Some standard content:
National Standard of the People's Republic of China
Metal coating
Cd-Ti plating of low hydrogen embrittlement
Metal coating
Cd-Ti plating of low hydrogen embrittlement 1 Subject content and applicable range
CB/T 13322 9T
This standard specifies the quality inspection requirements, inspection methods and pre-plating inspection requirements for low hydrogen embrittlement Cd-Ti plating of high-strength steel parts. This standard applies to the pre-plating and post-plating quality inspection of low hydrogen embrittlement Cd-Ti plating of high-strength steel parts. 2 Reference standards
(1238 Metal coating and coating treatment method GB3138 Common terms for electric chain
CB 4677-63
Metal oxide coating thickness test method Cross-section metallographic method GB 1953
GB 1956
GH5270
GB 6158
(136463
GB 8791
GB12609
GJH 594
3.1 High-strength steel
Metallic coating thickness measurement method Anode braid solution method Combustible metal and machine-mounted tunnel coating thickness measurement method Magnetic coating thickness test method Metal coating (electrodeposited layer and chemical deposition layer) on metal substrate Adhesion strength test method Metal coating layer Small salt spray test (NSS test) Metal and other inorganic coating thickness measurement method Review Zinc and galvanate conversion film test method
Electrodeposited metal coating and related finishing counting sampling inspection procedure Metal coating [Chemical coating selection principle and thickness series This standard defines steel that is heat treated to a tensile strength of less than or equal to 1240MPa (127kgf/mn*) as high-strength steel. 3. 2 Main surface
refers to the specified surface on the parts before and after plating. The coating on this surface plays a major role in the appearance and performance of the parts.
3.3 Minimum local thickness
refers to the lowest value of the local thickness measured on the main surface. 4 Information
4.1 Necessary information
The supplier shall provide the following information:
a. Number of this standard (/13322);
b. Required coating mark (see Chapter 5); Approved by the State Administration of Technical Supervision on December 13, 1991 and implemented on October 1, 1992
GB/T 13322—97
The main surfaces shall be indicated on the part drawing and (or samples shall be provided): c.
Surface appearance (see 7.1):
Adopted bonding strength test method (see 10.2 tea); adopted hydrogen embrittlement test method (see 10.3) f.
Adopted sampling method (see Chapter 9).
4.2 Supplementary information
If necessary, the purchaser may provide the following supplementary information: a. The nature of the base metal, surface state and roughness (see 6.1); h. Requirements for stress relief before electroplating and hydrogen removal at the bottom of electroplating Requirement: Special requirements for the coating, including thickness: c
d. Requirements for corrosion resistance and the test methods used (see 7.4). 5. Coating marking
Coating marking shall be in accordance with the regulations in GB1238.
6. Acceptance requirements for parts before plating
6.1 Base metal: The standard specifies the surface state of the base metal before plating. The specific requirements for the base metal shall be agreed upon by the supply and demand parties.
6.2 All machining processes such as welding and welding shall be completed before plating. 6.3 Inspection of raw materials, heat treatment, machining, magnetic flaw detection and other procedures. 6.4 Inspection stamps for stress relief before plating are required. In order to reduce the risk of oxygen embrittlement damage, high-strength steel parts that are electroplated should be heat treated before electroplating to eliminate residual stress on the surface of the parts. The temperature and time of heat treatment of parts should be selected to ensure the maximum stress elimination without reducing the strength and hardness of parts (generally the temperature is at least 30°C lower than the minimum tempering temperature of the material and the time is 1h or more).
7 Quality inspection requirements for coatings
7.1 Appearance
The coating should be clean and complete, and the crystals should be uniform and fine. The color of the coating without chromate treatment should be milky white, grayish white or gray: the color of the titanium coating treated with chromate is rainbow or golden yellow. There should be no obvious coating defects on the main surface of the electroplated parts, such as blistering, peeling, pitting, burning, searing or partial absence of coating: however, the unavoidable coating defects caused by defects in the substrate of the plated parts are excluded. The parts cannot be free of fixture contact marks, and their location and area should be agreed upon by the supply and demand parties. When necessary, the purchaser should provide samples that can illustrate the appearance requirements. 7.2 Thickness
The minimum local thickness requirement for the coating thickness shall be marked by the purchaser in the drawings in accordance with the method specified in GB1238. For parts without thickness requirements in the drawings, the thickness shall refer to the thickness requirements for saw coatings in GB 594. 7.3 Bonding strength
When the bonding strength is tested on the plated parts in accordance with Article 10.2, it shall meet the requirements of GB5270 for plated parts. The coating shall be firmly attached to the base metal without blistering or puncturing.
