【摘要】 某700 MW水轮机组的大型镜板采用25CrMo4钢锭锻造而成,其镜面硬度均匀性是国产化的技术难点之一.为了给镜板制造工艺的制定提供理论基础,必须对25CrMo4钢的热处理性能进行研究.本文从热处理工艺的角度,采用模拟实验方法分析了淬火温度、回火温度和淬硬深度对25CrMo4的微观组织及硬度均匀性的影响.根据研究结果,对镜板面硬度差的质量控制提出以下热处理参考意见:镜板面各点回火温度波动极限应小于40℃,淬火深度差应控制在30 mm以内,同时要避免淬火时镜板面的不均匀换热.更多还原

【Abstract】 A large runner plate of 700 MW domestic hydrogenerator is manufactured with ingot of 25CrMo4 by forging. The high standard of hardness uniformity of mirror surface is a main technical difficulty of domestic large runner plate. To provide basic theory for manufacturing process of large runner plate,the heat treatment properties of 25CrMo4 must be studied. From the point of heat treatment,the effect of temperature and harden ability on microstructure and hardness uniformity of 25CrMo4 is investigated by heat-treating test. According to the results,some advice about control hardness uniformity of mirror surface are giving: the range of holding temperature variation between any points of runner surface must be limited to 40 ℃,the difference of depth of hardening must be less than 30 mm,meanwhile,non-uniform heat transfer on mirror surface must be avoided.更多还原