A method for manufacturing a copper alloy connecting piece for a nuclear power steam turbine generator

Abstract

The application discloses a manufacturing method of a copper alloy connecting piece for a nuclear power steam turbine generator, and comprises the following steps: S1, continuously casting; S2, die forging: 3-4 times of upsetting and drawing, 2 times of forging; S3, solid solution; S4, aging; S5, rough machining of turning / milling; S6, fine milling machining; and S7, silver plating. The application uses a CuCr1Zr material die forging forming process to replace a traditional CuCr1 material sand casting forming process, and through heat treatment, aging precipitation strengthening is carried out to improve the mechanical properties of the product. The advantage of the process is that the product is changed from a cast structure to a forged structure through die forging, the defects such as cast loose caused by the smelting process of the metal can be eliminated, the microstructure is optimized, the grain is refined, and the complete metal flow line is ensured. The mechanical properties of the forging are better than those of the casting of the same material, so the forging is more suitable for use in a severe environment such as nuclear power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear power turbine generator parts manufacturing, in particular to a manufacturing method of a copper alloy connecting piece for nuclear power turbine generators. BACKGROUND

[0002] In today's world, the lack of energy is becoming more and more serious. After repeated argumentation, the cleanliness, reserves and relative safety and reliability of nuclear energy tell us that nuclear power is the most promising energy that can be developed at present. However, we have to see that the safety of nuclear power is relative. Once a nuclear power accident occurs, it is quite dangerous. If a large nuclear power accident occurs, the loss is greater and more terrible than any other energy utilization accident. Therefore, the development and safety of nuclear power have become the main topic of energy development in the world today. Therefore, higher requirements are put forward for the reliability of the parts required by the nuclear power station. The chromium bronze alloy connecting piece is a key connecting part for high-voltage power transmission of nuclear power turbine. There are strict requirements for internal and surface defects of the material. It is generally required to serve for 10 years under high voltage (more than 60KV).

[0003] The traditional process flow of the part adopts sand casting process, and the material adopts CuCr1 alloy. However, the mechanical property of the process is insufficient, the quality is unstable, the process is more, the influencing factors are more, many defects are easily produced, and there are casting defects such as loose inclusion and coarse grains. Moreover, the performance of CuCr1 is not as good as that of CuCr1Zr.

[0004] In addition, patent CN106191513B discloses a method for preparing CuCrZr ternary alloy by using CuZr intermediate alloy. Specifically, according to the requirements of the element content in the alloy, copper, copper-chromium alloy and copper-zirconium intermediate alloy are weighed, wherein the copper includes block pure copper for cladding and granular pure copper; the copper-chromium alloy and the copper-zirconium intermediate alloy are put into the block pure copper, and the granular pure copper is covered on the top to obtain a cladded whole material; the cladded whole material is melted into an alloy ingot by using electric arc melting-water cooled copper crucible method, and is subjected to aging treatment, so as to obtain the CuCrZr ternary alloy. In the patent technology, the Zr element is added in the form of intermediate alloy, which is beneficial to avoiding the oxidation and adsorption of Zr, reducing the burning loss of Zr element and improving the uniformity of the structure. The CuCrZr alloy is prepared by using electric arc melting-water cooled copper crucible, which is beneficial to obtaining fine-grained high-strength high-conductivity material, reducing production cost and obtaining CuCrZr alloy with Zr yield of more than 90%. However, the patent technology still has defects such as as-cast loose in the casting process. Therefore, it cannot be applied to the harsh nuclear power turbine high-voltage power transmission environment. SUMMARY

[0005] In view of the above problems, the present application provides a manufacturing method of a copper alloy connecting piece for nuclear power turbine generators.

