Metallic coatings-Electroplated coatings of chromium for engineering purposes
Some standard content:
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National Standard of the People's Republic of China
GB11379 -- 89
Metallic coatings
Engineering chromium electroplating layer
Metallic coatings--Electroplated coatings of chromiurrfnr engineering murposes
1989-06-29 Issued
198G-01-01 Implementation
National Technical Supervision Bureau Issued
National Standard of the People's Republic of China
Metallic charge cover
Engineering chromium electric hammer layer
Mieiallic coatings..Electroplared cosGngs ot chromumfor engineerint percposes
This standard adopts 1506158-184 gold coating process for electroplating and its content and scope of application
C11379-89
It specifies the type of electroplating process, the materials to be installed, the heat treatment process specifications, the quality requirements of the coating, the method of heat treatment, etc. This standard is applicable to non-ferrous metals or non-ferrous metal substrates with or without a bottom layer for electroplating. Engineering coatings are called "hard chromium" or "hard coatings". The standard does not refer to thin layers used for the purpose of anti-corrosion. For examples of chromium application in engineering and related instructions, see the appendix. 2 Reference standards
C3K1238 Metal coatings and chemical treatment methods CE5956 Gold coating thickness measurement with anodic dissolution coulometric method (1849F Magnetic energy Coulometric method for non-metallic coatings on metal substrates GBG158 Metal blue salt test (NSS test) GB62 Metal microfluidic layer full-break ratio energy trace method GB6 Other optical mechanical pre-coating thickness measurement methods These 3 terms
mainly refer to the work before and after the forging of the sheet. The chain system on this table is mainly used for the appearance and performance of the workpiece. 4 The display method of the sugar layer shall be inscribed with the relevant markings and the supplier shall comply with the provisions of GB1238. 5 The information that the purchaser shall provide to the supplier shall be the standard number of this standard; E: the composition of the body, the quality or speed and the gold file state of T: whether the sugar layer should be used as a stress relief group before delivery: whether the chain should be used as a guide, such as the front spray hole of the chain: the main surface, all surfaces without missing layers, all parts where the sugar layer is allowed to extend can be used with drawings or samples with appropriate markings. The National Change Technical Supervision Week 1999:0629 approved 1990-01-01 implementation: Detailed information: For seedling punishment Any specific increase or decrease in requirements, such as using sand instead of processing; or the requirement is that the bottom surface is specifically stated, the type of bottom surface will be stated, for example, glandular or non-grained, etc., g.
The minimum thickness of the bottom layer, the requirement for the bottom layer should also state the total thickness of the bottom layer, if necessary, the thickness of the layer should also be stated. h.
The maximum size of the defect, the repair of the casting or the out-of-tolerance parts, the thickness of the above layer refers to the thickness of the top layer before polishing:
The type of layer, such as porous, crack-free, micro-cracked, double-pressed or with a present (see B, 1 and B.2) The surface shape of the layer after the defect, the electroplating, polishing or grinding state (see 8.1.2) Full details of the defect include the type of defect, size, position, and any heat treatment after working. Requirements: its maintenance rate.
1 The quality of the material should be determined by the energy consumption. 6. Metal pre-treatment
6.1 Inspection before treatment
Before treatment, the supplier should check the main surface to confirm whether there are any surface depressions, pores, cracks and other defects that are not allowed, or any other defects that are inconsistent with the final finish of the product. All the parts should be noted by the buyer before any treatment. 6.2 Stress relief
Before any stress relief, heat treatment should be carried out. Generally, it is carried out according to the following table. Different working conditions can be used. However, it must be based on the effective experience of Baorong. Heat treatment should be carried out before any preparation and purification with aqueous solution. Table 1 Heat treatment requirements for copper steel parts before forging
Maximum strength before forging MP2
105tn.450
1450-tn5:800
n>:a0m
191-220 less 15
19~2218
[90- 22 2-24 3
If stress relief is carried out before shot peening or other cold working, the temperature should not exceed 220 °C. The surface heat treatment temperature should be within [3~.155 °C. If the surface temperature is reduced, it can be treated at a higher temperature for a longer time!
