ISO 7441:2015 PDF

Corrosion of metals and alloys — Determination of bimetallic corrosion in atmospheric exposure corrosion tests

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Title (English):

ISO 7441:2015

Corrosion of metals and alloys — Determination of bimetallic corrosion in atmospheric exposure corrosion tests

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 14
Publication date:: January 5, 2015
Edition:: ISO IS 7441 edition 2 version 1
ICS:: 77.060

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Description (English):

ISO 7441:2015 specifies and compares methods for the determination of bimetallic corrosion of metals and coated metals in atmospheric exposure corrosion tests. The methods are intended for the determination of the amount and type of corrosion effect, arising in natural atmospheres, caused by contact with different metals.

Technical details

Technical committee: ISO/TC 156 - Corrosion of metals and alloys
SKU: ISO 7441:2015

Abstract

Overview

ISO 7441:2015 - "Corrosion of metals and alloys - Determination of bimetallic corrosion in atmospheric exposure corrosion tests" - specifies and compares standardized methods to determine bimetallic (galvanic) corrosion of metals and coated metals under natural atmospheric exposure. The standard describes how to prepare specimens, expose them, evaluate corrosion (amount and type), and calculate the bimetallic effect - the relative increase in corrosion caused by electrical contact between dissimilar metals in an atmosphere.

Key features:

Compares three test configurations: rectangular plates, washers, and wire-on-bolt.
Covers specimen types (test, reference, standard, control), preparation, exposure and evaluation procedures.
Intended to quantify bimetallic effects that typically act within about 0.5 cm of the contact point in atmospheric conditions.

Key technical topics and requirements

Test methods compared
- Rectangular plates - allows evaluation of mechanical properties in addition to mass loss; recommended for tensile testing specimens (thickness 1–6 mm).
- Washers - useful when the anodic material is not known in advance.
- Wire-on-bolt - shorter exposure time (typically >90 days acceptable) but consult ASTM G116 for full method details.
Specimen preparation
- Types: test, reference, standard, control.
- Surface condition: free of visible defects; surface roughness better than 2.5 µm (0.4–0.5 µm recommended).
- Coated metals must follow appropriate coating standards (e.g., ISO 1456, ISO 2081, ISO 7599).
Assembly and electrical checks
- Use insulating washers/sleeves (ceramics, polyethylene/polypropylene) to isolate bolts.
- Bolts/washers typically stainless steel grade 1.4301/304 or higher.
- Typical tightening torque ≈ 1.0 ± 0.1 N·m; verify insulation (>10 kΩ between bolt and washers) and contact resistance (

Related standards

Standards mentioned in the description

ISO 7441:2015 PDF

Technical details

Abstract

Overview

Key technical topics and requirements

Related standards

Abstract

Overview

Key technical topics and requirements

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