[0006] The technical scheme of the present application is:

[0007] A manufacturing method of a copper alloy connecting piece for a nuclear power steam turbine generator, comprising the following steps:

[0008] S1, continuous downward casting: weighing the required electrolytic copper plate, copper-chromium intermediate alloy and copper-zirconium intermediate alloy, and performing downward casting through a round ingot crystallizer to obtain a CuCr1Zr alloy round ingot blank, the composition of the CuCr1Zr alloy round ingot blank, in terms of mass percentage, comprises: Cr: 0.5-1.2%, Zr: 0.03-0.3%, and the balance being Cu;

[0009] S2, die forging: taking the CuCr1Zr alloy round ingot blank obtained in step S1, heating using a box-type resistance furnace, the heating temperature is 900±20℃, the holding time is 180-210min, after taking out, performing 3-4 times of upsetting and drawing, the forging fire times is 2 times, then placing the CuCr1Zr alloy round ingot blank after upsetting and drawing into the box-type resistance furnace for heating, the heating temperature is 900±20℃, the holding time is 90-120min, after taking out, placing the CuCr1Zr alloy round ingot blank in a die for die pressing until the CuCr1Zr alloy round ingot blank fills the die cavity, the die preheating temperature is 200℃, the preheating time is 1h, to obtain a die forging piece;

[0010] S3, solid solution: performing solid solution heat treatment on the die forging piece obtained in step S2, the heating temperature of the solid solution heat treatment is 960±10℃, and the holding time is 60-90min;

[0011] S4, aging: performing aging heat treatment on the die forging piece after the solid solution heat treatment in step S3, the heating temperature of the aging heat treatment is 450±10℃, and the holding time is 4-5h, to obtain a rough piece;

[0012] S5, rough turning / milling: performing rough turning / milling on the rough piece obtained in step S4 to remove defects on the outer surface thereof;

[0013] S6, fine milling: performing fine milling on the rough piece after the rough turning / milling in step S5;

[0014] S7, silver plating: performing surface silver plating on the rough piece after the fine milling in step S6.

[0015] Further, in step S1, the diameter of the CuCr1Zr alloy round ingot blank is 360mm±50mm, the length of the CuCr1Zr alloy round ingot blank is 250-500mm, and the gas for atmosphere protection is argon.

[0016] Description: By optimizing the size of CuCr1Zr alloy round ingot blank, it can be adapted to the use of nuclear power turbine generator set, and it can facilitate the subsequent process, especially the realization of upsetting and drawing.

[0017] Further, in the step S2, the heating rate of the box-type resistance furnace is 10-15℃ / min, and the heating rate of the box-type resistance furnace is 5-10℃ / min.

[0018] Description: By optimizing the heating rate, the CuCr1Zr alloy round ingot blank can be uniformly heated.

[0019] Further, in the step S2, the process of upsetting and drawing is as follows: first, the CuCr1Zr alloy round ingot blank is straightened, and a 3T air hammer is used to perform one upsetting along the top surface direction, and the height reduction of one upsetting is 40-50%; then, the CuCr1Zr alloy round ingot blank is elongated along the horizontal direction using a 1600T forging press, and the length elongation of elongation is 30-40%; then, the edge generated by elongation is rounded using a 1600T forging press, and the length elongation of rounding is 5-10%; then, the CuCr1Zr alloy round ingot blank after rounding is straightened, and the rounded surface is used as the side surface, and a 3T air hammer is used to perform two upsets along the top surface direction, so that the CuCr1Zr alloy round ingot blank returns to the initial height, i.e. one upsetting and drawing is completed, each forging fire includes 1-2 times of upsetting and drawing, and the time of each forging fire is 10-15min, and each forging fire is to heat the CuCr1Zr alloy round ingot blank in the box-type resistance furnace, and the heating temperature is 910℃.

[0020] Description: By optimizing the process of upsetting and drawing, the internal temperature distribution of the CuCr1Zr alloy round ingot blank is more uniform, the temperature variance tends to be flat, and the internal stress distribution uniformity is better, which is more suitable for the use of nuclear power turbine generator set.

