US 12,290,848 B1
Efficient preparation method of bimetallic seamless composite pipe
Jianchao Han, Taiyuan (CN); Yanjun Wang, Taiyuan (CN); Yi Jia, Taiyuan (CN); Xinlong Zhang, Taiyuan (CN); Wei Zhang, Taiyuan (CN); Yizhi Zhang, Taiyuan (CN); Shuzhi Zhang, Taiyuan (CN); Changjiang Zhang, Taiyuan (CN); and Tao Wang, Taiyuan (CN)
Assigned to TAIYUAN UNIVERSITY OF TECHNOLOGY, Taiyuan (CN)
Filed by TAIYUAN UNIVERSITY OF TECHNOLOGY, Taiyuan (CN)
Filed on Jul. 10, 2024, as Appl. No. 18/768,250.
Claims priority of application No. 202410026985.9 (CN), filed on Jan. 9, 2024.
Int. Cl. B21C 23/22 (2006.01); B21C 23/00 (2006.01); B21C 29/00 (2006.01); C21D 1/30 (2006.01)
CPC B21C 23/22 (2013.01) [B21C 23/002 (2013.01); B21C 29/003 (2013.01); C21D 1/30 (2013.01)] 2 Claims
OG exemplary drawing
 
1. An efficient preparation method of a bimetallic seamless composite pipe, comprising following steps:
(1) material selection: materials of a base pipe blank and a cladding pipe blank are different, and a material of the base pipe blank is 6061 aluminum alloy or 5052 aluminum alloy; a material of the cladding pipe blank is 1060 aluminum alloy, AZ31B magnesium alloy or T2 copper;
(2) sheathing the base pipe blank on the cladding pipe blank to obtain a composite pipe blank;
selecting an outer diameter D0 of the composite pipe blank according to an inner diameter D1 of an extrusion cylinder, wherein a selection rule is D0=D1−(0.3-10) mm, and units of D1 and D0 are mm;
selecting an inner diameter do of the composite pipe blank according to a diameter D2 of a core rod, wherein a selection rule is d0=D2+(1-3) mm;
(3) a shape of an assembly interface between the base pipe blank and the cladding pipe blank: an outer contour of the cladding pipe blank is processed from a big end to a small end in transition, an outer diameter of the big end is 1.5-2.6 times an outer diameter of the small end, and an inner contour of the cladding pipe blank is cylindrical;
an outer contour of the base pipe blank is cylindrical, an inner contour of the base pipe blank is matched with the outer contour of the cladding pipe blank, and there is a gap of 0.05 mm between the inner contour of the base pipe blank and the outer contour of the cladding pipe blank;
(4) calculating a wall thickness b03 of the small end of the cladding pipe blank according to a wall thickness b1 of a formed base pipe wall, a wall thickness b2 of a cladding pipe wall, and a difference between an elastic modulus E2 of a cladding pipe material and an elastic modulus E1 of a base pipe material, wherein b03=b2+K, and K is a supplementary wall thickness of the cladding pipe blank; when E2−E1<−10 GPa, K=0.5-1 mm; when −10 GPa≤E2−E1≤0 GPa, K=0.2-0.5 mm; and when E2−E1>0 GPa, K=0-0.2 mm; and units of E1 and E2 are GPa;
(5) carrying out a stress relief annealing treatment on the composite pipe blank, wherein a temperature of the stress relief annealing treatment is 280-350° C., and a duration is 2 h; and
(6) heating the composite pipe blank obtained in step (2) after the stress relief annealing treatment to a hot working window temperature, then sheathing the composite pipe blank onto the core rod of the extrusion cylinder after an insulation treatment, and then extruding the composite pipe blank along an axial direction of the extrusion cylinder to obtain a bimetallic seamless composite pipe;
the hot working window temperature is 0.75-0.95 times of a melting point of a metal;
an outer diameter of a composite pipe blank is defined as D0 mm, and when D0<50 mm, an insulation duration for the insulation treatment is (1.5×D0) min; when 50 mm<D0<100 mm, the insulation duration for the insulation treatment is [(1.5+0.01×(D0−50))×D0] min; when D0>100 mm, the insulation duration for the insulation treatment is (2.5×D0) min;
a temperature for the extrusion is a same as the temperature for the insulation treatment; an extrusion ratio of the extrusion is 25, and an extrusion speed is 1-5 mm/s;
units of D1, D2, D0, d0, b1, b2, b03 and K are all mm.