This standard specifies a method for evaluating the solderability of metal coating products and specimens using soft (lead-tin) solder and rosin flux. This standard is only applicable to metal coatings that are usually easy to solder, such as tin, tin-lead alloys, silver and gold. GB/T 16745-1997 Standard test method for solderability of metal coating products GB/T16745-1997 standard download decompression password: www.bzxz.net
This standard specifies a method for evaluating the solderability of metal coating products and specimens using soft (lead-tin) solder and rosin flux. This standard is only applicable to metal coatings that are usually easy to solder, such as tin, tin-lead alloys, silver and gold.

CB/T16745
This standard is equivalent to the American Association for Testing and Materials standard ASTMB678-86 "Standard Test Method for Weldability of Metallic Covering Products".
This standard is slightly different from the adopted standard in terms of writing rules. The content of the "Factors Affecting the Test Results" chapter is inherited from the various chapters of the adopted standard, and the "Flux", "Solder" and "Accelerated Aging" in Chapter 5 of the adopted standard are arranged as Chapters 6, 7, and 8 of this standard.
The referenced standards of this standard, considering that the raw materials are based in China, quote the corresponding national standards. This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is organized by the National Technical Committee for Standardization of Metallic and Non-metallic Coverings. The main unit of this standard is: Wuhan Institute of Materials Protection, Ministry of Machinery. The main drafters of this standard are: Zhu Aosheng, Yang Fangming, and Jiang Xinhua. 1 Scopebzxz.net
National Standard of the People's Republic of China
Standard Test Method for Weldability of Metallic Covering Products
Stuadard lesl methud fur
solderability of metallic-coated products51997
CB/T 16745
This standard specifies a method for evaluating the solderability of metal coating products using soft (lead-coated) solder and loose flux. This standard is applicable to metal coatings such as tin, tin-coated alloys, silver and gold that are easily soldered. This standard provides a qualitative and long-term test method. The equipment required is simple and easy to implement. This method is a "transient" test and is not suitable for evaluating the solderability level of products. This standard may involve dangerous items, equipment and equipment, but does not discuss safety issues during use: those who use this standard should take necessary safety precautions and establish applicable regulations before use. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When the standard was published, the versions shown were valid. All standards will be revised. All existing standards using this standard shall be subject to revision. The possibility of using the latest version of the following standards is discussed. 33131-88 Tin-lead solder
(38745--87 Rosin
G811687 Rosin test method
3 Definitions
This standard adopts the following definitions:
3.1 Solderability
The property of the degree to which the metal covering surface is easily wetted by molten solder. 4 Method Overview
The test specimen with tin or lead is briefly immersed in molten lead solder and then tested for wetting by solder. 5 Significance and Use
5.1 Solderability of the metal surface to be covered may be related to its surface condition, the composition of the solder and the action of the flux. The molten solder must be easy to wet and cover the metal surface to be soldered, so the surface must be clean or have some residues that are easily removed by the selected flux. The activity of the flux is often! It is necessary to remove common dirt, highly corrosive flux may corrode the product and have other harmful effects. The standard flux used in this test is unactivated rosin isopropyl alcohol solution, which is a mild flux. The flux with strong specificity can better distinguish the qualified solder joints under critical conditions.
5.2 Metal coatings are often used to provide a solderable surface. If the coating is not properly produced, defects such as pores, co-deposited impurities, improper thickness and surface dyeing will lead to poor solderability. In this case, the product can be subjected to a solderability test. Those products that pass the solderability test can be used to obtain satisfactory solderability in production. For products that fail the test, the test results cannot reveal the cause of poor solderability. The process operator can determine the cause based on experience. 5.3 This test method uses a solder with a mass ratio of 60% pot and 10% diamond and an unactivated flux to evaluate the solderability of the coating. This solder and flux, or the activated form of the flux, are commonly used in the assembly of electronic products. 6 Flux
6.1 Normally, the grade and special grade rosin specified in Gl8146 are dissolved in isobutyl alcohol with a purity of not less than 99% (m/m) to obtain a rosin solution with a concentration of (25±5)% (m/m) as flux. This is a powdered rosin flux. In actual use, high-concentration commercial flux can also be diluted with isobutyl alcohol to the desired concentration. 6.2 If required by the organization formulating the technical conditions, other fluxes may be used, such as slightly activated and fully activated rosin fluxes. Any differences from the standard should be stated in the test report: Solder
7.1 The flux is an alloy of 0% lead and 40% lead in accordance with the 60A classification of (B3131). 7.2 The composition of the molten solder will gradually change due to oxidation, and the immersed specimen may also introduce metal and other impurities into the solder. Therefore, unless chemical analysis shows that its composition still meets the requirements of 7.1, the molten solder composition should be replaced. 8 Accelerated aging
