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Zinc abrasive media

Zinc abrasives are zinc particles that are used as abrasive media. They are usually available in a single teardrop shape (shot) that addresses different industrial applications.

Zinc shot refers to teardrop-shaped grains made of molten zinc through an atomization ("granulation") process, available in different sizes.

Zinc cut wire refers to pure zinc wire that is cut into extremely small pieces that may also be used as abrasive media.

Contents

·       1Properties

o  1.1Recyclability and environmental impact

o  1.2Hardness

o  1.3Bulk density

·       2Industrial applications

o  2.1Cleaning

o  2.2Flash removal

o  2.3Surface preparation

·       3Industrial uses

·       4Production

·       5See also

Properties[edit]

Most zinc abrasives are made of a mainly zinc composition, the best compromise between mechanical properties, efficiency and durability. Some properties for zinc abrasives include hardness, size, shape, durability (the time it takes for the particles to break down) and bulk density (the abrasive power of each particle). The most important property differentiating zinc abrasives from steel abrasives is malleability, as zinc’s considerably-higher malleability makes the zinc abrasives gentler on blasting equipment than steel (which tends to be more damaging to the equipment over time).

Recyclability and environmental impact[edit]

The recyclability of zinc shot ranges between 4500 cycles (for zinc cut wire abrasives) to 14000 cycles (for hard cast zinc shot). Hard cast zinc shot is an alloy of mostly zinc combined with small amounts of aluminum and copper to create a considerably more durable (3 times as durable) alternative to zinc cut wire. Due to its high recyclability level, zinc shot tends to generate less waste and almost no dust when compared to other expendable abrasives.

Hardness[edit]

Zinc shot is usually available at different hardness levels, ranging between 60 and 91 Knoop. This is so soft that it does not register on the Rockwell or Vickers hardness scales. However, its relatively high bulk density still allows it to be an effective blasting media.

Bulk density[edit]

Zinc shot is usually available with a bulk density of 240-250 lbs/ft3. This is slightly below the bulk density of steel shot, 280 lbs/ft3.

Industrial applications[edit]

Cleaning[edit]

ZInc shot is used in cleaning applications for removal of loose material on metal surfaces. This type of cleaning is common in automotive industry (motor blocks, cylinder heads, etc.) and in removing paint from metal surfaces (gas cylinders, powder coating removal, paint removal).

Flash removal[edit]

ZInc shot is also used in applications for removal of flash and other excess metal resulting from the metal casting process (mostly zinc, aluminum and magnesium castings).

Surface preparation[edit]

Surface preparation is a series of operations including cleaning and physical modification of a surface. Zinc shot is used in surface preparation process for cleaning metal surfaces which are covered with mill scale, dirt, rust, or paint coatings and for physically modifying the metal surface such as creating roughness for better application of paint and coating. The zinc shot pieces are generally employed in shot blasting machines.

Industrial uses[edit]

Zinc shot addresses numerous sectors since cleaning, surface preparation or flash removal applications are used by many industries as a part of their construction, renovation or repair processes. The main industrial sectors employing zinc abrasives are:

·       Automotive industry

·       Diecasting industry

·       Paint and coating removal industry

Production[edit]

The annual zinc shot production in the USA is estimated to be above 1 million pounds, the USA’s largest producer being Transmet Corporation by production and capacity.

See also[edit]

·       Abrasive blasting

·       Abrasive machining