CN111962120A

CN111962120A - Pipe fitting inner wall surface treatment process

Info

Publication number: CN111962120A
Application number: CN202010833004.3A
Authority: CN
Inventors: 杨平
Original assignee: Chongqing Baihong Machinery Equipment Co ltd
Current assignee: Chongqing Jianshe Industry Group Co Ltd
Priority date: 2020-08-18
Filing date: 2020-08-18
Publication date: 2020-11-20

Abstract

The invention relates to the field of electroplating, and discloses a surface treatment process for the inner wall of a pipe fitting, wherein in the installation step, the periphery of the centroid position of the pipe fitting is electrically connected with a negative electrode of a power supply part; in the plating step, electricity is simultaneously applied to both ends of the anode. In the invention, the two ends of the anode are simultaneously and forcibly electrified, and the cathode of the power supply part is electrically connected with the periphery of the position of the mass center of the pipe fitting, so that the difference between the current density of the end part of the anode and the current density of the middle part of the anode is greatly reduced, the difference between the current densities of the two ends of the anode is eliminated, and the difference between the current density of the end part of the pipe fitting and the current density of the middle part of the pipe fitting is also reduced.

Description

Pipe fitting inner wall surface treatment process

Technical Field

The invention relates to the field of electroplating, in particular to a surface treatment process for an inner wall of a pipe fitting.

Background

The electroplating process is a process for plating a layer of metal or alloy on the surface of some metals (i.e. workpieces) by utilizing the electrolysis principle, and the property of the surface of the workpiece or the size of the workpiece is changed by utilizing a plating layer formed by the electroplating process, so that the oxidation resistance (such as rust), the wear resistance and the light reflection performance of the workpiece are improved, the aesthetic degree of the workpiece is increased, and in addition, the workpiece with the worn surface can be repaired by utilizing the electroplating process.

The electroplating process of work piece is gone on in the plating bath usually, but to the pipe fitting that only needs the inner wall to electroplate, electroplate not only can form the cladding material at the pipe fitting outer wall or corrode the pipe fitting outer wall in the plating bath to extravagant plating solution, long time of extension processing, still have the problem that cladding material thickness on the pipe fitting inner wall is different, the product percent of pass is low. At present, people try to introduce the electroplating solution into the pipe fitting to make the electroplating solution only contact with the inner wall of the pipe fitting, and electrify the anode after the anode passes through the pipe fitting, so as to form the plating layer on the inner wall of the pipe fitting. However, although the waste of the plating solution can be avoided by the above method, the quality of the plating layer formed on the inner wall of the pipe is still not satisfactory, and the problem of non-uniform thickness of the plating layer still remains, resulting in low product yield.

Disclosure of Invention

The invention aims to provide a surface treatment process for the inner wall of a pipe fitting, so as to solve the problem of low product yield of the electroplated pipe fitting in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme: in the mounting step, electrically connecting the periphery of the centroid position of the pipe fitting with the negative electrode of the power supply part; in the plating step, electricity is simultaneously applied to both ends of the anode.

The principle and the advantages of the scheme are as follows: during the practical application, the circular telegram is forced simultaneously to the both ends of positive pole, and the negative pole of power supply portion is connected with the periphery electricity of the barycenter position of pipe fitting, so, compare in the electroplating mode of positive pole one end circular telegram among the prior art, this scheme can make the difference between the current density at positive pole tip and the current density at positive pole middle part reduce by a wide margin, and make the difference between the current density at positive pole both ends eliminate, simultaneously, also can make the difference between the current density at pipe fitting tip and the current density at pipe fitting middle part reduce by a wide margin, in other words, this scheme can make the current density difference of positive pole and pipe fitting each position department in the electroplating process reduce, thereby realize the even electroplating of pipe fitting, improve the homogeneity of cladding material thickness, thereby improve the product percent of pass, and the.

