SE2350736A1 - Cu-15ni-8sn-based alloy for ocean engineering, and preparation method therefor - Google Patents

Abstract

A Cu-15Ni-8Sn-based alloy for ocean engineering, and a preparation method therefor. The Cu-15Ni-8Sn-based alloy for ocean engineering of the present invention comprises the following components in percentages by weight: 14-16% of Ni, 7-9% of Sn, 0.3-2.0% of Zn, 0.2-1.5% of Si, 0.15-2.0% of Al, 0.2- 1.6% of Mn, 0.02-0.8% of Ce, 0.02-1.0% of Y and the balance of Cu. The Cu-15Ni-8Sn-based alloy for ocean engineering of the present invention is uniform in terms of as-cast structure, and the dendritic segregation is significantly improved; and the mechanical properties and the corrosion resistance are good, which is suitable for key components of ocean engineering.

Description

Background Field of the Invention The present invention belongs to the technical field of the metal material, and particularly relates to a Cu-ISNi-SSn-based alloy for ocean engineering, and a preparation method therefor.

Background Information Copper alloys have been Widely used in ships, ocean oil and gas exploitation, comprehensive utilization of seaWater resources and other fields due to their good mechanical properties, cold and hot processing properties, high heat transfer coefficient, excellent ocean organism adhesive-ability resistance and seaWater corrosion resistance, and the main application scenarios comprise: seaWater pump valve and filter, condenser tube for ocean steam turbine, copper tube for heat exchanger, propeller, petroleum drilling tool and equipment component, and the like. The commonly used corrosion resistant copper alloy systems mainly comprise aluminum brass, tin brass such as HSn70- 1, HSn60-1, tin bronze such as QSn4-4, QSn-5-5, QSn6-6-3, nickel White copper such as B10 (Cu- l0Ni-lFe-lMn), B30 (Cu-30Ni-lFe-lMn), and complex nickel aluminum bronze.

The Cu-15Ni-8Sn alloy (corresponding to the US label number C72900) Was successfully developed by American Bell Laboratories in the 1970s and named by the American Production Technology Standard in the early l980s. This alloy has the folloWing properties such as high strength, excellent Wear resistance, self-lubricating and Wear reducing and the like, particularly its strong high-temperature stress relaxation resistance, corrosion resistance in seaWater or acidic, oil and gas environments, as Well as Wear resistance under high load conditions, are superior to beryllium copper and aluminum bronze, and it is Widely used as key Wear and corrosion resistant components in the fields such as ocean oil and gas exploration, electronic infomïation, mechanical manufacturing and the like. At present, foreign companies that have achieved industrial production mainly comprise American Materion Corporation, SWiss Metal and American AMETEK Corporation. Wherein American Materion Corporation is the World's largest manufacturer of C72900 products, and the main product forms are tube, bar, ring and belt. At present, the vast majority of C72900 copper alloy pipe and bar products used in China's ocean oil and gas development are still purchased from American Materion Corporation. Therefore, the development of high strength and corrosion resistant Cu-ISNi-SSn-based alloy that meet the requirements of ocean engineering field, is great significance for achieving independent control of key materials in national key fields.

The Cu-15Ni-8Sn alloy is a typical high-performance copper alloy based on amplitude modulated decomposition strengthening. However, due to the high Sn content, low melting point, and wide range of alloy crystallization temperature in the alloy, it is easy to cause the macroscopic composition segregation and the microscopic dendritic segregation of Sn element under the traditional solidification condition, and the non-uniformity of the cast solidification structure also affects the subsequent defomiation processing perfomiance and the wear and corrosion resistance in the application process. Therefore, how to obtain Cu-15Ni-8Sn based alloy ingots with uniform composition and structure through the microalloying means and the smelting process control can lay the foundation for improving the strength and corrosion resistance of their finished products.

Accordingly, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art. SUMMARY It is an object of the present invention to provide a Cu-15Ni-8Sn-based alloy for ocean engineering, and a preparation method therefor, in order to solve or improve at least one of the problems in the prior art that the Cu-Ni-Sn alloy is prone to produce the macroscopic component segregation or the microscopic dendrite segregation, is not conducive to subsequent processing defomiation, and is needed to be improved in strength and corrosion resistance.

In order to achieve the above object, the present invention provides the following technical solutions: a Cu-ISNi-SSn-based alloy for ocean engineering that comprises the following components in percentages by weight: 14-16% ofNi, 7-9% of Sn, 0.3-2.0% of Zn, 0.2-1.5% of Si, 0.15-2.0% ofAl, 0.2-1.6% ofMn, 0.02-0.8% of Ce, 0.02-1.0% ofY and balance of Cu; a tensile strength of the Cu-ISNi-SSn-based alloy for ocean engineering is 2 1100 MPa, an elongation of the Cu-15Ni-8Sn-based alloy for ocean engineering is 2 3%, and an average corrosion rate of the Cu-ISNi-SSn-based alloy for ocean engineering is š 0.01 mm/a; in the Cu-ISNi-SSn-based alloy for ocean engineering, a contents of trace elements O, S, and P are: O š 5ppm, S š 3ppm, P š 3ppm, respectively.

The present invention also provides a preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering as described above, which adopts the following technical solutions: the preparation method of the Cu-l5Ni-8Sn-based alloy for ocean engineering as described above comprises the following steps (1) - (3), step (1) smelting: f1rstly, adding an electrolytic copper to a furnace to completely melt the electrolytic copper, secondly, adding a Ni source, then adding a Mn source, a Si source, a Ce source, and a Y source, and finally adding a Zn source, a Al source and a Sn source, and the smelting is at ll00-l200°C for 30-50 minutes; step (2) pouring: a molten liquid treated in the step (l) is alloWed to stand for 1-3 minutes after the molten liquid is mirror-like, and the molten liquid is poured into a metal mold after the stand is completed, and the molten liquid is solidified to obtain an ingot; step (3) performing homogenization annealing, hot eXtrusion deformation, solid solution heat treatment, cold draWing deformation, and aging heat treatment on the ingot.

