Differences between cast and forged grinding ball?
The ball mill grinding ball on the market now can be divided into two kinds according to the manufacturing process: Cast grinding Ball and forged steel ball, but their wear degree is not the same. Due to crushing and pulverizing materials, grinding balls need good abrasion resistance and enough impact toughness, and require steel balls cannot be broken, ball mill grinding balls can be divided into:
1. Cast Grinding Ball: Low Chromium grinding Ball, medium chromium grinding ball, high chromium grinding ball, super high chromium grinding ball (CR12%-28%).
2. Forged Steel Ball: Low Carbon Alloy grinding ball, medium carbon alloy grinding ball, high manganese grinding ball, rare earth Chromium-Molybdenum Alloy grinding Ball;
What’s the best grinding ball on the market right now? Now let’s look at this:
1. Quality index of High Chromium grinding balls: Chromium content ≥10.0%-12.0 %, carbon content between 1.80%-3.20% are called high chromium grinding balls, the national standard requires hardness (HRC) of high chromium grinding balls ≥58, impact value AK ≥3.0 j / 2. If the hardness high chromium grinding ball must adopt high-temperature quenching + tempering treatment (at present domestic high chromium grinding ball quenching oil quenching, wind quenching, water solution, and other quenching methods), if the hardness (HRC) is below 54, then the high chromium grinding ball has not been quenched.
2. Ultra-high Chromium grinding Ball Quality Index: Chromium contents ≥12.0%-28.0 %, carbon contents between 1.80%-3.30% are all called high chromium grinding ball, the national standard requires high chromium grinding ball hardness (HRC) must ≥58, impact value AK ≥3.0 j / 2. If the hardness of the ultra-high Chromium grinding Ball must adopt high-temperature quenching + tempering treatment (at present, there are two quenching methods of oil quenching and wind quenching for ultra-high Chromium grinding Ball), if the hardness (HRC) is below 54, the ultra-high chromium grinding ball has not been quenched.
3. Medium Chromium grinding Ball Quality Index: the chromium content is 3.0-7.0 %, the carbon content is 1.80%-3.20% is called medium chromium grinding ball, the national standard request medium chromium grinding ball hardness (HRC) must ≥47 above, the impact value AK ≥2.0 j /cm 2, high-temperature tempering or vibratory stress relief (VSR) is used to improve the quality of grinding balls. If the grinding ball surface dark red indicates that the product has been high-temperature tempering, if the grinding ball surface is still metallic color indicates that the product is not high-temperature tempering.
4. Low Chromium Grinding Balls Quality Index: containing 0.5% ~ 2.5% chromium, containing 1.80% ~ 3.20% carbon are called low chromium grinding balls, national standard requirements low chromium grinding balls hardness (HRC) must ≥45, impact value AK ≥1.5 j /2. In order to ensure the quality of grinding ball, low chromium grinding ball should be tempered at high temperature or vibratory stress relief (in order to eliminate casting stress). If the grinding ball surface dark red indicates that the product has been high-temperature tempering, if the grinding ball surface is still metallic color indicates that the product is not high-temperature tempering.
5.Quality Index of forged steel balls: 0.1% ~ 0.5% chromium content (forged steel balls generally do not contain chromium) , carbon content is below 1.0% and steel balls are made of high temperature forging Some forging steel ball surface hardness (HRC) although can reach ≥56 above (quenching layer only about 15) , because the forging steel ball material hardenability is poor the core hardness is generally only more than 30 degrees. Under normal conditions, water quenching is often used for forging steel balls, so the broken rate of forged steel balls is very high.
WEAR RESISTANCE COMPARISON: ultra-high Chromium grinding Ball > High Chromium grinding Ball > medium chromium grinding ball > low chromium grinding steel ball > forged steel ball.