Preferably, as an improvement, in the electroplating step, the step of increasing the flow is performed in a sectional reciprocating type when the two ends of the anode are simultaneously electrified, and the sectional reciprocating type flow increasing mode is as follows:

stage I: 9.5-10.5A; and stage II: 19.5-20.5A; stage III: 9.5-10.5A; stage IV: 4.5-5.5A; and (5) stage V: 6.5-7.5A; stage VI: 8.5-9.5A; stage VII: 11.5-12.5A; stage VIII: 13.5-14.5A; wherein the ratio of the duration of the stages I to III to the duration of the stages IV to VII is 1:1, the duration ratio among the stages I, II and III is 1:2:3, the duration ratio among the stages IV, V, VI and VII is 1:1:1:1, and the duration of the stage VIII is 90-120 min. .

In the scheme, the two ends of the anode are simultaneously and forcibly electrified in a sectional reciprocating type current increasing mode, so that the condition that preset current is input to the anode at the beginning is avoided, and the problems of short circuit, breakdown, scorching and the like of a circuit are avoided.

Preferably, as a modification, the anode is coaxial with the pipe member, and the unilateral gap between the anode and the inner wall of the pipe member is 1.60-2.50 μm.

When the unilateral clearance between the anode and the inner wall of the pipe fitting is less than 1.6 mu m, the problems of breakdown and scorching are easy to occur, and when the unilateral clearance between the anode and the inner wall of the pipe fitting is more than 2.5 mu m, the electroplating effect is poor, and the thickness, hardness and color of the plating layer are affected. Therefore, when the unilateral clearance between the anode and the inner wall of the pipe fitting is within 1.60-2.50 microns, the scheme can avoid breakdown and keep a good electroplating effect.

Preferably, as a modification, the flow rate of the plating solution is 3.82 to 5.94 cm/s.

In the scheme, 3.82-5.94cm/s is selected as the flow velocity range of the electroplating solution, so that metal ions to be plated in the electroplating solution can be well dispersed, and a uniform plating layer can be obtained more favorably.

Preferably, as a modification, the temperature of the plating solution at the first 1/10 stage in the plating process is 70 ℃, and the temperature of the plating solution at the last 9/10 stage in the plating process is 60 ℃.

In this scheme, through the control to the plating solution temperature at the different stages of electroplating, effectively improve the dispersion ability of cladding material toughness and plating solution, reduce the cladding material and inhale hydrogen volume, effectively improve the combination degree of cladding material and pipe fitting inner wall.

Preferably, as an improvement, the anode is guided by a guiding conductive unit while passing through the inside of the pipe member, and the guiding conductive unit moves to grip the outer circumference of the centroid position of the pipe member and conduct electricity to the pipe member.

In this scheme, utilize the electrically conductive unit of direction to lead the positive pole for the positive pole can penetrate the inside of pipe fitting fast, accurately, avoids the tip of positive pole to collide with the pipe fitting and impaired. And, the guide conductive unit can also clamp and conduct electricity to the pipe after guiding for the anode. Therefore, the guide conductive unit in the scheme has multiple functions and is ingenious in design.

Preferably, as an improvement, the guide conductive unit comprises a pneumatic clamping jaw and two clamping blocks, the two clamping blocks are respectively and fixedly connected to the two clamping jaws of the pneumatic clamping jaw, the clamping blocks are provided with semicircular guide grooves, and when the two clamping blocks are contacted with each other, the two semicircular guide grooves form guide holes for the anode to pass through; the grip block is electrically conductive and the grip block is electrically connected to an electrical connector.

In this scheme, when two grip blocks contacted each other, the semicircular guide slot on it formed the guide hole to for the positive pole direction, and after positive pole direction work, pneumatic clamping jaw removed, two grip blocks can the centre gripping pipe fitting, thereby realize electrically conductive, simple structure, ingenious to the pipe fitting.

