Is there no difference between high chromium balls and medium chromium balls, low chromium balls, and forged steel balls?

Different quality indicators for high chromium balls: Chromium content ≥ 10.0% and carbon content between 1.80% and 3.20% are called high chromium balls. According to national standards, high chromium balls must have a hardness (HRC) of 58 or above and an impact value of ak ≥ 3.0J/cm2. To achieve this hardness, high chromium balls must be subjected to high-temperature quenching and tempering treatment (currently, there are two quenching methods in China: oil quenching and air quenching), If the hardness (HRC) is lower than 54, it indicates that the steel ball has not undergone quenching treatment.
Quality indicators of medium chromium balls: chromium content of 3.0% to 7.0%, carbon content between 1.80% and 3.20% are all referred to as medium chromium balls, with an impact value of ak ≥ 2.0J/cm2. According to national standards, the hardness (HRC) of medium chromium balls must be ≥ 47 or above. To ensure the quality of steel balls, high temperature tempering treatment is required (to achieve the purpose of eliminating casting stress). If the surface of the steel ball is dark red, it indicates that the product has undergone high temperature tempering treatment If the surface of the steel ball still appears metallic, it indicates that the product has not undergone high-temperature tempering treatment.
Low chromium ball quality indicators: chromium content of 0.5% to 2.5%, carbon content between 1.80% and 3.20% are all referred to as low chromium balls. National standards require that the hardness (HRC) of low chromium balls must be ≥ 45, and the impact value ak ≥ 1.5J/cm2. To ensure the quality of steel balls, low chromium balls also need to be subjected to high-temperature tempering treatment (to eliminate casting stress). If the surface of the steel ball is dark red, it indicates that the product has undergone high-temperature tempering treatment If the surface of the steel ball still appears metallic, it indicates that the product has not undergone high-temperature tempering treatment.
Quality index of forged steel balls: with a chromium content of 0.1% to 0.5% (forged balls generally do not contain chromium), a carbon content of less than 1.0%, and the steel balls are manufactured by high-temperature forging. Although the surface hardness (HRC) of some forged steel balls can reach ≥ 56 or above (the quenching layer is only about 15mm), due to the poor hardenability of the forged steel ball material, the core hardness is usually only over 30 degrees. Under normal circumstances, water quenching treatment is often used for forged steel balls.