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Grinding Media & Grinding Balls

Grinding Media Specifications

Note: Click here to go directly to metallic media specifications or here for non-metallic media specs.

Grinding media, the objects used to refine material and reduce particle size, are available in a wide range of shapes, sizes and materials to meet an equally wide range of grinding and milling needs.

As the developer and manufacturer of industry-leading particle size reduction equipment, including Attritors (internally agitated ball mills) and DMQX horizontal media mills, Union Process is uniquely positioned to help you identify and source the correct grinding media for your application.

Union Process customers know they can rely on our extensive technical expertise and years of experience to ensure they get the right grinding media at the right time and the right price for their specific needs. Working in close consultation with our customers, our skilled technical service representatives review customer requirements like final particle size, physical compatibility and contamination concerns and then recommend media with the right characteristics, including:

Shape – balls, beads and satellites satisfy the bulk of our customers’ requirements, but we also source highly specialized shapes like ballcones and diagonals
Diameter – depending on the material, ranging from 0.05 mm to 2 mm for small media mills, up to 1/8” to 1” for traditional Attritors and up to ½” to 2” for ball mills
Compositionmetallic grinding media like carbon steel, forged steel, stainless steel or chrome steel grinding balls are best for some applications, while others require non-metallic media made of alumina, ceramics, glass, silicon carbide, zirconium oxide or other specialized materials

Offering the optimal combination of grinding media knowledge and manufacturing expertise, Union Process takes your entire operation into account to identify the best grinding media to consistently generate the final particle size and shape required by your application, optimizing the cost effectiveness of your process and extending the life of your mills.

Backed by our long-standing commitment to customer satisfaction, we ensure quality manufacturing and reliable supply of grinding balls and media specifically engineered to meet the requirements of your most demanding milling applications.

Scroll down to view our full line of grinding media, and click on any image to view that media’s specifications, or, for immediate technical assistance, call (330) 929-3333 x228.

Metallic Grinding Media

Click on any image to view that media’s specifications or to request a quote. (Click here to view non-metallic media specs.)

Note: Sizes shown in red indicate media that is recommended for use in bead mills except where stated otherwise.

Carbon Steel

THROUGH-HARDENED CARBON STEEL BALLS TYPE 1065
Through-Hardened Carbon Steel Balls are magnetic and can be used in the food industry along with 440C stainless steel media. They are a lowcost media that are superior and recommended over case-hardened carbon steel media which have a soft core. They are packaged with no oil finish—always dry packed—as they will rust in water.

Chrome Steel

CHROME STEEL BALLS TYPE 52100
Chrome Balls (steel type 52100) are through-hardened and tempered steel balls designed to achieve maximum strength and quality. Ball hardness is in the 60–67 HRC range. They wear better than 440C stainless steel and through-hardened carbon steel. They are also recommended for applications where a through-hardened steel ball is needed in larger sizes (½" and larger). They are sometimes packaged with a very light oil finish to reduce rust due to humidity.

Stainless Steel

440C STAINLESS STEEL BALLS
440C Stainless Steel Balls are through-hardened and tempered throughout for maximum strength and quality. They are magnetic, and corrosion-resistant (generally rust-resistant). They are recommended for food applications and lighter colored slurries.

Steel Shot

CARBON STEEL SHOT
Carbon Steel Shot media is through-hardened and very low cost. As such, they are not uniformly spherical and often can leave a gritty black residue.

Forged Steel

FORGED STEEL BALLS — LARGE DIAMETER
Forged Steel Balls are used for gold mining, cement factories, oil processing and large scale industrial applications. They are made by machine (standard) sizes 20mm–75mm. They are manually made (hit by air hammer) sizes 75mm–125mm. They have hardness 55–63 HRC. All forged balls are through-hardened, and shipped in 55-gallon steel drums. They range in sizes from 20mm–125mm.Standard lead time is 6–8 weeks FOB Akron, Ohio USA.

High Chrome Cast

HIGH CHROME CAST STEEL BALLS
High Chrome Steel Balls can be used for many different applications. They are available in two grades—10–13% chrome (surface hardness ≥ 60 HRC, core hardness ≥ 58 HRC), and 14–18% chrome (surface hardness ≥ 62 HRC, core hardness ≥ 60 HRC). They have a very rough black finish which quickly wears off during initial milling. After that, they have an excellent wear rate. They are available in sizes 6mm–120mm. They are shipped in 55-gallon steel drums with standard lead time of 6–8 weeks FOB Akron, Ohio USA.