Preferably, as an improvement, a driving cylinder for driving the guide conductive unit to move is connected to the pneumatic clamping jaw.

In this scheme, the removal that drives actuating cylinder and realize pneumatic clamping jaw is utilized to change the position of grip block, and then realize holding the pipe fitting and be the electrically conductive function of pipe fitting behind for the positive pole direction.

Preferably, as an improvement, the length of the anode is longer than that of the pipe fitting, and before electroplating, the two ends of the pipe fitting are provided with the replacing pipes respectively, and the replacing pipes are in sealed communication with the pipe fitting.

In this scheme, utilize the substitute pipe extension pipe fitting for original power line too concentrates on the both ends change of pipe fitting and is too concentrated on the substitute pipe for the power line, makes to form thicker cladding material on the inner wall of substitute pipe, avoids forming thicker cladding material on the inner wall of pipe fitting tip, thereby makes cladding material thickness on the pipe fitting inner wall even, improves product quality.

Preferably, as a modification, a first seal ring is fixedly connected to an end of the replacement pipe.

In this scheme, utilize sealing washer one to improve the leakproofness between replacement pipe and the pipe fitting, avoid the plating solution to spill from the department of meeting of pipe fitting and replacement pipe.

Drawings

Fig. 1 is a schematic flow chart of a pipe inner wall surface treatment process in embodiment 1 of the present invention;

FIG. 2 is a schematic structural view of an apparatus used for fixing the anode and the pipe in embodiment 1 of the present invention;

FIG. 3 is an enlarged view of A in FIG. 2;

FIG. 4 is an enlarged view of B in FIG. 2;

fig. 5 is a schematic structural view of a guide conductive unit in embodiment 1 of the present invention;

fig. 6 is a schematic structural view illustrating a structure of the anode fixed to the pipe in embodiment 1 of the present invention.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a pipe fitting 1, a replacing pipe 2, a first sealing ring 3, a movable die 4, a fixed die 5, an anode 6, a pneumatic clamping jaw 7, a clamping block 8, a semicircular guide groove 9, an electric connector 10, a driving cylinder 11, a telescopic cylinder 12, a conductive rod 13, a conductive clamping piece 14 and a sealing piece 15.

Example 1

In this embodiment, as shown in fig. 1, the pipe inner wall surface treatment process includes an installation step and an electroplating step, and the pipe inner wall surface treatment process uses the apparatus shown in fig. 2, and specifically includes the following operations:

s1, mounting:

(1) referring to fig. 3 and 4, the replacement pipe 2 is arranged at both ends of the pipe fitting 1, the inner diameter of the replacement pipe 2 is the same as that of the pipe fitting 1, and a first seal ring 3 is arranged between the end of the replacement pipe 2 and the end of the pipe fitting 1. In this embodiment, replace pipe 2 threaded connection in the mounting hole that movable mould 4 and cover half 5 were seted up, when movable mould 4 kept away from cover half 5, the top of pipe fitting 1 was kept away from to the replacement pipe 2 on the movable mould 4, and when movable mould 4 was close to cover half 5, the top that pipe fitting 1 was close to the replacement pipe 2 on the movable mould 4.

(2) The anode 6 penetrates through the inside of the pipe fitting 1, and in the process, the anode 6 is guided by a guide conductive unit, wherein the guide conductive unit comprises a pneumatic clamping jaw 7 and two clamping blocks 8 as shown in fig. 5, the two clamping blocks 8 are respectively and fixedly connected to the two clamping jaws of the pneumatic clamping jaw 7, the clamping blocks 8 are provided with semicircular guide grooves 9, and when the two clamping blocks 8 are contacted with each other, the two semicircular guide grooves 9 form guide holes for the anode 6 to pass through; the clamping block 8 is electrically conductive and the clamping block 8 is electrically connected with an electrical connector 10. As shown in fig. 2, a driving cylinder 11 is arranged above the pneumatic clamping jaw 7, and an output end of the driving cylinder 11 is fixedly connected with the pneumatic clamping jaw 7 through a screw, so as to drive the pneumatic clamping jaw 7 to move up and down.