7.4 Corrosion resistance
If the purchaser requires that the plated parts must undergo corrosion tests, the cadmium-titanium plated parts shall be tested in accordance with the neutral salt spray method in GB6158. The corrosion resistance of cadmium titanium coating with chromate conversion film is that no red rust corrosion products appear after 500h. The type of chromate conversion film on the radial chain layer is the same as that on the radial bond layer. There are detailed regulations and instructions in GB 9791. 7.5 Titanium content of the coating
GB/T 13322--91
Analyze the titanium content of the coating according to the method in Appendix A (Supplement). The content of titanium in the coating should be between 0.1% and -0.7%.
8 Requirements for hydrogen embrittlement performance of coated materials
8.1 Notch specimen endurance test
Qualification test and process control test The specimen is subjected to an endurance load test under a stress of 75% notch ultimate tensile strength and is not broken for at least 200°.
8.2 Oxygen measurement test
These control tests can be carried out using a hydrogen meter. The Ap value of the low oxygen brittle cadmium titanium plating solution should be within 80% [Appendix C (reference material)].
9 Sampling
The sampling method and acceptance level shall be in accordance with the provisions of (12609). 10 Test method
10.1 GB 46°, GB 49s5, GR4956 can be used Determine the thickness of the pin coating on high-strength steel by the method specified in the 663 standard. In addition, the thickness of the pot coating of the 663 standard is measured directly. If there is a dispute, the measurement is carried out by the method specified in 45, but the parts with a major attenuation of 10) mm\ are not included. 10.2 Joint frequency test
According to the palm rubbing and polishing test specified in 5270, or the test method for the strength of the pin coating is carried out. 10.3 Hydrogen embrittlement test
10.3.1 Oxygen embrittlement qualification test
10.3.1. 1 Prepare the notched tensile test specimens of high-strength steel according to the test specimen technical requirements and the following methods in Appendix B (Supplement). 10.3.1.2 The notched test specimens are individually bonded to the titanium alloy. During bonding, the test specimens shall be symmetrically mounted on the hanger. 1 The non-electroplated surface of the test specimen shall be properly edged. Electroplating shall be performed to a thickness of 12 μm at a current density of 2 to 3 A/dm. Within 4 hours after plating, the specimens shall be subjected to 12-hour testing at 190°C.
10.3.1.3 The samples are subjected to a sustained load test at a stress of 75% of the ultimate tensile strength of the notch, and the test lasts for at least 200 hours. If any of the samples breaks within 20 hours, it is considered that the brittleness of the electroplating solution is unqualified, so it is necessary to analyze and find the cause of the breakage. After the cause is found and corrected, the hydrogen brittleness test must be repeated. Only after it is qualified can formal production be carried out. 10.3.1.4 The brittleness qualification test must be carried out after the electroplating solution is prepared and adjusted. 10.3.2 Process Control Hydrogen Fracture Test
The process control oxygen brittleness test shall be based on the brittleness test of the notch sample in 1.1. During the process control, it can also be inspected with a hydrogen meter. 10.3.2.1 Notch Sample Endurance Test
Prepare three notch tensile specimens according to the sample technical requirements and processing methods in Table B for 1 hour. The three specimens are electrically bonded to the plated parts. When installing, pay attention to arrange the placement of the sample and parts in the plating tank reasonably, and try to make the sample and the part be electroplated under the same conditions. The sample and the part are removed from the work, c. The sample should be: under the stress of 75% of the ultimate tensile strength of the notch, for at least 200 hours. Any root in the sample shall break within 200 hours.If the process fails to meet the hydrogen embrittlement test, the production shall be stopped immediately. The parts produced during this period shall be returned for analysis and proper handling. After the electroplating liquid hydrogen embrittlement test is qualified, the production can be resumed. 10.3.2.2 Hydrogen tester test a: The hydrogen test shall be carried out by a full-time personnel with a qualification certificate or approved by the quality control department in accordance with the test method and instrument operation instructions specified in Appendix (5, GB/T13322--91 b. The hydrogen test shall be carried out at least twice a week. 10.3.2.3 At a maximum time interval of 30 days, the notched specimen endurance test shall be carried out in accordance with 10.3.2.1. If this test is not carried out within 30 days, the hydrogen embrittlement qualification test A1 in 10.3.1 must be carried out. Key points of the method GE/T 13322
Appendix A
Analysis method of titanium in titanium coating
(Supplement)
In 1.53.5N sulfuric acid solution, tetravalent titanium and rat peroxide form a stable yellow complex, which is determined by colorimetry. Titanium mother reagent
Ammonium nitrate (chemically pure) 10% aqueous solution;
Sulfuric acid (chemically pure) 1 volume ratio) aqueous solution: Sulfuric acid (chemically pure): specific gravity 1.84:
Nitric acid (chemically pure): specific gravity 1.42;
Phosphoric acid (chemically pure): specific gravity 1.70;
Acetic acid Ting (chemically pure);
Hydrogen peroxide (chemically pure): 3% solution: Standard solution: titanium 0.1mg/ml..