Non-Metallic Grinding Media

Click on any image to view that media’s specifications or to request a quote.

Note: Sizes shown in red indicate media that is recommended for use in bead mills except where stated otherwise.

Alumina Satellites

ALUMINA BALLS AND SATELLITES
Union Process is the one source for 90%, 94%, 99.5% and 99.9% alumina media. 90% alumina is available in satellites and rod/cylinders. 94% alumina balls have excellent wear resistance with higher impact strength to save running costs with less contamination. They have great wear rate generally better than 90% or 99.5%. 99.5% alumina balls have the highest alumina content for a moderate price. The .5% impurity is MgO that is added to inhibit grain growth during sintering in the kiln. There is less than 0.1% silica in the media. 99.9% alumina balls are made of very pure and reactive (expensive) raw materials. They are for high purity alumina applications where contamination is a factor.

Alumina Beads

ALUMINA BEADS
Alumina Beads are specially formulated to be used in high-energy mills in which a high degree of fineness is required. They are used in various industrial fields such as inks, paints, advanced ceramics, mining, cosmetics and pharmaceutical industries. They are a perfectly spherical shape with high mechanical properties and high wear resistance at a moderate price.

Ceramic

CERAMIC SATELLITES (STEATITE)
Ceramic Steatite is a very cost-efficient media. They are a satellite shape with composition of MgO 27.5% and SiO2 61.4% along with other minimal materials.

Glass

GLASS BEADS
This grade is used for milling applications with 85% roundness. All Glass Beads are lead-free and less expensive.

Silicon Carbide

SILICON CARBIDE BALLS
Silicon Carbide Balls are very high-cost grinding media that are used for milling same materials (silicon carbide ball to mill silicon carbide materials) to avoid contamination. They are only available in 5mm,10mm, 15mm and 20mm sizes. They are a special order item.

Silicon Nitride

SILICON NITRIDE BALLS
Silicon Nitride Balls are very high-cost grinding media that are used for milling same materials (silicon nitride ball to mill silicon nitride materials) to avoid contamination. They are now available in 2mm and 3mm and sizes up to 25mm. They are a special order item.

Tungsten Carbide

TUNGSTEN CARBIDE SATELLITES/BALLS
Tungsten Carbide media is the hardest and densest (highest specific gravity) media and is available in both satellites and balls upon request. They are now available in sizes 0.5mm, 0.6mm, etc., up to 1" diameter. They are a high-cost media and are a special order item.

Zirconium Oxide Y203 95% Balls

ZIRCONIUM OXIDE BALLS (YTTRIA STABILIZED) HIGH PURITY 95% ZrO2
Zirconium Oxide Balls (95% ZrO2) are the strongest, best wearing ceramic media for metal-free, pharmaceutical and food processing grinding. These balls have a white, shiny appearance. They are also available in 3⁄8" and ½" cylinders. This 95% grade is high-cost.

Zirconium Oxide Y203 93% Beads

ZIRCONIUM OXIDE BEADS (YTTRIA STABILIZED) 93% ZrO2
93% Zirconium Oxide Beads are another option for metal-free applications that are lower cost than 95% ZrO2.

Zirconium Oxide Rare Earth

ZIRCONIUM OXIDE SATELLITES/BEADS — CeO2 RARE EARTH STABILIZED
Zirconium Oxide Satellites—Ceria stabilized (rare earth)—are a cheaper zirconium oxide alternative for metal-free applications. They are a brown, shiny ball media that come in size ranges in the smallest sizes (ex: 0.4– 0.6mm), then at 6mm come in uniform sizes (6mm, 8mm, etc.) up to 31mm.

Zirconium Silicate

ZIRCONIUM SILICATE BEADS (FUSED AND SINTERED)
Zirconium Silicate Beads are available in fused 68% ZrO2 beads which are a standard reliable media at low cost, and sintered 58% ZrO2 beads which have high breakage resistance, are durable and cost effective. They are used to microgrind paints, inks, dyes, magnetic coatings, minerals, agrochemicals and ceramics.

