Phosphating treatment of steel parts before painti
Date：2012/2/11
Source：原创
Hits：3087
This standard applies to the phosphating iron and steel parts before painting. Address the formation of phosphate film used as a paint the bottom, in order to enhance the adhesion of the film and steel substrate and protection, and improve the paint quality of the steel workpiece.
A. Phosphate film classification
Phosphate coating according to their weight and purpose of the classification see Table 6-1.
Schedule 6-1
Classification
Membrane weight (g/m2)
The group of the membrane into
Use
Flyweight
0.2 ~ 1.0
Mainly composed of iron phosphate, calcium phosphate or other metal phosphates.
Used for large deformation of the steel workpiece paint the bottom.
Lightweight
1.1 ~ 4.5
Mainly composed of zinc phosphate and (or) metal phosphate.
Used as a paint the bottom
Cruiserweight
4.6 ~ 7.5
Mainly composed of iron phosphate and (or) other metal phosphate.
Can be used as a basic paint the bottom of deformation of the steel workpiece
Heavyweight
> 7.5
Mainly composed of iron phosphate, manganese phosphate, and (or) other metal phosphates.
No paint the bottom
2 Technical Requirements
2.1 workpiece to be processed should meet the following requirements
2.1 1 No special provisions, the workpiece machining, forming, welding and drilling should be completed before processing.
2.1 2 surface quality should be consistent with the provisions of the technical documentation.
2.2 workpiece heat treatment
Special-purpose parts, before the phosphating treatment to eliminate stress and post-processing to eliminate hydrogen embrittlement.
2.3 Pre-treatment
2.3 workpiece surface greasy dirt, rust and oxide scale can be used one or several methods to clean up.
2.3 2 skim the workpiece, there should be no grease, emulsion, such as dirt, the surface should be completely wetting water.
2 3 3 after pickling, the workpiece should not be a visual oxides, rust, and had corrosion, the surface color should be uniform.
2.3 4 spray the workpiece after shot blasting should not be tainted spray, abrasive adhesion, corrosion and oil, the surface should be exposed to the metal color.
2.4 phosphate treatment
2.4 1 phosphating construction methods can be used dipping method, spray method or the dip spray combination.
4.2 for mild oil or corrosion of the workpiece can be used pre-treatment and phosphating or degreasing, rust removal, phosphating and passivation one step carried out.
4.3 phosphating solution of zinc, manganese, zinc, calcium, alkali metal, other metal or ammonium dihydrogen phosphate as the main ingredient.
2 4.4 phosphating bath preparation, adjustment and management should process prescribed requirements.
4.5 costumes phosphating solution tank material or lined with materials resistant to phosphate corrosion, materials production phosphating equipment, materials or contact the bath should not affect the phosphating solution, and damage the quality of phosphating film.
2 4. 6 workpiece surface generated the phosphate coating shall comply with 2.6, 2. 7,2 8,2 9 technical requirements.
2.5 post-processing
Energy, 2.5 1 In order to improve the corrosion resistance of phosphating film after washing, phosphating workpiece recommendations in the passivation solution of chromic acid, dichromate or other types of passivation.
5.2 phosphide or passivation of the workpiece, under normal circumstances should be washed in order to improve the quality of cleaning of the surface can be deionized water for final rinse.
The workpiece after the 5.3 final washing, the general need to dry before painting.
2 5.4 In order to prevent the workpiece surface is contaminated or rust again, as soon as possible after drying paint.
Interval of 2.5. 5 phosphating and painting is generally not more than 16H, the special processing procedures and special parts may be appropriate to extend the interval of time, but this period of the surface shall not be contaminated or corroded.
2.6 phosphate film appearance
2.6 phosphating after the color of the workpiece should be light gray to dark gray or color film should be dense crystalline, continuous and uniform.
The workpiece 2. 6.2 phosphide has one of the following circumstances or were allowed defects.