Whether the gold layer requires stress relief heat treatment shall be agreed upon by both parties. E3 Shot peening introduces stress on the surface of workpieces that have not been electroplated and are about to be electroplated. It can improve the load-bearing and fatigue resistance of these parts. However, due to the impact effect on the internal structure of the parts, the lack of fatigue strength can be partially compensated. [Stress can be introduced by shot peening and other methods. The metal material will not be able to choose the correct shot peening intensity. E.3.1 Copper steel workpieces need to be shot peened to improve the fatigue strength of ordinary steel workpieces: their customary strength (unless otherwise specified) should be as high as 0.3m, with a tensile strength greater than 0MPa;
0.4mm, with a normal tension equal to or greater than 11cmPa. In fine work, in order to prevent deformation, a lower shot peening intensity should be selected. This may not achieve a more ideal effect in avoiding a reduction in strength.
GB11379-89
If no other regulations are made, the surface of the steel should be completely exposed to the heat treatment, and the old ball marks should be removed. 6.3.2 Nonferrous metal
The thickness of the nonferrous metal spraying furnace shall be determined by the user. If the user has requirements, the post-heat treatment of the workpiece shall be carried out in accordance with the provisions of Y. [Article 7 or 7.2. The heat treatment shall be carried out as soon as possible and shall not exceed 1. It shall be carried out before other mechanical processing operations. 7.1 Except for the heat treatment of steel products, the heat treatment of steel products is shown in Table 2. Note: The heat treatment of 498 is only suitable for those workpieces that have been subjected to labor during use. 7.1.2 The workpiece shall not exceed the intermediate temperature during heat treatment. 7.1. The workpiece with water on the surface shall be heated at 130~50℃ for not less than 56℃. If the temperature of the body is allowed to be lowered, it can also be treated at a higher temperature.
7.1.4 For workpieces that have not been shot peened, the treatment temperature and treatment time can be appropriately reduced, but it must be based on effective practical experience (Notes in Chapter 6 and Table 2).
Table 2 The relevant provisions for heat treatment of parts after chromium treatment are as follows:
New can be greatly tensile.
:05021459
150R190)
n>1aon
Undertaking is the unqualified parts
All parts
15)--22n C to -2 h
190--2206h
136--223at least 18h
:40-8Good management may also reduce the hardness of your substrate, the instrument may gradually reduce the workpiece's strength according to the point of epidemic prevention and control.
100--80 at least:b
1008 to
100480 to 1
7.1.5 If the workpiece is pulled according to the fixed trend treatment after the gland is used as the base, the surface of the annealing should be 130-~! 50 below the annual small place 2, if the basic resting point is reduced, it can also be walked in higher humidity, the bottom dirt degree less dry: m qualified after transportation should be carried out according to the provisions of Table 2 - the second heat treatment of the egg after the comprehensive treatment of the super-treatment of the non-hydrogen-free heat treatment
n5nnn 1250
19~-2 -8 r
1~223 C±IR
10-- 226 US-24 r.
If the party requires the oxygen release test of the structural or production strength steel after the electric heating, the sample should be provided with the formula test method and acceptance requirements agreed by the party providing the funding:
7.2. The heat treatment of aluminum and diamond alloys must be carried out with care, as it may have a negative impact on the mechanical properties of the parts. If the heat treatment is not allowed and the ideal strength is obtained on the alloy, the workpiece should be heated to a temperature of 13-110°C at a heating rate of 2-3min, and then kept at the temperature for 2-3h. 3
8 Requirements for coating
a.1 Specifications
a. 1-1 Appearance
GB11378--89
When observed by the naked eye, the main surface should be glossy and shiny, and there should be no pitting, blistering, puncture or any other defects that may have a negative impact on the finishing state after treatment. On the surface of the workpiece that is directly used after being electroplated or single-glazed after being galvanized, except for the edges, there are also some properties that are not elastic. The electroplated workpiece should have no cracks visible to the naked eye. The layer larger than 50μm is not allowed to have cracks that reach the body. When visible blistering or cracking occurs during the heat treatment and glazing process, and this process is carried out by the electroplating personnel, it should not be used as a reason for rejection. 8.1.2 Whether the roughness requirement of the surface of the avoidance part is stipulated by the purchaser. If there is a requirement, it can be measured with a wheel gauge and the acceptance shall be agreed upon by both parties.
