GB/T 46215-2025 Corrosion of metals and alloys—Evaluation of selective corrosion of Cu alloys and grey cast iron for power plant components by visual inspection and hardness measurement

Scope

This document specifies the procedures for on-site inspection and assessment to identify the impact of material degradation (such as material loss) on components and structures prone to selective corrosion in industrial facilities such as nuclear power plants.
The method includes in-situ visual inspection and hardness testing, supplemented by sampling. These procedures include: a) Representative sampling of components sensitive to selective corrosion; b) Visual inspection; c) Hardness testing. For accurate analysis, additional laboratory testing is recommended.
This method is particularly applicable to gray cast iron and copper alloys with a zinc content exceeding 15%. For other alloys, validated supporting evidence is required.
For nuclear power plant applications, the assessment criteria define the need for further engineering assessments and corresponding measures, such as additional sampling, increased inspection frequency, and component repair or replacement, within five years before the end of the extended operating period.
This document does not apply to representative components in contact with fluid surfaces that cannot be inspected by optical means or portable hardness gauges. Similarly, it does not apply to non-representative components such as HVAC systems or building service facilities. For components not used in nuclear power plants, the assessment criteria must be agreed upon by both parties. The evaluation criteria using hardness testing alone are not applicable to the structural integrity assessment of aluminum bronze, nickel-aluminum bronze (NAB), and copper-nickel alloys.

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