1, high chromium ball quality indicators:
Chromium content ≥ 10%, carbon content between 1.8%-3.2% is called high chromium ball, national standards require high chromium ball hardness (HRC) must be ≥58 above, impact value ak≥3.0j/㎝2, if the hardness of high chromium ball must be high temperature quenching + tempering treatment (at present, the domestic high chromium quenching oil quenching and wind quenching two quenching methods), such as detection of hardness (HRC) less than 54 of the following indicates that high chromium ball has not been quenched.
2, medium chromium ball quality index:
Chromium content 3.0%~7.0%, carbon content between 1.8%-3.2% is called the middle chromium ball, impact value ak≥2.0j/㎝2, the national standard requirements of chromium ball hardness (HRC) must ≥47 above, in order to ensure the quality of steel ball, the medium chromium ball must adopt high-temperature tempering treatment (in order to achieve the elimination of casting stress), such as the surface of the steel ball dark red indicates that the product has been high-temperature tempering treatment, such as the surface of the steel ball is still metal color indicates that products do not have high-temperature
3, low chromium ball quality indicators:
Chromium content 0.5% ~ 2.5%, carbon content between 1.8%-3.2% is known as low chromium ball, national standards require low chromium ball hardness (HRC) must be ≥45 above, impact value ak≥1.5j/㎝2, in order to ensure the quality of steel ball, low chromium ball also need to adopt high-temperature tempering treatment (to achieve the goal of eliminating casting stress), such as the surface of the steel ball is dark red indicates that the product has been high-temperature tempering treatment, such as steel ball surface still metal color indicates that the product does not have high-temperature
4, forged steel Ball quality index:
Chromium content 0.1% ~ 0.5% (the forging ball generally does not contain chromium), carbon content under 1% and steel balls are made of high temperature forge, some forge steel ball surface hardness (HRC) Although can reach above the ≥56 (quenching layer only 15mm or so), because the forging steel ball material hardenability is poorer its heart hardness generally only has 30 degrees, under normal circumstances the forging steel ball often uses the water quenching treatment.
5, wear resistance comparison:
Quenched and processed high chromium ball, medium chrome ball, low chrome ball, forged steel ball.