Degreasing

Before assembling or surface-treating metallic materials, their surfaces need to be cleaned; the nature of this preparation depends on the objective to be achieved. To achieve this, the practitioner has a number of mechanical, chemical or electrolytic treatments at his or her disposal, including a routine operation often mistakenly regarded as simple cleaning: degreasing.

Degreasing is used both in the metal processing industry (after machining or cold or hot forming, before and after heat treatment, before welding or diffusion soldering, etc.) and in surface treatment workshops (before galvanizing, metallic deposits, enameling, chemical or electrolytic conversions). Other more marginal applications, such as cleaning prior to repair or assembly of electronic or electrotechnical parts, may also require this step.

The subject appears complex and vast, with each application imposing specific processing conditions. It is therefore impossible to deal with degreasing in its entirety, so this text is limited to degreasing as a key step in preparing the metal interface for subsequent surface treatments, particularly wet treatments.

The aim of this article is to provide practitioners with the information they need to answer the following questions: Which degreasing procedure should be chosen? What should be done during degreasing? How can its effectiveness be controlled? How to limit rejects?