Corrosion properties

The self-repair mechanism of stainless steel

Stainless steel is self-healing. This is why it does not require any coating or other corrosion protection.

Webinars: Understanding corrosion

Material decay and corrosion are natural processes. Almost all materials will in one way or another decay over time. The effects of corrosion in our daily lives can be seen both in our households, but also in the infrastructure we use to e.g. travel from home to work or school and in the industrial facilities that produce what we need to have comfortable and healthy lives.

Even materials, which we believe to be resistant to corrosion like stainless steels, do corrode in certain circumstances. To protect materials from corrosion we first have to understand why it occurs after which we can find solutions to avoid it as much as possible.

Avoiding corrosion means we can save costs and in extreme situations even save lives.

worldstainless has three recorded webinars on the subject of corrosion available. You can contact us at education@worldstainless.org with any questions you might have.

Introduction to corrosion resistance of stainless steels

The corrosion resistance of stainless steel arises from a “passive”, chromium-rich, oxide film that forms naturally on the surface of the steel. The mechanisms of corrosion include crevice corrosion, pitting corrosion, intercystalline (or intergranular) corrosion (ICC), stress corrosion cracking (SCC) and galvanic (bi-metallic) corrosion and are often associated with chlorides or acid conditions.
Source: British Stainless Steel Association

Chloride stress corrosion cracking

The combination of tensile stress and a specific corrosive environment can crack stainless steels.  This mode of attack is termed stress corrosion cracking (SCC). The most common environmental exposure condition responsible for SCC of stainless steels is the presence of chlorides.  Although no stainless steel grade is totally immune to chloride SCC, the relative resistance of stainless steels varies substantially.
Source: Specialty Steel Industry of North America

Abrasive corrosive wear of stainless steels

Laboratory abrasive and abrasive-corrosive testing has been carried out on a range of ferritic, austenitic and martensitic stainless steels and the results compared with the testing of similar materials in situ in the abrasive­corrosive conditions of a gold mine. All grades were found to have better abrasive-corrosive resistance than proprietary abrasion-resistant alloys.

Stainless steel in contact with other metallic materials

Complex design requirements can make it necessary to combine different metallic materials within the same component. Also, chance combinations can often be found, governed only by the availability of, for instance, fasteners or shims. In certain circumstances, such mixed-material designs can lead to corrosion in one of the partner materials. This phenomenon includes galvanic corrosion, in which two different metals form a galvanic couple.
The present publication describes the principles of galvanic corrosion and the main parameters that allow designers to estimate corrosion risk.

This brochure is available in English, Czech, Dutch, Finnish, French, Italian, Polish, Spanish, Swedish and Turkish
[clicking on the language will open the pdf]

Deicing Salt - Recognizing the Corrosion Threat

Many designers are not aware that deicing salt is very corrosive to architectural materials, and inadequate knowledge can lead to inappropriate material selection and premature failure.

This article discusses the impact of deicing salt on architectural materials and has an in-depth discussion of the relative performance of competitive materials.

Source: International Molybdenum Association

Stainless steel for coastal and salt corrosion applications

This handbook is designed to acquaint the reader with the 300 series stainless steels, particularly grades 304 and 316 and their applications in areas where coastal or salt corrosion is a factor in the life of a metal component.
Source: Specialty Steel Industry of North America

Corrosion resistance of stainless steels in soils and in concrete

Corrosion by soil is a complex phenomenon due to the great number of variables involved. In principle, stainless steels should be in the passive state in soils, but the presence of water and aggressive chemical species such as chloride ions, sulphates and as well as types of bacteria and stray current, can cause localised corrosion.

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Galvanic corrosion

When two different metals are immersed in a corrosive solution, each will develop a corrosion potential. If the corrosion potential of the two metals is significantly different, and they are in direct contact and immersed in an electrolyte, the more noble metal will become the cathode and the more active metal will become the anode. A measurable current may flow between the anode and the cathode. The corrosion rate of the anode will be increased and the cathode decreased. The increased corrosion of the anode is called “galvanic corrosion”.
Source: Specialty Steel Industry of North America

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Published 08 November 2019

Seawater resistance of stainless steels

Stainless steels are susceptible to crevice or pitting attack in chloride bearing waters. Their behavior has been studied by a number of investigators. There is considerable variation in the percentage of apparently identical sites where attack occurs, when it occurs.
Source: The Hendrix Group, Materials and Corrosion Engineers

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Published 01 October 2021

Preventing coastal corrosion

When used properly, stainless steel enjoys a strong and enduring reputation for visual appeal and structural integrity in a wide range of applications and environments.
But, like all materials, stainless steel may become stained or discoloured over time, impairing the overall look. This brown discolouration – tea staining – has been identified in coastal applications in Australia and overseas.
Source: Australian Stainless Steel Development Association

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Published 08 August 2023

Corrosion barriers for thermally-insulated stainless steels

Pitting and stress corrosion can result from moist thermal insulation where chlorides are present. This information sheet provides background information on the sources of chlorides within such insulation materials and describes two corrosion prevention methods.
Source: British Stainless Steel Association

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Published 24 November 2020

Corrosion of metals in composite cements

The paper describes an investigation which seeks to understand the corrosion mechanisms of Aluminium, Magnesium Mild Steel and Stainless Steel in different cement systems.
Source: University of Sheffield

Please note this resource is not free

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Published 08 November 2019

Corrosion basics – an introduction

A general textbook on all types of corrosion. Contains a chapter on metals and alloys including stainless steels (to order as a hard copy).
Source: Corrosion Doctors

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Published 08 November 2019