[0021] Further, in the step S2, the CuCr1Zr alloy round ingot blank is turned over by 180° at the end of each upsetting and drawing, i.e. the bottom surface of the second upsetting in the previous upsetting and drawing is used as the top surface of the one upsetting in the next upsetting and drawing.

[0022] Description: By optimizing the specific operation process of upsetting and drawing, the internal temperature and stress distribution uniformity of the CuCr1Zr alloy round ingot blank can be further improved.

[0023] Further, in the step S2, the rolling speed of the 1600T forging press during the rolling is 3-5mm / s, 2-3 flame spray guns are arranged in front of the rolling surface to heat and warm the rolling surface, the rolling surface is divided into 3 equal parts or 4 equal parts by the flame spray guns, the distance between the flame spray guns and the rolling surface is always kept at 50-80mm, the temperature of the flame spray guns is 800-900 DEG C, and the duration of the flame spray guns is 20-60s.

[0024] Description: By optimizing and adjusting the rolling speed during the upsetting and drawing, the CuCr1Zr alloy round ingot blank after rolling is ensured to have smooth side surface, the rolling surface is heated and warmed in real time by adding the flame spray guns, so that the grain crushing of the rolling surface is more uniform, the upsetting and drawing efficiency is improved, and the upsetting and drawing times are saved.

[0025] Further, in the step S3, the heating speed of the solid solution heat treatment is 10-15 DEG C / min, and the holding time is to the later furnace-out water cooling to normal temperature 26 DEG C.

[0026] Further, in the step S4, the heating speed of the aging heat treatment is 5-10 DEG C / min, and the holding time is to the later furnace-out air cooling to normal temperature 26 DEG C.

[0027] Further, in the step S7, the silver plating layer thickness of the surface silver plating is 25um.

[0028] Description: By the surface silver plating, the surface of the blank is uniform, without defects such as bubbles, peeling and peeling.

[0029] The beneficial effects of the present application are:

[0030] (1) The manufacturing method of the copper alloy connecting piece for nuclear power turbine generator of the present application replaces the traditional CuCr1 material sand casting forming process by using CuCr1Zr material die forging forming process, and the mechanical properties of the product are improved by aging and precipitation strengthening through heat treatment, the advantages of the process are mainly that the product is changed from cast structure to forged structure by die forging, the cast defects generated in the smelting process can be eliminated, the microstructure is optimized, the grain is refined, and the complete metal flow line is ensured, the mechanical properties of the forging are better than those of the casting of the same material, so the forging is more suitable for use in the harsh environment of nuclear power, compared with CuCr1, the former adds Zr element, and has more excellent mechanical properties, higher softening temperature and wear resistance.

[0031] (2) The manufacturing method of the copper alloy connecting piece for nuclear power steam turbine generators optimizes and adjusts the upsetting and drawing process in the die forging process, adopts a three-dimensional upsetting and drawing method of one-time upsetting-drawing-rolling-rounding-two-time upsetting, and limits and optimizes the deformation amount in each step, so that the internal temperature distribution of the CuCr1Zr alloy round ingot blank is more uniform, the temperature variance tends to be flat, and the internal stress distribution is more uniform, which is more suitable for use in nuclear power steam turbine generator sets; by optimizing and adjusting the rolling speed during forging upsetting and drawing, the side surface of the CuCr1Zr alloy round ingot blank after rolling is smooth, and by adding a flame spray gun to heat the rolling surface in real time, the grain crushing of the rolling surface is more uniform, the upsetting and drawing efficiency is improved, and the number of upsetting and drawing is saved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a plan view of the rolling process during forging upsetting and drawing in the manufacturing method of the copper alloy connecting piece for nuclear power steam turbine generators of the present application;

[0033] Figure 2 is a front view of the rolling process during forging upsetting and drawing in the manufacturing method of the copper alloy connecting piece for nuclear power steam turbine generators of the present application. DETAILED DESCRIPTION

