一、螺旋埋弧焊钢管公称外径、公称壁厚和单位长度质量(BG/T9711.1-1997、GB/T9711.2-1999、API Spec 5L) Ⅰ、The specified outside、specified wall thickness and weight per unit length of the spiral submerged are weling steel pipe(BG/T9711.1-1997、GB/T9711.2-1999、API Spec 5L)