3 Analysis procedure
A3.1 Wash and clean the cadmium titanium plated sample and put it into a 120C oven for 30min, take it out and put it into a desiccator to cool to room temperature. Weigh it, put the sample into a 150mL beaker, add 20ml of 10% ammonium nitrate solution. After the titanium coating is dissolved, use a glass rod with an eraser to wipe the old attachments on the surface of the test piece into the beaker, take it out and rinse it with water, dehydrate it with 2.5% alcohol, and then put it into a 120 oven for 30min, take it out and put it into a desiccator to cool to room temperature and weigh it. The difference between the two weights is the mass of the cadmium titanium coating to be tested. A3.2 Add 1-2 ml nitric acid and 5 ml sulfuric acid to the above 150 ml beaker, heat until white smoke appears, cool and dilute with water to the mark and record. Use 2 cm colorimetric blood, perform colorimetry at a wavelength of 16 μm, and measure the extinction value: the corresponding content is set on the titanium standard curve. A3.3 Drawing of titanium standard curve: Take 0, 1, 2, 3, 4, and 5 ml of titanium standard solution respectively. Put them into 6 50 ml volumetric flasks. Add 20 ml of 1:9 sulfuric acid solution, 1~2 ml of phosphoric acid, and 2 ml of 3% hydrogen peroxide to each. Color, then, add 1:9 sulfuric acid solution to the scale, evenly use 2 cm colorimetric blood, perform colorimetry at a wavelength of 460 μm to measure the extinction value, and draw a standard curve A4 Calculation
In the formula: G: The mass of titanium found from the standard curve, mg:, the mass of the coating taken during the colorimetric determination, mgX100
(AI)
Juice: This method requires that the sample substrate is steel, and the size is preferably 30 mmx25 mmx: mm. Take some of the inner quality of the coating and put it in the center. 05~℃. 1. The surface roughness of the sample must be only. 0.8, when taking the bar, be sure to wash off the attachment. 1 Technical requirements
GB/T 13322--91 Www.bzxZ.net
Appendix B
Processing method of notched endurance test specimen
(Supplement)
B1.1 The notched endurance test specimen for identifying brittleness should be prepared with the same material as the plated piece. After heat treatment, the tensile strength of the basic material of the sample should be close to the upper limit.
B12 The shape and size of the test specimen shall comply with the provisions of Figure B1 and Figure. 1x45°
1 ×.45°
B2 Processing method
(k )S2 2:*It
Notched 1 endurance specimen (R0.12, K, 4)
R0. 25±0, 01
Figure B2 Notched endurance specimen (R0.25, K, = 1) B2.1 Process the specimen according to the figure, and the sampling axis should be parallel to the rolling fiber direction of the material. Torsion processing, heat treatment to the tensile strength required by the specimen, and then fine processing to the specified size. The notch is ground with a soft fine-grained aluminum oxide grinding wheel, and the grinding amount is not too large. The cold printing liquid should be sufficient. The test GB/T 13322-91
sample T feed is 0.02~~0.01mm at the beginning and 0.005mm during fine processing. After grinding, the root of the notch should be smooth. After grinding, projection inspection is carried out to ensure that the defect meets the requirements. 2.2 In order to ensure the concentricity of the sample, the grooves at both ends of the sample should be fine-machined to the required size after heat treatment. 2.3 Before electroplating, the sample should eliminate the grinding stress. The temperature and time for eliminating stress are the same as those of the plated piano. Appendix C
Hydrogen meter test method
(reference number)
C1 Test principle
The hydrogen meter is an instrument that measures the oxygen absorption during electroplating and the hydrogen permeability of the plated. It uses an iron shell electrode as a probe for reverse electroplating. Part of the original material generated during the electroplating process penetrates into the electron tube through the coating and the tube wall, reducing the internal vacuum (the hydrogen embrittlement caused by electroplating is caused by this part of the original material inside the component). The hydrogen atoms are ionized by the impact of the emission current in the tube, causing the electrode current of the electrode to change. This change is amplified and recorded by the micro-current effect. This is to convert the change in vacuum caused by nitriding into a current signal. The curve recorded by the instrument during the entire electroplating test process is shown in the figure: The figure is as follows: IEF
Electric key code
20CY: Hong Gao
Figure (1 Schematic diagram of the test process of the hydrogen tester
During electroplating, some hydrogen atoms penetrate into the tube to make its hydrogen pressure current rise (vacuum decreases), and the curve rises (stage 1). After the electroplating is completed, the tube wall is cleaned. The curve drops slightly, that is, the hydrogen inside the tube begins to diffuse outside (stage 1). Finally, the electron tube is placed in a 200 (oven for baking. At this time, the hydrogen absorbed by the coating and the tube wall continues to diffuse into the tube, and the vacuum inside the tube is reduced. The degree of vacuum continues to decrease and the curve continues to rise; when the diffusion reaches equilibrium, the output line reaches a maximum point, which is the peak low HP: then, the internal atmosphere diffuses outward through the tube wall and the coating, the vacuum degree in the tube increases, and the output line begins to decrease (stage III). The rate of decrease of the line is directly related to the permeability of the coating to oxygen. Therefore, the time required for the measurement curve to drop from the highest point HP to HP is "\ in seconds ()". This indicates the permeability of the coating to hydrogen. The smaller the signal, the smaller the risk of hydrogen in the coating.
