CN105397050A - Semi-solid forming method for copper alloy - Google Patents

Abstract

The invention relates to a copper alloy semi-solid forming method, which belongs to the technical field of metal semi-solid forming. First measure the solidus and liquidus temperatures of the copper alloy; heat the copper alloy billet to T+50°C~T+150°C in a vacuum or inert gas protection atmosphere, where T is the liquidus temperature; In the gas protection atmosphere, the heated copper alloy is chilled and high-energy ultrasonic vibration is applied to make the alloy temperature in the temperature range of solidus and liquidus. After the chilling and high-energy ultrasonic vibration are completed, heat preservation is carried out to obtain a semi-solid slurry; The obtained semi-solid slurry is extruded and formed, and air-cooled to room temperature after forming; the formed copper alloy is subjected to heat treatment to obtain a copper alloy product. The purpose of the method is to solve the problems of copper alloy semi-solid blank preparation, difficult forming, long forming cycle, high product cost, etc., and widen the deep processing technology and method of copper alloy products.

Description

A kind of copper alloy semi-solid forming method

technical field

The invention relates to a copper alloy semi-solid forming method, which belongs to the technical field of metal semi-solid forming.

Background technique

In the early 1970s, the research group of the Massachusetts Institute of Technology proposed the semi-solid forming technology for the first time. It is a method of forming metals according to their characteristics during the transition from liquid to solid or from solid to liquid (that is, solid-liquid coexistence). The method has the characteristics of stable filling, less spatter, small shrinkage, low yield strength, good fluidity, small thermal shock to the mold, high mechanical properties, and high-speed near-net forming. Therefore, metal semi-solid forming technology is increasingly valued by governments, enterprises and scientific research institutions, and is known as one of the most promising metal forming technologies in the 21st century. With the continuous deepening of research, semi-solid forming has developed into a new material forming technology with great application potential, and has initially realized industrial application.

The metal semi-solid forming process is mainly divided into rheological forming and thixoforming. Rheological deformation is a kind of solid-liquid mixed slurry in which nearly spherical solid phase components are evenly suspended in the liquid metal mother liquor through vigorous stirring or control of the solidification process during the solidification process of metals, and the slurry is used to directly The method of forming processing; thixoforming is to cool and solidify the semi-solid billet with non-dendritic structure obtained by stirring and other processes, then cut the billet according to the need, and then reheat the cut billet to the solid-liquid state. Phase region, the method of forming by pressure working at semi-solid temperature. The first step of both needs to prepare a semi-solid slurry with uniform structure and small grain size. At present, there are many thixotropic forming methods, and there are many industrial applications, but this method needs to prepare the slurry first, then solidify, then quantitatively cut and remelt, obtain the slurry again, and finally form the product, resulting in a long process flow , high energy consumption and high product cost. The rheological forming reduces the secondary heating process of the semi-solid slurry, and it is directly processed from the metal semi-solid, so the process is short, the operation is simple, the energy consumption is small, the cost is low, the production efficiency is high, and there are few oxidized inclusions in the forming process, The finished products and waste materials of castings can be completed in one workshop, which improves the utilization rate of waste materials. Therefore, it is of great significance to develop short-flow semi-solid metal rheological deformation.

At present, most of the metal semi-solid forming technologies are aimed at low-melting point alloys such as aluminum and magnesium, and there are relatively few semi-solid researches on high-melting point alloys such as copper alloys. This is mainly due to the high melting point of copper alloy, easy oxidation, and high thermal conductivity. When using traditional pulping methods to prepare semi-solid billets, there will be problems such as difficult operation, high mold requirements, and oxidation of copper liquid, which makes the prepared copper alloy semi-solid billets Organizations with poor performance or high costs. In addition, copper alloys are used in a wide range of fields. Traditional casting has problems such as short mold life, easy oxidation, high product energy consumption, and gas absorption. However, the use of semi-solid forming technology will significantly reduce mold temperature, improve mold life, and reduce energy consumption. Therefore, the semi-solid forming of copper alloys has important application value.

Contents of the invention

Aiming at the problems and deficiencies in the above-mentioned prior art, the present invention provides a copper alloy semi-solid forming method. The purpose of the method is to solve the problems of copper alloy semi-solid blank preparation, difficult forming, long forming cycle, high product cost, etc., and widen the deep processing technology and method of copper alloy products.

