Metal Inclusion Characteristics and Causes
Metal inclusions are particles of metals or their compounds that form during the formation process of non-metallic materials such as plastics, and affect the performance of the host material. These particles are often derived from the processing or contamination of the raw materials. Inclusions can cause many problems, such as porosity, cracks, sawing and extrusion defects, surface defects, fatigue and wear damage in molding or machining processes.
Physical characteristics of metal inclusions
The physical characteristics of metal inclusions are determined by the composition and structure of the material itself. Based on the size, shape and physical properties of the particles, those that are harder than the material in which they are embedded can cause chips and burrs, which can then cause surface defects. If the particle is softer than the material, on the other hand, it can cause a decrease in material strength and impact toughness.
Size of metal inclusions
The size of metal inclusions refers to their length, width and thickness. Smaller particles are generally easier to remove from the material during machining and finishing processes. Large particles, on the other hand, can cause severe damage, requiring a longer duration and more difficult operation to machine. The size of particles also depends on the type of metal used and the skill of the machinist.
Form of metal inclusions
The form of metal inclusions depends largely on the type and composition of the material used. For example, steel and iron based alloys usually form homogeneous particles whereas copper, aluminum and zinc form irregular particles with sharp edges or points. The presence of such particles may be detrimental to the strength of the material, leading to wear and fatigue under pressure.
Origin of metal inclusions
The origin of metal inclusions can be divided into two categories. The first is based on the raw materials used in the manufacturing process. Contaminants from the raw materials, such as mould dust, grinding chips, plating residues and paint overspray, can lead to inclusions. The second is based on the processing techniques used in production. The manufacturing process itself can be the source of metal inclusions, particularly those caused by the use of cutting tools. Abrasive materials or excessive heat caused by improper cooling can also be the source of metal inclusion.
The effects of metal inclusions
Metal inclusions may cause significant damage or defects in the materials they are embedded in. These particles can interfere with the proper operation of the material and lead to surface defects, porosity, fatigue and wear damage. In some cases, these particles may also cause the machine to malfunction or cause an accident due to shredded pieces of foreign material from the inclusions.
Conclusion
Metal inclusions can affect the performance of the material in various ways. They can be present in the raw materials or generated during the manufacturing process through the use of improper tools and techniques. The physical characteristics, size, form and origin of the particles all need to be taken into consideration in order to prevent any damage to the material or the tools. It is also important to inspect the materials for inclusions to ensure that there are no degrading factors present in the materials being used.
