阅读说明：本技术 一种风力发电机组用铜排喷漆工艺 (Copper bar paint spraying process for wind generating set ) 是由 杨帆 庾高峰 马明月 宁超 曹延江 靖林 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种风力发电机组用铜排喷漆工艺,包括以下步骤：S1、铜排表面缺陷打磨；S2、酸洗处理；S3、钝化处理；S4、涂料调配；S5、喷涂；S6、漆膜烘干固化；S7、漆膜质量检测。本发明的工艺对铜排的结构和规格尺寸无特定要求,适用对象的范围较广；本发明对现有技术的酸洗液、钝化液、涂料的配方做了一定的改进和调整,有效地防止了铜排表面的氧化现象,提高了涂层综合性能,并提高了产品的一次合格率；且本发明的工艺采用与被喷涂铜排相同材质的裸铜排为基材进行涂层测厚仪的校准或校零,有效消除测量误差,使测量值更接近真实值。(The invention discloses a copper bar paint spraying process for a wind generating set, which comprises the following steps: s1, polishing the surface defects of the copper bar; s2, acid washing; s3, passivating; s4, blending the coating; s5, spraying; s6, drying and curing the paint film; and S7, detecting the quality of the paint film. The process has no specific requirements on the structure and the specification and the size of the copper bar, and the applicable range of objects is wide; the invention improves and adjusts the formulas of the pickling solution, the passivation solution and the coating in the prior art to a certain extent, effectively prevents the oxidation phenomenon on the surface of the copper bar, improves the comprehensive performance of the coating and improves the first-time qualification rate of the product; in the process, the bare copper bar with the same material as the sprayed copper bar is used as the base material to calibrate or zero the coating thickness gauge, so that the measurement error is effectively eliminated, and the measured value is closer to the true value.)

1. The copper bar paint spraying process for the wind generating set is characterized by comprising the following steps of:

s1, polishing the surface defects of the copper bar:

polishing the pits, scratches, inclusions and scratches on the surface of the copper bar by adopting a pneumatic grinding tool and a scouring pad;

s2, acid pickling treatment:

soaking and pickling the copper bar treated in the step S1 in a pickling solution for 5-20 min, fishing out after pickling, cleaning in clear water, and drying at 30-50 ℃ for 10-30 min;

s3, passivation treatment:

soaking the copper bar processed in the step S2 in a passivation solution for passivation for 10-30 min, keeping the temperature of the passivation solution at 42-55 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 30-50 ℃ for 10-30 min;

s4, blending the paint:

blending the paint and the diluent according to the weight ratio of 1-10: 1, and uniformly stirring;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in an oven at 30-60 ℃, and drying and curing for 30-60 min;

s7, paint film quality detection:

visual inspection is adopted to inspect the appearance, a coating thickness gauge is adopted to measure the thickness of a paint film, and a grid cutting method is adopted to inspect the adhesive force of the paint film.

2. The copper bar spray painting process for the wind generating set according to claim 1, wherein the structure of the copper bar in the step S1 is a simple long straight copper bar, a complex bent copper bar formed through multiple three-dimensional forming, or an assembly copper bar formed through one or more welding.

3. The copper bar spray painting process for the wind generating set according to claim 1, wherein the pickling solution in the step S2 comprises the following components in parts by weight: 0.05-0.5 wt% of carboxylic acid vinyl ester, 0.01-0.02 wt% of N-alkyl-N-acylglucamine, 0.6-1.8 wt% of phosphoric acid, 0.1-0.18 wt% of nitric acid and the balance of water.

4. The copper bar spray painting process for the wind generating set according to claim 1, wherein the passivation solution in the step S3 comprises the following components in parts by weight: 9-20 wt% of benzotriazole, 0.6-3.1 wt% of stabilizer, 0.3-4.5 wt% of complexing agent, 0.02-0.05 wt% of potassium fluotitanate and the balance of absolute ethyl alcohol.

5. The copper bar spray painting process for the wind generating set according to claim 4, wherein the stabilizer comprises 8-30 parts by weight of sodium dodecyl sulfate, 8-30 parts by weight of OP emulsifier, and 10-20 parts by weight of OP emulsifier; the complexing agent is sodium cyanide.

