Specification for phosphate treatment of iron and steel parts before painting
Some standard content:
National Standard of the People's Republic of China
Technical conditions for phosphate treatment of iron and steel parts before paintingSpecification for phosphate treatment oflron and steel parts before paintingUDC621.9.03
621. 794.62
GB 6807-86
This standard applies to the phosphate treatment of iron and steel parts before painting. The phosphate film formed by the treatment is used as the paint base to enhance the adhesion and protection of the paint film to the steel substrate and improve the painting quality of the steel workpiece. 1 Classification of phosphate film
The classification of phosphate film according to its weight and purpose is shown in Table 1. Table 1
Sublight grade
Subheavy grade
Grade
2 Technical requirements
Film weight $/m2
2.1 The workpiece to be treated shall meet the following requirements: Composition of the membrane
Mainly composed of iron iodate, calcium phosphate or other metal phosphates
Mainly composed of zinc phosphate and (or) phosphates of other metals
Mainly composed of zinc phosphate and (or) phosphates of other metals
Mainly composed of zinc phosphate. Manganese phosphate and (or) other metal phosphates are used as paint for large deformation steel and titanium workpieces. Used as paint base. Can be used as paint base for steel and titanium workpieces that are basically not deformed. Not used as paint base. 2.1.1 Unless otherwise specified, mechanical processing, shaping, welding and drilling of workpieces should be completed before treatment. 2.1.2 The surface quality of the workpiece should meet the requirements of the technical documents. 2.2 Heat treatment of workpieces. Parts with special cutting edges should be stress-relieved before phosphating treatment and hydrogen embrittlement should be eliminated after treatment. 2.3 Pretreatment 2.8.1 Oil, rust and oxide scale on the surface of the workpiece can be cleaned by one or more methods. After degreasing, the workpiece should not have dirt such as grease, emulsion, etc., and its surface should be wetted by water. 2.8.21
2.3.3 After pickling, the workpiece should not have visible oxides, rust and excessive corrosion, and its surface should be uniform in color. 2.3.4 After shot blasting, the workpiece should not have missed spraying, abrasive adhesion, rust and oil stains, and its surface should show the original color of the gold screen. 2.4 Phosphating treatment
2.4.1 The main construction method of phosphating treatment can be carried out by immersion method, spraying method or diffuse spraying combination method. National Bureau of Standards 1986-08-28 Issued
1987-06-01 Implementation
GB 680T-86
2.4.2 For workpieces with slight oil stains or rust, pretreatment and phosphating or degreasing, depreciation, phosphating and passivation can be used.
Phosphating treatment can be carried out in a solution with zinc, manganese, zinc calcium, alkali metal, other metal or ammonia dihydrogen phosphate as the main component.
The preparation, adjustment and management of phosphating solution should be carried out in accordance with the requirements of the above regulations. 2.4.4
2.4.5The tank body material or lining material containing phosphating solution should be resistant to phosphate corrosion. All materials used to make phosphating equipment or materials in contact with tank liquid should not affect the phosphating solution and damage the quality of phosphating film. .2.4.6The phosphating film formed on the surface of the workpiece should meet the technical requirements of 2.6, 2.7, 2.8 and 2.9. 2.5 Post-treatment
2.5.1 In order to improve the corrosion resistance of the phosphating film, it is recommended that the phosphating workpiece after water washing be passivated in chromic acid, chromate or other types of passivation.
.2.5.2 After phosphating or passivating, the workpiece should generally be washed with water. In order to improve the cleaning quality of the workpiece surface, deionized water can be used for the final washing.
2.5.9 After the final washing, the workpiece generally needs to be dried before painting. 2.5.4 In order to prevent the surface of the workpiece from being contaminated or re-rusted, the paint should be applied as soon as possible after drying. 2.5.5 The interval between phosphating and painting generally does not exceed 16 hours. For special processing procedures and special parts, the interval can be appropriately extended. The surface of the workpiece during this period must not be contaminated or re-rusted. 2.6 Appearance of phosphate film
The color of the workpiece after phosphating should be light gray to dark gray or color: the film should be dense, continuous and uniform. 2.6.1
2.6.2 When the workpiece after phosphating has any of the following conditions or one of them, it is an allowable defect: slight water marks, dichromate 2.6.2.19
Color and crystallization are uneven due to the different heat treatment, welding and surface processing conditions. 2.6.2.2
No phosphate film on the pores and slag inclusions of the seam. 2.6.2.32
2.6.3 If the phosphating T-piece has any of the following conditions, it is an unacceptable defect: loose phosphate film;
