar structure comprises the following steps:

the method comprises the following steps that firstly, an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C are prepared, the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material and is of a circular ring structure with steps on the inner surface, namely, the inner surface of the auxiliary cathode A forms steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of the narrow-ring planar structure to be plated, the auxiliary cathode A can be sleeved outside the narrow-ring planar structure to be plated, the auxiliary cathode B is a solid cylinder in a step shape, the outer diameter of a large cylinder is matched with the inner diameter of the narrow-ring planar structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow-ring planar structure to be plated;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 200 ℃, the treatment time is 24 hours, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on the step on the inner surface of the auxiliary cathode A to obtain a first combination body when hanging, placing the auxiliary cathode C on the step on the outer surface of the auxiliary cathode B to obtain a second combination body, then placing the second combination body in the center of the first combination body to obtain a hanging combination body, and confirming that the electric conductivity of the hanging combination body is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 40g/L, the temperature of the activating treatment is room temperature, and the time of the activating treatment is 1min, and the activating treatment aims to remove an oxide film and grease dirt naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure the subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 60 ℃;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 40A/dm²The distance between the cathode and the anode is 300 mm; the chromium plating time is 25 h;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring plane structure with a chromium coating;

and eighthly, carrying out heat treatment on the narrow ring plane structure of the obtained chromium coating to eliminate hydrogen embrittlement, wherein the heat treatment temperature is 200 ℃, and the treatment time is 24 hours.

The chromium plating on the narrow ring plane structure has no peeling and falling phenomena after dehydrogenation, which shows that the plating is well combined with the matrix; detecting the thickness of the chromium plating layer to be 200-215 μm and the microhardness to be HV 717; and the chromium coating and the substrate material have no cracks in magnetic powder inspection.

Example 2

A method for preparing a wear-resistant sealing chromium coating with a narrow-ring planar structure comprises the following steps:

the method comprises the following steps that firstly, an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C are prepared, the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material and is of a circular ring structure with steps on the inner surface, namely, the inner surface of the auxiliary cathode A forms steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of the narrow-ring planar structure to be plated, the auxiliary cathode A can be sleeved outside the narrow-ring planar structure to be plated, the auxiliary cathode B is a solid cylinder in a step shape, the outer diameter of a large cylinder is matched with the inner diameter of the narrow-ring planar structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow-ring planar structure to be plated;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 200 ℃, the treatment time is 24 hours, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on the step on the inner surface of the auxiliary cathode A to obtain a first combination body when hanging, placing the auxiliary cathode C on the step on the outer surface of the auxiliary cathode B to obtain a second combination body, then placing the second combination body in the center of the first combination body to obtain a hanging combination body, and confirming that the electric conductivity of the hanging combination body is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 40g/L, the temperature of the activating treatment is room temperature, and the time of the activating treatment is 1min, and the activating treatment aims to remove an oxide film and grease dirt naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure the subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 60 ℃;

the current values when the chromium layer was plated were: defining the product of the current density multiplied by the area of the chromium coatingIs S, the current density is 45A/dm²The distance between the cathode and the anode is 300 mm; the chromium plating time is 25 h;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring plane structure with a chromium coating;

and eighthly, carrying out heat treatment on the narrow ring plane structure of the obtained chromium coating to eliminate hydrogen embrittlement, wherein the heat treatment temperature is 200 ℃, and the treatment time is 24 hours.

The chromium plating on the narrow ring plane structure has no peeling and falling phenomena after dehydrogenation, which shows that the plating is well combined with the matrix; detecting the thickness of the chromium plating layer to be 200-215 μm; microhardness is HV 717; and the chromium coating and the substrate material have no cracks in magnetic powder inspection.

Example 3

A method for preparing a wear-resistant sealing chromium coating with a narrow-ring planar structure comprises the following steps:

the method comprises the following steps that firstly, an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C are prepared, the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material and is of a circular ring structure with steps on the inner surface, namely, the inner surface of the auxiliary cathode A forms steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of the narrow-ring planar structure to be plated, the auxiliary cathode A can be sleeved outside the narrow-ring planar structure to be plated, the auxiliary cathode B is a solid cylinder in a step shape, the outer diameter of a large cylinder is matched with the inner diameter of the narrow-ring planar structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow-ring planar structure to be plated;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 200 ℃, the treatment time is 24 hours, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on the step on the inner surface of the auxiliary cathode A to obtain a first combination body when hanging, placing the auxiliary cathode C on the step on the outer surface of the auxiliary cathode B to obtain a second combination body, then placing the second combination body in the center of the first combination body to obtain a hanging combination body, and confirming that the electric conductivity of the hanging combination body is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 40g/L, the temperature of the activating treatment is room temperature, and the time of the activating treatment is 1min, and the activating treatment aims to remove an oxide film and grease dirt naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure the subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 59 ℃;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 40A/dm²The distance between the cathode and the anode is 300 mm; the chromium plating time is 25 h;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring plane structure with a chromium coating;

and eighthly, carrying out heat treatment on the narrow ring plane structure of the obtained chromium coating to eliminate hydrogen embrittlement, wherein the heat treatment temperature is 200 ℃, and the treatment time is 24 hours.

The chromium plating on the narrow ring plane structure has no peeling and falling phenomena after dehydrogenation, which shows that the plating is well combined with the matrix; detecting the thickness of the chromium plating layer to be 200-215 μm; microhardness is HV 717; and the chromium coating and the substrate material have no cracks in magnetic powder inspection.