6. The copper bar spray painting process for the wind generating set according to claim 1, wherein the paint in the step S4 is varnish.

7. The copper bar spray painting process for the wind generating set according to claim 1, wherein the diluent in the step S4 is selected from any one of a B02-17-B diluent, an S02-4-B diluent or an S04 diluent.

8. The copper bar spray painting process for the wind generating set according to claim 1, wherein the diluent in the step S4 comprises the following components in parts by weight: 2.8 to 5.3 percent of fluorocarbon emulsion, 0.2 to 1.5 percent of sodium m-nitrobenzenesulfonate, 1.5 to 3 percent of polyalkylene glycol and the balance of methanol.

9. The copper bar spray painting process for the wind generating set according to claim 1, wherein in the step S5, the copper bar is coated by a high-pressure airless spray painting method or a high-pressure spray painting method, a spray can is made of stainless steel, copper or aluminum, the diameter of a nozzle is phi 0.7-1.5 mm, and the spray painting pressure is 0.3-0.6 MPa.

10. The copper bar spray painting process for the wind generating set according to claim 1, wherein when the thickness of the paint film is measured by using the coating thickness gauge in the step S7, the bare copper bar made of the same material as the sprayed copper bar is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper bar is polished to be smooth and clean.

Technical Field

The invention relates to the technical field of copper bar processing and manufacturing, in particular to a copper bar paint spraying process for a wind generating set.

Background

According to the targets of 30-carbon peak reaching and 60-carbon neutralization, the wind power and photovoltaic power generation accumulated assembly machine reaches more than 12 hundred million kilowatts in 2030 year, and the industries such as wind power and photovoltaic are increased in an explosive manner. The wind generating set is one of core devices of a wind power generation system. The copper bar for the wind generating set is assembled and installed on the generating set and plays roles in conducting electricity, converging electricity and the like.

Before formal assembly and installation, a plurality of insulation layers are required to be made on the copper bar for the wind generating set, wherein the first insulation layer is formed by spraying an anti-static, anti-oxidation and anti-fingerprint varnish coating layer with a certain thickness on the surface of the copper bar.

At present, in the prior art, a common treatment method is spraying after polishing the surface, but after polishing the surface of a copper bar, the surface activity is higher, and for the copper bar with a larger surface area, spraying is not started, and spots which are oxidized and yellow or blackened appear on the surface of the copper bar. Particularly, the surface of the copper bar is more easily affected with damp and oxidized in rainy days. This easily leads to a decrease in adhesion of the paint film after spraying, poor appearance, uneven thickness, and easy rework and rework.

Disclosure of Invention

Aiming at the problems pointed out by the background technology, the invention provides a copper bar paint spraying process for a wind generating set.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a copper bar paint spraying process for a wind generating set comprises the following steps:

s1, polishing the surface defects of the copper bar:

adopting a pneumatic grinding tool and scouring pad to grind and polish the pits, scratches, inclusions and scratches on the surface of the copper bar, and if necessary, grinding more serious surface defects by using an angle grinder and fine abrasive paper with the grade larger than 600 #;

s2, acid pickling treatment:

soaking and pickling the copper bar treated in the step S1 in a pickling solution for 5-20 min, fishing out after pickling, cleaning in clear water, and drying at 30-50 ℃ for 10-30 min;

s3, passivation treatment:

soaking the copper bar processed in the step S2 in a passivation solution for passivation for 10-30 min, keeping the temperature of the passivation solution at 42-55 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 30-50 ℃ for 10-30 min;

s4, blending the paint:

blending the paint and the diluent according to the weight ratio of 1-10: 1, and uniformly stirring;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in an oven at 30-60 ℃, and drying and curing for 30-60 min;

s7, paint film quality detection:

visual inspection is adopted to inspect the appearance, a coating thickness gauge is adopted to measure the thickness of a paint film, and a grid cutting method is adopted to inspect the adhesive force of the paint film.

Further, in the above scheme, the structure of the copper bar in step S1 is a simple long straight copper bar, a plurality of three-dimensionally formed complex bent copper bars, or an assembly copper bar formed by one or more welding. The copper bar can be not welded copper bar parts, also can be welded copper bar components, and the specification and size of copper bar does not have specific requirements, and any specification and size can all be suitable for.

