Stainless Steel Ball 420 Application Fields: 420 Stainless Steel Balls are commonly used in industries that require high precision and corrosion resistance, such as motorcycle accessories, pulleys, stainless steel bearings, plastic bearings, craftwork, valves, and oil industry. Material Comparison: Domestically, 420 stainless steel balls are mainly categorized into two types: 2Cr13 steel balls (equivalent to Japanese standard SUS420J1), and 3Cr13 steel balls (equivalent to Japanese standard SUS420J2). Both types of balls have hardness, but many customers have a misconception that 410 stainless steel balls (equivalent to Chinese standard 1Cr13) and 430 stainless steel balls (1Cr17) also have hardness. Although both are 4-series stainless steel balls, their microstructure is different: one is a martensitic steel, and the other is a ferritic steel. (All provided materials are original; any similarity is coincidental and not plagiarism.) Characteristics: Representative of the martensitic steel, commonly known as stainless iron, it has magnetism, good corrosion resistance, and high hardness of HRC50-55.