ISO/TC 156/WG 6 - General principles of testing and data interpretation

This document specifies procedures for the removal of corrosion products formed on metal and alloy corrosion test specimens during their exposure in corrosive environments. For the purpose of this document, the term "metals" refers to pure metals and alloys. The specified procedures are designed to remove all corrosion products without significant removal of base metal. This allows an accurate determination of the mass loss of the metal, which occurred during exposure to the corrosive environment. In some cases, these procedures are also applicable to metal coatings, providing the possible effects from the substrate are considered.

This document gives guidelines for the corrosion testing of metals and alloys exposed in deep-sea water, including the selection of the test site, components and assembly of the test system, specimen preparation, testing procedure, evaluation after the retrieval from exposure sites and test report. This document is applicable to the general corrosion exposure testing of metals and alloys as well as localized corrosion tests such as stress corrosion cracking (SCC) testing, galvanic corrosion testing and crevice corrosion testing of specimens exposed in deep-sea water. Testing with exposure in deep sea of other materials such as composites and elastomers can also be carried out with reference to these guidelines, but the evaluation of these materials after the retrieval is different from that of metals and alloys. This document does not include the performance testing of sacrificial anodes for cathodic protection in the field of deep sea, which can be conducted using specified testing cells and equipment in the deep-sea exposure. However, this guidance can also provide useful information as reference for conducting performance testing of sacrificial anodes in deep-sea water.

This document gives guidelines for the selection of procedures that can be used in the identification and examination of corrosion pits and in the evaluation of pitting corrosion and pit growth rate.

This document specifies general principles for carrying out corrosion tests under conditions of constant immersion. Some of these general principles are applicable to other types of corrosion testing. This document does not cover important procedures for stress corrosion testing, such as those given in ISO 7539 (all parts).

ISO 18069:2015 specifies the measurements of the corrosion rate of uniform corrosion for stainless steels and nickel based alloys in the intended liquids and the ability for the material to passivate after activation. This method is intended to be used for estimation of the uniform corrosion rate in liquids, under atmospheric conditions, for the chemical industry under specific environmental conditions and not as a qualification test. It can also be used to determine iso-corrosion diagrams and at which temperature the corrosion rate exceeds 0,1 mm/a. ISO 18069:2015 is not intended for excessive corrosion rates above 1 mm/a since an even higher corrosion rate indicates that the stainless steel is not suitable in the application. Nor is it intended to be used for solutions containing halides, especially chlorides, since these might cause localized corrosion.

ISO 14802:2012 gives guidance on some generally accepted methods of statistical analysis which are useful in the interpretation of corrosion test results. ISO 14802:2012 does not cover detailed calculations and methods, but rather considers a range of approaches which have applications in corrosion testing. Only those statistical methods that have wide acceptance in corrosion testing have been considered in ISO 14802:2012.

ISO 8407:2009 specifies procedures for the removal of corrosion products formed on metal and alloy corrosion test specimens during their exposure in corrosive environments. For the purpose of this International Standard, the term “metals” refers to pure metals and alloys. The specified procedures are designed to remove all corrosion products without significant removal of base metal. This allows an accurate determination of the mass loss of the metal, which occurred during exposure to the corrosive environment. These procedures may, in some cases, also be applied to metal coatings. However, possible effects from the substrate must be considered.

Gives guidance on the selection of procedures that can be used in the identification and examination of pits and in the evaluation of pitting corrosion.

Contains the most important general guidelines for carrying out corrosion test under conditions of constant immersion. Does not cover procedures for stress corrosion testing.

Specifies procedures designed to remove all corrosion products without significant removal of base metal. These procedures may, in some cases, also be applied to metal coatings. Annex A is for information only.