Fatigue-resistant internal thread copper pipe and preparation method thereof

• Main Authors: QIAO GAOPAN, YU CHAOJIE, HUANG HONGBING, MAO XIANGFEI
• Format: Patent
• Language: Chinese; English
• Published: 22.12.2023
• Subjects: AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKINGWITHOUT ESSENTIALLY REMOVING MATERIAL; BLASTING; CHEMISTRY; ENGINEERING ELEMENTS AND UNITS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; JOINTS OR FITTINGS FOR PIPES; LIGHTING; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES,OTHERWISE THAN BY ROLLING; MEANS FOR THERMAL INSULATION IN GENERAL; MECHANICAL ENGINEERING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PIPES; PUNCHING METAL; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; THERMAL INSULATION IN GENERAL; TRANSPORTING; WEAPONS

The invention discloses a preparation method of a fatigue-resistant internal-thread copper pipe. The preparation method comprises the following steps: horizontally and continuously casting molten copper into a cast ingot; the cast ingot is subjected to face milling, rolling and duplex drawing in sequence to form a hard-state duplex drawing pipe blank, and the rolling process is as follows: the deformation temperature is 700-800 DEG C, the elongation coefficient is 5-8, the water flow rate for rolling once is 5-10 m < 3 >/h, and the water temperature is 35-55 DEG C; performing multi-pass disc drawing on the hard joint drawing pipe blank to obtain an internal thread mother pipe; carrying out on-line induction annealing on the internal thread mother pipe to obtain a soft internal thread mother pipe; and internal thread forming and finished product annealing are sequentially carried out on the soft-state internal thread mother pipe to obtain the fatigue-resistant internal thread copper pipe, the finished product