During guiding, as shown in fig. 2, the bottom end of the anode 6 is inserted through the guide hole, so that the bottom end of the anode 6 is guided to the inside of the pipe member 1, and the bottom end of the anode 6 is prevented from colliding with the pipe member 1 (the substitute pipe 2).

When the top of positive pole 6 was close grip block 8, started pneumatic clamping jaw 7, pneumatic clamping jaw 7 makes two grip blocks 8 keep away from each other (two grip blocks 8 keep away from each other the back, and the distance between the two is greater than the external diameter of pipe fitting 1), then starts immediately and drives actuating cylinder 11, drives actuating cylinder 11 and drives pneumatic clamping jaw 7 downstream for two grip blocks 8 are located the periphery of pipe fitting 1.

(3) After passing positive pole 6 the inside of pipe fitting 1, utilize telescopic cylinder 12 and the holder on movable mould 4 and the cover half 5, it is tensile to carry out the centre gripping at the both ends of positive pole 6, above-mentioned holder includes conducting rod 13 and two deformable electrically conductive clamping pieces 14, electrically conductive clamping piece 14 and conducting rod 13 fixed connection, conducting rod 13 has been seted up and has been supplied the male blind hole of positive pole 6 tip, conducting rod 13 and telescopic cylinder 12's output fixed connection, the perisporium fixed connection of conducting rod 13 has sealing member 15, sealing member 15 and movable mould 4, the perisporium of the guiding hole that cover half 5 was seted up offsets tightly, in this embodiment, sealing member 15 is three sealing washer. The conducting rod 13 and the conducting clamping piece 14 are located in a guide hole (the guide hole is formed in the movable mold 4 and the fixed mold 5), specifically, the conducting rod 13 is located in a straight section of the guide hole, the conducting clamping piece 14 is located in an opening expanding section, the inner diameter of the opening expanding section is gradually increased along the direction towards the substitution tube 2, and the outer wall of the conducting clamping piece 14 is attached to the inner wall of the opening expanding section. The conductive rod 13 is electrically connected to a power supply unit (not shown) through a wire, in this embodiment, the power supply unit is a rectifier, that is, the conductive rod 13 on the movable mold 4 is electrically connected to the positive electrode of the first rectifier through a wire, and the conductive rod 13 on the fixed mold 5 is electrically connected to the positive electrode of the second rectifier through a wire.

The process of clamping and stretching the two ends of the anode 6 is as follows: the tip of positive pole 6 stretches into two electrically conductive clamping pieces 14 in, start flexible cylinder 12, flexible cylinder 12 drives conducting rod 13 and removes, electrically conductive clamping piece 14 gets into less space (electrically conductive clamping piece 14 gets into straight section by flaring section) by great space, receive the extrusion to take place deformation and press from both sides the tip of tight positive pole 6, thereby realize the centre gripping tensile to positive pole 6, make positive pole 6 tensioning, ensure the axiality of positive pole 6 and pipe fitting 1, and make the unilateral clearance of positive pole 6 and pipe fitting 1 inner wall be 1.60-2.50 mu m, in this embodiment, the unilateral distance of positive pole 6 and pipe fitting 1 inner wall is 1.71 mu m.

In the process of tensioning the anode 6, the movable mold 4 moves towards the fixed mold 5, so that the substitute pipe 2 on the movable mold 4 moves towards the top end of the pipe fitting 1 until the first sealing ring 3 on the substitute pipe 2 on the movable mold 4 abuts against the top end of the pipe fitting 1, and the pipe fitting 1 is pressed between the movable mold 4 and the fixed mold 5, which is shown in fig. 6. Alternatively, the anode 6 may be inserted into the pipe 1 after the tip of the anode 6 is fixed to the movable die 4.