The technical solution of the present invention is: firstly measure the solid-liquid temperature range of the copper alloy, heat the copper alloy above the liquidus temperature in a vacuum or inert gas protection, then rapidly cool the melt, and cool the melt while cooling. Apply high-energy ultrasonic vibration, and when the melt cools to the semi-solid temperature range, stop the chilling and vibration, and at the same time keep the melt warm and perform rapid extrusion molding, then air-cool to room temperature, and perform corresponding heat treatment, and finally obtain the copper alloy flow To become a shaped product, the specific steps are as follows:

(1) Measure the solidus and liquidus temperatures of copper alloys;

(2) Heating the copper alloy billet to T+50℃～T+150℃ in a vacuum or inert gas protection atmosphere, where T is the liquidus temperature;

(3) In a vacuum or an inert gas protective atmosphere, chill the copper alloy heated in step (2) and apply high-energy ultrasonic vibrations to keep the alloy temperature within the temperature range of solidus and liquidus. Chilling and high-energy ultrasonic vibration After the vibration is completed, heat preservation is carried out to obtain a semi-solid slurry;

(4) Extrude the semi-solid slurry obtained in step (3), and air cool to room temperature after forming;

(5) heat-treating the copper alloy formed in step (4) to obtain a copper alloy product.

The vacuum condition of the steps (2) and (3) is 10 ^-1 ~ 10 ^-4 Pa.

The step (2) chilling is to insert a steel rod, copper rod or graphite rod with cooling water inside into the heated copper alloy and stay for 5-10s, then take it out, and then do it again after an interval of 3-10s Putting in and taking out, so reciprocating, so that the temperature of the melt is within the temperature range of the solidus and liquidus, the number of times of putting in and taking out is determined by the liquid phase ratio of the semi-solid slurry to be obtained: high semi-solid slurry liquid The number of times to put in and take out the phase ratio is less, and the number of times to put in and take out the liquid phase ratio of the low semi-solid slurry is more.

In the step (2), the ultrasonic power of the high-energy ultrasonic vibration is 150W-1200W, and the vibration frequency is 15kHZ-40kHZ.

The heat preservation time of the step (2) is 2-10 minutes.

The above-mentioned step (2) does not apply high-energy ultrasonic vibrations during the chilling putting in and taking out process.

The extrusion die in the above step (4) should be preheated to avoid rapid cooling of the semi-solid slurry.

The purpose of the heat treatment in the step (5) is to further improve the uniformity of the structure and obtain high-performance copper alloy products. (The conditions of heat treatment are set according to the composition and requirements of the alloy, which are conventional parameters)

The heat treatment and extrusion methods described in the present invention are conventional methods.

The beneficial effects of the present invention are:

(1) With the present invention, the alloy is subjected to chilling above the liquidus temperature, and the temperature in the chilling zone drops rapidly, thereby forming a large number of crystal nuclei and obtaining a semi-solid slurry; at the same time, applying high-energy ultrasonic waves to the liquid copper alloy, In the cavitation effect, the pressure shock wave caused by the bursting of the bubbles will cause the breakage of the dendrite arms, and the acoustic flow phenomenon will evenly distribute the broken dendrite arms in the melt, so that the structure of the semi-solid slurry is uniform and fine. After the comprehensive treatment of ultrasonic vibration and chilling, the grains in the melt can be refined, the dendrite structure can be suppressed, the uniformity of the melt can be improved, and the segregation can be reduced. In addition, proper heat preservation after treatment can make the temperature uniform, and finally can be obtained Uniform and fine spheroidized semi-solid slurry solves the problems of high cost, short mold life, easy oxidation of slurry and long cycle time for preparing copper alloy semi-solid slurry by traditional methods.

(2) With the present invention, the prepared copper alloy semi-solid slurry is directly sent to the extrusion die, which reduces the problems of oxidation and cooling of the semi-solid slurry, high forming efficiency, compact and uniform structure of the product, and excellent performance. The average grain size of rheologically formed parts is 80~140um, the tensile strength is increased by 5~10%, and the elongation is increased by 6~8%.

(3) The present invention has the advantages of short process, high forming efficiency, low energy consumption, low product cost, uniform performance, and complex product structure.

Description of drawings

Fig. 1 is a process flow diagram of the present invention;

Fig. 2 is a microstructure diagram of the ZCuSn10 tin bronze alloy prepared in Example 1 of the present invention.

detailed description

The present invention will be further described below in combination with the accompanying drawings and specific embodiments.