2.6 2 1 minor water stains, traces of Dichromate, rub white and hung gray phenomenon.
2.6 2.2 due to the different local heat treatment, welding and surface processing state and result in uneven color and crystallization.
2.6 2.3 in the weld pores and slag at the phosphate film.
The workpiece 2. 6.3 phosphide is one of the following conditions are not allowed to defect.
2.6 3.1 loose phosphide film.
2.6 3 2 rust or green spots.
2.6 3.3 local phosphate film (except the pores of the weld and slag at).
2.6 3 4 surface serious hanging gray.
2.7 phosphate film weight
The determination of the phosphate coating weight, in accordance with Appendix A (Supplement) shall comply with Table 6-1. The value of the conversion of the phosphate film thickness and weight relations refer to Appendix C (reference) listed.
2.8 Phosphating and Corrosion Resistance
3.3 provides methods of testing the corrosion resistance of the phosphate film:
2.8 1 impregnation method: by 1H, base metal should not emerged rust (edge, hole, angle and weld).
2.8 2 drip France: as processes between the phosphate film quality inspection.
Film corrosion resistance of 2.9
3.4 provides methods of test film corrosion performance: zinc salts, manganese salts, zinc and calcium salts, phosphate film painted sample after 24H resistance to salt spray test, iron phosphate film painted sample 8H after the closing of the resistance to salt spray test, in addition to the scratch site of the film should be no blistering, off and rust.
Note: scratches site means scratches any one near the measured width of 05mm.
(3) test methods
3.1 Appearance inspection
Natural light or mixed lighting conditions, visual inspection of natural illumination requirements not less than 100lx, the minimum value of daylight factor of 2%, with mixed lighting illumination of not less than 500lx.
3.2 phosphate film gravimetric method
2 3,2 4 and 2.5 (1) processing and drying of the sample, according to the method specified in appendix A to the determination of coating weight.
3.3 phosphate film corrosion performance test
3.3 1 impregnation method: the workpiece or sample (down to room temperature) immersed in 3% aqueous solution of sodium chloride (NaCl), 15-25 ℃, to maintain a specified time, remove the workpiece or sample , at any time of the wash, dry, phosphide surface of the visual inspection whether there is rust.
3.3 drop method: topical application test of the corrosion resistance of the phosphate film, see Appendix D (reference)
3.4 film corrosion performance test.
3.4 by 2 3 2 4 2.5 4.1 phosphide sample processing and drying, according to GB1765-79 "Determination of resistance to heat, salt spray resistance, weather resistance (accelerated into the work ) of the film preparation method in a three provisions of the plate method of spraying a layer of thickness 25-35μm of the A04 White amino-9 Hongqi, dried at room temperature 30min, and then into a heated blast oven to temperature 102 -107 ℃ bake 2h, dried specimens, with a mixture of paraffin and rosin 1:1 or performance better self-dry paint edge banding, sealing, placed in the outdoor temperature for 24h, pending trial.
3 4.2 Preparation of the sample, using the sewing machine needle on the 18th will be the film program to grow the cross-diagonal 2cm (scratches to the steel substrate, diagonal throughout diagonal, diagonal endpoint and diagonal into a wait until the distance), sample taken three scratches face down, and then the specimen shall be placed in the salt spray chamber in line with GB of 1771-79 << resistance to salt spray Determination >>, in accordance with the provisions of The experimental conditions for test.
3.4 3 checks, remove the sample, the deposition of salt in the water rinse on the surface of the sample, the cold fast drying (or towel, filter paper, sucking up), visual inspection of the surface of the sample.
4 acceptance rules
4 1 the quality inspection of parts after phosphating including appearance, the weight of the phosphate film, the phosphate film corrosion performance and film corrosion resistance test.
4.2 Appearance inspection and acceptance in accordance with the following provisions:
4.2 for large workpieces and important work piece should be 100 percent inspection and acceptance of one by one.