2.6.3.2 Rust or green spots
2.6.3.3 No phosphate film (except for the pores and slag inclusions of the weld), and the surface is seriously dusty.
2. B.3. Year
2.7 Phosphate film weight
The weight of the phosphate film measured according to Appendix A (supplement) shall conform to the values listed in Table 1. For the conversion relationship between the thickness and weight of the phosphate film, refer to Appendix C (reference).
2.8 Corrosion resistance of phosphate film
When the corrosion resistance of the phosphate film is tested according to the method specified in Article 3.3: 2.8.1 Immersion method: After 1 hour, the base metal should not show rust (except edges, holes, corners and welds) 2.8.2 Drip method: It can be used as a quick test of the quality of the phosphate film between processes. 2.9 Corrosion resistance of paint film
Inspect the paint film according to the method specified in Article 3.4 Corrosion resistance: After 24h salt spray test for zinc salt, manganese salt and zinc calcium salt phosphate coating, and 8h salt spray test for iron salt phosphate coating, except for the scratched part, the coating has no blistering, peeling and rusting.
Note: The scratched part refers to the width of the scratches near the lower side of 0.5m plus. 3 Inspection method
3.1 Appearance inspection
In natural light or mixed lighting conditions, use H-scope inspection, the natural light illuminance is required to be not less than 100lx, and the minimum value of the lighting factor is 2%: the illuminance of mixed lighting is required to be not less than 600[x. 3.2 Phosphate coating weight determination method
GB 6807—86
After the samples are treated and dried in 2.3, 2.4 and 2.5.1, the weight of the film layer shall be determined according to the method specified in Appendix A. 3.8 Inspection of corrosion resistance of phosphate film
3.3.1 Immersion method: Immerse the workpiece or sample (which has been cooled to room temperature) in a 3% aqueous solution of sodium chloride (NaCl) at 15~25℃ for a specified time, take out the workpiece or sample, wash it, blow it dry, and check whether there is rust on the phosphated surface by daylight. 3.3.2 Drip method: For the drip method inspection of the corrosion resistance of phosphate film, see Appendix D (reference). 3.4 Test of corrosion resistance of paint film
3.4.1 After being treated in 2.3, 2.4 and 2.5.1 and dried, the phosphating specimens shall be sprayed with a layer of A04-9 white base baking varnish with a thickness of 25 to 35 μm in accordance with the provisions of Article 3 of GB1765-79 "Paint film preparation method for determining moisture and heat resistance, salt spray resistance and weathering resistance (artificial acceleration)", dried in a room with leakage for 30 minutes, and then placed in a warm air drying oven at a temperature of 102 to 107°C for 2 hours. After drying, seal the edges and holes of the sample with a mixture of 1:1 wax and rosin or a self-painted paint with good performance, and place it at room temperature for 24 hours before testing. 3.4.2 For the prepared sample, use a 1% sewing machine needle to scratch the paint film into a 12cm long cross diagonal line (the scratch is deep to the steel substrate, the diagonal line does not penetrate the diagonal, and the diagonal end points are equidistant from the diagonal). Take the sample with the scratched side facing 1, and then place the sample in a salt spray test chamber that complies with GB1771-79 "Determination of Salt Spray Resistance of Paint Films" 1, and test continuously according to the test conditions specified therein. 3..3 During inspection, take out the sample, rinse the salt deposited on the surface of the sample with tap water, blow cold air quickly (or absorb with a towel or filter paper), and visually pick up the sample surface.
