The grain refinement of the extruded mother tubes with water quenched extrusion and the quality improvements of seamless copper tubes for ACR

摘要

To improve the quality of seamless copper tubes, we have modified the extrusion method from conventional extruding into reducing gas to water quenched extrusion. The mother tubes are extruded into a jet stream of water for quickly quenching by Water Jet Tube device made by Mitsui Engineering & Shipbuilding Co. From these modifications, we can improve the copper tube quality such as the grain refinement and the decrease in number and depth of outer surface defects for extruded mother tubes. In addition, for final products, the number of cracking in tube expanding process at customers, which is caused by micro axial defects on outer surface of tube, was greatly decreased.