[0034] Example 1

[0035] A manufacturing method of a copper alloy connecting piece for nuclear power steam turbine generators, comprising the following steps:

[0036] S1, continuous downward casting: weigh the required electrolytic copper plate, copper-chromium intermediate alloy and copper-zirconium intermediate alloy, and cast downward through a round ingot crystallizer to obtain a CuCr1Zr alloy round ingot blank, the composition of the CuCr1Zr alloy round ingot blank, by mass percent, includes: Cr: 0.8%, Zr: 0.1%, impurity Fe: 0.04%, impurity Si: 0.05%, and the balance is Cu, the diameter of the CuCr1Zr alloy round ingot blank is 360mm, the length of the CuCr1Zr alloy round ingot blank is 400mm, and the atmosphere protection gas is argon;

[0037] S2, swaging: taking the CuCr1Zr alloy round ingot blank obtained in step S1, heating using a box-type resistance furnace, the heating rate of the box-type resistance furnace is 12 ℃ / min, the heating temperature is 900 ℃, the holding time is 200 min, after taking out, performing 3 times of upsetting and drawing, the forging fire times is 2 fire times, then placing the CuCr1Zr alloy round ingot blank after upsetting and drawing into the box-type resistance furnace for heating, the heating rate of the box-type resistance furnace is 7 ℃ / min, the heating temperature is 900 ℃, the holding time is 100 min, after taking out, placing the CuCr1Zr alloy round ingot blank in a die for die pressing until the CuCr1Zr alloy round ingot blank fills the die cavity, the die preheating temperature is 200 ℃, the preheating time is 1 h, obtaining a swaging piece;

[0038] The process of upsetting and drawing is as follows: first, standing the CuCr1Zr alloy round ingot blank upright, using a 3T air hammer to perform once upsetting along the top surface direction, the height reduction of once upsetting is 45%, then using a 1600T forging press to perform lengthening along the horizontal direction, the length elongation of lengthening is 35%, then using the 1600T forging press to perform rounding of the edge generated by lengthening, the length elongation of rounding is 8%, the rounding speed of the 1600T forging press is 4 mm / s, 3 flame spray guns are arranged in front of the rounding surface to heat and raise the temperature of the rounding surface, the rounding surface is divided into 4 equal parts by the flame spray guns, the distance between the flame spray guns and the rounding surface is always kept at 60 mm, the temperature of the flame spray guns is 850 ℃, and the duration of the flame spray guns is 30 s, then standing the CuCr1Zr alloy round ingot blank upright after rounding, using a 3T air hammer to perform twice upsetting along the top surface direction, so that the CuCr1Zr alloy round ingot blank returns to the initial height, that is, one upsetting and drawing is completed, the first forging fire time includes once upsetting and drawing, the second forging fire time includes twice upsetting and drawing, the time of each forging fire time is 12 min, and each forging fire time is heating the CuCr1Zr alloy round ingot blank in the box-type resistance furnace, the heating temperature is 910 ℃, the CuCr1Zr alloy round ingot blank is turned over by 180° at the end of each upsetting and drawing, that is, the bottom surface in the twice upsetting and drawing in the previous upsetting and drawing is used as the top surface of once upsetting and drawing in the next upsetting and drawing;

[0039] S3, solutionizing: performing solutionizing heat treatment on the swaging piece obtained in step S2, the heating temperature of the solutionizing heat treatment is 960 ℃, the holding time is 80 min, the heating rate of the solutionizing heat treatment is 12 ℃ / min, and the holding time is out of the furnace and water-cooled to normal temperature 26 ℃;

[0040] S4, aging: performing aging heat treatment on the swaging piece after the solutionizing heat treatment in step S3, the heating temperature of the aging heat treatment is 450 ℃, the holding time is 4.5 h, the heating rate of the aging heat treatment is 7 ℃ / min, the holding time is out of the furnace and air-cooled to normal temperature 26 ℃, obtaining a blank piece;

[0041] S5, rough turning / milling: the blank obtained in step S4 is subjected to rough turning / milling to remove defects on the outer surface thereof;

[0042] S6, fine milling: the blank subjected to rough turning / milling in step S5 is subjected to fine milling;

[0043] S7, silver plating: the blank subjected to fine milling in step S6 is subjected to surface silver plating, and the thickness of the silver plating layer is 25 pm.

