Stress corrosion - what is it?


Stress corrosion occurs only with certain groups of materials. It occurs when a certain tensile stress or residual stress is present. Which conditions are still crucial for stress corrosion, read here. Also, what measures can be taken to avoid them.

Materials susceptible to stress corrosion

Stress corrosion does not occur with all materials. It only plays a role in the following material groups:

  • all copper-zinc alloys, such as brass
  • high-strength steels in certain circumstances (such steels are also used in reinforced concrete)
  • many rust- and acid-resistant steels, as well as so-called maraging steels
  • unalloyed steels and low-alloyed steels
  • certain plastics

With aluminum it can come in exceptional cases also to stress corrosion. As a rule, however, other types of corrosion play a greater role in aluminum.

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In order for stress corrosion to occur, an attacking agent must act on the material. This is a chemical compound that weakens the material of the workpiece. In the case of steel, chlorine compounds in particular act as an attack agent, but also amines and ammonia and the associated salts. Sulfur and nitrogen oxides as well as nitrate and nitrite can also act as an attack agent.

Without existing means of attack there is no stress corrosion. The concentration of the attacking agent does not have to be high. Even at low concentrations, corrosion can occur. The higher the concentration, the faster the progress of the corrosion process.

Measures against stress corrosion

The prevention of stress corrosion must be done differently than against other types of corrosion. Especially important is the reduction of tensile loads, where possible.

In certain areas, where tensile loads can not be avoided, a suitable material selection should always be made. This selection of materials is particularly important with regard to the corrosion of steels.

Keeping away the means of attack is not always possible in practice. For brass, for example, already suffices the usual air pollution, so that sufficient attack means are available in effective concentration. Also, storing ammonia-containing cleaners in the vicinity can cause a sufficient concentration of ammonia.

Tips & Tricks

When building, the possibility of stress corrosion should always be considered. To prevent corrosion damage, only one factor needs to be avoided. Either the action of the means of attack is excluded, a tensile load is reduced or an insensitive material is chosen.


Video Board: Stress Corrosion Cracking by Krittin Rattakham