Preparation method of ultra-large-diameter copper-nickel alloy seamless tube

Abstract

The invention discloses a preparation method of an ultra-large-diameter copper-nickel alloy seamless tube, which comprises the following steps of: obtaining a cold-rolled raw material which is uniform in internal structure and free from pores by using forging and cross piercing methods, and then performing cold rolling to eliminate an as-cast state, performing hot working on the structure to fully refine crystal grains and drawing the raw material which meets the equipment requirements in diameter and wall thickness; the large-diameter seamless pipe with the diameter of 508 mm is prepared, and the produced large-diameter seamless pipe is excellent in mechanical performance, uniform in grain size and internal structure and high in practicability and economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of alloy seamless pipe preparation, and in particular to a method for preparing an ultra-large-caliber copper-nickel alloy seamless pipe. Background Art

[0002] Large-diameter copper-nickel alloy seamless pipes with a diameter of Ф508mm and a unit weight of more than 600KG are high-end copper alloy pipes that are widely used in large-tonnage submarines and marine engineering fields and are extremely scarce in the market. Due to their large diameter, existing technical equipment is unable to complete the processing and preparation of copper-nickel alloy pipes with a diameter of Ф508mm. Currently, welded pipes are mainly used to replace seamless pipes. However, since the overall strength and compressive resistance of welded pipes are inferior to those of seamless pipes, they cannot be the best substitute for seamless pipes. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a method for preparing ultra-large diameter copper-nickel alloy seamless pipes, which is used to solve the problem that existing process equipment cannot complete the processing and production of large diameter copper-nickel alloy seamless pipes.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows: 1. A method for preparing an ultra-large diameter copper-nickel alloy seamless pipe, comprising the following steps: S1. Casting: casting a solid ingot with a diameter greater than 440 mm, and a single solid ingot weight greater than 600 kg; S2, heating, heating the cast solid ingot to 920℃-940℃, and keeping the temperature for 60min-90min after heating; S3, forging, forging the heated solid ingot by a fast forging press, and forging the solid ingot with a diameter greater than 440 mm into a blank tube with a diameter of 650 mm; S4, oblique rolling, oblique rolling and punching the blank tube with a diameter of 650 mm after forging, the hole diameter after oblique rolling and punching is 560 mm, and the oblique rolling and punching temperature is 880℃-920℃; S5, hot rolling, hot rolling the blank tube after oblique rolling and piercing, the hot rolling temperature is 750℃-820℃, and the diameter of the blank tube after hot rolling is 560mm; S6, cold rolling, the tube blank after hot rolling is cold rolled at room temperature, and the diameter of the tube blank after cold rolling is 508mm; S7, heat treatment, annealing the tube blank after cold rolling, annealing temperature is 750℃-780℃, heat preservation time is 60min-90min; S7, stretching, using a stretching machine of more than 300 tons to stretch the annealed tube embryo, and adjust the wall thickness of the tube embryo to 4-7mm.

[0005] Preferably, the heating method in step S2 is heating using a high-temperature box-type resistance furnace.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention utilizes the forging and oblique rolling and perforation methods to obtain a cold-rolled raw material with uniform internal structure and no pores, and then cold-rolls to eliminate the cast state and hot-processed structure to make the grains fully refined and the diameter and wall thickness of the stretched raw material meet the equipment requirements, and prepares a large-diameter seamless pipe with a diameter of 508 mm. The produced ultra-large-diameter seamless pipe has excellent mechanical properties, uniform grain size and internal structure, and has strong practicality and economic benefits. DETAILED DESCRIPTION

[0007] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0008] Embodiment 1, A BFe10-1.6-1 ultra-large diameter copper-nickel alloy seamless pipe with a specification of Ф508×4mm is produced. The pipe diameter is 508mm and the wall thickness is 4mm. The raw material is BFe10-1.6-1 white copper for casting.

[0009] A method for preparing an ultra-large-caliber copper-nickel alloy seamless pipe comprises the following steps: S1. Casting: casting a solid ingot with a diameter of 445 mm and a single solid ingot weight of 610 kg; S2. Heating: using a high temperature box-type resistance furnace to heat the cast solid ingot to 920°C, and then keeping the temperature for 60 minutes; S3, forging, forging the heated solid ingot by a fast forging press, and forging the solid ingot with a diameter of 445 mm into a blank tube with a diameter of 650 mm; S4, oblique rolling, oblique rolling and piercing the billet tube with a diameter of 650 mm after forging, the hole diameter after oblique rolling and piercing is 560 mm, and the oblique rolling and piercing temperature is 880°C; S5, hot rolling, hot rolling the blank tube after oblique rolling and piercing, the hot rolling temperature is 750°C, and the diameter of the blank tube after hot rolling is 560mm; S6, cold rolling, the tube blank after hot rolling is cold rolled at room temperature, and the diameter of the tube blank after cold rolling is 508mm; S7, heat treatment, annealing the tube blank after cold rolling, annealing temperature is 750℃, and heat preservation is 60min; S8, stretching, using a stretching machine of more than 300 tons to stretch the annealed tube embryo, and adjust the wall thickness of the tube embryo to 4mm.