AdVantageous effects: On the basis of Cu-l5Ni-8Sn alloy, the present inVention improVes the macro composition and the micro segregation in the alloy solidification structure by adding the micro alloying elements such as Zinc (Zn), silicon (Si), aluminum (Al), manganese (Mn), cerium (Ce) and yttrium (Y), and synergistically enhances the strength and the corrosion resistance of the alloy. Wherein, the addition of Zn element can shorten the alloy solid-liquid phase line temperature range, Which is beneficial for suppressing segregation. The addition of Si element can suppress the formation of reverse segregation during the alloy solidification, obtain fine grains, and improVe processing deformation ability, and the addition of Si element can enhance the alloy strength by forming a series of NiSi strengthening phases (Ni2Si, NigSi) through Si and Ni. Al element and Ni element can form a series of NiAl strengthening phases (Ni3Al, NigAl), and together With Si element, so as to cause the alloy to superpose the aging precipitation strengthening on the basis of solid solution strengthening, Which significantly improVe the alloy strength. At the same time, Al element in the corrosion process are prone to form AlgOg passiVation film, Which is beneficial for improVing the corrosion resistance. Mn element can refine the as-cast grain structure, improVe the alloy aging hardening peak strength, and suppress the grain boundary reaction and the grain coarsening, Which significantly improVe the strength and corrosion resistance of the alloy. The addition of rare earth Ce element can purify the alloy melt, refine the as-cast structure, improVe the alloy deformation ability, and increase the strength. Adding rare earth element Y can accelerate the amplitude modulation decomposition of the alloy, sloW doWn the groWth of the grain boundary precipitates, improVe the strength and plasticity of the alloy, reduce the segregation of the alloy, and form NiSnY and NigY compounds, Which improve the strength and corrosion resistance of the alloy. At the same time, due to the addition of multiple alloy components and different characteristics, the mechanisms for improving the strength and corrosion resistance of the alloy are vary.

The Cu-ISNi-SSn-based alloy for ocean engineering of the present invention has the following advantageous effects. (1) The as-cast structure is uniform, and the dendritic segregation is significantly improved; (2) Excellent mechanical properties: the strength is 2 1100 MPa, the elongation is 2 3%; (3) Excellent corrosion resistance: the average corrosion rate is š 0.01 mn1/a. The multi-element, high strength, and corrosion resistance copper alloy prepared by the method of the present invention is suitable for key components of ocean engineering. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a microstructure diagram of the prepared conventional Cu-15Ni-8Sn alloy; Fig. 2 is a rnicrostructure diagram of the Cu-ISNi-SSn-based alloy for ocean engineering in example 2 of the present invention. DETAILED DESCRIPTION OF EMBODIMENTS The folloWing content Will provide a detailed explanation of the present invention in conjunction With examples. It should be noted that, the examples and features in the examples of the present invention can be combined With each other, Without conflict.

For at least one of the problems in the prior art that the Cu-Ni-Sn alloy is prone to produce the macroscopic component segregation or the microscopic dendrite segregation, is not conducive to subsequent processing defomaation, and is needed to be improved in strength and corrosion resistance, the present invention provides the folloWing technical solutions: a Cu-ISNi-SSn-based alloy for ocean engineering comprises the folloWing components in percentages by Weight: 14-16% ofNi, 7-9% of Sn, 0.3-2.0% ofZn, 0.2-1.5% of Si, 0.15-2.0% ofAl, 0.2-1.6% of Mn, 0.02-0.8% of Ce, 0.02-1.0% ofY and the balance of Cu.

In the preferred example of the present invention, in the Cu-ISNi-SSn-based alloy for ocean engineering, the contents of the trace elements O, S, and P are: O š Sppm, S š 3ppm, P š 3ppm, respectively.

In the preferred example of the present invention, the Cu-ISNi-SSn-based alloy for ocean engineering comprises the folloWing components in percentages by Weight: 15% of Ni, 8% of Sn, 1.2% ofZn, 0.8% of Si, 0.8% ofAl, 1.2% ofMn, 0.2% of Ce, 0.5% ofY and the balance of Cu.

In the preferred example of the present inVention, the tensile strength of the Cu-15Ni-8Sn-based alloy for ocean engineering is 2 1100 MPa, the elongation of the Cu-15Ni-8Sn-based alloy for ocean engineering is 2 3%, and the aVerage corrosion rate of the Cu-15Ni-8Sn-based alloy for ocean engineering is š 0.01 mm/a.

The present inVention also proVides a preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering, the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the following steps (1)-(3), step (1) smelting: firstly, adding an electrolytic copper to a furnace to completely melt the electrolytic copper, secondly, adding a Ni source, then adding a Mn source, a Si source, a Ce source, and a Y source, and finally adding a Zn source, a Al source and a Sn source, and the smelting is at 1100-1200°C for 30-50 minutes; step (2) pouring: a molten liquid treated in the step (1) is alloWed to stand for 1-3 minutes after the molten liquid is mirror-like, and the molten liquid is poured into a metal mold after the stand is completed, and the molten liquid is solidified to obtain an ingot; step (3) performing homogenization annealing, hot extrusion deformation, solid solution heat treatment, cold draWing defomfiation, and aging heat treatment on the ingot.

In the preferred example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering of the present inVention, in the step (1), Cu 2 99.95 Wt% in the electrolytic copper; the Ni source is electrolytic nickel, and in the electrolytic nickel, Ni 2 99.96 Wt%; the Sn source is pure tin, and in the pure tin, Sn 2 99.99 Wt%; the Zn source is pure zinc, and in the pure zinc, Zn 2 98 Wt%; the Si source is pure silicon, and in the pure silicon, Si 2 99.99 Wt%; the Al source is pure aluminum, Al 2 99.7 Wt%; the Mn source is Cu-Mn intermediate alloy; the Ce source is Cu-Ce intennediate alloy; the Y source is Cu-Y intennediate alloy.

