seat ring短语¹⁴⁴⁹⁷²⁺² 基本例句 座圈 Contrasting machining technology with punch technology of elastic seat ring, analyzing the error created by punching, introducing the characteristic of punching and the structure of cut and carry die. 对弹性阀座的机械加工工艺和冲压加工工艺进行了对比，并分析了冲压加工所产生的误差，介绍了冲压加工的特点及级进模的结构。 chemyq