[0044] Example 2

[0045] The difference between this example and Example 1 is that the number of upsetting and drawing is different.

[0046] In step S2, forging is performed by upsetting and drawing 4 times, and 2 forging heats are performed, each of which includes 2 times of upsetting and drawing.

[0047] Example 3

[0048] The difference between this example and Example 1 is that the number of upsetting and drawing is different.

[0049] In step S2, forging is performed by upsetting and drawing 3 times, and 2 forging heats are performed, the first of which includes 2 times of upsetting and drawing, and the second of which includes 1 time of upsetting and drawing.

[0050] Comparative Example 1

[0051] The difference between this example and Example 1 is that the number of upsetting and drawing is different.

[0052] In step S2, forging is performed by upsetting and drawing 2 times, and 2 forging heats are performed, each of which includes 1 time of upsetting and drawing.

[0053] Example 4

[0054] The difference between this example and Example 1 is that the rolling speed and the distance between the flame spray gun and the rolling surface are different.

[0055] The rolling speed of the 1600T forging press during rolling is 3 mm / s, 2 flame spray guns are arranged in front of the rolling surface to heat and warm the rolling surface, the rolling surface is divided into 3 equal parts by the flame spray guns, the distance between the flame spray guns and the rolling surface is always kept at 50 mm, the temperature of the flame spray guns is 800°C, and the duration of the flame spray guns is 60 s.

[0056] Example 5

[0057] The difference between this example and Example 1 is that the rolling speed and the distance between the flame spray gun and the rolling surface are different.

[0058] The rolling speed of the 1600T forging press during the rolling is 5mm / s. Three flame spray guns are arranged in front of the rolling surface to heat and warm the rolling surface. The rolling surface is divided into four equal parts by the flame spray guns. The distance between the flame spray guns and the rolling surface is always kept at 80mm. The temperature of the flame spray guns is 900℃. The duration of the flame spray guns is 20s.

[0059] Comparative Example 2

[0060] The difference between this example and Example 1 is that no flame spray gun is arranged during the rolling.

[0061] Example 6

[0062] The difference between this example and Example 1 is that the conventional parameters are different.

[0063] S1, downward continuous casting: electrolytic copper plates, copper-chromium intermediate alloy and copper-zirconium intermediate alloy required are weighed and put into a furnace, and a CuCr1Zr alloy round ingot blank is obtained by downward continuous casting through a round ingot crystallizer. The composition of the CuCr1Zr alloy round ingot blank, by mass percent, includes: Cr: 0.5%, Zr: 0.03%, impurity Fe: 0.02%, impurity Si: 0.02%, and the balance being Cu. The diameter of the CuCr1Zr alloy round ingot blank is 310mm. The length of the CuCr1Zr alloy round ingot blank is 250mm. The atmosphere protection gas is argon.

[0064] S2, die forging: the CuCr1Zr alloy round ingot blank obtained in step S1 is heated using a box-type resistance furnace. The heating rate of the box-type resistance furnace is 10℃ / min. The heating temperature is 880℃. The holding time is 180min. After being taken out, the CuCr1Zr alloy round ingot blank is forged for three times. The forging fire times are two. The time of each forging fire time is 10min. Then the forged CuCr1Zr alloy round ingot blank is heated in the box-type resistance furnace. The heating rate of the box-type resistance furnace is 5℃ / min. The heating temperature is 880℃. The holding time is 90min. After being taken out of the furnace, the CuCr1Zr alloy round ingot blank is placed in a die for die pressing until the die cavity is filled with the CuCr1Zr alloy round ingot blank. The preheating temperature of the die is 200℃. The preheating time is 1h. A die forging piece is obtained.

