Mechanical stripping of metal surfaces

In the technical literature, the term "mechanical pickling" is often used to refer to a variety of mechanical treatments of very different types, all of which involve the use of abrasives. These operations consist in removing oxides, among other things:

• by repeated rubbing of parts in contact with metal fragments or abrasive powders, held in (or on) a suitable system, usually rotating;

• by stripping, thanks to the multiple impacts of small abrasive particles, projected with sufficient kinetic energy.

Friction treatment involves two disciplines of mechanical surface treatment:

• the first is work on individual parts using hand tools (files or scrapers) or simple machines (buffing or grinding wheels); the abrasive is then applied to a solid support;

• the second is mechanical pickling by rolling, better known as tonnelage or barillage, which takes advantage of the friction of parts stirred dry or with an abrasive charge added; in this case, the abrasive is entrained in a fluid flow. Friction machining encompasses a very wide range of operations in which oxide removal is not the primary function. These operations are aimed either at removing excess metal left on the surface during part manufacturing (deburring or trimming), or at modifying its surface condition to satisfy aesthetic requirements, with a view to obtaining a surface free from tool marks resulting from previous machining operations (polishing or brightening).

These treatments (known as tribo-finishing) will not be developed further in this article, and we will confine ourselves to impact stripping operations.

This type of stripping raises the same questions as chemical stripping: Which media to choose? Which blasting system to use? How to recycle the abrasive after treatment?...

The complete study of the subject includes the articles :

• M 1455 – Metal stripping ;

• M 1456 – Chemical stripping of metal surfaces ;

• M 1457 – Mechanical stripping of metal surfaces (this article) ;

• M 1458 – Treatment of coated materials ;

• Doc. M 1459 – Stripping.