In the preferred example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering of the present inVention, in the filmace, molten liquid surface is completely coVered by charcoal, and is deoxidized using a pure phosphorus deoxidant; a dosage of the pure phosphorus deoxidant is 0.1% -0.3% of the total Weight of the molten liquid; process of the smelting also comprises a step of using a graphite stirrer for stirring, and using a skimmer bar for skimming. Wherein, due to the preferential reaction of phosphorus element in pure phosphorus deoxidant With oxygen in the melt, an appropriate addition amount of the pure phosphorus deoxidant can purify the melt. HoWever, if the addition amount is too high (exceeding 03% of the total Weight of the melt), the excessive phosphorus Will remain in the alloy, so as to increase the brittleness of the material, Which is not conducive to the subsequent plastic deformation.

In the preferred example of the preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering of the present invention, in the step (2), a temperature for the pouring is ll50-l250°C. The temperature for the pouring is an important parameter in the melting and casting process of materials. If the temperature for the pouring is too loW, the fluidity of the melt is poor, and the casting defects such as insufficient pouring or shrinkage, hole, and cold shut are prone to occur; if the temperature for the pouring is too high, it Will not only cause the element buming loss, but also cause the coarse grains in the solidification structure and decrease perfomiance.

In the preferred example of the preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering of the present invention, after the pouring is completed, also comprising a step of applying an electromagnetic field outside the metal mold; a current application range of the electromagnetic field is 20-100 A. The strength of the electromagnetic field is mainly controlled by adjusting the magnitude of the current, Which mainly affects the magnitude of the stirring force exerted by the electromagnetic field on the melt, and the magnitude of the stirring force Will have a direct relationship With the degree to Which the dendrite structure is broken during the solidification process. Therefore, by controlling the intensity of the electromagnetic field through different current sizes, it can affect the fomiation and distribution of the y phase Which is Sn-rich, suppress the effect if the dendrite segregation, and improve the subsequent comprehensive perfomiance of the alloy. The present invention improves the segregation of the casting solidification structure by a series of operations, of example, adding different alloying elements, melting and casting processes, especially microalloying elements + electromagnetic stirring. The quality of the casting structure directly affects the difficulty of subsequent processing processes and affects the comprehensive performance of the final material.

In the preferred example of the preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering of the present invention, a temperature for the homogenization annealing is 900-950°C , a temperature for the hot extrusion defomiation is 850-950°C, a temperature for the solid solution heat treatment is 750-900 °C , an amount of the cold draWing defomiation is 50-90%, and a temperature for the aging heat treatment is 300-500°C.

The following content provides a detailed explanation of the Cu-15Ni-8Sn-based alloy for ocean engineering, and a preparation method therefor of the present inVention through specific examples.

Example 1 The present example of the Cu-15Ni-8Sn-based alloy for ocean engineering is composed of the following components in percentages by weight: 15% of Ni, 8% of Sn, 0.3% of Zn, 0.2% of Si, 0.15% ofAl, 0.2% ofMn, 0.02% of Ce, 0.02% ofY, the other trace elements O, S, and P are: O š 5ppm, S š 3ppm, P š 3ppm, and the balance of Cu.

The present example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the following steps (1) - (5), (1) raw material preparation: selecting 1# electrolytic copper (Cu 2 99.95%), 1# electrolytic nickel (Ni 2 99.96%), pure tin (Sn 2 99.99%), pure zinc (Zn 2 98%), pure silicon (Si 2 99.99%), pure aluminum (Al 2 99.7%), Cu-Mn interinediate alloy, Cu-Ce interinediate alloy, and Cu-Y interinediate alloy produced by Henan Yixin Nonferrous Metal Materials Co., Ltd. and then cutting, drying, and surface degreasing those for use. (2) batching: weighing the raw materials treated by the step (1) according to the present example of the the composition of the Cu-15Ni-8Sn-based alloy for ocean engineering; (3) smelting: firstly, adding the electrolytic copper to the fiirnace to melt it, and adding the pure nickel after the electrolytic copper is completely melted, and then adding the Cu-Mn interinediate alloy, the pure silicon, the Cu-Ce interinediate alloy, the Cu-Y intennediate alloy, and finally adding the pure zinc, the pure aluminum, and the pure tin. The temperature for smelting is 1100°C for 50 minutes; It is ensured that the molten liquid surface is completely coVered by charcoal during the heating and melting process, and most of the air are isolated through the charcoal coVering layer to achieVe the melting process in a slightly oxidized atrnosphere. During the smelting process, pure phosphorus deoxidant is used for deoxidation, and the dosage of deoxidation is 0.1% of the total weight of the molten liquid. During the smelting process, a graphite stirrer is used for stirring, and a skimmer bar is used for skimming. (4) pouring: after there is no dross on the molten liquid surface, it is allowed to stand for 1 minute after the molten liquid surface is removed and the molten liquid is mirror-like. the molten liquid is directly poured into the metal mold, and the temperature for pouring is 1150°C; At the same time, in order to further improve the segregation of the solidification structure, an electromagnetic field is applied outside the metal mold, after the molten liquid is poured into the metal mold, the magnitude of the force is changed by adjusting the current of the electromagnetic field, and an extemal influence is applied to the solidification process of the melt, and the current application range is 30 A. Under the combined action of the electromagnetic field and the cooling device, the molten liquid is solidified to obtain ingot. (5) on the basis of uniforinly structured ingot prepared by smelting and casting, performing subsequent homogenization annealing-*hot extrusion deformation-*solid solution heat treatment ->cold draWing deformation-*aging heat treatment. Wherein, a temperature for the homo genization annealing is 920°C, a temperature for the hot extrusion defomïation is 870°C, a temperature for the solid solution heat treatment is 780°C, an amount of the cold draWing deformation is 60%, and a temperature for the aging heat treatment is 350°C.

The Cu-15Ni-8Sn-based alloy for ocean engineering prepared in the present example has uniform composition, and the as-cast rnicrostructure thereof has a smaller dendrite spacing and uniform distribution compared to conventional Cu-15Ni-8Sn alloy; the tensile strength is 1107 MPa, and the elongation is 5.1%; the average corrosion rate is 0.0093 mm/a.

Example 2 The present example of the Cu-15Ni-8Sn-based alloy for ocean engineering is composed of the folloWing components in percentages by Weight: 15% of Ni, 8% of Sn, 1.2% of Zn, 0.8% of Si, 0.8% ofAl, 1.2% ofMn, 0.2% of Ce, 0.5% ofY, the other trace elements O, S, and P are: O š 5ppm, S š 3ppm, P š 3ppm, and the balance of Cu.

