Grinding Media Steel

Grinding media steel is classified into three main types: forged, cast, and hot-rolled grinding media steel.

1. Forged Grinding Media Steel:Forged grinding media steel balls are produced by cutting round steel into sections and forging them using an air hammer. The wear resistance of these balls is closely linked to the quality and material of the round steel used, including the presence of impurities.

• Primary Materials:45# steel, 50Mn, 60Mn, 65Mn, with 75MnCr material currently providing wear resistance comparable to high-chromium balls.
• Advantages:These balls have a breakage rate of less than 1%, excellent wear resistance, and are cost-effective.

2. Cast Grinding Media Steel:Cast grinding media steel balls mainly consist of chromium alloys, which offer varying degrees of oxidation resistance and resistance to corrosion from high sulfur content, diesel fuel, and seawater. However, they have lower strength and density compared to forged steel balls, with a higher breakage rate.

• Low Chromium Alloy Cast Balls:Containing 1%-3% chromium, with hardness HRC≥45. These are typically produced using medium-frequency electric furnaces and are suitable for applications with lower precision grinding requirements, such as in metallurgical mining and slag processing.
• Multi-Element Alloy Cast Balls:With 4%-6% chromium content, hardness HRC≥47, offering slightly better strength and wear resistance than low-chromium balls.
• Medium Chromium Alloy Cast Balls:Containing 7%-10% chromium, hardness HRC≥50, superior in performance compared to multi-element alloy balls.
• High Chromium Alloy Cast Balls:Containing 10%-14% chromium, hardness HRC≥58. Widely used in the cement industry, these balls offer excellent wear resistance but are gradually being replaced by forged products due to their lower cost-effectiveness.
• Special High Chromium Steel Balls:With over 14% chromium content and hardness HRC≥58, these are used in industries requiring fine grinding and high wear, though they come with a higher price and lower cost-effectiveness compared to other high-chromium balls.

3. Hot-Rolled Grinding Media Steel:The performance of hot-rolled grinding media steel balls varies depending on the material used. These balls are produced through a rotary cutting production line and have seen rapid growth in recent years due to their high production efficiency and enhanced wear resistance.

• Examples:For 100mm steel balls, the surface hardness and core hardness vary across different grades:
  • Surface HRC55-60, Core 20-25
  • Surface HRC55-60, Core 30-35
  • Surface HRC58-63, Core 40-45
  • Surface HRC58-63, Core 55-60
  • Surface HRC60+, Core 58+

Large and medium-sized enterprises typically use the second and third grades, while ultra-large enterprises prefer the fourth and fifth grades.