8.1 Due to the natural aging effect, the solderability of some ammonium products may deteriorate significantly with time. In order to understand in advance the performance of these products after long-term storage, artificial accelerated aging is required before soldering. 8.? This standard uses water vapor to artificially reverse aging the specimens. The water used in the aging box should be distilled water or deionized water. 9 Sampling
9.1 The number and method of sampling and the characteristics of the specimens shall be in accordance with the technical specifications and other management documents of the relevant coating products. 9.2 Sample collection·Generally, it is a component of an electronic product or other products with the same shape and mass: the length of the specimen should not exceed 23me
10 Device
10.1 Solder tank: The capacity of the solder tank should be large enough, and the mass of the solder it contains should be at least 100 times the mass of the sample to be tested. 11 Procedures
11.1 The sample to be tested does not need to be decontaminated before the test, and the test should generally be carried out in its incoming state. If the production process of the product requires the product to be cleaned before welding, it should be specifically mentioned: the sample It is best to decontaminate in the same manner as: 11.2 For tin and tin-lead coatings and other coatings that require accelerated aging before some tests, proceed as specified in 11.3: If the specimen does not require accelerated aging, the test begins with 11.5. 11.3 Hang the specimen above the boiling water in the container, with the lower edge of the specimen 50-~100mm from the boiling water surface and not in contact with the container. The container must always be covered or use a condenser during the test. The container and condenser must not be placed so that condensed water does not drip onto the specimen. Instructions for use:
JASIMn678-86 uses the lead in accordance with the ASTM1>500 method, and ASTMD678-86 uses the alloy that complies with the ASTMB32 solder metal specification for 60A grade. 3.AST MB678--35 is distilled water or deionized water that meets the requirements of Class 1 reagent water in the standard of A.STM131193 reagent water. GB/T16745-1997
11.4 After removing the aged sample from the container, dry and cool it in the air at room temperature. 115 Immerse the sample in the flux and keep it in the air for 30~60s after taking it out. 71.6 Heat the solder and control the solder temperature to (245±5)℃. Stir the solder with a clean stainless steel hammer and scrape the slag on the surface of the solder with a clean stainless steel scraper before proceeding to the next test. 11.7 Use a manual or dynamic soaking device to soak the sample into the above solder at a speed of (25±5)mm/s, keep it in it for (5+0.5)s and then take it out at a speed of (25±5)mm/s. 11.8 After the solder coating solidifies, remove the flux residue with isoflurane or other solvent. 11.9 Use a self-viewing glass or a 10x magnifying glass to examine the solder coating of the specimen. Use a sharp needle or blade to scrape the coating to test adhesion.
11.10 If 95% of the test surface has a solder coating that is firmly adhered, smooth, flat, and even, the specimen is considered to have passed the test. The remaining 5% may have defects such as small pinholes, non-wetting areas, and roughness. If the specimen is flat, the area 3 mm from the edge is not evaluated. It is recommended that the worst acceptable specimen be retained and used as the acceptance standard. 12 Factors Affecting Test Results
12.1 Immersion Temperature
If there is insufficient solder in the solder tank or the specimen is too heavy, the solder will cool beyond the immersion test temperature range after the specimen is immersed in the solder, or the temperature rise is too slow, affecting the test results. Therefore, the test specimen with a mass greater than that of a human being must be immersed for a longer period of time, which is determined by the test: 12.2 Specimen length
If the specimen length exceeds 25mm1, when immersed for the specified time, its bottom end may stay in the solder* for much longer than the specified time. Therefore, the test result of the bottom end of the specimen is invalid and should be removed in the result evaluation. Another specimen can be tested. In this test, only part of the specimen is immersed in the solder to evaluate the elasticity of the bottom end. 12. 3 Immersion speed and time
The immersed specimen must comply with the specified immersion time and speed, otherwise the test results may change significantly. If an automatic immersion device is used, the variability caused by the operator can be eliminated. 12.4 Cleanliness
The samples for solderability test generally do not need to be cleaned, but dirt should be avoided. For samples that need to be cleaned, especially the test surface cannot be touched with bare hands, tweezers, pliers, cotton yarn sleeves or other suitable tools should be used, otherwise non-wetting areas may be caused, affecting the test results. 13 Precision and Bias
13.1 This standard does not give the precision and bias of the measurement of solderability. This is because the test results only indicate whether the coating specimens tested meet the acceptance criteria specified in this method.
14 Test Report
The test report shall include the following:
) This standard number:
b) Description of the specimen;
whether the specimen was cleaned before the test, and if so, the method used (see 11.1)! d)
whether the specimen was aged;
whether the test was conducted on a sintering machine or using a white film immersion tester; e)
any deviations from the method of this standard (e.g., flux, solder properties, immersion time and speed);
number of specimens and the number of specimens that failed the test; g)
a description of the characteristics of all specimens that failed the test: the testing laboratory and the test personnel.
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