Further, in the above scheme, the pickling solution in step S2 comprises the following components in parts by weight: 0.05-0.5 wt% of carboxylic acid vinyl ester, 0.01-0.02 wt% of N-alkyl-N-acylglucamine, 0.6-1.8 wt% of phosphoric acid, 0.1-0.18 wt% of nitric acid and the balance of water.

And phosphoric acid and nitric acid in the pickling solution can remove oxides on the surface of the copper bar. The carboxylic acid vinyl ester contains an active functional group, namely double bonds, can carry out addition and polymerization reactions, can be combined with oil stains on the surface of the copper bar to remove the oil stains when used in a pickling solution, and basically has no corrosivity on the copper bar. The N-alkyl-N-acyl glucosamine can be used as a mild surfactant, and the interface state of the pickling solution system can be obviously changed by adding a small amount of the N-alkyl-N-acyl glucosamine, so that the interface adsorption is promoted, the surface tension of the pickling solution system is reduced, and the pickling effect of the pickling solution is further promoted.

After the copper bar is subjected to acid pickling treatment by the acid pickling solution, a clean active surface without oxides and oil stains can be obtained on the surface.

Further, in the above scheme, the passivation solution in step S3 includes the following components in parts by weight: 9-20 wt% of benzotriazole, 0.6-3.1 wt% of stabilizer, 0.3-4.5 wt% of complexing agent, 0.02-0.05 wt% of potassium fluotitanate and the balance of absolute ethyl alcohol.

And a trace amount of potassium fluotitanate is additionally added into the passivation solution, the potassium fluotitanate has certain adhesion capability and better corrosion resistance and biocompatibility, and compared with the passivation solution in the prior art, the bonding force between the passivation solution and the copper bar matrix can be improved by adding the trace amount of potassium fluotitanate.

The passivation solution can generate a passivation film on the surface of a workpiece, so that the surface of the copper bar has long-term moisture resistance and oxidation resistance, and the surface of the copper bar cannot be oxidized within a period of time (2-3 days) after passivation and before spraying.

Furthermore, in the scheme, the stabilizer comprises 8-30 parts by weight of sodium dodecyl sulfate and 10-20 parts by weight of OP emulsifier; the complexing agent is sodium cyanide.

Further, in the above scheme, the paint in step S4 is a varnish.

Further, in the above scheme, the diluent in the step S4 is selected from any one of B02-17-B diluent, S02-4-B diluent or S04 diluent.

As an improvement, the diluent in the step S4 comprises the following components in parts by weight: 2.8 to 5.3 percent of fluorocarbon emulsion, 0.2 to 1.5 percent of sodium m-nitrobenzenesulfonate, 1.5 to 3 percent of polyalkylene glycol and the balance of methanol.

The fluorocarbon emulsion is added into the diluent, so that the weather resistance of the paint can be prolonged, the stain resistance of the paint can be further improved, and a formed paint film is plump, good in fluidity and not easy to fall off. The sodium m-nitrobenzenesulfonate has the effect of promoting the film formation of the paint. The polyalkylene glycol has a leveling and dispersing effect.

Compared with the thinner in the prior art, the thinner disclosed by the invention is used for diluting the varnish, so that the formed paint film is more stable and smooth, and the film forming speed is higher.

After the copper bar is sprayed with the paint, the copper bar has uniform appearance, no oxidation blackening or yellowing spots and high adhesive force.

Further, in the above scheme, in the step S5, the coating is performed by high-pressure airless spraying or high-pressure spraying, the material of the spray can is stainless steel, copper or aluminum, the diameter of the nozzle is phi 0.7-1.5 mm, and the spraying pressure is 0.3-0.6 MPa.

Further, in the above scheme, when the thickness of the paint film is measured by using the coating thickness gauge in step S7, the bare copper busbar made of the same material as the copper busbar to be sprayed is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper busbar should be polished to be flat and clean. So as to effectively eliminate the measurement error and make the measured value closer to the true value.

