Method for preparing high-performance difficult-to-deform metal precision seamless pipe

A method for preparing a high-performance difficult-to-deform metal precision seamless pipe, comprising steps of:

• 1) performing a first heat treatment:
• heating a solid metal blank (101) after sizing to reduce a metal resistance;
• wherein the sized solid metal blank (101) is transported into a heating furnace (1) through a furnace bottom roller bed (11), and four sets of furnace flame nozzles (12) are divided into an upper layer and a lower layer in the heating furnace (1);
• a heating temperature is determined according to metal properties of the solid metal blank (101);
• during heating, an error between an actual heating temperature and the heating temperature determined according to the metal properties of the solid metal blank (101) is ±10° C.;
• 2) drilling:
• drilling a hole on the heated solid metal blank (101) to obtain a hollow blank pipe (102);
• wherein the heated solid metal blank (101) is drilled through large rolling angle drilling, to obtain the hollow blank pipe (102);
• during the large rolling angle drilling, an upper cylindrical roller (21) and a lower cylindrical roller (22) rotate oppositely to in-take the solid metal blank (101);
• under a pulling force of the upper cylindrical roller (21) and the lower cylindrical roller (22), the solid metal blank (101) contacts with a rotating head (23) which drills a cavity in a center of the solid metal blank (101) to obtain the hollow blank pipe (102);
• a total deformative compression of the solid metal blank (101) is 10%-25%, a tip compression of the rotating head (23) is 3%-12%, and a roller taper angle is 12°-25°;
• 3) externally grinding:
• grinding an external wall of the hollow blank pipe (102);
• 4) internally grinding:
• grinding an internal wall of the hollow blank pipe (102);
• 5) cleaning oil stains:
• cleaning the internal wall and the external wall of the ground hollow blank pipe (102);
• 6) straightening:
• straightening the cleaned hollow blank pipe (102) to eliminate bending and collapse of the hollow blank pipe (102) due to uneven metal strain distribution caused by drilling and grinding;
• 7) performing four-roller warm-rolling:
• processing the straightened hollow blank pipe (102) with the four-roller warm-rolling to perform large-deformation isothermal-rolling, thereby obtaining a metal seamless pipe (103) with a reduced diameter;
• 8) degreasing:
• degreasing the metal seamless pipe (103) with the reduced diameter;
• 9) brightening:
• brightening the degreased metal seamless pipe (103);
• 10) performing surface grinding:
• processing the brightened metal seamless pipe (103) with the surface grinding;
• 11) cleaning dust:
• cleaning the ground metal seamless pipe (103) to obtain the high-performance difficult-to-deform metal seamless pipe (103);
• 12) detecting flaws:
• processing the high-performance difficult-to-deform metal seamless pipe (103) with ultrasonic flaw detection and discarding unqualified high-performance difficult-to-deform metal seamless pipe (103);
• 13) testing metal structure performance:
• sampling the qualified high-performance difficult-to-deform metal seamless pipe (103) and testing the metal structure performance;
• and repeating the steps 7-13 to the unqualified high-performance difficult-to-deform metal seamless pipe (103) until the qualified high-performance difficult-to-deform metal seamless pipe (103) is obtained;
• and
• 14) sizing and packaging:
• packaging the qualified high-performance difficult-to-deform metal seamless pipe (103).