4.2 2 general workpiece (including small parts or small parts) according to GB 2828-81 batch check the degree of sampling procedures and sampling tables sampling inspection and acceptance, inspection rules, see Appendix B (Supplement).
4.3 Determination of the weight of the phosphate film, the subjects of the three parallel sample average failure, and then take three reinspection, if the average is still unqualified, then the product to be ineligible.
4.4 Phosphating workpiece due to the number, size and shape can not be according to the method specified in corrosion resistance test should be one of the following methods of production samples.
4.4 from the actual workpiece cut a part of.
4.4 2 with the same material and workpiece length and width of 70mm × 150mm sample workpiece processing.
4.5 phosphate film corrosion test from each batch of workpieces extract three samples tested, which have a failure and then take double samples reinspection. If there is still a failure, then the provisions of 4.7 test and its results shall prevail.
Phosphating film weight and film the corrosion resistance test for the testing, should be one of the following conditions:
4.6 1 new design products into production;
4.6 2 business cycle test;
4.6 3 equipment, process or bath formula change;
4.6 4 that the inspection when necessary.
4.7 film corrosion performance test methods
Three samples of subjects, including one sample failed, and then take double the sample reinspection, if there are still a specimen failed, the batch to be ineligible.
Appendix A phosphate film gravimetric method (Supplementary)
This method is suitable for the determination of the weight of the phosphate film per unit area of steel surface generated.
A1 in general requires
A1 1 instrument
a container: a container of glass or other suitable material.
(b) Analysis of Balance: 0.1mg.
(c) heating equipment: used to control the temperature of the retirement membrane liquid.
A1 2 sample
Sample of the total surface area should be as large as possible. The film weight is less than 1 g/m2 of the total surface area of the specimen should not be less than 300cm2, the film re-1-10g/m2 the total surface area of the specimen should not be less than 200cm2.
A1.3 reagents
Stripping solution should be prepared by analytical reagents and distilled water.
A2 determination method
Accurate 0.1mg analytical balance weighing the sample, and then immersed in the membrane solution in the following table provides the refund immediately, remove and rinse with tap water, then rinse with distilled water, rapidly dried and then weighed. Repeat this procedure until a stable weight so far.
Phosphate film type
Back membrane liquid composition
Working conditions
Material Name
Content / (g / L),
Temperature / ° C
Time / min
Zinc phosphate film
Sodium hydroxide
Ethylenediamine acetic acid four sodium
Triethanolamine
100
90
4
65 to 75
15
Iron phosphate film, manganese phosphate film, the zinc phosphate film of zinc phosphate calcium film
Chromium trioxide
50
70 to 80
15
Note: The preparation of the retreat membrane liquid, with a little water and reagents dissolved, and then diluted with water to 1L.
A3 calculation method
Coating weight of phosphate film per unit area W calculated as follows:
W = × 10
Where W - the film weight, g/m2.
P1 - refund the weight of the sample in addition to the phosphate film, mg.;
P2 - phosphide sample weight, mg.;
S - total surface area of the phosphate specimen, cm2.
Take the average of three parallel test sample.
Appendix B of phosphating film appearance inspection rules (Supplement)
This rule applies to the workpiece phosphide appearance inspection.
B1 phosphate film appearance test should be consistent with the GB 282-81 "batch inspection to count the relevant provisions of the sampling procedures and sample forms".
B2 defect classification: the appearance of defects of the phosphate film is divided into light defects and re-defect. 2.6 2 allows the defect belong Light defect. Defects in the 2.6 3 styles are heavy defects. .
B3 appearance inspection, is generally based on the appearance of the color of the phosphate film and the film quality for acceptance, with or without re-defect to determine the pass or fail, light defects generally not used to determine pass or fail.
The B4 batch inspection using a sampling plan, the initial inspection to normal inspection, the type of defect, the provisions of acceptable quality level and check the level of take over the table.