The present example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the folloWing steps (1) - (5), (1) raW material preparation: selecting 1# electrolytic copper (Cu 2 99.95%), 1# electrolytic nickel (Ni 2 99.96%), pure tin (Sn 2 99.99%), pure zinc (Zn 2 98%), pure silicon (Si 2 99.99%), pure aluminum (Al 2 99.7%), Cu-Mn interinediate alloy, Cu-Ce interinediate alloy, and Cu-Y interinediate alloy produced by Henan Yixin Nonferrous Metal Materials Co., Ltd. and then cutting, drying, and surface degreasing those for use. (2) batching: Weighing the raW materials treated by the step (1) according to the present example of the the composition of the Cu-15Ni-8Sn-based alloy for ocean engineering; (3) smelting: firstly, adding the electrolytic copper to the fumace to melt it, and adding the pure nickel after the electrolytic copper is completely melted, and then adding the Cu-Mn interinediate alloy, the pure Silicon, the Cu-Ce interinediate alloy, the Cu-Y intennediate alloy, and finally adding the pure Zinc, the pure aluminum, and the pure tin. The temperature for smelting is ll50°C for 45 minutes; It is ensured that the molten liquid surface is completely coVered by charcoal during the heating and melting process, and most of the air are isolated through the charcoal coVering layer to achieVe the melting process in a slightly oxidized atrnosphere. During the smelting process, pure phosphorus deoxidant is used for deoxidation, and the dosage of deoxidation is 0.2% of the total Weight of the molten liquid. During the smelting process, a graphite stirrer is used for stirring, and a skimmer bar is used for skimming. (4) pouring: after there is no dross on the molten liquid surface, it is alloWed to stand for 2.5 minute after the molten liquid surface is remoVed and the molten liquid is in a mirror-like. the molten liquid is directly poured into the metal mold, and the temperature for pouring is l200°C ; At the same time, in order to further improVe the segregation of the solidification structure, an electromagnetic field is applied outside the metal mold, after the molten liquid is poured into the metal mold, the magnitude of the force is changed by adjusting the current of the electromagnetic field, and an extemal influence is applied to the solidification process of the melt, and the current application range is 60 A. Under the combined action of the electromagnetic field and the cooling device, the molten liquid is solidified to obtain ingot. (5) on the basis of uniformly structured ingot prepared by smelting and casting, performing subsequent homogenization annealing-*hot extrusion defomiation-*solid solution heat treatment -*cold draWing deformation-*aging heat treatment. Wherein, a temperature for the homo genization annealing is 940°C, a temperature for the hot extrusion defomiation is 950°C, a temperature for the solid solution heat treatment is 820°C, an amount of the cold draWing deformation is 85%, and a temperature for the aging heat treatment is 450°C.

The microstructure diagram of the Cu-15Ni-8Sn-based alloy for ocean engineering in example 2 of the present example is shoWn in Fig. 2.

The Cu-l5Ni-8Sn-based alloy for ocean engineering prepared in the present example has uniform composition, and the as-cast rnicrostructure thereof has a smaller dendrite spacing and uniform distribution, and consistent distribution direction compared to conventional Cu-15Ni-8Sn alloy; the tensile strength is 1162 MPa, and the elongation is 3.4%; the average corrosion rate is 0.0042 mm/a.

Example 3 The present example of the Cu-15Ni-8Sn-based alloy for ocean engineering is composed of the following components in percentages by weight: 15% ofNi, 8% of Sn, 2% of Zn, 1.5% of Si, 2.0% ofAl, 1.6% ofMn, 0.8% of Ce, 1.0% ofY, the other trace elements O, S, and P are: O š 5ppm, S š 3ppm, P š 3ppm, and the balance of Cu.

The present example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the following steps (1) - (5), (1) raw material preparation: selecting 1# electrolytic copper (Cu 2 99.95%), 1# electrolytic nickel (Ni 2 99.96%), pure tin (Sn 2 99.99%), pure zinc (Zn 2 98%), pure silicon (Si 2 99.99%), pure aluminum (Al 2 99.7%), Cu-Mn intermediate alloy, Cu-Ce intermediate alloy, and Cu-Y interinediate alloy produced by Henan Yixin Nonferrous Metal Materials Co., Ltd. and then cutting, drying, and surface degreasing those for use. (2) batching: weighing the raw materials treated by the step (1) according to the present example of the the composition of the Cu-15Ni-8Sn-based alloy for ocean engineering; (3) smelting: firstly, adding the electrolytic copper to the fumace to melt it, and adding the pure nickel after the electrolytic copper is completely melted, and then adding the Cu-Mn interinediate alloy, the pure silicon, the Cu-Ce interinediate alloy, the Cu-Y intennediate alloy, and finally adding the pure Zinc, the pure aluminum, and the pure tin. The temperature for smelting is 1200°C for 50 minutes; It is ensured that the molten liquid surface is completely covered by charcoal during the heating and melting process, and most of the air are isolated through the charcoal covering layer to achieve the melting process in a slightly oxidized atrnosphere. During the smelting process, pure phosphorus deoxidant is used for deoxidation, and the dosage of deoxidation is 03% of the total weight of the molten liquid. During the smelting process, a graphite stirrer is used for stirring, and a skimmer bar is used for skimming. (4) pouring: after there is no dross on the molten liquid surface, it is allowed to stand for 3 minute after the molten liquid surface is removed and the molten liquid is mirror-like. the molten liquid is directly poured into the metal mold, and the temperature for pouring is 1250°C; At the same time, in order to further improve the segregation of the solidification structure, an electromagnetic field is applied outside the metal mold, after the molten liquid is poured into the metal mold, the magnitude of the force is changed by adjusting the current of the electromagnetic field, and an extemal influence is applied to the solidification process of the melt, and the current application range is 100 A. Under the combined action of the electromagnetic field and the cooling deVice, the molten liquid is solidified to obtain ingot. (5) on the basis of uniforinly structured ingot prepared by smelting and casting, performing subsequent homogenization annealing-*hot extrusion deformation-*solid solution heat treatment ->cold draWing deformation-*aging heat treatment. Wherein, a temperature for the homo genization annealing is 950°C, a temperature for the hot extrusion defomïation is 950°C, a temperature for the solid solution heat treatment is 900°C, an amount of the cold draWing deformation is 90%, and a temperature for the aging heat treatment is 500°C.