(4) Remove grip block 8 for grip block 8 centre gripping pipe fitting 1's the periphery of the barycenter position, specifically operate as follows: start and drive actuating cylinder 11, drive actuating cylinder 11 and drive pneumatic clamping jaw 7 and reciprocate to the position of adjustment grip block 8 makes grip block 8 be located the periphery of the barycenter position of pipe fitting 1, starts pneumatic clamping jaw 7, makes two grip blocks 8 be close to each other, thereby centre gripping pipe fitting 1. Then, the electrical connector 10 on the clamping block 8 is electrically connected with the negative poles of the first rectifier and the second rectifier through a lead.

S2, electroplating step:

(1) the flow rate of the plating solution is 3.82 to 5.94cm/s, and in this example, the flow rate of the plating solution is 4.88 cm/s.

(2) Starting the first rectifier and the second rectifier simultaneously, forcibly feeding electricity to the two ends of the anode 6 simultaneously for electroplating, and forcibly electrifying the two ends of the anode 6 simultaneously in a sectional reciprocating flow increasing mode, wherein the sectional reciprocating flow increasing mode comprises the following steps:

stage I: 9.5-10.5A; and stage II: 19.5-20.5A; stage III: 9.5-10.5A; stage IV: 4.5-5.5A; and (5) stage V: 6.5-7.5A; stage VI: 8.5-9.5A; stage VII: 11.5-12.5A; stage VIII: 13.5-14.5A; wherein the time from stage I to stage VII is 60min, and the duration of stage VIII is 90-120 min.

In this example, stage i: 10A; and stage II: 20A; stage III: 10A; stage IV: 5A; and (5) stage V: 7A; stage VI: 9A; stage VII: 12A; stage VIII: 14A. Wherein the duration time from the stage I to the stage III is 30min, and the duration time ratio of the stage I to the stage II to the stage III is 1:2: 3; the duration time from stage IV to stage VII is 30min, and the duration time ratio of stage IV, stage V, stage VI and stage VII is 1:1:1: 1; the duration of stage VIII was 97 min. In this embodiment, the duration from stage i to stage viii in the above-mentioned case can further improve the quality of the plating layer, that is, further improve the bonding degree between the plating layer and the inner wall of the pipe and the uniformity of the thickness of the plating layer.

In addition, the temperature of the plating solution in the first 1/10 stage of the plating process was 70 ℃ and the temperature of the plating solution in the last 9/10 stage of the plating process was 60 ℃ during the plating process.

(3) And after the electroplating is finished, taking down the pipe fitting 1.

Examples 2 to 5

Examples 2 to 5 differ from example 1 only in the selection of the parameters (plating solution flow rate and one-sided gap), examples 1 to 5 were as shown in Table 1, and the rest of the operations were the same.

TABLE 1

	Flow rate of plating solution (mm/s)	Single side gap (mum)
			Example 1	4.88	1.71
Example 2	3.82	1.71
			Example 3	5.94	1.71
Example 4	4.88	1.60
			Example 5	4.88	2.50

Examples 6 to 7

Examples 6 to 7 differ from example 1 only in the current values at the respective stages in the stepwise reciprocating current increasing manner, and the current values at the respective stages are specifically referred to in table 2.

TABLE 2

Comparative example

The comparative example was electroplated by applying current to one end of the anode as is common in the prior art, and the stepwise reciprocating current increasing method of example 1 was not used.

The results of testing the pipes plated in examples 1 to 7 and comparative example are summarized in table 3, wherein the internal diameter of the pipes plated was measured by a plug gauge, the number of the pipes plated in examples 1 to 7 was 100, and the criteria were as follows: the plug gauge tool is just inserted into the electroplated pipe fitting, and the plug gauge tool can completely penetrate through the electroplated pipe fitting, so that the pipe fitting is qualified; if the plug gauge cannot be inserted into the electroplated pipe fitting or the plug gauge cannot penetrate through the electroplated pipe fitting, the pipe fitting is judged to be unqualified; and after the plug gauge tool is inserted into the interior of the electroplated pipe fitting, the plug gauge tool can shake relative to the electroplated pipe fitting, and the pipe fitting is judged to be unqualified.