Example 1

Take the preparation of ZCuSn10 tin bronze products as an example.

As shown in Figure 1, the copper alloy semi-solid forming method, its specific steps are as follows:

(1) Measure the solidus and liquidus temperatures of the copper alloy; the ZCuSn10 tin bronze alloy uses differential scanning calorimetry (DSC) to measure the solidus temperature of the alloy to be 830°C and the liquidus temperature to be 1020°C;

(2) Heat the copper alloy blank (ZCuSn10) to T+100°C (1120°C) in an argon protective atmosphere, where T is the liquidus temperature;

(3) In an argon protective atmosphere, chill the copper alloy heated in step (2) and apply high-energy ultrasonic vibration to keep the temperature of the alloy within the temperature range of solidus and liquidus. The chilling and high-energy ultrasonic vibration are completed. Finally, heat preservation for 5 minutes to obtain a semi-solid slurry; among them, the quenching is to insert a steel rod with a diameter of 40 mm and cooling water inside into the heated copper alloy and stay for 5 seconds, then take it out, and then repeat it for the second time after an interval of 10 seconds. Put in and take out, so reciprocate 4 times; the ultrasonic power of the high-energy ultrasonic vibration is 1200W, and the vibration frequency is 40kHZ;

(4) Extrude the semi-solid slurry obtained in step (3), and air-cool to room temperature under the protection of nitrogen atmosphere after forming;

(5) The copper alloy formed in step (4) is subjected to heat treatment (heated to 680° C. for 4 hours), and a copper alloy product (ZCuSn10 tin bronze product) is obtained.

The microstructure diagram of the ZCuSn10 tin bronze product prepared in this example is shown in Figure 2. From Figure 2, it can be seen that the structure is uniform, fine, and rounded, and the average grain diameter is 118um.

The results show that the invention has the advantages of short process and high molding efficiency, and can obtain products with complex structure, dense and uniform structure and uniform performance, and can be applied to the preparation of copper alloy semi-solid rheomorphic products.

Example 2

Take the preparation of ZCuSn10P1 tin bronze products as an example.

As shown in Figure 1, the copper alloy semi-solid forming method, its specific steps are as follows:

(1) Measure the solidus and liquidus temperatures of copper alloys; ZCuSn10P1 tin bronze alloy uses differential scanning calorimetry (DSC) to measure the solidus temperature of the alloy to be 820°C and the liquidus temperature to be 1003°C;

(2) Heat the copper alloy blank (ZCuSn10P1) to T+117°C (1120°C) in an argon protective atmosphere, where T is the liquidus temperature;

(3) In an argon protective atmosphere, chill the copper alloy heated in step (2) and apply high-energy ultrasonic vibration to keep the temperature of the alloy within the temperature range of solidus and liquidus. The chilling and high-energy ultrasonic vibration are completed. Afterwards, keep warm for 2 minutes to obtain a semi-solid slurry; among them, the quenching is to insert 6 steel rods with a diameter of 30 mm and cooling water inside into the heated copper alloy and stay for 5 seconds, then take it out, and then wait for another 10 seconds. Put in and take out for the second time, and reciprocate until the temperature drops to 850°C; the ultrasonic power of high-energy ultrasonic vibration is 1200W, and the vibration frequency is 20kHZ;

(4) Extrude the semi-solid slurry obtained in step (3), and air-cool to room temperature under the protection of nitrogen atmosphere after forming;

(5) The copper alloy formed in step (4) is subjected to heat treatment (heating to 630° C. for 2 hours) to obtain a copper alloy product (ZCuSn10P1 tin bronze product).

Example 3

Take the preparation of ZCuSn10P1 tin bronze products as an example.

