... ’ requirements. The main technical parameters of gearStandard of materials: GB/T3077-1999The grade of materials: 45, 20Cr, 40Cr , ... method: electric arc furnace + refining furnacePrecision accuracy: according to GB/T10095-88 standard, within five degradeHardness: 56-60 HRC ... ultrasonic flaw detectionAll forging pieces must go through the GB/T6402-1999 standard ultrasonic flaw detection, grade two. ...