8.1.3 Thickness
The minimum thickness of the main surface, the finishing and the backing layer shall meet the requirements of the belt (see h). The thickness requirement of the plating layer determines the durability of the component. The application of the coating in industry is very complex and it is difficult to strictly determine the thickness of the coating. Appendix A provides some application examples and the selection range of the minimum thickness. B.1.4
If there is no other provision, the microscopic thickness value HV of the defective layer shall not be less than 750. 9.1.5 The thickness
When the number of strips specified in 1U.2 is reversed, the defective layer shall not separate from the substrate. If there is a bottom layer, there shall be no separation between the bottom layer and the substrate, and between the bottom layer and the defective layer.
3.1.6 Number of pores per unit area (pore breakage rate)
Whether there are requirements for the pore rate of the pores on the renal path layer that reach the substrate must also be specified. The test method is shown in Article 10.3. The evaluation and acceptance level of the test results shall be agreed upon by the supplier and the buyer. 3.2 Other types of products
3.2.1 General provisions
According to the different use conditions of the workpiece, in addition to the standard chrome layer, other types of chain layers can be selected. The appearance, hardness and other performance of these types of plastic layers can be significantly different from those of the conventional ones. Whether their quality also meets the requirements of the relevant specifications in 5.1 is agreed upon by the supplier and the buyer.
When the buyer has requirements for the number of no-cracks per unit area or the number of micro-cracks per unit length, the test method is as follows: 10.3. The evaluation and acceptance level of the test results shall be agreed upon by the supplier and the buyer, except for the relevant provisions in 8.2.2. If the buyer has requirements for the basic test of no-crack double layer or micro-crack groove of the bottom layer, the test method is as follows: 1 .4, the certification and acceptance level of the test drill results shall be agreed upon by the supply and demand parties. 8.7.2 The characteristics of the three types of age layers and the corresponding quality requirements B.2.2.1 "Six-crack mosquito"
Compared with the book period inscription, its hardness is lower, its brittleness is smaller, its wood is larger, and its corrosion resistance is weaker. For example, for the lead road, the core chromium density is generally less than 2 and no foot decoration is performed. It is not used on the surface of the material. When it is treated according to the provisions of the first inspection, it may have an adverse effect on the previous properties.
8.2.2.2 Porous inscription
A porous inscription surface can be obtained by a chemical or chemical method. If the porous surface is porous, the demander shall make corresponding test specifications for the type of inscription, such as urine spot or groove shape, pore depth and related indicators. 8.2.2.3 Micro-cracks
GH115/8-89
Compared with the cracks formed on the chromium layer, the cracks are formed by a specific process. The cracks of micro-cracks are invisible to the naked eye in any direction of the whole surface. There are more than 250 cracks in the length of 41cm, while the number of cracks per 1cm is much smaller than 250. The cracks are close to the normal cracks. Because the cracks have a relatively large crack structure, the product can be compared. If the continuous layer is used, the micro-cracks will spread faster than the corresponding cracks. 8.2.2.4 The continuous layer of chromium
is usually formed on the cracks of the bottom layer. Therefore, its hardness is similar to that of the regular layer, and it has a higher corrosion resistance.
