Needle Bearing Rollers are made from bearing steel (JIS SUJ-2/SAE 52100/DIN 100 Cr6) and have been subjected to heat treatment and precision grinding radius diameter deviation; the hardness is HV700-860 (HRC60-66), All the raw material comes from Japan directly, High-purity Chromium Molybdenum alloy steel (JIS SCM415) with Carbon Nitriding heat-treatment process, The hardness specification is at HV500~HV600; it can meet the requirement of high-speed engine applications, Heat treated and ground to precision tolerances for reduced heat and extended life