ASTM B858-2018 pdf free download

ASTM B858-2018 pdf free download.Standard Test Method for Ammonia Vapor Test for Determining Susceptibility to Stress Corrosion Cracking in Copper Alloys
1. Scope
1.1 This test method describes a procedure to determine the presence of residual stresses in wrought copper alloy products that may lead to stress corrosion cracking. An ammonia vapor atmosphere is used as an accelerated test. 1.2 This test method is only suitable for products fabricated from copper alloys that are known to be susceptible to stress corrosion cracking in ammonia vapor atmospheres. It is in- tended to create an environmental condition of reproducible severity. N OTE 1—It is well known that the critical step in the cracking mechanism is the development of an environment in the condensate film that occurs on the surface of the test specimen, and is rich in copper complex ions. 1.3 The severity of this test method depends upon the pH of the corrosive solution. In Annex A1 are given four different atmospheres to which the product may be exposed, and the appropriate pH of the solution to be used for the test, depending on the risk level associated with the intended application. 1.3.1 The appropriate pH value for the test shall be specified in the product specification, or as per established agreement between the supplier and purchaser, with respect to the alloy and its intended application. 1.4 Units—The values stated in SI units are to be regarded as standard. No other units ofmeasurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 This test method is an accelerated test to determine if a copper alloy product will be susceptible to stress-corrosion cracking when exposed to a particular atmospheric condition during service with the appropriate risk level—see Annex A1. 5.1.1 This test method is generally intended to determine if a copper alloy product will crack because of internal stresses when subjected to the test, and is not intended for testing assemblies under applied stress. Ifused for this purpose, it shall be for information only and not a cause for rejection of the assembly, its component parts, or the original mill product.
8. Test Media
8.1 Slowly add the sodium hydroxide solution to the am- monium chloride solution to give a test solution with a pH value appropriate for the intended application (see Annex A1). Maintain the solution at ambient temperature and dilute with DI water up to a volume of 1 L. Check the pH value with the pH meter after dilution. Prepare the solution preferably in a fume hood in a laboratory using appropriate safe laboratory procedures and store it in a closed vessel. Before use, check the pH value again, and adjust if necessary. 8.1.1 In the closed test vessel, the ratio of surface area of test solution to air volume ofthe vessel above the solution shall be a minimum of 20 cm 2 /L. 8.2 The pickling solution for cleaning test pieces before and after testing shall be 5 % sulfuric acid. If necessary, for cleaning test pieces after testing, a small amount of hydrogen peroxide solution may be added to the pickling solution (for example, 20 to 30 mL of hydrogen peroxide solution per litre of pickling solution).