Corrosion features edges

Ensure stress-raising features such as holes, welds, edges, rapid changes in section, etc, are minimised in their exposure to the stress-corrosion cracking risk environment. Heat treatment of components may give beneficial results. 

An outward curled rim is frequently used on containers for ointments and creams, keeping the raw edge away from the product and away from the customer s finger. The lid itself may also feature a similar outward curled rim. The use of curled rims is more common with tinplate than with aluminium, since cut edges are sharper and there is a higher risk of corrosion. 

The size and shape of corrosion specimens are affected by several factors and cannot be rigidly defined. All convenient sizes are acceptable. Preferably, the edges of corrosion specimens should be machined in order to remove cold-worked metal. When the application demands, the specimens should include welds, cold-worked areas, and other features of the intended service. 

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