Compared with the prior art, the beneficial effects of the invention are embodied in the following points:

firstly, the process has no specific requirements on the structure and the specification and the size of the copper bar, and the applicable range of objects is wide.

Secondly, the designed process of the invention is to polish the defects of pits, scratches and the like on the surface of the copper bar, then carry out acid cleaning passivation, and finally carry out spraying and curing. The invention improves and adjusts the formula of the pickling solution and the passivating solution in the prior art to a certain extent, effectively prevents the oxidation phenomenon on the surface of the copper bar, can keep the copper bar after pickling and passivating on the surface for at least three days without oxidation, yellowing and blackening even in rainy days, and also adjusts the coating to a certain extent, effectively improves the comprehensive performance of the coating and improves the primary qualified rate of the product.

Thirdly, the process of the invention adopts the bare copper bar with the same material as the sprayed copper bar as the base material to calibrate or zero the coating thickness gauge, effectively eliminates the measurement error and enables the measured value to be closer to the true value.

Drawings

FIG. 1 is a schematic view of the coating structure of the present invention;

wherein, 1-copper bar matrix, 2-passive film, 3-coating;

fig. 2 is a schematic structural view of a long straight copper bar in embodiment 1 of the present invention;

fig. 3 is a schematic structural view of a bent copper bar in embodiment 2 of the present invention;

fig. 4 is a schematic structural diagram of a welded copper bar in embodiment 3 of the present invention.

Detailed Description

Example 1

In the embodiment, the copper bar is used as an example of a long straight copper bar, and is painted, wherein the copper bar is 1000mm long, 100mm wide and 10mm thick, as shown in fig. 2, the two ends are respectively in the range of 100m, and are installation areas, and the middle shadow area is a painting area.

The specific paint spraying process comprises the following steps:

s1, polishing the surface defects of the copper bar:

the surface of the copper bar is polished by a pneumatic grinding tool and 600# abrasive paper to scratch the local area, and then is polished by scouring pads

S2, acid pickling treatment:

soaking the copper bar treated in the step S1 in a pickling solution for pickling for 12min, fishing out after pickling, cleaning in clear water, and then drying at 40 ℃ for 20 min; the pickling solution comprises the following components in percentage by weight: 0.25 wt% of vinyl carboxylate, 0.015 wt% of N-alkyl-N-acylglucamine, 1.3 wt% of phosphoric acid, 0.15 wt% of nitric acid and the balance of water;

s3, passivation treatment:

soaking the copper bar processed in the step S2 in a passivation solution for passivation for 20min, keeping the temperature of the passivation solution at 48 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 42 ℃ for 20 min; the passivation solution comprises the following components in percentage by weight: 15 percent of benzotriazole, 1.8 percent of stabilizer, 2.5 percent of sodium cyanide, 0.035 percent of potassium fluotitanate and the balance of absolute ethyl alcohol; the stabilizer comprises 16 parts of sodium dodecyl sulfate and 15 parts of OP emulsifier in parts by weight;

s4, blending the paint:

blending the B02-17-A acrylic varnish and the B02-17-B diluent according to the weight ratio of 5:1, and uniformly stirring;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3 by adopting a high-pressure spraying method; the material of the spray can is stainless steel, copper or aluminum, the diameter of the nozzle is phi 1.2mm, and the spraying pressure is 0.4 MPa;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in a 50 ℃ oven, and drying and curing for 40 min;

s7, paint film quality detection:

the appearance was checked by visual inspection, the paint film thickness was measured by a coating thickness gauge, the paint film adhesion was checked by a cross-hatch method, and the results are shown in table 1. When the coating thickness gauge is used for measuring the thickness of a paint film, the bare copper busbar which is made of the same material as the sprayed copper busbar is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper busbar is polished to be smooth and clean. So as to effectively eliminate the measurement error and make the measured value closer to the true value.

Example 2

In the embodiment, a copper bar is taken as an example, the copper bar is a complicated bent copper bar, and the copper bar is painted, wherein the specifications of the copper bar are (calculated according to a projection view) 1500mm in total length, 1000mm in total width and 100mm in total height, as shown in fig. 3, the two ends are respectively in a range of 200m and are installation areas, no painting is performed, and the middle shadow area is a painting area.