The Cu-15Ni-8Sn-based alloy for ocean engineering prepared in the present example has uniform composition, and the as-cast rnicrostructure thereof has a smaller dendrite spacing and uniform distribution compared to conventional Cu-15Ni-8Sn alloy; the tensile strength is 1134 MPa, and the elongation is 4.1%; the average corrosion rate is 0.0065 mm/a.

Example 4 The present example of the Cu-ISNi-SSn-based alloy for ocean engineering is composed of the folloWing components in percentages by Weight: 14% of Ni, 7% of Sn, 1.5% of Zn, 1.2% of Si, 1.5% ofAl, 0.8% ofMn, 0.5% of Ce, 0.8% ofY, the other trace elements O, S, and P are: O š 4ppm, S š 3ppm, P š 3ppm, and the balance of Cu.

The present example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the folloWing steps (1) - (5), (1) raW material preparation: selecting 1# electrolytic copper (Cu 2 99.95%), 1# electrolytic nickel (Ni 2 99.96%), pure tin (Sn 2 99.99%), pure zinc (Zn 2 98%), pure silicon (Si 2 99.99%), pure aluminum (Al 2 99.7%), Cu-Mn interinediate alloy, Cu-Ce interinediate alloy, and Cu-Y interinediate alloy produced by Henan Yixin Nonferrous Metal Materials Co., Ltd. and then cutting, drying, and surface degreasing those for use. (2) batching: Weighing the raW materials treated by the step (1) according to the present example of the the composition of the Cu-15Ni-8Sn-based alloy for ocean engineering; 11 (3) smelting: firstly, adding the electrolytic copper to the fumace to melt it, and adding the pure nickel after the electrolytic copper is completely melted, and then adding the Cu-Mn interinediate alloy, the pure Silicon, the Cu-Ce interinediate alloy, the Cu-Y intennediate alloy, and finally adding the pure Zinc, the pure aluminum, and the pure tin. The temperature for smelting is ll20°C for 50 minutes; It is ensured that the molten liquid surface is completely covered by charcoal during the heating and melting process, and most of the air are isolated through the charcoal covering layer to achieve the melting process in a slightly oxidized atrnosphere. During the smelting process, pure phosphorus deoxidant is used for deoxidation, and the dosage of deoxidation is 0.1% of the total Weight of the molten liquid. During the smelting process, a graphite stirrer is used for stirring, and a skimmer bar is used for skimming. (4) pouring: after there is no dross on the molten liquid surface, it is alloWed to stand for 1 minute after the molten liquid surface is removed and the molten liquid is mirror-like. the molten liquid is directly poured into the metal mold, and the temperature for pouring is ll70°C; At the same time, in order to further improve the segregation of the solidification structure, an electromagnetic field is applied outside the metal mold, after the molten liquid is poured into the metal mold, the magnitude of the force is changed by adjusting the current of the electromagnetic field, and an extemal influence is applied to the solidification process of the melt, and the current application range is 45 A. Under the combined action of the electromagnetic field and the cooling device, the molten liquid is solidified to obtain ingot. (5) on the basis of uniformly structured ingot prepared by smelting and casting, performing subsequent homogenization annealing-*hot extrusion defomiation-*solid solution heat treatment -*cold draWing deformation-*aging heat treatment. Wherein, a temperature for the homo genization annealing is 900°C, a temperature for the hot eXtrusion defomiation is 890°C, a temperature for the solid solution heat treatment is 770°C, an amount of the cold draWing deformation is 65%, and a temperature for the aging heat treatment is 380°C.

The Cu-l5Ni-8Sn-based alloy for ocean engineering prepared in the present example has uniform composition, and the as-cast rnicrostructure thereof has a smaller dendrite spacing and uniform distribution compared to conventional Cu-l5Ni-8Sn alloy; the tensile strength is 1130 MPa, and the elongation is 4.3%; the average corrosion rate is 0.0069 mm/a. 12 Example 5 The present example of the Cu-l5Ni-8Sn-based alloy for ocean engineering is composed of the following components in percentages by Weight: 16% of Ni, 9% of Sn, 0.7% of Zn, 0.4% of Si, 0.5% ofAl, l.0% ofMn, 008% of Ce, 0.l2% ofY, the other trace elements O, S, and P are: O š 5ppm, S š 3ppm, P š 3ppm, and the balance of Cu.

The present example of the preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering comprises the folloWing steps (l) - (5), (1) raW material preparation: selecting l# electrolytic copper (Cu 2 99.95%), l# electrolytic nickel (Ni 2 99.96%), pure tin (Sn 2 99.99%), pure zinc (Zn 2 98%), pure silicon (Si 2 99.99%), pure aluminum (Al 2 99.7%), Cu-Mn intermediate alloy, Cu-Ce intermediate alloy, and Cu-Y intermediate alloy produced by Henan Yixin Nonferrous Metal Materials Co., Ltd. and then cutting, drying, and surface degreasing those for use. (2) batching: Weighing the raW materials treated by the step (l) according to the present example of the the composition of the Cu-l5Ni-8Sn-based alloy for ocean engineering; (3) smelting: firstly, adding the electrolytic copper to the furnace to melt it, and adding the pure nickel after the electrolytic copper is completely melted, and then adding the Cu-Mn intermediate alloy, the pure silicon, the Cu-Ce intermediate alloy, the Cu-Y intennediate alloy, and finally adding the pure Zinc, the pure aluminum, and the pure tin. The temperature for smelting is ll70°C for 40 minutes; It is ensured that the molten liquid surface is completely coVered by charcoal during the heating and melting process, and most of the air are isolated through the charcoal coVering layer to achieVe the melting process in a slightly oxidized atrnosphere. During the smelting process, pure phosphorus deoxidant is used for deoxidation, and the dosage of deoxidation is 0. 1% of the total Weight of the molten liquid. During the smelting process, a graphite stirrer is used for stirring, and a skimmer bar is used for skimming. (4) pouring: after there is no dross on the molten liquid surface, it is alloWed to stand for l minute after the molten liquid surface is removed and the molten liquid is mirror-like. the molten liquid is directly poured into the metal mold, and the temperature for pouring is l240°C; At the same time, in order to further improVe the segregation of the solidification structure, an electromagnetic field is applied outside the metal mold, after the molten liquid is poured into the metal mold, the 13 magnitude of the force is changed by adjusting the current of the electromagnetic field, and an external influence is applied to the solidification process of the melt, and the current application range is 85 A. Under the combined action of the electromagnetic field and the cooling device, the molten liquid is solidified to obtain ingot. (5) on the basis of uniformly structured ingot prepared by smelting and casting, performing subsequent homogenization annealing-*hot extrusion deformation-*solid solution heat treatment ->cold draWing deformation-*aging heat treatment. Wherein, a temperature for the homo genization annealing is 930°C, a temperature for the hot extrusion deformation is 910°C, a temperature for the solid solution heat treatment is 860°C, an amount of the cold draWing deformation is 55%, and a temperature for the aging heat treatment is 420°C.

