405 Piping erection work include: prefabrication, placing, aligning, welding and bolting.
405 Piping erection work include: prefabrication, placing, aligning, welding and bolting.
管道安装工作包括：预制加工、安置、对准、焊接和连接。
405 Piping erection work include: prefabrication, placing, aligning, welding and bolting.
管道安装工作包括：预制加工、安置、对准、焊接和连接。