TABLE 3

As can be seen from table 3, the yield of the pipe produced in examples 1 to 7 is significantly higher than that of the pipe produced in the comparative example, and therefore, the present invention can improve the production yield of the pipe electroplating process and the productivity of the enterprise.

The foregoing is merely an example of the present invention and common general knowledge in the art of designing and/or characterizing particular aspects and/or features is not described in any greater detail herein. It should be noted that, for those skilled in the art, without departing from the technical solution of the present invention, several variations and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. A surface treatment process for the inner wall of a pipe fitting is characterized by comprising the following steps: in the mounting step, electrically connecting the periphery of the centroid position of the pipe fitting with the negative electrode of the power supply part; in the plating step, electricity is simultaneously applied to both ends of the anode.

2. The pipe inner wall surface treatment process according to claim 1, wherein: in the electroplating step, when the two ends of the anode are electrified simultaneously, the segmented reciprocating flow increasing mode is adopted, and the segmented reciprocating flow increasing mode is as follows:

stage I: 9.5-10.5A; and stage II: 19.5-20.5A; stage III: 9.5-10.5A; stage IV: 4.5-5.5A; and (5) stage V: 6.5-7.5A; stage VI: 8.5-9.5A; stage VII: 11.5-12.5A; stage VIII: 13.5-14.5A; wherein the ratio of the duration of the stages I to III to the duration of the stages IV to VII is 1:1, the duration ratio among the stages I, II and III is 1:2:3, the duration ratio among the stages IV, V, VI and VII is 1:1:1:1, and the duration of the stage VIII is 90-120 min.

3. The pipe inner wall surface treatment process according to claim 2, wherein: the anode is coaxial with the pipe fitting, and the unilateral gap between the anode and the inner wall of the pipe fitting is 1.60-2.50 mu m.

4. The pipe inner wall surface treatment process according to claim 3, wherein: the flow rate of the plating solution is 3.82-5.94 cm/s.

5. The pipe inner wall surface treatment process according to claim 4, wherein: the temperature of the plating solution in the front 1/10 stage of the plating process is 70 ℃, and the temperature of the plating solution in the rear 9/10 stage of the plating process is 60 ℃.

6. The pipe inner wall surface treatment process according to any one of claims 1 to 5, wherein: when the anode passes through the inside of the pipe fitting, the anode is guided by the guide conductive unit, and the guide conductive unit clamps the periphery of the centroid position of the pipe fitting after moving and conducts electricity for the pipe fitting.

7. The pipe inner wall surface treatment process according to claim 6, wherein: the guide conductive unit comprises a pneumatic clamping jaw and two clamping blocks, the two clamping blocks are respectively and fixedly connected to the two clamping jaws of the pneumatic clamping jaw, the clamping blocks are provided with semicircular guide grooves, and when the two clamping blocks are contacted with each other, the two semicircular guide grooves form guide holes for the anode to pass through; the grip block is electrically conductive and the grip block is electrically connected to an electrical connector.

8. The pipe inner wall surface treatment process according to claim 7, wherein: and the pneumatic clamping jaw is connected with a driving cylinder for driving the guide conductive unit to move.

9. The pipe inner wall surface treatment process according to claim 8, wherein: the length of the anode is longer than that of the pipe fitting, and both ends of the pipe fitting are provided with the replacing pipes before electroplating, so that the replacing pipes are communicated with the pipe fitting in a sealing manner.

10. The pipe inner wall surface treatment process according to claim 9, wherein: the end part of the replacing pipe is fixedly connected with a first sealing ring.