Type of defect
Heavy defects
Inspection items
6. 3. 1,2 6 3 2,2 6 3 3 and 2 6. 3.4
Acceptable quality level (AQL)
0.25
Check the level
Ⅱ
B5 to relax check of scrutiny and suspension of the check according to 3.2. 4.2 GB 2828-81 in the transfer rules.
Appendix C phosphate film thickness and unit area of film weight conversion relationship (reference)
Phosphate film thickness (μm) per unit area of coating weight (g/m2) conversion relationship in the table below.
Thickness / μm
Unit area of film weight / (g/m2)
Thickness / μm
Unit area of film weight / (g/m2)
A
3
5
1 to 2
3 to 6
5 to 15
10
15
10 to 30
15 to 45
Note: (1) the flyweight phosphide weight and thickness ratio of about 1.
2 lightweight weight of the phosphate film thickness ratio of about 1 to 2.
Phosphate film weight and thickness than the average between 1 to 3.
Appendix D drip method (reference case)
This method is suitable for the stability of production, the rapid inspection of the corrosion resistance of the phosphate film in the process.
D1 `test the composition and content of the solution
Copper sulphate CuSO4.5H2O 41g / L
NaCl of NaCl 35g / L
0.1N hydrochloric acid of HCl 13ml / L
Note: ① The test solution should be used to chemically pure reagents and distilled water.
② solution in 5-35 ℃ valid for one week.
D2 test methods
15-23 ℃, the phosphide surface of a drop test dissolved, and at the same time start the stopwatch to observe the drops from sky blue to pale yellow or reddish.
D3 acceptance criteria
The drop method used for the rapid inspection of the quality of the phosphate film in the process, the discoloration time agreed upon by both supply and demand.
Additional notes:
This standard proposed by the People's Republic of China Ministry of Machinery Industry, the sub-technical committee under the jurisdiction of the coatings and pigments Standardization Technical Committee before painting metal surface treatment and painting process standards.
Responsible for drafting the standard by the Ministry of Machinery Industry, Wuhan Institute of Material Protection.
Of the main drafters of this standard Luxian Geng, Yan Xiongzhi weeks mo silver, Tang Lixin, Xu Bristol, Wu Wenping, summer right, Cai Song, Han Bing, Lei Chengjun.
Appendix 6-2 GB / T 12612-90 multi-functional steel processing liquid-General technical requirements
A subject and use
This standard specifies the phosphoric acid and phosphate as the main ingredient to add other additives consisting of multi-purpose steel surface treatment liquid (hereinafter referred to as the treatment solution) classification, technical requirements, test methods and inspection rules.
This standard applies to manufactured products of the steel workpiece generally coating the front surface of the integrated treatment of the working fluid; also applies to the same characteristics as the solid and liquid components of the factory packaging or condensed state, the application of matched products made from the working fluid.
2 reference standards
GB 601 Chemical Reagent Preparation of standard solution method
GB 1720 film adhesion Determination
GB 1771 film Determination of resistance to salt spray
6 463 GB of metals and other inorganic coatings thickness measurement methods of Review
GB 6807 steel parts before painting, phosphating treatment
3 Terms
3.1 multi-purpose degreasing, rust, phosphating, passivation of the four functions or rust phosphating more than two functions.
3.2 The working fluid
Actually use liquid.
4 Classification and marking symbols
4.1 The treatment solution according to the functions are divided into:
, Rust, phosphating, passivation four functions deal with the fluid, marks, 4;
Rust, phosphating, degreasing (or passivation) three function processing liquid marks, 3;
Rust phosphating two functions deal with liquid, marks 2.
4.2 treatment solution according to the rust ability is divided into:
In addition to heavy rust and general oxide treatment fluid, marks A1;
Addition to the rust, and light rust in rust treatment fluid, marking symbols A2,.
4.3 treatment solution according to the use of temperature is divided into:
At room temperature (15 ~ 45 ° C), marks, B1;
In temperature (45 ~ 65 ° C), marks, B2,.
