Manufacturing method of thin-walled large-diameter pipe with high-pressure copper-nickel alloy for marine engineering

Abstract

The invention relates to a manufacturing method of a thin-walled large-diameter pipe with high-pressure copper-nickel alloy for marine engineering. The manufacturing method comprises the following steps: (1), performing semi-continuous casting on copper and nickle as raw materials to obtain a copper-nickel alloy solid round billet; (2), performing boring: boring in the center of the copper-nickelalloy solid round billet to obtain an inner hole which can penetrate through the center of the copper-nickel alloy solid round billet in the axial direction; (3), performing reaming: heating a billetmaterial, controlling the outside diameter to be invariable, and reaming the inner hole by 3.5 times to 7 times; (4), performing hot extrusion: carrying out water sealing and extrusion on the billet material into hot extrusion pipe in a way of matching with an extrusion module and extruding a steel pipe in the radial direction and in the axial direction, enabling a discharging end of the extrusionmodule to be directly in abutting joint with a water sealing tank, and directly immersing a pipe billet subjected to hot extrusion molding into water to ensure that the pipe billet is isolated from the air so as to prevent oxidation, removing a surface layer of the pipe billet subjected to hot extrusion, and eliminating surface defects; (5), performing straightening: straightening the pipe billetsubjected to hot extrusion; (6), stretching or cold-rolling the pipe billet in several times until a final specification of the pipe billet is obtained, and carrying out annealing after stretching orcold rolling is performed every time; (7) shaping; and (8) performing formation and thermal treatment.

Description

technical field

[0001] The invention belongs to the technical field of manufacturing copper-nickel alloy pipes, and in particular relates to a method for manufacturing thick-walled medium-high pressure copper-nickel alloy large-diameter pipes for marine engineering liquefied natural gas (LNG) transmission. Background technique

[0002] Copper-nickel alloy has high mechanical properties and corrosion resistance, and has good press workability in hot and cold states. Copper-nickel alloys are widely used in marine engineering as medium and high pressure pipes. A certain wall thickness is an effective guarantee for medium and high pressure pipes. It is difficult to realize the production of large-diameter thick-walled copper-nickel alloy main pipes through traditional processes. Only by improving the manufacturing method of copper-nickel alloy pipes can the thick-walled large-diameter seamless pipe main pipes be guaranteed. production.

[0003] The patent document with the not...