[0065] The process of the forging upsetting is as follows: the CuCr1Zr alloy round ingot blank is first straightened, and then the CuCr1Zr alloy round ingot blank is upset once along the top surface direction using a 3T air hammer. The height reduction of the first upsetting is 40%. Then the CuCr1Zr alloy round ingot blank is elongated along the horizontal direction using a 1600T forging press. The length elongation of the elongation is 30%. Subsequently, the edges generated by the elongation are rolled using the 1600T forging press. The length elongation of the rolling is 5%.

[0066] S3, solid solution: the die forging piece obtained in step S2 is subjected to solid solution heat treatment, the heating temperature of the solid solution heat treatment is 950 DEG C, the holding time is 60 min, the heating speed of the solid solution heat treatment is 10 DEG C / min, and the holding time is out of the furnace and water cooling to normal temperature 26 DEG C after the holding time;

[0067] S4, aging: the die forging piece after the solid solution heat treatment in step S3 is subjected to aging heat treatment, the heating temperature of the aging heat treatment is 440 DEG C, the holding time is 4 h, the heating speed of the aging heat treatment is 5 DEG C / min, the holding time is out of the furnace and air cooling to normal temperature 26 DEG C after the holding time, and the blank piece is obtained.

[0068] Example 7

[0069] The difference between this embodiment and example 1 is that the conventional parameters are different.

[0070] S1, downward continuous casting: the required electrolytic copper plate, copper-chromium intermediate alloy and copper-zirconium intermediate alloy are weighed and put into the furnace, and the CuCr1Zr alloy round ingot blank is obtained by downward casting through a round ingot crystallizer, the composition of the CuCr1Zr alloy round ingot blank, in terms of mass percentage, includes: Cr: 1.2%, Zr: 0.3%, impurity Fe: 0.08%, impurity Si: 0.1%, and the balance is Cu, the diameter of the CuCr1Zr alloy round ingot blank is 410 mm, the length of the CuCr1Zr alloy round ingot blank is 500 mm, and the atmosphere protection gas is argon;

[0071] S2, die forging: the CuCr1Zr alloy round ingot blank obtained in step S1 is taken out and heated using a box-type resistance furnace, the heating speed of the box-type resistance furnace is 15 DEG C / min, the heating temperature is 920 DEG C, and the holding time is 210 min, and then the CuCr1Zr alloy round ingot blank is subjected to three times of upsetting and drawing, the forging fire times are 2, and the time of each forging fire time is 15 min, then the CuCr1Zr alloy round ingot blank after the upsetting and drawing is heated in the box-type resistance furnace, the heating speed of the box-type resistance furnace is 10 DEG C / min, the heating temperature is 920 DEG C, and the holding time is 120 min, and then the CuCr1Zr alloy round ingot blank is placed in a die for die pressing after being taken out of the furnace, until the CuCr1Zr alloy round ingot blank fills the die cavity, the preheating temperature of the die is 200 DEG C, and the preheating time is 1 h, and the die forging piece is obtained.

[0072] The process of the upsetting and drawing is as follows: the CuCr1Zr alloy round ingot blank is first stood upright, and then once upsetting is performed along the top surface direction using a 3T air hammer, the height reduction of the once upsetting is 50%, then the CuCr1Zr alloy round ingot blank is elongated along the horizontal direction using a 1600T forging press, the length elongation of the elongation is 40%, and then the edge generated by the elongation is rolled using the 1600T forging press, and the length elongation of the rolling is 10%.