9 Test method
10.1 Determination of layer thickness
The thickness of the layer shall be within the range of 10% or less. The limit value used shall ensure that the thickness is less than 10%. 13.1.1 Engineering quantity measurement
Select a test point and measure the size of the workpiece at that point. A thickness straight line can be obtained. Commonly used tools include micrometer, depth gauge, etc., which can be used to measure the diameter of cylindrical workpieces (external or internal diameter). Only when the thickness distribution of the layer is uniform can it represent the thickness of the layer. The uniformity of the layer thickness can be measured by appropriate methods, such as the axis of the electroplated workpiece. The lack of dry meter reading or other indirect methods to measure the base, 0.1.2 Avoid transport
When there is no bottom member, the friction of the chromium chain layer is measured according to the heat determination of GB1956, :3.1.3 Cut-off thickness expansion microscope side wind method This method belongs to the destructive thickness measurement method. According to the provisions of 16452, the thickness of the grid inlay layer and other bottom chain layers is measured, :5.1.4 Coulomb method
This method is a destructive sequence planning method, connected4. The certification and acceptance level of the test drill results shall be agreed upon by the supply and demand parties. 8.7.2 The characteristics of the three types of age layers and the corresponding quality requirements B.2.2.1 "Six-crack mosquito"
Compared with the book period inscription, its hardness is lower, its brittleness is smaller, its wood is larger, and its corrosion resistance is weaker. For example, for the lead road, the core chromium density is generally less than 2 and no foot decoration is performed. It is not used on the surface of the material. When it is treated according to the provisions of the first inspection, it may have an adverse effect on the previous properties.
8.2.2.2 Porous inscription
A porous inscription surface can be obtained by a chemical or chemical method. If the porous surface is porous, the demander shall make corresponding test specifications for the type of inscription, such as urine spot or groove shape, pore depth and related indicators. 8.2.2.3 Micro-cracks
GH115/8-89
Compared with the cracks formed on the chromium layer, the cracks are formed by a specific process. The cracks of micro-cracks are invisible to the naked eye in any direction of the whole surface. There are more than 250 cracks in the length of 41cm, while the number of cracks per 1cm is much smaller than 250. The cracks are close to the normal cracks. Because the cracks have a relatively large crack structure, the product can be compared. If the continuous layer is used, the micro-cracks will spread faster than the corresponding cracks. 8.2.2.4 The continuous layer of chromium
is usually formed on the cracks of the bottom layer. Therefore, its hardness is similar to that of the regular layer, and it has a higher corrosion resistance.
9 Test method
10.1 Determination of layer thickness
The thickness of the layer shall be within the range of 10% or less. The limit value used shall ensure that the thickness is less than 10%. 13.1.1 Engineering quantity measurement
Select a test point and measure the size of the workpiece at that point. A thickness straight line can be obtained. Commonly used tools include micrometer, depth gauge, etc., which can be used to measure the diameter of cylindrical workpieces (external or internal diameter). Only when the thickness distribution of the layer is uniform can it represent the thickness of the layer. The uniformity of the layer thickness can be measured by appropriate methods, such as the axis of the electroplated workpiece. The lack of dry meter reading or other indirect methods to measure the base, 0.1.2 Avoid transport
When there is no bottom member, the friction of the chromium chain layer is measured according to the heat determination of GB1956, :3.1.3 Cut-off thickness expansion microscope side wind method This method belongs to the destructive thickness measurement method. According to the provisions of 16452, the thickness of the grid inlay layer and other bottom chain layers is measured, :5.1.4 Coulomb method
This method is a destructive sequence planning method, connected4. The certification and acceptance level of the test drill results shall be agreed upon by the supply and demand parties. 8.7.2 The characteristics of the three types of age layers and the corresponding quality requirements B.2.2.1 "Six-crack mosquito"
Compared with the book period inscription, its hardness is lower, its brittleness is smaller, its wood is larger, and its corrosion resistance is weaker. For example, for the lead road, the core chromium density is generally less than 2 and no foot decoration is performed. It is not used on the surface of the material. When it is treated according to the provisions of the first inspection, it may have an adverse effect on the previous properties.