The specific paint spraying process comprises the following steps:

s1, polishing the surface defects of the copper bar:

grinding the bent bulges by using a pneumatic grinding tool with No. 200 abrasive paper, and then grinding and polishing by using scouring pad;

s2, acid pickling treatment:

soaking and pickling the copper bar treated in the step S1 in pickling solution for 5min, fishing out after pickling, cleaning in clear water, and then drying at 30 ℃ for 10 min; the pickling solution comprises the following components in percentage by weight: 0.05 wt% of vinyl carboxylate, 0.01 wt% of N-alkyl-N-acylglucamine, 0.6 wt% of phosphoric acid, 0.1 wt% of nitric acid and the balance of water;

s3, passivation treatment:

soaking the copper bar processed in the step S2 in a passivation solution for passivation for 10min, keeping the temperature of the passivation solution at 42 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 30 ℃ for 10 min; the passivation solution comprises the following components in percentage by weight: 9 percent of benzotriazole, 0.6 percent of stabilizer, 0.3 percent of sodium cyanide, 0.02 percent of potassium fluotitanate and the balance of absolute ethyl alcohol; the stabilizer comprises 8 parts of sodium dodecyl sulfate and 10 parts of OP emulsifier in parts by weight;

s4, blending the paint:

blending the S02-4-A polyurethane varnish and the S02-4-B diluent according to the weight ratio of 1:1, and uniformly stirring;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3 by adopting a high-pressure spraying method; the material of the spray can is stainless steel, copper or aluminum, the diameter of the nozzle is phi 0.7mm, and the spraying pressure is 0.3 MPa;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in a drying oven at 30 ℃, and drying and curing for 30 min;

s7, paint film quality detection:

the appearance was checked by visual inspection, the paint film thickness was measured by a coating thickness gauge, the paint film adhesion was checked by a cross-hatch method, and the results are shown in table 1. When the coating thickness gauge is used for measuring the thickness of a paint film, the bare copper busbar which is made of the same material as the sprayed copper busbar is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper busbar is polished to be smooth and clean. So as to effectively eliminate the measurement error and make the measured value closer to the true value.

Example 3

In the embodiment, a copper bar is taken as an example, the copper bar is welded at multiple positions, and the copper bar is painted, and the specifications of the copper bar are (calculated according to a projection view) 2400mm in total length, 1200mm in total width and 30mm in total height, as shown in fig. 4, a range of 50mm of each welding fin end is an installation area, no painting is performed, and all shadow areas are painting areas.

The specific paint spraying process comprises the following steps:

s1, polishing the surface defects of the copper bar:

grinding all scratches and gouges on the surface of the copper bar by using a pneumatic grinding tool with 800# abrasive paper, then grinding and polishing by using scouring pad, and then grinding all welding seams to obtain metallic luster by using a stainless steel wire brush;

s2, acid pickling treatment:

soaking the copper bar treated in the step S1 in a pickling solution for pickling for 20min, fishing out after pickling, cleaning in clear water, and then drying at 50 ℃ for 30 min; the pickling solution comprises the following components in percentage by weight: 0.5 wt% of vinyl carboxylate, 0.02 wt% of N-alkyl-N-acylglucamine, 1.8 wt% of phosphoric acid, 0.18 wt% of nitric acid and the balance of water;

s3, passivation treatment:

soaking and passivating the copper bar processed in the step S2 in a passivation solution for 30min, keeping the temperature of the passivation solution at 55 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 50 ℃ for 30 min; the passivation solution comprises the following components in percentage by weight: 20 percent of benzotriazole, 3.1 percent of stabilizer, 4.5 percent of sodium cyanide, 0.05 percent of potassium fluotitanate and the balance of absolute ethyl alcohol; the stabilizer comprises 30 parts of sodium dodecyl sulfate and 20 parts of OP emulsifier in parts by weight;

s4, blending the paint:

blending the paint and the diluent according to the weight ratio of 10:1, and uniformly stirring;

the paint is PVB varnish;