4.4 treatment solution according to the factory state is divided into:
The working fluid, marks, L;
Concentrate, marks Mx, x is the concentration factor
Solid and liquid components, respectively, packaging, marks, N.
4.5 labeling of products
4.5.1 The labeling of products by product name, product category tag symbols and standards composition, as follows:
4.5.2 Product Name (including custom models) by the production plant.
4.5.3 markup example:
Four functions, in addition to heavy rust and oxidation of the skin, at room temperature, liquid processing factory by the state of the working fluid, labeled:
Steel processing liquid 4AlBIL GB / T 2621
5 Technical requirements
5.1 Appearance and sensory requirements
Working fluid appearance was uniform liquid, no obvious precipitate Ru Xu bar; no strong irritating odor.
5.2 Physical and chemical properties
The main technical indicators of physical and chemical properties of the liquid as follows: pH, total acidity (points), free acidity (points) and density. Various types of treatment solution should be clear that the major technical indicators, the factory should be consistent with the requirements of the indicators.
5.3 the use of performance
Rust ability classification (A1, A2), two types of products the 5.3.1 rust capable of the provisions of 4.2, visual specimen after treatment should be free of rust, or by the supply and demand sides agreed that the original corrosion condition evaluation refer to Appendix C (reference case).
5.3.2 degreasing ability of the treated specimen, visual water film should be continuous.
5.3.3 phosphating film apparent mass
5.3.3.1 after the specimen surface should form a uniform gray, black or rainbow colors phosphate film.
5.3.3.2 specimens treated with one of the following circumstances or, are allowable defects:
(A) minor water stains
(B) to remove the rust at the inconsistency with the overall color.
5.3.3.3 handling of the specimen surface when one of the following conditions, does not allow defects:
(A) The residual oil film on the surface;
(B) corrosion is not divisible, or re-emergence of water rust;
(C) The surface of the hanging gray.
5.3.4 phosphide film unit phosphating film unit mass of the specimen in the quality of treatment should be consistent with the provisions of the GB 6 807 in Table 1 shows the lightweight or lightweight. The membrane per unit mass of the flyweight 0.2 ~ 1.0g/m2, lightweight membrane per unit mass of 1.1 ~ 4.5g/m2
5.3.5 phosphide and Corrosion Resistance
5.3.5.1 rust of treated dry specimens stored in a relative humidity less than 70%, non-corrosive gases at room temperature, the rust of not less than 5d.
5.3.5.2 immersion test according to 6.3.6.1 the provisions of the methods of inspection, 1h corroded steel surfaces should not appear (edge, edge excluded).
5.3.5.3 The spot test can be used as the process between the phosphate film quality inspection discoloration time agreed upon by both supply and demand.
5.3.6 film supporting performance
5.3.6.1 film corrosion resistance of the test method specified in 6.3.7, after 8h resistant to salt spray test, in addition to the scratches part of any side of the 0.5mm, the film should be no blistering, loss, rust and other phenomena .
5.3.6.2 film adhesion test according to GB1720 provisions method, the adhesion should not be less than 2.
5.4 storage performance
Product at ambient temperature -30 to +40 ° C Packaging good storage conditions, valid for one year over the storage period from the date of production, according to the requirements of this standard case-by-case basis test, qualified product can still be used.
6 test methods
6.1 deal with the liquid appearance of the check in natural light or mixed lighting, visual inspection with or without precipitation or floc.
Determination of 6.2 treatment fluid physical and chemical properties
6.2.l pH value of pH of test strips or pH meter determination.
6.2.2 free acidity and total acidity determination in accordance with Appendix A (Supplement).
6.2.3 The density of 20 ± 1 ° C, measured hydrometer.
6.3 treatment solution to use performance measurement methods
6.3.1 Specimen preparation
6.3.1.1 corrosion specimens used 50mm × 120mm × 1mm different corrosion status of cold-rolled steel specimen, the specimen corrosion assessment of the situation, see Appendix C.
