Chiu and Seman (1971) studied the head loss of flows transporting sediment in circular and square pipes with spiraling motion.

邱和思门(1971)研究了在圆管和方形管中输沙时具有螺旋运动的水流的水头损失问题。

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The vertical feed fly saw, equiped on most straight welding pipe sets, can not be suitable to cut square shaped pipes because of serious deformation on the cut face.

当前一些直缝焊管机组所配备的垂直进锯型飞锯因易造成切断端面严重变形，不适合锯切正位生产的方矩型类管材。

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ERW pipe and profile machine complete line to manufacture, round square and rectangular pipes. install and start the BTM520 (76-165mm) hot and cold rolled steel coils.

中径电阻焊管生产线，用来生产圆管、方管和矩形管，起始原料是根据BTM 520标准的76 - 165 mm的热轧和冷轧钢卷。

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