Acceptance rules
4.1 The quality inspection of the workpiece after phosphating includes the appearance, weight of the phosphating film, corrosion resistance of the phosphating film and corrosion resistance of the paint film. 4.2 The appearance inspection and acceptance shall be in accordance with the following provisions;
4.2.1 100% of the workpieces and important parts shall be inspected and accepted one by one. 4.2.2 General workpieces (including small workpieces or small parts) can be sampled and inspected and accepted according to GH2828-81 "Batch Inspection Count Sampling Procedure and Sampling Clothing". The inspection rules are shown in Appendix B (Supplement). 4.3 When determining the weight of the phosphating film, if the average value of the test sample in one row is unqualified, take another piece for re-inspection. If the average value is still unqualified, the batch of products will be unqualified. 4.When the number, size and shape of phosphating parts cannot be inspected for corrosion resistance according to the prescribed method, the sample should be made according to one of the following methods:
Cut a part from the actual part
4.4.2 Use the same material as the T part and the length and width of the sample of 70×150mm to process it at the same time as the L part. .5 When inspecting the corrosion resistance of the phosphating film, three samples should be taken from each batch of workpieces for inspection. If one of the samples is not qualified, double samples should be taken for re-inspection. If there is still one piece that is not qualified, the inspection shall be carried out in accordance with the provisions of Article 1.7 and the results shall be used as the basis. 4.6 The inspection of the weight of the phosphating film and the corrosion resistance of the paint film is a random inspection, which shall be carried out in one of the following situations: 4.6.1 Newly designed products
4.6.2 The curing period inspection stipulated by the enterprise
4.6.3 No equipment, or the bath liquid formula is changed
4.6.4 Other inspections deemed necessary.
1.7 During the corrosion resistance test of the paint film, if one of the samples tested is not qualified, double the sample shall be taken for retest. If one sample still does not meet the requirements, the batch of products shall be deemed unqualified. CB6807-56
Appendix A
Determination of phosphate film weight
(Supplement)
This method is applicable to the determination of the weight of the phosphate film per unit area formed on the surface of steel. A.1 General provisions
A.1.1 Apparatus
． Container: glass or other appropriate material container; b, analytical balance, sensitivity 0,1mg!
c. Heating equipment: used to control the temperature of the film stripping solution. A.1.2 Sample
The total surface area of the sample should be as large as possible. The total surface area of the sample with a film weight of less than 1g/m2 should not be less than 300cm2, and the total surface area of the sample with a film weight of 1-10g/m2 should not be less than 200cm2. A.1.3 Reagents
The stripping solution should be prepared with analytical reagents and distilled water. A.2 Determination method
Weigh the sample accurately to U.1mB with an analytical balance, and then immerse it in the stripping solution specified in the table below. After taking it out, immediately rinse it with tap water, then rinse it with distilled water, quickly dry it and weigh it again. Repeat this operation until a stable weight is obtained. Stripping solution components or categories
Phosphating film type
Zinc phosphate film
Iron phosphate film, manganese phosphate film, zinc phosphate film
Zinc calcium phosphate film, etc.
Material name
Sodium hydroxide
Ethylene-amine tetraacid tetrasodium salt
Triethanolamine
Chromium trioxide
Note: When preparing stripping solution, only use a little water to dissolve the reagent, and then dilute with water to 1L. A.3 Calculation method
The film weight ratio per unit area of phosphate film is calculated as follows: W
Where, W—film weight, g/m2
Pl—weight of the sample after stripping phosphate film, mgsP—weight of the sample after phosphating, mg1
—total surface area of phosphating sample, cm2.
Take the average value of the sample to be measured.
Working rules
GB 680786
Appendix B
Rules for the appearance inspection of phosphating film
(Supplement)
These rules apply to the appearance inspection of general workpieces after phosphating. B.1 The appearance inspection of phosphating film shall comply with the relevant provisions of GB2828-81 "Batch Inspection Counting Sampling Procedure and Sampling Table". B.2 Defect classification, the appearance defects of phosphating film are divided into light defects and heavy defects. The allowable defects in 2.6.2 are light defects, while the non-deceptive defects in 2.6.3 are heavy defects. B. During the appearance inspection, the phosphating film is generally inspected and accepted based on its appearance color and film quality. The pass or fail is determined by the presence or absence of heavy defects, and light defects are generally not judged as pass or fail. B.4 The inspection of the batches shall adopt the sampling plan. The initial inspection shall be a normal inspection. The defect type, qualified quality level and inspection level shall be in accordance with the provisions of the following table.