the diluent comprises the following components in percentage by weight: 5.3 wt% of fluorocarbon emulsion, 1.5 wt% of sodium m-nitrobenzenesulfonate, 1.5-3 wt% of polyalkylene glycol and the balance of methanol;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3 by adopting a high-pressure airless spraying method; the material of the spray can is stainless steel, copper or aluminum, the diameter of the nozzle is phi 1.5mm, and the spraying pressure is 0.6 MPa;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in a 60 ℃ oven, and drying and curing for 60 min;

s7, paint film quality detection:

the appearance was checked by visual inspection, the paint film thickness was measured by a coating thickness gauge, the paint film adhesion was checked by a cross-hatch method, and the results are shown in table 1. When the coating thickness gauge is used for measuring the thickness of a paint film, the bare copper busbar which is made of the same material as the sprayed copper busbar is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper busbar is polished to be smooth and clean. So as to effectively eliminate the measurement error and make the measured value closer to the true value.

Example 4

In the embodiment, a copper bar is taken as an example, the copper bar is a complicated bent copper bar, and the copper bar is painted, wherein the specifications of the copper bar are (calculated according to a projection view) 1500mm in total length, 1000mm in total width and 100mm in total height, as shown in fig. 3, the two ends are respectively in a range of 200m and are installation areas, no painting is performed, and the middle shadow area is a painting area.

The specific paint spraying process comprises the following steps:

s1, polishing the surface defects of the copper bar:

grinding all scratches and gouges on the surface of the copper bar by using a pneumatic grinding tool with 800# abrasive paper, then grinding and polishing by using scouring pad, and then grinding all welding seams to obtain metallic luster by using a stainless steel wire brush;

s2, acid pickling treatment:

soaking and pickling the copper bar treated in the step S1 in pickling solution for 9min, fishing out after pickling, cleaning in clear water, and then drying at 50 ℃ for 25 min; the pickling solution comprises the following components in percentage by weight: 0.25 wt% of vinyl carboxylate, 0.015 wt% of N-alkyl-N-acylglucamine, 1.5 wt% of phosphoric acid, 0.14 wt% of nitric acid and the balance of water;

s3, passivation treatment:

soaking the copper bar processed in the step S2 in a passivation solution for passivation for 20min, keeping the temperature of the passivation solution at 50 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 42 ℃ for 20 min; the passivation solution comprises the following components in percentage by weight: 16 wt% of benzotriazole, 1.6 wt% of stabilizer, 2.5 wt% of sodium cyanide, 0.04 wt% of potassium fluotitanate and the balance of absolute ethyl alcohol; the stabilizer comprises 20 parts of sodium dodecyl sulfate and 15 parts of OP emulsifier in parts by weight;

s4, blending the paint:

blending the paint and the diluent according to the weight ratio of 5:1, and uniformly stirring;

the paint is PVB varnish;

the diluent comprises the following components in percentage by weight: 4.2 wt% of fluorocarbon emulsion, 0.8 wt% of sodium m-nitrobenzenesulfonate, 2.4 wt% of polyalkylene glycol and the balance of methanol;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3 by adopting a high-pressure spraying method; the material of the spray can is stainless steel, copper or aluminum, the diameter of the nozzle is phi 1.0mm, and the spraying pressure is 0.45 MPa;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in a 45 ℃ oven, and drying and curing for 50 min;

s7, paint film quality detection:

the appearance was checked by visual inspection, the paint film thickness was measured by a coating thickness gauge, the paint film adhesion was checked by a cross-hatch method, and the results are shown in table 1. When the coating thickness gauge is used for measuring the thickness of a paint film, the bare copper busbar which is made of the same material as the sprayed copper busbar is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper busbar is polished to be smooth and clean. So as to effectively eliminate the measurement error and make the measured value closer to the true value.

Example 5

In the embodiment, a copper bar is taken as an example, the copper bar is welded at multiple positions, and the copper bar is painted, and the specifications of the copper bar are (calculated according to a projection view) 2400mm in total length, 1200mm in total width and 30mm in total height, as shown in fig. 4, a range of 50mm of each welding fin end is an installation area, no painting is performed, and all shadow areas are painting areas.

