Steel Grinding Media

Sigma DURMAX Grinding Media is available in chrome alloy steel, Carbon steel or stainless steel. This media is especially popular for use in the manufacture of printing inks, magnetic tape coatings and various other applications.

The superior manufacturing process used for DURMAX beads results in highest wear resistance and fewest media changes.



DURMAX Steel Grinding Media is made for maximum durability due to our Cold Heading manufacturing process.

DURMAX beads are NOT cut from wire and rolled like other media. Cold Heading shapes the ball into a roughly finished size leaving only de-flashing and polishing operations. Cold Heading virtually eliminates all fissures and cracks which lead to bead fragmentation and reduced wear resistance. Cold Heading may cost slightly more than a bead made from a cut wire process, but the result is a media that lasts longer.

DURMAX media surface finish is free of cracks and fissures for minimal splitting and higher wear resistance. The difference is visible even under low magnification. Hardness tolerance is strictly controlled to eliminate “overhardening” which leads to brittle material and splitting.

Competitor's Steel Grinding Media

Competitor’s Steel Grinding Media

Sigma DURMAX Steel Grinding Media

Sigma DURMAX Steel Grinding Media

DURMAX Chrome Alloy beads and Stainless Steel beads are through-hardened. Carbon steel beads are Case-Hardened to 1/2 diameter, not 1/4 diameter like other brands.

DURMAX beads have a size tolerance of +/- 1% of diameter, NOT 10% like other beads.



  • Through-Hardened Chrome Alloy grade E52100, R63C +/- 3
  • Case-Hardened Carbon Steel grade 1018, R63C +/-3
  • Through-Hardened Stainless Steel Grade 410, R58C +/-3


  • Specific Gravity – 7.85 g/cc
  • Bulk Density – 4.9 g/cc

PACKING: 25 lb. boxes in plastic bag with light rust-preventive oil coating

SIZES: 1.0mm, 1.5mm, 2.0mm, 3/32″,1/8″, 5/32″,3/16″, 1/4″, 9/32″, larger as special
NOTE: Other sizes are available. Please contact us to inquire.

Sigma Steel Grinding Media - Cold-heading Method

Cold Heading Method

  1. Wire Rod is fed into the Header
  2. Rough Ball is produced with an “equator” of flashing
  3. Ball is de-flashed and polished

Sigma Steel Grinding Media - Cut-Wire Method

Cut Wire Method

  1. Wire Rod is fed into the Cutter
  2. Cylindrical slug is cut with length shorter than finished ball diameter.
    Finished ball diameter is shown by red circle.
  3. Material is folded into the void to produce a finished ball

Also Available: Steel Shot

DURMAX Steel Shot is a drop-chilled shot which undergoes extra processing to eliminate as many odd shaped pieces as possible. Most pieces with voids, tails or hollows are removed. Steel Shot is heat treated for slightly higher hardness.

Sizes range from 0.1 to 4 mm. Hardness is R55-60C. Packing is in 50 lb. bags. Bulk density is 4.6 g/cc. Specific Gravity is 7.85 g/cc.
NOTE: Other sizes are available. Please contact us to inquire.