Defect type
Inspection item
Qualified quality level (AQL)
Inspection level
Major defect
Item 2.6.3.1, 2.6.3.2, 2.6.3.3 and 2.6.3.4 0.25
B.5 Relaxed inspection, strict inspection and suspended inspection shall be in accordance with the provisions of the transfer rules of item 3.2.4.2 in GB 2828-81. GB 6807-86
Appendix C
Conversion relationship between phosphate film thickness and unit area film weight (reference)
The conversion relationship between phosphate film thickness (μm) and unit area film weight (g/m\) is shown in the table. Serial density, μm
Note: 2) The ratio of weight to thickness of sub-light phosphate film is about 1.3, and the ratio of weight to thickness of light phosphate film is about 1~2.3 The ratio of phosphate film weight to original density is generally between 1 and 3. Unit surface film density, g/u2
15 ~ 45
GB 6807-86
Appendix D
(reference)
This method is applicable to the rapid inspection of corrosion resistance of phosphate film between processes in stable production. D.1 Composition and content of test solution
Copper sulfate
Sodium chloride
0.1N hydrochloric acid
Cus.-5H.0
13ml/L
Note: (1) The test solution should be prepared with chemically pure reagents and distilled water. The validity period of the solution at 5-35℃ is one week. D.2 Test method
At 15-25℃, drop the test solution on the phosphating surface: start the stopwatch at the same time and observe the time when the drop changes from sky blue to light yellow or light red.
D.3 Acceptance Standard
The drip method is used as a rapid test of the quality of the phosphate coating between the previous steps, and the color change time is agreed upon by the supply and demand parties. Additional Notes
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China and is under the jurisdiction of the National Technical Committee for Standardization of Paints and Pigments, Metal Surface Treatment Before Painting and Painting Process Standards Sub-Technical Committee. This standard was drafted by the Wuyi Materials Protection Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Lu Xiangeng, Yin Zhi, Zhou Duyin, Tang Lixin, Xu Xiantao, Wu Wenping, Xia Jingquan, Jin Songnian, Han Bing, and Lei Eyun.3 Calculation method
The ratio of the film layer per unit area of the phosphate film is calculated as follows: W
Wherein, W—film weight, g/m2
Pl—weight of the sample after the phosphate film is removed, mgsP,—weight of the sample after phosphating, mg1
—total surface area of the phosphating sample, cm2.
Take the average value of the sample to be measured.
Working conditions
GB 680786
Appendix B
Rules for the appearance inspection of phosphate film
(Supplement)
This rule applies to the appearance inspection of general workpieces after phosphating. B.1 The appearance inspection of phosphate film shall comply with the relevant provisions of GB2828-81 "Batch inspection counting sampling procedures and sampling tables". B.2 Defect classification, the appearance defects of phosphate film are divided into light defects and heavy defects. The allowable defects in 2.6.2 are minor defects, while the non-deceptive defects in 2.6.3 are major defects. B. During the appearance inspection, the phosphate coating is generally inspected based on its appearance color and film quality. The presence or absence of major defects is used to determine whether it is qualified or unqualified. Minor defects are generally not judged as qualified or unqualified. B.4 The batch inspection adopts a sampling plan. The initial inspection is a normal inspection. The defect type, qualified quality level and inspection level are as specified in the following table.
Defect type
Inspection item
Qualified quality level (AQL)
Inspection level
Major defects
Items 2.6.3.1, 2.6.3.2, 2.6.3.3 and 2.6.3.4 0.25
B.5 Relaxed inspection, strict inspection and suspended inspection shall be in accordance with the transfer rules of 3.2.4.2 in GB2828-81. GB 6807 ---86
Appendix C
Conversion relationship between phosphate film thickness and unit area film weight (reference)
The conversion relationship between phosphate film thickness (μm) and unit area film weight (g/m\) is shown in the table. Sequential density, μm
Note: 2) The ratio of weight to thickness of sub-light phosphate film is about 1.3, and the ratio of weight to thickness of light phosphate film is about 1~2.3 The ratio of phosphate film weight to original density is generally between 1 and 3. Unit area film weight, g/u2
15 ~ 45
GB 6807-86
Appendix D
(reference)
This method is applicable to the rapid inspection of the corrosion resistance of phosphate film between processes in stable production. D.1 Composition and content of test solution
Copper sulfate
Sodium chloride
0.1N hydrochloric acid
Cus.-5H.0
13ml/L
Note: (1) The test solution should be prepared with chemically pure reagents and distilled water. The validity period of the solution at 5-35℃ is one week. D.2 Test methodwwW.bzxz.Net
At 15-25℃, drop the test solution on the phosphating surface: start the stopwatch at the same time and observe the time when the drop changes from sky blue to light yellow or light red.