[0010] Embodiment 2, A method for preparing an ultra-large-caliber copper-nickel alloy seamless pipe comprises the following steps: A BFe10-1.6-1 ultra-large diameter copper-nickel alloy seamless pipe with a specification of Ф508×5.5mm is produced. The pipe diameter is 508mm and the wall thickness is 5.5mm. The raw material is BFe10-1.6-1 white copper for casting.

[0011] S1. Casting: a solid ingot with a diameter of 450 mm and a single hollow ingot with a weight of 620 kg; S2. Heating: using a high temperature box-type resistance furnace to heat the cast solid ingot to 930°C, and then keeping the temperature for 75 minutes; S3, forging, forging the heated solid ingot by a fast forging press, and forging the hollow ingot with a diameter of 450 mm into a blank tube with a diameter of 650 mm; S4, oblique rolling, oblique rolling and piercing the billet tube with a diameter of 650 mm after forging, the hole diameter after oblique rolling and piercing is 560 mm, and the oblique rolling and piercing temperature is 900°C; S5, hot rolling, hot rolling the blank tube after oblique rolling and piercing, the hot rolling temperature is 795°C, and the diameter of the blank tube after hot rolling is 560mm; S6, cold rolling, the tube blank after hot rolling is cold rolled at room temperature, and the diameter of the tube blank after cold rolling is 508mm; S7, heat treatment, annealing the tube blank after cold rolling, annealing temperature is 765℃, and heat preservation is 75min; S8, stretching, using a stretching machine of more than 300 tons to stretch the annealed tube embryo, and adjust the wall thickness of the tube embryo to 5.5mm.

[0012] Embodiment 3, A BFe10-1.6-1 ultra-large diameter copper-nickel alloy seamless pipe with a specification of Ф508×4mm is produced. The pipe diameter is 508mm and the wall thickness is 7mm. The raw material is BFe10-1.6-1 white copper for casting.

[0013] A method for preparing an ultra-large-caliber copper-nickel alloy seamless pipe comprises the following steps: A BFe10-1.6-1 ultra-large diameter copper-nickel alloy seamless pipe with a specification of Ф508×7mm is produced. The pipe diameter is 508mm and the wall thickness is 7mm. The raw material is BFe10-1.6-1 white copper for casting.

[0014] S1. Casting: casting a solid ingot with a diameter of 450 mm, and the weight of the solid ingot is 630 kg; S2. Heating: using a high-temperature box-type resistance furnace to heat the cast solid ingot to 940°C, and then keeping the temperature for 90 minutes; S3, forging, forging the heated solid ingot by a fast forging press, and forging the solid ingot with a diameter of 450 mm into a blank tube with a diameter of 650 mm; S4, oblique rolling, oblique rolling and piercing the billet tube with a diameter of 650 mm after forging, the hole diameter after oblique rolling and piercing is 560 mm, and the oblique rolling and piercing temperature is 920°C; S5, hot rolling, hot rolling the blank tube after oblique rolling and piercing, the hot rolling temperature is 820°C, and the diameter of the blank tube after hot rolling is 560mm; S6, cold rolling, the tube blank after hot rolling is cold rolled at room temperature, and the diameter of the tube blank after cold rolling is 508mm; S7, heat treatment, annealing the tube blank after cold rolling, annealing temperature is 780℃, and heat preservation is 90min; S8, stretching, using a stretching machine of more than 300 tons to stretch the annealed tube embryo, and adjust the wall thickness of the tube embryo to 7mm.

[0015] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an ultra-large diameter copper-nickel alloy seamless pipe, characterized in that: The following steps are involved: S1. Casting: solid ingot with a diameter greater than 440 mm and a single hollow ingot with a weight greater than 600 kg; S2, heating, heating the cast solid ingot to 920℃-940℃, and keeping the temperature for 60min-90min after heating; S3, forging, forging the heated solid ingot by a fast forging press, and forging the hollow ingot with a diameter greater than 440 mm into a blank tube with a diameter of 650 mm; S4, oblique rolling, oblique rolling and punching the blank tube with a diameter of 650 mm after forging, the hole diameter after oblique rolling and punching is 560 mm, and the oblique rolling and punching temperature is 880℃-920℃; S5, hot rolling, hot rolling the blank tube after oblique rolling and piercing, the hot rolling temperature is 750℃-820℃, and the diameter of the blank tube after hot rolling is 560mm; S6, cold rolling, the tube blank after hot rolling is cold rolled at room temperature, and the diameter of the tube blank after cold rolling is 508mm; S7, heat treatment, annealing the tube blank after cold rolling, annealing temperature is 750℃-780℃, heat preservation time is 60min-90min; S7, stretching, using a stretching machine of more than 300 tons to stretch the annealed tube embryo, and adjust the wall thickness of the tube embryo to 4-7mm.

2. The method for preparing an ultra-large diameter copper-nickel alloy seamless pipe according to claim 1, characterized in that: The heating method in step S2 is to use a high-temperature box-type resistance furnace for heating.