Bulk Steel Ball Product Introduction The Ball Bearings are usually used in industries that require high accuracy and rust prevention performance, such as aviation, aerospace, bearings, motors, high-precision instruments, valves, petroleum, etc. They are made of high-quality stainless steel, which has the characteristics of acid resistance, alkali resistance and corrosion resistance. In addition, our Ball Bearings are two times harder than copper and ten times harder than aluminum. They are also anti-pull, anti-moisture and anti-oxidation. Advantages These Ball Bearings can be made in different specifications to meet customers' requirements. We have advanced production equipment and perfect testing instruments for roundness testing, vibration testing, gauge testing, surface finish testing, rockwell hardness testing. So you can rest assure that the quality of our steel balls is guaranteed and the price we offer is reasonable. 440C STAINLESS STEEL BALL Size range0.50mm (0.02") up to 50.8mm (2") GradesG3, G5, G10, G16, G20, G24, G28, G40, G60, G100, G200 HardnessHRC 58 Min. MATERIAL CONVERSION GB (China)9Cr18Mo ASTM/AISI (USA)440C JIS (Japan)SUS440C CHEMICAL COMPOSITION STEEL NUMBER440C Carbon (C)0.95% - 1.10% Silicon (Si)0.8% Max. Manganese (Mn)0.8% Max. Phosphorous (P)0.035% Max. Sulphur (S)0.03% Max Nickel (Ni)3% Chromium (Cr)16% - 18% PHYSICAL CHARACTERISTICS Tensile strength285,000 psi Yield strength275,000 psi Modulus of Elasticity29,000,000 psi Density0.277 lbs/in3 Corrosion resistanceYes, comparison details as below chart. MagneticYes APPLICATION Bearings, stamping / hydraulic parts, valves, seals refrigeration equipment, aerospace high-precision mechanical parts, crafts, toys,etc.Bulk Steel Ball website:http://www.mz-balls.com/steel-balls/