The Cu-15Ni-8Sn-based alloy for ocean engineering prepared in the present example has uniform composition, and the as-cast rnicrostructure thereof has a smaller dendrite spacing and uniform distribution compared to conventional Cu-15Ni-8Sn alloy; the tensile strength is 1159 MPa, and the elongation is 3.7%; the average corrosion rate is 0.0046 mm/a.

Example 6 The present example of the Cu-15Ni-8Sn-based alloy for ocean engineering is composed of the folloWing components in percentages by Weight: 14% of Ni, 9% of Sn, 2.0% of Zn, 0.2% of Si, 1.2% ofAl, 1.0% ofMn, 0.02% of Ce, 1.0% ofY, the other trace elements O, S, and P are: O š 5ppm, S š 3ppm, P š 3ppm, and the balance of Cu.

The present example of the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the folloWing steps (1) - (5), (1) raW material preparation: selecting 1# electrolytic copper (Cu 2 99.95%), 1# electrolytic nickel (Ni 2 99.96%), pure tin (Sn 2 99.99%), pure zinc (Zn 2 98%), pure silicon (Si 2 99.99%), pure aluminum (Al 2 99.7%), Cu-Mn intermediate alloy, Cu-Ce intermediate alloy, and Cu-Y intermediate alloy produced by Henan Yixin Nonferrous Metal Materials Co., Ltd. and then cutting, drying, and surface degreasing those for use. (2) batching: Weighing the raW materials treated by the step (1) according to the present example of the the composition of the Cu-15Ni-8Sn-based alloy for ocean engineering; (3) smelting: firstly, adding the electrolytic copper to the furnace to melt it, and adding the pure nickel after the electrolytic copper is completely melted, and then adding the Cu-Mn intermediate 14 alloy, the pure silicon, the Cu-Ce intermediate alloy, the Cu-Y intennediate alloy, and finally adding the pure zinc, the pure aluminum, and the pure tin. The temperature for smelting is 1180°C for 40 minutes; It is ensured that the molten liquid surface is completely covered by charcoal during the heating and melting process, and most of the air are isolated through the charcoal covering layer to achieve the melting process in a slightly oxidized atrnosphere. During the smelting process, pure phosphorus deoxidant is used for deoxidation, and the dosage of deoxidation is 0.1% of the total Weight of the molten liquid. During the smelting process, a graphite stirrer is used for stirring, and a skimmer bar is used for skimming. (4) pouring: after there is no dross on the molten liquid surface, it is alloWed to stand for 1 minute after the molten liquid surface is removed and the molten liquid is mirror-like. the molten liquid is directly poured into the metal mold, and the temperature for pouring is 1260°C; At the same time, in order to further improve the segregation of the solidification structure, an electromagnetic field is applied outside the metal mold, after the molten liquid is poured into the metal mold, the magnitude of the force is changed by adjusting the current of the electromagnetic field, and an extemal influence is applied to the solidification process of the melt, and the current application range is 75 A. Under the combined action of the electromagnetic field and the cooling device, the molten liquid is solidified to obtain ingot. (5) on the basis of uniformly structured ingot prepared by smelting and casting, performing subsequent homogenization annealing-*hot extrusion deformation-*solid solution heat treatment -*cold draWing deformation-*aging heat treatment. Wherein, a temperature for the homo genization annealing is 910°C, a temperature for the hot eXtrusion defomiation is 930°C, a temperature for the solid solution heat treatment is 820°C, an amount of the cold draWing deformation is 70%, and a temperature for the aging heat treatment is 410°C.

The Cu-15Ni-8Sn-based alloy for ocean engineering prepared in the present example has uniform composition, and the as-cast rnicrostructure thereof has a smaller dendrite spacing and uniform distribution compared to conventional Cu-15Ni-8Sn alloy; the tensile strength is 1129 MPa, and the elongation is 4.2%; the average corrosion rate is 0.0039 mm/a.

Contrast Example 1 The conventional Cu-15Ni-8Sn alloy of the present contrast example is composed of the following components in percentages by weight: 15% of Ni, 8% of Sn, and the balance of Cu.

The conventional Cu-15Ni-8Sn alloy of the present contrast example is prepared using a method that comprises the following steps: the non vacuum melting fiimace is used to melt the electrolytic copper (Cu 2 99.95%), the electrolytic nickel (Ni 2 99.96%), the pure tin (Sn 2 99.99%), and the alloying elements such as Zn, Si, Al, Mn, Ce, Y, etc. that are beneficial for improving the segregation of solidification structure and properties are not added during the melting process; At the same time, the control range for other trace elements O, S, and P is relatively broad, generally, O content is greater than l0ppm, S content is greater than Sppm, and P content is greater than Sppm. After the melt is completely melted, it is directly poured into the metal mold without applying electromagnetic stirring, and the ingot is obtained by cooling and solidification; Then subsequent homogenization annealing-*hot extrusion deformation-*solid solution heat treatment-*cold drawing deformation *aging heat treatment are performed. Due to the severe segregation problem in the solidification structure of conventional processes during the melting and casting stage, the subsequent defomaation becomes more difficult and the material yield decreases. Wherein, a temperature for the homogenization annealing is 940°C, a temperature for the hot extrusion deformation is 950°C, a temperature for the solid solution heat treatment is 820°C, an amount of the cold drawing deformation is 85%, and a temperature for the aging heat treatment is 450°C.

