This standard specifies the technical requirements and test methods for zinc-chromium coatings on steel parts and components. GB/T 18684-2002 Technical conditions for zinc-chromium coatings GB/T18684-2002 Standard download decompression password: www.bzxz.net
This standard specifies the technical requirements and test methods for zinc-chromium coatings on steel parts and components.

5 25. 220. 20
National Standard of the People's Republic of China
GB/T:16684--2002
Technical Conditions for Zinc/Chromate Coatings
Specifications of Zinc/Chromate coatings20020310Promulgated
National Quality Inspection and Quarantine Commission of the People's Republic of China
Implementation on 2002-08-01
The Appendix A and Appendix Requirements marked in it are the appendices for sudden material production. This environmental standard is issued by China Machinery Industry Federation and is under the jurisdiction of the National Enterprise Standardization Technical Committee. The starting units of this standard are: Wujiang Material Protection Research Institute, Nanzong Hongguang Airborne Equipment Factory: GB/T18684:2002
This standard is drafted by: Wushuang Yongtaihe Technology Co., Ltd., Beijing Shuitaihe Metal Technology Co., Ltd.: The three main drafters of this standard are: Wu Yong, Xue Zhongzuo, Zhang Weiyuan, Bu Qiyan, and Zhang Hongwei. 1 Scope
Zinc-chromium coating
Technical conditions
This standard specifies the technical requirements and test methods for closed doors and parts after the needle is removed. 2 Normative references
GA/T18684-2C02
The following documents and clauses become clauses of this standard through the use of this standard: The referenced documents with the specified period, their subsequent amendments (including errata); or revised editions are not applicable to this standard. However, it is encouraged to study whether the contents of this standard are within the scope of this standard. The latest editions of these documents may be used. Expired references are not noted. The latest editions are used for the standards. /527)-198 Test method for adhesion strength of intermetallic layers (deposited layers and chemically deposited layers) on substrates (e5028.91a)
GB63 Measurement method for micro-fractionation of gold and oxide layers (eg150) 1463) 12519 Corrosion test for thermal conductivity, etc. 503 Definition
The following applies to zinc coating ZineiChromnle cnatings will be water-based zinc chromium coating coating, special or spray on the steel parts or components, the material is good with flaky zinc and zinc salt as the main components of the total coating,
4 classification
according to the comprehensive quality of the zinc coating to give the requirements of the four grades, 1 zinc chromium coating classification
material density / (zug/dm)
East degree m
one hungry
one flood || tt||one except one into
three beams three floods
: the parent's plate is also clean and the father and the effect are not required. The original degree of the layer is the test side. The unlisted ones are the health ability and the loss of life. It is to change 3. The first change. The layer is added and the people are added! The inheritance of the people makes the layer not completely related, so the coating thickness changes only. The shape of the two pieces is complex, and the surface cannot catch up with the product. When the number of particles is measured, it will explode. When the ratio is caused by the need for double cutting, the comprehensive people's original internal road is divided, and the belt should be supplied to the supplier. 5) The required temperature of the parts to be coated is: the zinc-chromium layer is baked at a temperature of 00<100°C. The buyer should consider the influence of the speed on the performance of the workpiece.
E Technical requirements
6.1 Appearance
The base color of the coating should be silver-gray. Other colors can also be used, such as black. The coating should be continuous, without temperature flow, bubbles, thorns, cracks, pitting, impurities and other defects. The coating should be basically uniform and not prone to local over-thickness. The coating should not be discolored, but small yellow spots are allowed. bzxz.net
6.2 Coating efficiency and coating thickness
The coating efficiency should not be lower than the requirements of Table 1. 6.3 Check the strength
According to 8.3, the coating should not be broken after the strength test. However, it is allowed to change the color of zinc and aluminum powder.
E.4 Salt corrosion resistance
The coating should not be rusted after the salt test. Table 2 Salt spray corrosion resistance test requirements
Time for red rust to appear /
6.5 Water resistance
After the coating of level 3 and 4 is subjected to water test according to the method specified in 8.5, the coating shall not be shaved off or attached to the base: Level 1 and Level 2 are not required to have water resistance.
5.6 Moisture and heat resistance
Level 3 and 4 are tested in accordance with the standard method. Red rust shall not appear within 241. Level 1 and Level 2 are not required to have heat resistance.
Samples
7.1 From the same product, three samples are randomly selected from each test machine for testing. If any of them fails after the test, three samples are randomly selected for the same test. If any of them fails, the batch of products is considered unqualified. 7.2 For components or units with a mass of more than 1 g, a portion of the workpiece shall be cut out as a sample for testing. In order to avoid the steel defects at the cut edge, the cut shall be protected with wax or tape. For complex shapes that are difficult to calculate, the same method can be used to prepare the test piece. 8 Test method 8.1 Appearance Observe with the naked eye under natural scattered light. 8.2 Coating weight test 8.2.1 Decomposition weighing method For samples with a mass of more than 1 g, weigh the original mass W (g) with a 1 g flat plate. Place the sample in a 20 °C water bath at 7 °C for 1 min to allow the chromium coating to decompose completely. Take out the sample. Wash with water and dry immediately for 10 minutes. Then weigh the decomposition weight (Wrg) of the sample. Calculate the surface rent of the workpiece
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