D.3 Acceptance Standard
The drip method is used as a rapid test of the quality of the phosphate coating between the previous steps, and the color change time is agreed upon by the supply and demand parties. Additional Notes
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China and is under the jurisdiction of the National Technical Committee for Standardization of Paints and Pigments, Metal Surface Treatment Before Painting and Painting Process Standards Sub-Technical Committee. This standard was drafted by the Wuyi Materials Protection Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Lu Xiangeng, Yin Zhi, Zhou Duyin, Tang Lixin, Xu Xiantao, Wu Wenping, Xia Jingquan, Jin Songnian, Han Bing, and Lei Eyun.3 Calculation method
The ratio of the film layer per unit area of the phosphate film is calculated as follows: W
Wherein, W—film weight, g/m2
Pl—weight of the sample after the phosphate film is removed, mgsP,—weight of the sample after phosphating, mg1
—total surface area of the phosphating sample, cm2.
Take the average value of the sample to be measured.
Working conditions
GB 680786
Appendix B
Rules for the appearance inspection of phosphate film
(Supplement)
This rule applies to the appearance inspection of general workpieces after phosphating. B.1 The appearance inspection of phosphate film shall comply with the relevant provisions of GB2828-81 "Batch inspection counting sampling procedures and sampling tables". B.2 Defect classification, the appearance defects of phosphate film are divided into light defects and heavy defects. The allowable defects in 2.6.2 are minor defects, while the non-deceptive defects in 2.6.3 are major defects. B. During the appearance inspection, the phosphate coating is generally inspected based on its appearance color and film quality. The presence or absence of major defects is used to determine whether it is qualified or unqualified. Minor defects are generally not judged as qualified or unqualified. B.4 The batch inspection adopts a sampling plan. The initial inspection is a normal inspection. The defect type, qualified quality level and inspection level are as specified in the following table.
Defect type
Inspection item
Qualified quality level (AQL)
Inspection level
Major defects
Items 2.6.3.1, 2.6.3.2, 2.6.3.3 and 2.6.3.4 0.25
B.5 Relaxed inspection, strict inspection and suspended inspection shall be in accordance with the transfer rules of 3.2.4.2 in GB2828-81. GB 6807 ---86
Appendix C
Conversion relationship between phosphate film thickness and unit area film weight (reference)
The conversion relationship between phosphate film thickness (μm) and unit area film weight (g/m\) is shown in the table. Sequential density, μm
Note: 2) The ratio of weight to thickness of sub-light phosphate film is about 1.3, and the ratio of weight to thickness of light phosphate film is about 1~2.3 The ratio of phosphate film weight to original density is generally between 1 and 3. Unit area film weight, g/u2
15 ~ 45
GB 6807-86
Appendix D
(reference)
This method is applicable to the rapid inspection of the corrosion resistance of phosphate film between processes in stable production. D.1 Composition and content of test solution
Copper sulfate
Sodium chloride
0.1N hydrochloric acid
Cus.-5H.0
13ml/L
Note: (1) The test solution should be prepared with chemically pure reagents and distilled water. The validity period of the solution at 5-35℃ is one week. D.2 Test method
At 15-25℃, drop the test solution on the phosphating surface: start the stopwatch at the same time and observe the time when the drop changes from sky blue to light yellow or light red.
D.3 Acceptance Standard
The drip method is used as a rapid test of the quality of the phosphate coating between the previous steps, and the color change time is agreed upon by the supply and demand parties. Additional Notes
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China and is under the jurisdiction of the National Technical Committee for Standardization of Paints and Pigments, Metal Surface Treatment Before Painting and Painting Process Standards Sub-Technical Committee. This standard was drafted by the Wuyi Materials Protection Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Lu Xiangeng, Yin Zhi, Zhou Duyin, Tang Lixin, Xu Xiantao, Wu Wenping, Xia Jingquan, Jin Songnian, Han Bing, and Lei Eyun.
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