ISO 25018:2026

Description

This document specifies a method for the determination of resistance to stress corrosion cracking (SCC) of copper and copper-zinc alloys in ammonia vapour.

This document covers the method of sampling, the types of specimens, the loading procedure, the type of environment and the interpretation of results.

This document is aimed at determining resistance to SCC as a function of the chemical composition, the method of manufacture of copper and copper-zinc alloys.

This document applies to wrought copper and copper-zinc alloys in the form of products and parts.

This document can be used to rank materials performance and select candidate materials under atmospheres containing ammonia. However, the results of this test should not be considered as an absolute criterion for the quality of alloys.

This document specifies a method for exposing test specimens in ammonia vapour coexisting with an aqueous ammonia solution and specifies the environmental conditions and test procedures.

This document specifies two methods of loading:

• under constant total strain;
• under constant load.

It does not cover slow strain rate test methods and determination of maximum admissible stress by the method of permanent deformation for copper and copper-zinc alloys, although an effort is now being made to apply such methods to these alloys (see ISO 7539-7).