铸铁蝶阀的开度与流量之间的关系，基本上呈线性比例变化。如果用于控制流量，其流量特性与配管的流阻也有密切关系，如两条管道安装阀门口径、形式等全相同，而管道损失系数不同，阀门的流量差别也会很大。
The relationship between the opening and flow of cast iron butterfly valve is basically linear proportional change. If it is used to control the flow, its flow characteristics are also closely related to the flow resistance of the piping. For example, the diameter and form of the valve installed in the two pipelines are the same, and the loss coefficient of the pipeline is different, the flow rate of the valve will be greatly different.
如果阀门处于节流幅度较大状态，阀板的背面容易发生气蚀，有损坏阀门的可能，一般均在15°外使用。
If the valve is in a large throttling range, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, it is used outside 15 ℃.
铸铁蝶阀处于中开度时，阀体与蝶板前端形成的开口形状以阀轴为中心，两侧形成完成不同的状态，一侧的蝶板前端顺流水方向而动，另一侧逆流水方向而动，因此，一侧阀体与阀板形成似喷嘴形开口，另一侧类似节流孔形开口，喷嘴侧比节流侧流速快的多，而节流侧阀门下面会产生负压，往往会出现橡胶密封件脱落。
When the cast iron butterfly valve is in the middle opening, the shape of the opening formed by the front end of the valve body and the butterfly plate is centered on the valve shaft, and the two sides are formed in different states. The front end of the butterfly plate on one side moves in the direction of water flow, and the other side moves against the direction of water flow. Therefore, one side of the valve body and the valve plate form a nozzle shaped opening, and the other side is similar to a throttle orifice type opening. The flow velocity of the nozzle side is much faster than that of the throttling side Negative pressure will be generated under the valve at the flow side, and the rubber seal will often fall off