CARBON STEEL GRINDING BALLS
(SAE 1065–through-hardened)
Specific Gravity: 7.8
Hardness: ROCKWELL C 60–62
Relative Cost: Low
Sizes Available: 1/8", 3/16", 1/4", 5/16", 3/8", 1/2, 3/4"


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CHROME STEEL GRINDING BALLS
(SAE 52100)
Specific Gravity: 7.8
Hardness: ROCKWELL C 60–67
Relative Cost: Low to Moderate
Sizes Available: 1mm, 2mm,1/8", 5/32", 3/16", 7/32", 1/4", 5/16", 3/8", 1/2", 3/4", 1"


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STAINLESS STEEL GRINDING BALLS
(AISI 440-C)
Specific Gravity: 7.7
Hardness: ROCKWELL C 58–65
Relative Cost: Moderate
Sizes Available: 2mm,1/8", 5/32", 3/16", 7/32", 1/4", 5/16", 3/8", 1/2", 3/4", 1"


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STEEL SHOT, THROUGH-HARDENED
Specific Gravity: 7.6
Hardness: ROCKWELL C 55–60
Relative Cost: Low
Sizes Available: .25mm, .50mm, .6mm,.71mm, .85mm, 1mm, 1.18mm, 1.40mm, 1.70mm, 2mm, 2.36mm, 2.80mm


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FORGED STEEL GRINDING BALLS
Specific Gravity: N/A
Hardness: 55–63HRC
Relative Cost: Very Low
Sizes Available: 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 65mm, 75mm, 90mm, 100mm, 125mm


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HIGH CHROME CAST GRINDING BALLS 10-13%
Specific Gravity: N/A
Hardness: Surface=≥60HRC, Core=≥58HRC
Relative Cost: Very Low
Sizes Available: 6mm, 8mm, 10mm, 12mm, 15mm, 17mm, 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm

HIGH CHROME CAST GRINDING BALLS 14-18%
Specific Gravity: N/A
Hardness: Surface=≥62HRC, Core=≥60HRC
Relative Cost: Very Low
Sizes Available: 6mm, 8mm, 10mm, 12mm, 15mm, 17mm, 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm

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ALUMINA 99.9% BALLS
Specific Gravity: 3.9
Hardness: Hv10 = 1800
Relative Cost: High
Sizes Available: .5mm, 1mm, 2mm, 3mm, 5mm, 10mm, 15mm, 20mm, 25mm

ALUMINA 99.5% BALLS
Specific Gravity: 3.8
Hardness: Hv 1300 kg/mm2
Relative Cost: Moderate
Sizes Available: 0.2mm, 0.3mm, 0.5mm, 1mm, 2mm, 3mm, 5mm, 8mm, 10mm, 15mm, 20mm

ALUMINA 99.8% SATELLITES
Specific Gravity: 3.4-3.7
Hardness: ROCKWELL 45N 78 – 79
Relative Cost: Moderate
Sizes Available: 1/4"

ALUMINA 94% BALLS
Specific Gravity: 3.59
Hardness: Hv 1200 kg/mm2
Relative Cost: Low to Moderate
Sizes Available: 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 13mm, 15mm, 20mm

ALUMINA 90% BEADS AND SATELLITES
Specific Gravity: 3.4 - 3.7
Hardness: ROCKWELL 45N 75
Relative Cost: Low
Sizes Available: 3mm, 7/32", 1/4", 3/8", 1/2"
Note: 3mm size are Beads-remaining four sizes are satellites
ALUMINA BEADS
Specific Gravity: N/A
Hardness: Mohs 9, VICKERS (0.5 kg) 1200 ± 50
Relative Cost: Low to Moderate
Sizes Available: 0.25–0.34mm, 0.34–0.44mm, 0.4–0.6mm, 0.8–1.2mm, 1.2–1.6mm, 1.4–1.6mm, 1.6–1.8mm, 1.8–2.0mm, 2.0–2.5mm, 2.5–3.0mm
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CERAMIC (STEATITE) SATELLITES
Specific Gravity: 2.6-2.7
Hardness: ROCKWELL 45N 60-65
Relative Cost: Low to Moderate
Sizes Available: 1/4", 5/16", 3/8", 1/2", 20mm, 25mm

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GLASS BEADS (LEAD FREE)
Specific Gravity: 2.5
Hardness: KNOOP 515 kg/mm2
Relative Cost: Low
Sizes Available: 0.25–0.50mm, 0.40–0.60mm, 0.60.8mm, 0.75–1.0mm, 0.80–1.0mm, 1mm, 1.5mm, 1.0–1.25mm, 1.25–1.55mm, 1.55–1.85mm, 1.7–2.0mm, 2mm, 2.0–2.4mm, 2.4–2.9mm, 2.85–3.45mm, 3mm, 3.5mm, 3.6–4.1mm, 3.8–4.1mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 12mm, 14mm, 16mm