Example 4

A method for preparing a wear-resistant sealing chromium coating with a narrow-ring planar structure comprises the following steps:

the method comprises the following steps that firstly, an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C are prepared, the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material and is of a circular ring structure with steps on the inner surface, namely, the inner surface of the auxiliary cathode A forms steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of the narrow-ring planar structure to be plated, the auxiliary cathode A can be sleeved outside the narrow-ring planar structure to be plated, the auxiliary cathode B is a solid cylinder in a step shape, the outer diameter of a large cylinder is matched with the inner diameter of the narrow-ring planar structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow-ring planar structure to be plated;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 200 ℃, the treatment time is 24 hours, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on the step on the inner surface of the auxiliary cathode A to obtain a first combination body when hanging, placing the auxiliary cathode C on the step on the outer surface of the auxiliary cathode B to obtain a second combination body, then placing the second combination body in the center of the first combination body to obtain a hanging combination body, and confirming that the electric conductivity of the hanging combination body is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 40g/L, the temperature of the activating treatment is room temperature, and the time of the activating treatment is 1min, and the activating treatment aims to remove an oxide film and grease dirt naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure the subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 59 ℃;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 45A/dm²The distance between the cathode and the anode is 300 mm; the chromium plating time is 25 h;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring plane structure with a chromium coating;

and eighthly, carrying out heat treatment on the narrow ring plane structure of the obtained chromium coating to eliminate hydrogen embrittlement, wherein the heat treatment temperature is 200 ℃, and the treatment time is 24 hours.

The chromium plating on the narrow ring plane structure has no peeling and falling phenomena after dehydrogenation, which shows that the plating is well combined with the matrix; detecting the thickness of the chromium plating layer to be 200-215 μm; microhardness is HV 717; and the chromium coating and the substrate material have no cracks in magnetic powder inspection.

Example 5

A method for preparing a wear-resistant sealing chromium coating with a narrow-ring planar structure comprises the following steps:

the method comprises the following steps that firstly, an auxiliary cathode A, an auxiliary cathode B and an auxiliary cathode C are prepared, the prepared auxiliary cathode A and the auxiliary cathode B are made of the same material as a narrow-ring planar structure to be plated, the auxiliary cathode C is made of an insulating material and is of a circular ring structure with steps on the inner surface, namely, the inner surface of the auxiliary cathode A forms steps, the inner diameter of the auxiliary cathode A is matched with the outer diameter of the narrow-ring planar structure to be plated, the auxiliary cathode A can be sleeved outside the narrow-ring planar structure to be plated, the auxiliary cathode B is a solid cylinder in a step shape, the outer diameter of a large cylinder is matched with the inner diameter of the narrow-ring planar structure to be plated, the outer diameter of a small cylinder is matched with the inner diameter of the auxiliary cathode C, the auxiliary cathode C is of a circular ring structure, and the outer diameter of the auxiliary cathode C is matched with the inner diameter of the narrow-ring planar structure to be plated;

and secondly, cleaning the outer surface of the narrow ring planar structure to be plated, optionally removing oil by one of organic solvent oil removal and chemical oil removal according to the oil stain condition on the surface of the part during cleaning, and also removing oil by adopting a combined mode, wherein the common solvent for removing oil by the organic solvent comprises the following steps: aviation washing gasoline, alcohol or other organic solvent, wherein chemical oil removal adopts 60 ℃ alkaline solution consisting of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate, and the time is based on the clean removal of oil stains;

thirdly, carrying out heat treatment on the narrow ring plane structure to be plated after cleaning in the second step to eliminate stress; the heat treatment temperature is 200 ℃, the treatment time is 24 hours, and the purpose of the heat treatment is to remove residual stress formed by pretreatment such as machining and the like, increase the binding force of a plating layer and reduce the risk of hydrogen embrittlement;

fourthly, hanging the narrow ring planar structure to be plated by using the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C prepared in the first step, placing the narrow ring planar structure to be plated on the step on the inner surface of the auxiliary cathode A to obtain a first combination body when hanging, placing the auxiliary cathode C on the step on the outer surface of the auxiliary cathode B to obtain a second combination body, then placing the second combination body in the center of the first combination body to obtain a hanging combination body, and confirming that the electric conductivity of the hanging combination body is good;

fifthly, activating the hanging assembly obtained in the fourth step, wherein the activating solvent is sulfuric acid, the concentration of the sulfuric acid is 40g/L, the temperature of the activating treatment is room temperature, and the time of the activating treatment is 1min, and the activating treatment aims to remove an oxide film and grease dirt naturally generated on the surface of the part, fully expose crystals of the metal matrix and ensure the subsequent quality;

sixthly, plating a chromium layer on the surface of the hanging assembly subjected to the activation treatment in the fifth step, wherein the temperature for plating the chromium layer is 59 ℃;

the current values when the chromium layer was plated were: defining a product of current density multiplied by the area of the chromium coating layer as S, the current density being 45A/dm²The distance between the cathode and the anode is 350 mm; the chromium plating time is 25 h;

the current value is from 0 to 10% S from 0min to 1 min;

the current value is from 10% S to 20% S from 1min to 2 min;

the current value is from 20% S to 40% S from the 2 nd min to the 3 rd min;

the current value is from 40% S to 70% S from 3min to 4 min;

the current value is from 70% S to 100% S from the 4 th min to the 5 th min;

seventhly, removing the auxiliary cathode A, the auxiliary cathode B and the auxiliary cathode C to obtain a narrow-ring plane structure with a chromium coating;

and eighthly, carrying out heat treatment on the narrow ring plane structure of the obtained chromium coating to eliminate hydrogen embrittlement, wherein the heat treatment temperature is 200 ℃, and the treatment time is 24 hours.

The chromium plating on the narrow ring plane structure has no peeling and falling phenomena after dehydrogenation, which shows that the plating is well combined with the matrix; detecting the thickness of the chromium plating layer to be 200-215 μm; microhardness is HV 717; and the chromium coating and the substrate material have no cracks in magnetic powder inspection.