Technical Paper


Typical impact wear leading to a hole in the Riser wall of a FCCU, as result of misaligned feed nozzle

All these classifications say something of the behaviour of the material, either on vertical impact or when polishing parallel to the surface. Hence, both extremes in view of ordinary and daily practice.

One would wish that it was that easy sometimes.

5.5 Angle of Impact In daily practice it looks like next figure: in a compact area all phenomena occur at the same times or in a small restricted area, whereas the erosion resistant material in use, is still the same.

Investigations in practice as well on laboratory scale have been executed in order to understand and to specify erosion in properties or in verifiable data.

Abrasion test have been developed, but as always one has to compare as these test are executed with specific equipment and specific abrasive materials to make the tests reliable and exchangeable.

Formation of depressions in 90° elbows with chilled cast iron tiles for pneumatic transport line

The hardness of particles is critical under small angles of impact, or Hardness of abrasive

Habr Hardness of base material Hmat

and can be estimated by the above figure, and as described by Wahl, Wellinger and Üetz.

That the angle of impact is of great influence can be demonstrated by tests executed with various abrasive materials on some types of steel and other materials, which is highlighted with following figures.

With a real abrasive, which is often a poly-phase material, one has to take into account the nature of the most durable phase. For example, the

March 2019 Issue Influence of impinging angle at varying particle size on Steel 37 ENGINEER THE REFRACTORIES 21

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