Contrast Example 2 The difference between the present contrast example and example 1 is only that the addition amount of Zn element is 0.27% (less than 03%), and the rest are consistent with example 1.

Contrast Example 3 The difference between the present contrast example and example 2 is only that the addition amount of Si element is 0.19% (less than 0.2%), and the rest are consistent with example 2.

Contrast Example 4 The difference between the present contrast example and example 3 is only that the addition amount of Al element is 0.14% (less than 0.15%), and the rest are consistent with example 3.

Contrast Example 5 The difference between the present contrast example and example 4 is only that the addition amount of Mn element is 0.18% (less than 0.2%), and the rest are consistent with example 4. 16 Contrast Example 6 The difference between the present Contrast example and example 5 is only that the addition amount of Ce element is 0.017% (less than 0.02%), and the rest are consistent with example 5.

Contrast Example 7 The difference between the present contrast example and example 6 is only that the addition amount of Y element is 0.018% (less than 0.02%), and the rest are consistent with example 6.

Contrast Example 8 The difference between the present contrast example and example 3 is only that is composed of the following components in percentages by weight: 15% of Ni, 8% of Sn, 23% of Zn, 1.7% of Si, 2.1% ofAl, 1.8% ofMn, 0.9% of Ce, 1.1% ofY, and the balance of Cu.

The rest are consistent with example 3.

Experimental examples The mechanical properties and corrosion resistance of the Cu-15Ni-8Sn-based alloy for ocean engineering in examples 1-6, the conventional Cu-15Ni-8Sn alloy of the contrast example 1, and the Cu-ISNi-SSn-based alloy in the contrast examples 2-8 are tested respectively: The testing method for tensile strength uses the SHIMADZU AG-I250KN precision universal testing machine for tensile testing, with the tensile rate of 1 mn1/min, to obtain the alloy stress-strain curve and tensile strength value.

The testing method for elongation uses the SHIMADZU AG-I250KN precision universal testing machine for tensile testing, with the tensile rate of 1 mn1/min, to obtain the alloy stress-Strain curve, and the change in alloy gauge length before and after stretching is measured using an extensometer to obtain the elongation value.

The testing method for the average corrosion rate is that immerses the sample in a corrosion medium containing 3.5wt% of NaCl aqueous solution for the static full immersion experiment. After a certain period of corrosion, the mass damage of the sample before and after corrosion is measured, and then the average corrosion rate is calculated.

The mechanical properties and average corrosion rate of the Cu-15Ni-8Sn-based alloy for ocean engineering in examples 1-6, the conventional Cu-15Ni-8Sn alloy of the contrast example 1, and the Cu-15Ni-8Sn-based alloy in the contrast examples 2-8 are compared, specifically, as shown in Table 1. 17 Table 1 Average corrosion Alloy system Tensile strength/MPa Elongation/% rate/(mn1/a) Example 1 1107 5.1 0.0093 Example 2 1162 3.4 0.0042 Example 3 1134 4.1 0.0065 Example 4 1130 4.3 0.0069 Example 5 1159 3.7 0.0046 Example 6 1129 4.2 0.0039 Contrast example 1 1028 6.9 0.0207 Contrast example 2 1047 6.4 0.0395 Contrast example 3 1031 6.8 0.0253 Contrast example 4 1029 6.9 0.0331 Contrast example 5 1043 6.5 0.0218 Contrast example 6 1058 6.0 0.0226 Contrast example 7 1052 6.1 0.0309 Contrast example 8 1121 2.3 0.0225 Combining the contrast example 1 and examples 1-6, the Cu-15Ni-8Sn-based alloy for ocean engineering of the present inVention has better tensile strength and significantly reduced aVerage corrosion rate compared to conventional Cu-15Ni-8Sn alloy, Which is suitable for use in key component of the ocean engineering. 18 Combining the Contrast example 2 and example l, the addition of Zn element can shorten the alloy solid-liquid phase line temperature range, Which is beneficial for suppressing segregation. If the content of Zn element is too loW (less than 03%), the effect of inhibiting the formation of reverse segregation during alloy solidification is Weakened, and the corrosion resistance of the alloy is also reduced.

Combining the contrast example 3 and example 2, the addition of Si element can suppress the formation of reverse segregation during the alloy solidification, obtain fine grains, and improve processing deformation ability, and the addition of Si element can enhance the alloy strength by forming a series of NiSi strengthening phases (NigSi, NigSi) through Si and Ni. If the content of Si element is too loW (less than 0.2%), the effect of inhibiting the fomiation of reverse segregation during alloy solidification is Weakened, and the grain is fine and inconspicuous, Which is not conducive to improving the hot/cold Working perfomiance of the alloy. At the same time, due to the lack of a series of NiSi strengthening phases formed by Si and Ni, so as to reduce the strength of the alloy.

Combining the contrast example 4 and example 3, Al element and Ni element can form a series of NiAl strengthening phases (NigAl, NigAl), and together With Si element, so as to cause the alloy to superpose the aging precipitation strengthening on the basis of solid solution strengthening, Which significantly improve the alloy strength. At the same time, Al element in the corrosion process are prone to form AlgOg passivation film, Which is beneficial for improving the corrosion resistance. If the Al element content is too loW (less than 0. 15%), it Will prevent the fomiation of a series of NiAl strengthening phases and passivation films betWeen Al and Ni elements, resulting in a significant decrease in the strength and corrosion resistance of the alloy.

Combining the contrast example 5 and example 4, Mn element can refine the as-cast grain structure, improve the alloy aging hardening peak strength, and suppress the grain boundary reaction and the grain coarsening, Which significantly improve the strength and corrosion resistance of the alloy. If the Mn element content is too loW (less than 0.2%), resulting in coarse grain in the as-cast structure, and Weakening of the strength and Wear resistance of the alloy.