6.3.1.2 degreasing rust specimens selected 6.3.1.1 the provisions of the corroded specimens, dipping 30 # oil (at room temperature oil hanging about 1.2mg/cm2).
6.3.1.3 painted specimen
The choice of 70mm × 150mm × 1mm cold rolled steel specimens 6.3.2 The method of handling dry, spray a layer of thickness is 25 ~ 35μm A04-9 white amino baking, dried at room temperature 30min; blast drying box (102 ~ 107 ° C) thermostat 2h at room temperature for one day and night, under test.
6.3.2 The specimen processing method
6.3.2.1 three, four functions deal with the liquid processing method will be 6.3.1.2 Preparation of oiled corrosion specimens into a 1000mL beaker filled with the working fluid temperature requirements according to different treatment, dip 10 ~ 20min, which put washing 3 ~ 6min, after removing the natural drying.
6.3.2.2 two, three function processing liquid processing method according to the requirements 6.3.ll prepared specimen processing steps and the same method as the 6.3.2.1 provisions.
6.3.3 degreasing ability of testing methods
6.3.2.1 handling of the specimen, immediately wash with water and in natural light or mixed lighting conditions, visual inspection of the water film continuity.
6.3.4 rust ability test methods treated specimens, visual check for any signs of residual rust.
6.3.5 phosphating film unit mass 6.3.2 The method of processing the specimen, determined in accordance with Appendix B (Supplement) per unit mass of the phosphate film.
6.3.6 phosphating film corrosion test methods
6.3.6.1 dipping test
Treated specimen immersed in 3% sodium chloride solution (20 ± 2 ° C), removed after 1h, washed and dry. Mouth visual inspection whether the specimen surface rust.
6.3.6.2 The spot test according to GB6807 Appendix D.
6.3.7 The film corrosion performance test
According to 6.3.1.3 Preparation of paint specimens using a sewing machine needle on the 18th, the film program grow 120mm cross-diagonal, scratch deep into the specimen matrix. Sampled three scratches face up, placed in salt spray chamber test conditions prescribed by GB1771. Rinse with tap water to check the sample deposited on the surface salinity, cold quick-drying after visual inspection of the specimen surface.
7 Inspection rules
7.1 factory inspection
7.1.1 of manufactured products were identified by inspection by the quality inspection department to ensure the technical requirements, together with product quality certification.
7.1.2 factory inspection items include: 5.3.3,5.3.5,5.3.6 of the appearance of physical and chemical properties and performance requirements.
7.1.3 increased by supply and demand agreement between the test items should be included in the factory test content.
7.2 Type test
7.2.1 should be the standard and the technical requirements of product standards to conduct a comprehensive examination.
7.2.2, one of the following situations, the general type of inspection should be carried out:
(a) new product testing and identification stereotypes;
(b) process and formula have major changes may affect product performance;
c. national and provincial and municipal quality supervision agency requirements for the type of inspection.
7.3 The sampling method
Extract sample container from each batch of production of 5%, respectively, the total sample volume of 500mL. Clean fine jar, to be seized. If the test failed, they should redouble their sampling; test and then failed, not the factory.
8 signs, packaging, transportation, storage
8.1 mark
Manufactured products must be labeled with manufacturer name, product tags, product model and date of manufacture or production lot.
8.2 Packaging
The treatment solution should be plastic or other acid-resistant containers and packaging.
8.3 storage and transportation
This product is non-food items, general merchandise and alkali substances during storage or shipment.
Appendix A free acidity, total acidity method (Supplement)
This Law, using the acid-base titration. Ml sample taken 10mL, 0.1 mol / L sodium hydroxide standard solution titration, consumption represented by points.
