| 摘要 |
Apparatus for reducing the diameter, rounding or straightening of pipe or tubing by rolling comprising a plurality of closely and equallyspaced, long, narrow, parallel-cylindrical rollers arranged in a parallelcylindrical array through which said pipe or tubing is passed at a constant linear speed, said rollers being skewed to displace their central contact zones radially inwards bringing them into forceful contact with the external surface of said pipe or tubing, and being rotated to cause said central contact zones to describe continuous, parallel, overlapping, helical paths along the external surface of said pipe or tubing and thereby to progressively apply locally to the whole of the external surface of said pipe or tubing a compressive force in excess of the yield strength of its material, causing said pipe or tubing to adopt a set at a smaller diameter.
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