As shown in Figure 1, the copper alloy semi-solid forming method, its specific steps are as follows:

(1) Measure the solidus and liquidus temperatures of copper alloys; ZCuSn10P1 tin bronze alloy uses differential scanning calorimetry (DSC) to measure the solidus temperature of the alloy to be 820°C and the liquidus temperature to be 1003°C;

(2) Heat the copper alloy blank (ZCuSn10P1) to T+50°C (1053°C) in an argon protective atmosphere, where T is the liquidus temperature;

(3) In an argon protective atmosphere, chill the copper alloy heated in step (2) and apply high-energy ultrasonic vibration to keep the temperature of the alloy within the temperature range of solidus and liquidus. The chilling and high-energy ultrasonic vibration are completed. Afterwards, keep warm for 2 minutes to obtain a semi-solid slurry; among them, the quenching is to insert 4 graphite rods with a diameter of 20 mm and cooling water inside into the heated copper alloy and stay for 10 seconds, then take it out, and then wait for another 3 seconds. Put in and take out for the second time, and reciprocate until the temperature drops to 900°C; the ultrasonic power of the high-energy ultrasonic vibration is 150W, and the vibration frequency is 15kHZ;

(4) Extrude the semi-solid slurry obtained in step (3), and air-cool to room temperature under the protection of nitrogen atmosphere after forming;

(5) The copper alloy formed in step (4) is subjected to heat treatment (heating to 630° C. for 2 hours) to obtain a copper alloy product (ZCuSn10P1 tin bronze product).

Example 4

Take the preparation of ZCuSn10P1 tin bronze products as an example.

As shown in Figure 1, the copper alloy semi-solid forming method, its specific steps are as follows:

(1) Measure the solidus and liquidus temperatures of copper alloys; ZCuSn10P1 tin bronze alloy uses differential scanning calorimetry (DSC) to measure the solidus temperature of the alloy to be 820°C and the liquidus temperature to be 1003°C;

(2) Heat the copper alloy billet (ZCuSn10P1) to T+150°C (1153°C) under a vacuum condition of 10 ^-1 Pa, where T is the liquidus temperature;

(3) In an argon protective atmosphere, chill the copper alloy heated in step (2) and apply high-energy ultrasonic vibration to keep the temperature of the alloy within the temperature range of solidus and liquidus. The chilling and high-energy ultrasonic vibration are completed. Afterwards, keep warm for 10 minutes to obtain a semi-solid slurry; among them, the quenching is to insert 4 graphite rods with a diameter of 20 mm and cooling water inside into the heated copper alloy and stay for 8 seconds, then take it out, and wait for another 7 seconds. Put in and take out for the second time, and reciprocate until the temperature drops to 900°C; the ultrasonic power of the high-energy ultrasonic vibration is 650W, and the vibration frequency is 40kHZ;

(4) Extrude the semi-solid slurry obtained in step (3), and air-cool to room temperature under the protection of nitrogen atmosphere after forming;

(5) The copper alloy formed in step (4) is subjected to heat treatment (heating to 630° C. for 2 hours) to obtain a copper alloy product (ZCuSn10P1 tin bronze product).

The specific embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Variations.

Claims (5)

1. an Albatra metal-semi-solid-state shaping method, is characterized in that concrete steps are as follows:

(1) solidus and the liquidus temperature of copper alloy is measured;

(2) in vacuum or inert gas shielding atmosphere, copper alloy blank is heated to T+50 DEG C ~ T+150 DEG C, wherein T is liquidus temperature;

(3) in vacuum or inert gas shielding atmosphere, copper alloy Quench after step (2) heating is applied High-power ultrasonic vibrations and makes alloy temperature be in solidus and liquidus temperature interval, be incubated after Quench and High-power ultrasonic vibrations complete, obtain semi solid slurry;

(4) semi solid slurry that step (3) obtains is carried out extrusion molding, be shaped and terminate rear air cooling to room temperature;

(5) copper alloy after step (4) is shaped is heat-treated, and obtains copper alloy products.

2. copper alloy semi-solid-state shaping method according to claim 1, is characterized in that: the vacuum condition of described step (2) and (3) is 10 ^-1~ 10 ^-4pa.

3. copper alloy semi-solid-state shaping method according to claim 1, it is characterized in that: described step (2) Quench is inside is connected with the rod iron of cooling water, copper rod or graphite rod to be inserted in the copper alloy after heating and to stop 5 ~ 10s, then take out, after the 3 ~ 10s of interval, second time is put into and takes out again, carry out and so forth, melt temperature is in solidus and liquidus temperature interval.

4. copper alloy semi-solid-state shaping method according to claim 1, is characterized in that: the ultrasonic power of described step (2) High-power ultrasonic vibrations is 150W ~ 1200W, vibration frequency is 15kHZ ~ 40kHZ.

5. copper alloy semi-solid-state shaping method according to claim 1, is characterized in that: described step (2) temperature retention time is 2 ~ 10min.