A1 reagents
Sodium hydroxide: 0.1 mol / L standard solution preparation and calibration (according to GB 601);
Phenolphthalein indicator; 1% ethanol solution;
Methyl orange indicator: 1g soluble 1000mL20% ethanol.
A2 test methods
The A2.1 free acidity of
Pipette 10mL test solution in a 250mL conical flask, add 50mL of distilled water, add 2 to 3 drops of methyl orange indicator solution (bromophenol blue indicator solution). In droplets with standard sodium hydroxide solution was orange (or instructions bromophenol blue droplet set to change from yellow to blue-violet) is the end point, note the consumption of sodium hydroxide standard solution (ml) A.
A2.2 total acidity measurement pipette 10mL test solution in a 250mL conical flask, add 50mL of distilled water, add 2 to 3 drops of phenolphthalein indicator solution. Droplets with standard sodium hydroxide is given to the solution was pink, is the end point. Write down the consumption of sodium hydroxide standard solution (ml) B.
A3 calculation method
The acidity Points by the following formula:
Free acidity (point) = (A1)
The total acidity (point) = (A2)
Where A, B-titration consumes standard sodium hydroxide solution (ml) mL;
the actual concentration of the c-standard sodium hydroxide solution, mol / L;
V-sampling ml, ml.
Appendix B of phosphating film unit mass spectrometry (Supplement)
This law applies to determination of the quality of the film on the steel surface of the phosphate coating per unit area.
B1 instrument
Analytical balance; sense of the amount was 0.1 mg;
Heating equipment: used to control the temperature of the liquid Stripping.
B2 sample
Membrane per unit mass of less than 1 g/m2 of the total surface area of the specimen should not be less than 400cm2; membrane unit mass in the 1 ~ 10g/m2 sample total surface area of not less than 200cm2.
B3 retreat membrane liquid
Take 50g of chromium trioxide (of CrO3 Additive), distilled water 1000mL solution.
B4 test methods
Processed dry specimens with a sensitivity of 0.1mg of the analytical balance weighing (m1). Then immersed in the test piece Stripping liquid temperature was maintained at 75 ± 5 ° C, 15 min soak, rinse immediately with water, then distilled water wash. Dry and weighed until constant (m2).
B5 calculation
Phosphate film per unit area of film quality by the following formula:
mA = × 10 (B1)
: MA-phosphate film unit mass g/m2;
sample mass m1-phosphide, g/m2;
m2-retirement membrane sample quality, g/m2;
A-sample total surface area, cm2.
Take the average of three parallel test sample.
Appendix C steel surface corrosion condition evaluation (reference)
This method is suitable for the assessment of the general workpiece corroded state.
Determination of the corrosion depth of C1
Determination according to GB 6463 1.2.3 profilometer method.
Determination of C2 the extent of corrosion
4mm × 4mm square lattice of 100 using corrosion assessment board determined that the assessment board made of 50mm × 50mm × 2mm colorless transparent plate, the middle box of 40mm × 40mm box engraved. Determination, corrosion assessment board and the measured specimen overlap, visually check the 100 box rust box number, expressed as a percentage, is the extent of corrosion.
C3 corrosion state assessment
Corrosion depth assessment, supplemented by the extent of corrosion and surface state, comprehensive assessment. As shown in Table C1 as shown.
Table C1
Status of the project corrosion
Rust, light rust
In rust
Heavy rust
Corrosion depth / μm
<30
≥ 30 ~ 80
> 80
The extent of corrosion /%
1 to 10
11 to 50
51 to 100
Surface state
Yellow or reddish
Surface rough, brown or pale ocher color
Dark brown, flaky rust layer bulge
Additional notes:
This standard is proposed by the People's Republic of China Aerospace Industry.
This standard covered by the National Metal and nonmetal layer Standardization Technical Committee.
This standard by the Aerospace Industry of Hospitals 31 is responsible for drafting.
The main drafters Hu Meihua, Jaipur, Zhang Hua.