8.2.2.2 Porous inscription
A porous inscription surface can be obtained by a chemical or chemical method. If the porous surface is porous, the demander shall make corresponding test specifications for the type of inscription, such as urine spot or groove shape, pore depth and related indicators. 8.2.2.3 Micro-cracks
GH115/8-89wwW.bzxz.Net
Compared with the cracks formed on the chromium layer, the cracks are formed by a specific process. The cracks of micro-cracks are invisible to the naked eye in any direction of the whole surface. There are more than 250 cracks in the length of 41cm, while the number of cracks per 1cm is much smaller than 250. The cracks are close to the normal cracks. Because the cracks have a relatively large crack structure, the product can be compared. If the continuous layer is used, the micro-cracks will spread faster than the corresponding cracks. 8.2.2.4 The continuous layer of chromium
is usually formed on the cracks of the bottom layer. Therefore, its hardness is similar to that of the regular layer, and it has a higher corrosion resistance.
9 Test method
10.1 Determination of layer thickness
The thickness of the layer shall be within the range of 10% or less. The limit value used shall ensure that the thickness is less than 10%. 13.1.1 Engineering quantity measurement
Select a test point and measure the size of the workpiece at that point. A thickness straight line can be obtained. Commonly used tools include micrometer, depth gauge, etc., which can be used to measure the diameter of cylindrical workpieces (external or internal diameter). Only when the thickness distribution of the layer is uniform can it represent the thickness of the layer. The uniformity of the layer thickness can be measured by appropriate methods, such as the axis of the electroplated workpiece. The lack of dry meter reading or other indirect methods to measure the base, 0.1.2 Avoid transport
When there is no bottom member, the friction of the chromium chain layer is measured according to the heat determination of GB1956, :3.1.3 Cut-off thickness expansion microscope side wind method This method belongs to the destructive thickness measurement method. According to the provisions of 16452, the thickness of the grid inlay layer and other bottom chain layers is measured, :5.1.4 Coulomb method
This method is a destructive sequence planning method, connectedRequires wear resistance, but does not need decoration and dense matching surface, A2.2 sugar after grinding to a certain size layer
language layer of magic and can only be added to the specified size by cutting or similar methods, such as used for; on new parts: the thickness of the staggered layer to be retained after polishing is determined by the back heat, generally 5D25μm or machine added than the out-of-tolerance workpiece repair (see Research 1), the required light layer thickness should be the same as the gold, such as b
requires a thicker missing layer, can be recognized and sufficient thickness of the bottom gold cold, steel like a peak, so that the missing layer after polishing, the chromium chain layer is! U0～25Dm raw material, if the product is a cladding layer, the material used or the material with large thickness is not machined, A23 uses the bottom chain layer of the United States adhesive and other parts
must be pressed in a serious corrosion environment chain parts: the construction uses tin as the bottom layer, and it may be necessary to perform corrosion resistance tests on the cladding layer itself. The quality of the bottom layer should comply with the requirements of the engineering nickel bond. If there are special requirements, other metal solutions can be used as the layer. A5 Description
The chrome layer on the hard surface cannot withstand large deformation, otherwise it will cause the layer to crack or fall off. It must be noted that the base material should be able to resist the stress L applied in the longitudinal direction of the key layer. When the parts are subjected to deformation and impact, the thickness of the additional layer should take the minimum value. GB11379
Repair of parts when the chrome layer thickness is insufficient (reference part)
Before rework, check whether the parts have cracks. Parts with cracks cannot be chrome-plated. Under such circumstances, the original chrome layer on the parts to be reworked should be removed before rework. For the parts that need to be re-plated due to insufficient lead layer thickness, the original layer can be plated with the approval of the purchaser. Before the coating, the parts should be anodic etched for 10~24 hours at the current density of the current test, and then immediately activated at the cathode with a low current density of about 5 A/cm\. In addition, the low current test activation lasts for 5 mln and then the current density is gradually increased to the positive value. Appendix
Test method for shot strength
Supplementary)
