Mid chrome grinding ball

Grinding Balls-Mid Chrome

Mid chrome grinding ball

Specification

Ball Diameter (mm)
 ¢ 10 ¢ 12.7 ¢ 15 ¢ 17 ¢ 20 ¢ 25 ¢ 30 ¢ 40 ¢ 50 ¢ 60 ¢ 70 ¢ 80 ¢ 90 ¢ 100 ¢ 110 ¢ 120 ¢ 125 ¢ 130

Chemical Composition

Designation Chemical Composition
C Si Mn Cr Mo Cu Ni Nb Ti Zr V B P S

Mid chrome grinding ball I

1.8-3.2 0.5-1.5 0.3-1.5 3.2-7.0 ≤0. 5 ≤0. 8 ≤0. 5 ≤0. 2 ≤0. 5 ≤0. 5 ≤0. 5 ≤0.1 ≤0.15 ≤0. 1
Mid chrome grinding ball II 1.8-3.2 0.5-1.5 0.3-1.5 7.0-10 ≤0. 5 ≤0. 5 ≤0. 5 ≤0. 2 ≤0. 5 ≤0. 5 ≤0. 5 ≤0.1 ≤0.15 ≤0. 1

Properties and Microstructure

Designation (HRC) Hardness Ak(J/cm2) Microstructure Time of Falling Balls
Mid chrome grinding ball     I 48-56 ≥2.0 P+C

≥18000

Mid chrome grinding ball II 50-62 ≥2.5 M+C

≥18000

The ball with chromium content from 3.0% to 7.0% and the carbon content between 1.80% -3.20% is called middle chrome grinding ball. Its impact value ak≥2.0J / cm 2, and the hardness (HRC) must be above ≥47 in national standard. In order to ensure the balls quality, it need high-temperature tempering to eliminate the stress of casting. If the balls surface is dark red, it indicates that the product has been tempering treatments, and the original color in ball surface indicates that the product is not hot tempered.