Combining the contrast example 6 and example 5, the addition of rare earth Ce element can purify the alloy melt, refine the as-cast structure, improve the alloy deformation ability, and increase the strength. If the Ce element content is too loW (less than 0.02%), resulting in affecting of the as-cast 19 structure and subsequent deformation ability of the alloy, and reducing the strength of the alloy.

Combining the contrast example 7 and example 6, adding rare earth element Y can accelerate the amplitude modulation decomposition of the alloy, slow down the growth of the grain boundary precipitates, improVe the strength and plasticity of the alloy, reduce the segregation of the alloy, and form NiSnY and NigY compounds, which improve the strength and corrosion resistance of the alloy. If the content of Y element is too low (less than 0.02%), resulting in reducing of the strength and wear resistance of the alloy.

Combining the contrast example 8 and example 3, the addition of excessiVe alloying elements not only leads to excess elements are insolVable during the melting and casting process, the formed coarse second phase is remained in the as-cast structure, which result in coarse grain size and unfaVorable for subsequent plastic defomaation, but also, more intennetallic compounds are formed during the heat treatment process, which increases the brittleness of the alloy, and excessiVe rare earth elements Ce andY tend to aggregate at grain boundaries, which result in a significant decrease in elongation and corrosion that is more prone to occur.

In summary, through the analysis of the data of the tensile strength, the elongation, and the aVerage corrosion rate of the examples and the contrast examples, it is found that the present inVention improVes the macro composition and the micro segregation in the alloy solidification structure by adding the micro alloying elements such as Zinc (Zn), silicon (Si), aluminum (Al), manganese (Mn), cerium (Ce) and yttrium (Y) on the basis of Cu-l5Ni-8Sn alloy through multiple microalloying means, which synergistically enhances the strength and the corrosion resistance of the alloy while elongation is rnaintained good (elongation 2 3%): the tensile strength is 2 1100 MPa, the aVerage corrosion rate is š 0.01 mm/a, which can meet the comprehensive perfomaance requirements of the alloy in the field of ocean engineering.

Claims (8)

Claims

1. A Cu-15Ni-8Sn-based alloy for ocean engineering, characterized in that, the Cu-15Ni-8Sn- based alloy for ocean engineering comprises the following components in percentages by Weight: 14-16% ofNi, 7-9% of Sn, 0.3-2.0% ofZn, 0.2-1.5% of Si, 0.15-2.0% ofAl, 0.2-1.6% ofMn, 0.02- 0.8% of Ce, 0.02-1.0% ofY and a balance of Cu; a tensile strength of the Cu-15Ni-8Sn-based alloy for ocean engineering is 2 1100 MPa, an elongation of the Cu-15Ni-8Sn-based alloy for ocean engineering is 2 3%, and an average corrosion rate of the Cu-15Ni-8Sn-based alloy for ocean engineering is š 0.01 mm/a; in the Cu-15Ni-8Sn-based alloy for ocean engineering, a contents of trace elements O, S, and P are: O š 5ppm,S š 3ppm,P š 3ppm,respectiVely.

2. The Cu-15Ni-8Sn-based alloy for ocean engineering according to claim 1, characterized in that, the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the folloWing components in percentages by Weight: 15% ofNi, 8% of Sn, 1.2% of Zn, 0.8% of Si, 0.8% ofAl, 1.2% of Mn, 0.2% of Ce, 0.5% of Y and the balance of Cu.

3. A preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering according to any one of claims 1-2, characterized in that, the preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering comprises the following steps (1) - (3), step (1) smelting: firstly, adding an electrolytic copper to a furnace to completely melt the electrolytic copper, secondly, adding a Ni source, then adding a Mn source, a Si source, a Ce source, and a Y source, and finally adding a Zn source, a Al source and a Sn source, and the smelting is at 1100-1200°C for 30-50 minutes; step (2) pouring: a molten liquid treated in the step (1) is alloWed to stand for 1-3 minutes after the molten liquid is mirror-like, and the molten liquid is poured into a metal mold after the stand is completed, and the molten liquid is solidified to obtain an ingot; step (3) performing homogenization annealing, hot extrusion defomaation, solid solution heat treatment, cold draWing defomaation, and aging heat treatment on the ingot.

4. The preparation method of the Cu-15Ni-8Sn-based alloy for ocean engineering according to claim 3, characterized in that, in the step (1), Cu 2 99.95 Wt% in the electrolytic copper;the Ni source is electrolytic nickel, and in the electrolytic nickel, Ni 2 99.96 Wt%; the Sn source is pure tin, and in the pure tin, Sn 2 99.99 Wt%; the Zn source is pure zinc, and in the pure zinc, Zn 2 98 Wt%; the Si source is pure silicon, and in the pure silicon, Si 2 99.99 Wt%; the A1 source is pure aluminum, A1 2 99.7 Wt%; the Mn source is Cu-Mn intennediate alloy; the Ce source is Cu-Ce intennediate alloy; the Y source is Cu-Y intennediate alloy.

5. The preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering according to claim 3, characterized in that, in the step (1), in the furnace, molten liquid surface is completely coVered by charcoal, and deoxidized using a pure phosphorus deoxidant; a dosage of the pure phosphorus deoxidant is 0.1% -0.3% of the total Weight of the molten liquid; a process of the smelting also comprises a step of using a graphite stirrer for stirring, and using a skimmer bar for skimming.

6. The preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering according to claim 3, characterized in that, in the step (2), a temperature for the pouring is 1 150- 1250°C.

7. The preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering according to claim 3, characterized in that, after the pouring is completed, the preparation method of the Cu- 15Ni-8Sn-based alloy for ocean engineering also comprises a step of applying an electromagnetic field outside the metal mold; a current application range of the electromagnetic field is 20- 100 A.

8. The preparation method of the Cu-ISNi-SSn-based alloy for ocean engineering according to claim 3, characterized in that, a temperature for the homogenization annealing is 900-950°C, a temperature for the hot extrusion deformation is 850-950°C , a temperature for the solid solution heat treatment is 750-900°C, an amount of the cold draWing defomaation is 50-90%, and a temperature for the aging heat treatment is 300-500°C.