The specific paint spraying process comprises the following steps:

s1, polishing the surface defects of the copper bar:

grinding all scratches and gouges on the surface of the copper bar by using a pneumatic grinding tool with 800# abrasive paper, then grinding and polishing by using scouring pad, and then grinding all welding seams to obtain metallic luster by using a stainless steel wire brush;

s2, acid pickling treatment:

soaking and pickling the copper bar treated in the step S1 in pickling solution for 15min, fishing out after pickling, cleaning in clear water, and then drying at 50 ℃ for 30 min; the pickling solution comprises the following components in percentage by weight: 0.4 wt% of vinyl carboxylate, 0.012 wt% of N-alkyl-N-acylglucamine, 1.5 wt% of phosphoric acid, 0.15 wt% of nitric acid and the balance of water;

s3, passivation treatment:

soaking the copper bar processed in the step S2 in a passivation solution for passivation for 22min, keeping the temperature of the passivation solution at 50 ℃ in the passivation process, taking out the copper bar after passivation, cleaning the copper bar in clear water, and drying the copper bar at 50 ℃ for 30 min; the passivation solution comprises the following components in percentage by weight: 13 percent of benzotriazole, 2.0 percent of stabilizer, 3.0 percent of sodium cyanide, 0.04 percent of potassium fluotitanate and the balance of absolute ethyl alcohol; the stabilizer comprises 30 parts of sodium dodecyl sulfate and 20 parts of OP emulsifier in parts by weight;

s4, blending the paint:

blending the paint and the diluent according to the weight ratio of 2:1, and uniformly stirring;

the paint is PVB varnish;

the diluent comprises the following components in percentage by weight: 5.0 wt% of fluorocarbon emulsion, 1.5 wt% of sodium m-nitrobenzenesulfonate, 3 wt% of polyalkylene glycol and the balance of methanol;

s5, spraying:

coating the paint prepared in the step S4 on the surface of the copper bar processed in the step S3 by adopting a high-pressure spraying method; the material of the spray can is stainless steel, copper or aluminum, the diameter of the nozzle is phi 1.0mm, and the spraying pressure is 0.5 MPa;

s6, drying and curing the paint film:

placing the copper bar sprayed with the coating in the step S5 in a 50 ℃ oven, and drying and curing for 60 min;

s7, paint film quality detection:

the appearance was checked by visual inspection, the paint film thickness was measured by a coating thickness gauge, the paint film adhesion was checked by a cross-hatch method, and the results are shown in table 1. When the coating thickness gauge is used for measuring the thickness of a paint film, the bare copper busbar which is made of the same material as the sprayed copper busbar is used as a base material for calibration or zero calibration, and before the calibration or zero calibration, the surface of the bare copper busbar is polished to be smooth and clean. So as to effectively eliminate the measurement error and make the measured value closer to the true value.

Comparative example 1

Essentially the same as in example 4, except that the pickling solution used was: 55 wt% of phosphoric acid, 10.5 wt% of nitric acid and the balance of water.

Comparative example 2

The same as example 4, except that the passivation solution used was: 9 wt% of benzotriazole, 20 wt% of sodium dodecyl sulfate, 5 wt% of OP emulsifier, 4 wt% of sodium cyanide and the balance of absolute ethyl alcohol.

The performance of the coatings of the examples 1-5 and the comparative examples 1-2 were respectively tested, the appearance was checked by visual method, the thickness of the paint film was measured by a coating thickness meter, the adhesion of the paint film was checked by a cross-cut method, and the test results are shown in table 1.

TABLE 1 results of testing the coating properties of examples 1-5 and the blank control

In Table 1, the coatings of examples 3 to 5 were complete and continuous in appearance, free from cracking, oxidation, blackening or yellowing, and high in adhesion, and completely met the requirements. The comparative example 1 adopts common pickling solution to cause slight oxidation blackening on the surface of the copper bar, the comparative example 2 adopts common passivation solution to cause partial oxidation blackening on the surface of the copper bar, and the blank control group does not have any pickling passivation treatment to cause severe oxidation blackening and yellow spots, so that the coating adhesion force does not meet the requirement. Examples 1-2 the coating adhesion was not as good as in examples 3-5 due to the use of a conventional diluent as the coating diluent. Therefore, when the process is used for spraying paint on the copper bar, the primary qualified rate of the obtained product is higher.