核主泵转子屏蔽套真空热胀形原理及技术

目的 为保证真空热胀形工艺对屏蔽套的成形精度,进而保证后续的套装质量,研究真空热胀形工艺的矫形能力及成形原理.方法 利用有限元软件MSC.Marc,建立了核主泵转子屏蔽套热胀形过程的二维轴对称热力耦合有限元模型,通过对焊接后屏蔽套测量得到模型中屏蔽套尺寸,通过此模型计算了屏蔽套在热胀形过程中的温度场、应力场、应变场及径向位移场,预测了屏蔽套胀形后的形状,分析了热胀形对屏蔽套的矫形原理,并对屏蔽套进行了真空热胀形实验,从而对有限元模型的可靠性进行验证.结果 计算结果表明,热胀形过程中,屏蔽套上发生了较大的塑性应变和蠕变应变,热胀形后,屏蔽套的内径在276.879～276.883 mm之间.实验结果表明,热胀形实验后屏蔽套的半径分布与有限元模型计算结果符合良好.结论 热胀形工艺通过使屏蔽套发生塑性变形和蠕变变形,实现了对屏蔽套尺寸及形状的精确控制,其中,塑性变形是热胀形工艺可以对屏蔽套上的形状缺陷进行治理的原因.

Principle and Technique of Vacuum Hot Bulge Forming Process of Reactor Coolant Pump Rotor-can

The work aims to study the shape-righting capacity and forming principle of vacuum hot bulge forming process to ensure the forming precision of vacuum hot bulge forming process on rotor-can and further ensure the fitting quality. The finite element software MSC.Marc was used to establish a 2-D axisymmetric thermo-mechanical coupled finite element model for the vacuum hot bulge forming process of reactor coolant pump. The initial dimension of the rotor-can was measured from the rotor-can after welding. Using this model, the temperature field, stress/strain field and radical displacement field on rotor-can during vacuum hot bulge forming process were calculated, the shape of rotor-can after vacuum hot bulge forming process was predicted, and the forming principle of vacuum hot bulge forming process was analyzed. Vacuum hot bulge forming experiment was conducted on the rotor-can to verify the reliability of the finite element. The calculation results indicated that large plastic strain and creep strain occurred on roton-can during vacuum hot bulge forming process. After vacuum hot bulge forming process, the radius of the rotor-can was 276.879-276.883 mm. The experimental results of the radius distribution of the rotor-can after vacuum hot bulge forming process was in good agreement with the calculation result of the finite element model. The vacuum hot bulge forming process can realize the precise control of the size and shape of the rotor-can by plastic deformation and creep deformation, in which plastic deformation is the reason why the vacuum hot bulge forming process can repair the shape defects on the rotor-can.