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一、前言拖拉机底盘齿轮的典型材料是低合金渗碳钢,如20Cr、18CrMnTi、20MnVB、25MnTiBR等。其传统生产工艺是锻造→正火→机加工→渗碳淬火→回火。但近年来,上述材料在生产过程中多次发生不正常情况:锻造正火后所得组织中有不同程度和数量的异常组织——粒状贝氏体。由于这种组织的出现,硬度随之增高,给冷加工带来了困难。下面简要叙述出现不正常组织的具体情况、产生原因以及消除的措施。
First, the foreword Tractor chassis gear typical material is low alloy carburized steel, such as 20Cr, 18CrMnTi, 20MnVB, 25MnTiBR and so on. The traditional production process is forging → normalizing → machining → carburizing and quenching → tempering. However, in recent years, these materials occur many times in the production process abnormalities: after forging normalizing the organization has varying degrees and the number of abnormal tissue - granular bainite. As a result of this organization, the hardness increases, resulting in difficulties in cold-working. The following brief description of the specific circumstances of abnormal organizations, causes and elimination of measures.