[0073] S3, solid solution: the die forging piece obtained in step S2 is subjected to solid solution heat treatment, the heating temperature of the solid solution heat treatment is 970 DEG C, the holding time is 90 min, the heating speed of the solid solution heat treatment is 15 DEG C / min, and after the holding time, the die forging piece is taken out of the furnace and water-cooled to normal temperature 26 DEG C;

[0074] S4, aging: the die forging piece subjected to the solid solution heat treatment in step S3 is subjected to aging heat treatment, the heating temperature of the aging heat treatment is 460 DEG C, the holding time is 5 h, the heating speed of the aging heat treatment is 10 DEG C / min, and after the holding time, the die forging piece is taken out of the furnace and air-cooled to normal temperature 26 DEG C, thereby obtaining a blank piece.

[0075] Comparative Example 3

[0076] The difference from example 1 is that the raw materials are selected differently.

[0077] S1, downward continuous casting: CuCr1 alloy round ingot blank is cast by an 8t atmosphere-protected semi-continuous downward melting and casting furnace under atmosphere protection, and the CuCr1 alloy round ingot blank includes, in terms of weight percentage, Cr: 1%, impurity Fe: 0.04%, impurity Si: 0.05%, and the balance of Cu.

[0078] Experimental Example 1

[0079] The blank pieces prepared in examples 1-3 and comparative example 1 are subjected to performance detection, and the detection results are shown in Table 1.

[0080] Table 1 Performance parameters of the blank pieces prepared in examples 1-3 and comparative example 1

[0081]

[0082] As can be seen from the data in Table 1, the upsetting and drawing times in comparative example 1 are the least, so the grains in the alloy are not broken to a certain extent, which ultimately affects the performance of the finished workpiece, but the influence is not great. Although the performance in example 2 is the best, the number of upsetting and drawing is the most, which increases the working time. Under the premise of being able to meet the use requirements, the method parameters in example 1 are the most reasonable in comprehensive consideration.

[0083] Experimental Example 2

[0084] The blank pieces prepared in examples 1, 4, 5 and comparative example 2 are subjected to performance detection, and the detection results are shown in Table 2.

[0085] Table 2 Performance parameters of the blank pieces prepared in examples 1, 4, 5 and comparative example 2

[0086]

[0087] As can be seen from the data in Table 2, in the comparative example 2, no flame spray gun is arranged during the rounding, so that the breaking degree of the grains in the alloy is affected to a certain extent, and finally the performance of the finished workpiece is affected, but the influence is not large. The multi-flame medium speed can maximize the breaking degree of the grains during the rounding process, and plays an auxiliary role in upsetting and drawing. Under the premise of meeting the use requirements, the method parameters in the preferred example 1 are the most reasonable in comprehensive consideration.

[0088] Experimental example 3

[0089] The performance of the blank parts prepared in examples 1, 6, 7 and comparative example 3 is detected, and the detection results are shown in Table 3.

[0090] Table 3 Performance parameters of blank parts prepared in examples 1, 6, 7 and comparative example 3

[0091]

[0092] As can be seen from the data in Table 3, in the comparative example 3, Zr is not added, so that the performance of each parameter is obviously decreased compared with examples 1, 6 and 7, thereby causing the CuCr1 alloy to be prone to fatigue damage in the high-pressure environment of the nuclear power turbine generator set. Further comparison between examples 1, 6 and 7 shows that increasing the content of Zr helps to improve the performance, but too much Zr will produce more zirconium oxide. Zirconium is more oxygen, and the formation of metal oxide inclusion defects will reduce the forgeability. In addition, zirconium also has a limit solid solubility in the copper matrix, and too much will also reduce the electrical conductivity. Under the premise of meeting the use requirements, the method parameters in the preferred example 1 are the most reasonable in comprehensive consideration.

