... custumers’ requirements.The main technical parameters of gear1.Standard of materials: GB/T3077-19992.The grade of materials: 45, 20Cr, 40Cr ... Mo , 42Cr Mo, 20CrMnMo, 20CrMnTi, 17CrNiMo6, 20CrNi2Mo3.Standard of pruduction: ISO1328-19954.Smelting method: electric arc furnace + refining ... test is done according to GB/T231 standardStandard of ultrasonic flaw detectionAll forging pieces must go through ...