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SILICON CARBIDE BALLS
Specific Gravity: 3.1
Hardness: KNOOP 2500 kg/mm2
Relative Cost: Very High
Sizes Available: 5mm, 10mm, 15mm, 20mm

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SILICON NITRIDE BALLS
Specific Gravity: 3.2
Hardness: Hv10 = 1300
Relative Cost: Very High
Sizes Available: 2mm, 3mm, 5mm, 10mm, 15mm, 20mm, 25mm

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TUNGSTEN CARBIDE SATELLITES
Specific Gravity: 14.4-14.8
Hardness: 92.0 ± 0.5 Hra
Relative Cost: Moderate to High
Sizes Available: 3/32", 1/8", 5/32", 3/16", 7/32", 1/4", 9/32", 5/16", 3/8", 7/16", 1/2", 9/16", 3/4", 1"
Note: Smaller sizes beginning at 0.5mm available upon request.

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ZIRCONIUM OXIDE, High-Purity (Y20 3 STABILIZED)
95% Balls
Specific Gravity: 6.0
Hardness: Hv 1150 kg/mm2
Relative Cost: High
Sizes Available: 0.03mm, 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.65mm, 0.8mm, 1mm, 1.25mm, 1.5mm, 2mm, 3mm, 5mm, 6mm, 8mm, 10mm, 15mm, 20mm, 25mm
Note: 6mm and 8mm limited availability. Cylinders available in 3/8" and 1/2" sizes.

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ZIRCONIUM OXIDE, High-Purity (Y203 STABILIZED)
93% Beads
Specific Gravity: 6.0
Hardness: Hv 1250 HV1
Relative Cost: Moderate
Sizes Available: 0.1mm, 0.15–0.28mm, 0.25–0.35mm, 0.35–0.45mm, 0.45–0.55mm, 0.6mm, 0.8mm, 1.0mm, 1.25mm, 1.5mm, 1.75mm, 2.0mm, 2.3mm

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ZIRCONIUM OXIDE (CeO2 RARE EARTH-STABILIZED)
Specific Gravity: 6.0
Hardness: Hv 1200 – 1250
Relative Cost: Moderate
Sizes Available: 0.4–0.6mm, 0.6–0.8mm, 0.8–1.0mm, 0.7–1.2mm, 1.0–1.2mm, 1.2–1.4mm, 1.4–1.6mm, 1.7–2.4mm, 2.4–2.8mm, 2.8–3.3mm, 6mm, 8mm, 10mm, 12.5mm, 16mm, 21mm, 26mm, 31mm
Note: Sizes up to 2.8-3.3mm are beads. 6mm and larger are satellites.

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ZIRCONIUM SILICATE BEADS
Sintered (58% Zr02, 37% SiO2)

Specific Gravity: 4.0
Hardness: 800 HVI
Relative Cost: Moderate
Sizes Available: 0.8–1.0mm, 1.0–1.2mm, 1.2–1.4mm, 1.4–1.6mm, 1.6–1.8mm, 1.8–2.0mm, 2.0–2.2mm, 2.2–2.4mm, 2.4–2.6mm, 2.5–2.8m

ZIRCONIUM SILICATE BEADS
Fused (68% Zr02, 30% SiO2)

Specific Gravity: 3.8
Hardness: 700 HVI
Relative Cost: Moderate
Sizes Available: 0.1–0.2mm, 0.2–0.3mm, 0.3–0.4mm, 0.4–0.6mm, 0.6–0.8mm, 0.8–1.0mm, 1.0–1.25mm, 1.25–1.6mm, 1.6–2.0mm, 2.0-2.5mm
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NOTE:Grinding balls and media are sold on a per pound basis, but ATTRITORS and DMQX-Mills are loaded by volume. Therefore, the more dense the media, the more pounds of media required. For instance, a machine requiring only 40 lbs. of stainless steel may require up to 80 lbs. of tungsten carbide. Information contained herein is accurate and reliable to the best of our knowledge, but our suggestions and recommendations cannot be guaranteed because the conditions of use are beyond our control.

Our skilled technical service representatives also are available for consultation and are always ready to assist you with the selection of grinding media that best answer your particular needs. For assistance, contact Media Sales by calling (330) 929-3333 x228 or by .