Claims

1. A method for manufacturing a copper alloy connector for a nuclear power turbine generator, characterized in that, Includes the following steps: S1. Downward Continuous Casting: Weigh the required electrolytic copper plates, copper-chromium master alloy, and copper-zirconium master alloy and load them into the furnace. Then, perform downward casting through a round ingot crystallizer to obtain CuCr1Zr alloy round ingot billets. The composition of the CuCr1Zr alloy round ingot billets, by mass percentage, includes: Cr: 0.5~1.2%, Zr: 0.03~0.3%, balance Cu; S2. Die forging: Take the CuCr1Zr alloy round ingot billet obtained in step S1, heat it in a box-type resistance furnace at a temperature of 900±20℃ for 180~210min, remove it and forge it 3~4 times for 2 forging cycles. Then put the forged and uplifted CuCr1Zr alloy round ingot billet back into the box-type resistance furnace for heating at a temperature of 900±20℃ for 90~120min. After removing it from the furnace, place the CuCr1Zr alloy round ingot billet in a mold for die pressing until the CuCr1Zr alloy round ingot billet fills the mold cavity. The mold preheating temperature is 200℃ and the preheating time is 1h to obtain the die forging. In step S2, the forging upsetting and drawing process is as follows: First, the CuCr1Zr alloy round ingot billet is stood upright, and a 3T air hammer is used to perform a first upsetting along the top surface direction, with a height reduction of 40-50% during the first upsetting. Then, the CuCr1Zr alloy round ingot billet is drawn horizontally using a 1600T forging press, with a length elongation of 30-40%. Subsequently, the edges generated by the drawing are rounded using a 1600T forging press, with a length elongation of 5-10%. 0%, the rounded CuCr1Zr alloy ingot billet is stood upright, with the rounded surface as the side. A 3T air hammer is used to perform a second upsetting along the top surface to bring the CuCr1Zr alloy ingot billet back to its initial height, thus completing one forging upsetting and drawing. Each forging cycle includes 1 to 2 upsetting and drawing cycles, and each forging cycle takes 10 to 15 minutes. After each forging cycle, the CuCr1Zr alloy ingot billet is sent back to the box-type resistance furnace for heating at a temperature of 910℃. S3, Solution treatment: The forging obtained in step S2 is subjected to solution heat treatment. The heating temperature of the solution heat treatment is 960±10℃ and the holding time is 60~90min. S4. Aging: The forgings after solution heat treatment in step S3 are subjected to aging heat treatment. The heating temperature of the aging heat treatment is 450±10℃ and the holding time is 4~5h to obtain the blank. S5. Rough turning / milling: The blank obtained in step S4 is turned / milled to remove defects on its outer surface. S6. Finish milling: Perform finish milling on the blank after rough turning / milling in step S5. S7. Silver plating: Silver plating is performed on the surface of the blank after precision milling in step S6.

2. The manufacturing method of a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S1, the diameter of the CuCr1Zr alloy round ingot billet is 360mm±50mm, the length of the CuCr1Zr alloy round ingot billet is 250~500mm, and the protective atmosphere is argon.

3. The manufacturing method of a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S2, the heating rate of the box-type resistance furnace is 10~15℃ / min for the first time and 5~10℃ / min for the second time.

4. The manufacturing method of a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S2, at the end of each forging and upsetting process, the CuCr1Zr alloy ingot billet is flipped 180°, that is, the bottom surface during the second upsetting in the previous forging and upsetting process is used as the top surface during the first upsetting in the next forging and upsetting process.

5. A method for manufacturing a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S2, the rolling speed of the 1600T forging press is 3~5mm / s during rolling, and 2~3 flame torches are set in front of the rolling surface to heat the rolling surface.

6. A method for manufacturing a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S3, the heating rate of the solution heat treatment is 10~15℃ / min, and after the holding time is up, the product is taken out of the furnace and cooled to room temperature by water.

7. A method for manufacturing a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S4, the heating rate of the aging heat treatment is 5~10℃ / min, and after the holding time is up, the furnace is removed and air-cooled to room temperature.

8. A method for manufacturing a copper alloy connector for a nuclear power turbine generator according to claim 1, characterized in that, In step S7, the thickness of the silver plating layer on the surface is 25 μm.

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