短语词组短语nodular cast -iron pipe 球墨铸铁管unannealed nodular cast iron pipe 铸态球墨铸铁管centrifugal nodular cast iron pipe 离心球铁管nodular iron cast pipe 球铁铸管centrifugally cast nodular iron pipe 离心球墨铸铁管 返回 nodular cast iron pipe