This document provides the test method for the shot strength of the workpiece. Under the specified operation, the C1 specimen is made of HV420 to HV50 with a thickness of 1.mm. The size of mm×(2±02)mm is: the original thickness is 1.3±c.U2mm. After the sample is made, the flatness of the auxiliary sample: when measured by <:3 method, its height shall not exceed 6
C2 Fixture assembly and shot peening
As shown in Figure C1, the sample is fastened in the fixture, the clamp length is only one year, the surface is shot peened, the shot peening time and shot peening conditions are the same as those for the electrical parts,
C3 Measurement of height
After shot peening, remove the test piece from the fixture and take a shot of the gauge. The curvature of the surface is measured by four balls with a diameter of 5 mm, forming a short shape of 32m×16. The center of the plate gauge is aligned with the center of the sample. The height of the center of the sample is measured at 32m. The measuring end is accurate to 25Lm. The test station result should meet the requirements of the reduced height and width specified in Article 3.1. Then the shot peening design should be adjusted to obtain the required bamboo double interest low, Tianminben you, 1 wise
Lang! Test lucky soldiers
Sichuan paste mixed paper method
11.1 Specification GB1137989
Appendix P
Measurement of hole cracks
(Supplement)
This book can measure the most common cracks or cracks in the layer that can reach the matrix with the naked eye. >1.2 Test solution
Use distilled water to prepare a solution containing the following ingredients: potassium ferric chloride
sodium fluoride
KCF(<'N>;
The reagents used are of chemically pure grade,
.5 Test steps
60 g/L
The test environment should be kept clean and free from dust such as copper and other dusts in the air. Use ethanol or other suitable degreasing agent to remove the dirt on the test surface, and then wash it clean. Attach the filter paper without shrinkage (see 11.2) to the test surface tightly and keep it for 10131. If the filter paper is dry for a period of time, moisten it with a little test dust, remove the filter paper, and observe the surface in contact with the coating. The blue mark indicates that there are holes in the coating that reach the steel substrate, and the red mark indicates that there are holes in the copper alloy substrate.
11.4 Record the test surface and marks for a few months, and calculate the porosity as required. The unit is point/e m*, whenever possible measure and record the size of the marks or other phenomena observed. Some methods other than those specified in the chapter may be used to determine the porosity of the stratigraphic surface. Different combinations or different test procedures may be used, or different test procedures may be adopted. The results may vary greatly from those given in the chapter. 2 Visual inspection method
12.1 This method can only be used to determine the number of pores or grains in conventional stratigraphic surfaces. 12.2 The surface of the stratigraphic surface is examined with reflected light under an optical microscope with a magnification of 1.0. For more accurate counting of fine grains, a higher magnification is required. For more accurate counting, a micrometer or similar microscope may be used. The degree of the test is relatively high, and the magnification of the display is adjusted. At least 40 cracks can be counted in the test. 13 Electrodeposited copper measurement method
3.1 This method is used to measure the pores or cracks of the chrome-plated layer when the rust is used as the base layer. It can quickly measure the uniformity of the crack effect. The method should be carried out according to the provisions of D2, 2. 13.2 In an acidic acid solution, a copper layer is deposited on the chrome-plated layer with a current. The deposition machine is used to count. If the chrome layer is not continuous on the base layer, the chrome layer is not continuous on the base layer.
.5 The operation step is stopped immediately after the sample is removed. If the sample is not continuous, the sample should be removed. Any electrolytic treatment can be carried out by removing the micro-particles or oxidizing the water. The micro-particles can be removed by electrolysis. The test should be carried out by placing the sample into a 1% to 20% caustic soda meter before rolling. The rolling temperature is 95°C. There is an assistant to show cracking or pores. The pre-treated material is brought into the acid-plated copper electrodeposition system. The composition of the electrolytic solution is caustic soda (Cu50.4H2O): sodium sulfate (Cu50.5H2O): sodium sulfate (HSO4, p1.4): negative current rate (0) preparation time, additional instructions: 300 Year/L
0. 3 A/cma
This standard was proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China and is under the jurisdiction of the Metal and Non-metallic Materials Standardization Technical Committee. This standard was drafted by the Wuhan Institute of Materials Protection. The main drafters of this standard are Tao Weizheng and Sun Yousong.
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