C2 calibration
C21 calibration Calibration operation and electroplating operation: The process of testing the penetration performance of the probe tube alone is called calibration operation. The solution used is basically the same as the electroplating solution, and does not contain the metal salt to be plated: the probe is charged during calibration. The electroplating operation is the process of testing the permeability of the probe tube and the plated metal by the electroplating solution.
C2.2: The hydrogen pressure current of the probe is the vertical scale of the record line, the unit is 1=1×10-A, C2.3 Hydrogen phobic value H1: The maximum 1m obtained when the charged or electroplated probe is placed in a 200)℃ oven. C2. 3.1
Hydrogen peak value obtained by difficult calibration
C2.3.2HPp: Hydrogen peak value obtained by electroplating operation. GB/T 13322
C2.4A: The time required for the hydrogen peak value HP to decay to HP when baked in a 200℃ oven, in seconds (g). C2.4.1.: The value obtained by the initial calibration of a new probe, generally less than 40 s. C2.4.22.: The input value obtained by the calibration operation. C2.4.3: The input value obtained by the electroplating operation. C3 Test procedure
The specific test steps and test methods are carried out according to the instruction manual of the specific hydrogen tester. C3.1 Test preparation: The vacuum degree of the probe used as the probe is required to be greater than or equal to 8×10-5-. Use the abrasive spraying method to remove the old insulating layer on the surface of the probe that has passed the vacuum inspection, and then leave the appropriate area as the electroplating port, and the rest are insulated. C3.2 Calibration operation: Charge the cathode of the electron tube probe with a fixed solution, then wash it with water, rinse it with acetone, absorb it with filter paper, and bake it in a 200℃ oven, and record the curve of its hydrogen pressure current changing with time. Mark H and calculate its value by - method on the curve. When the curve decays to
H, the calibration operation can be completed. The position at
H, and use geometric drawing
C3.3 Electroplating operation: Key the electron tube probe that has passed the calibration, then wash it with water, rinse it with acetone, absorb it with filter paper, and bake it in a 200T oven, record the surface line of its oxygen pressure current changing with time, and mark HP on the training line.And find out its value. When the curve decays to HPp, the electroplating operation can be completed. C4 Conversion of test pieces and results
C4.1 Provisions of test conditions
Test conditions are shown in Table C1.
Test items
Test current
Test current
Test time
HP, position, and use geometric drawing method to calculate the baking temperature
200±2
20n±2
Window area
C4. 2 Conversion of test results; Take the average value of at least three test results. The following formula is converted into lr to evaluate the hydrogen embrittlement performance of electroplated plating:
Ap = Ap ×
Additional instructions:
This standard is proposed by the National Technical Committee for Standardization of Metallic and Non-metallic Micro-Coatings and is under the jurisdiction of the National Technical Committee for Standardization of Metallic and Non-metallic Micro-Coatings. This standard is formulated by the Sixth Institute of the Ministry of Aeronautics and Astronautics, and is participated in by the Beijing University of Aeronautics and Astronautics and the China International Aviation Corporation Maintenance Base.
The main drafters of this standard are Qin Yuewen, Zhai Jinzhong, and Xie Xiangfu. This standard refers to the American standard MII, STD) 150-core A (UISAF> "Low Hydrogen Embrittlement Titanium Plating".
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