JPH0452024A - Method for controlling extruding work for metal - Google Patents

Abstract

PURPOSE:To allow the extruding work in the stable half-melted state with adding the control of the heating means corresponding to the change by elevating the temperature of the material mounted in the container of the extruder to the half-melted state especially at the neighborhood of the extruding dies, and setting the pressure for extruding. CONSTITUTION:The blank material 4 is inserted in the container for extruding, the load of the prescribed hydraulic pressure is applied to the extruding cylinder 13 and the blank material 4 is loaded with the extruding force. Next, when the electric power is supplied to the heating device 5 set nearby the extruding dies 6, the temperature of the blank material 4 near the inlet side of the dies 6 is raised, then soon after, reaches the prescribed solid phase ratio and the extruding is started. In this time, because there is some clearance between the sleeve 8 and the container 3 with the blank material, so some of softened blank material 4 is passed through this clearance and made to flow to the rear side, but the temp. of blank material 4 of the rear side from the heating device 5 and the temperature of the container 3 is not reached to the temperature as high as to make the blank material 4 to flow, soon after, the blank material 4 flowing in the clearance is solidified, on this result it is sealed and closed, and the blank material 4 of the high temperature in the neighborhood of the heating device 5 is prevented from contacting with the outdoor air, and the oxidation of the blank material 4 is prevented.

Description

[Detailed Description of the Invention] (Industrial Field of Application) Metal (or alloy) materials, including other metal matrix composite materials such as cermets, are particularly relevant to extrusion processing control methods using these materials as raw materials. The results of development research on advantageously realizing extrusion processing in a semi-molten, ie, solid-liquid coexistence temperature range are disclosed here.

(Prior art) Extrusion processing of metal materials is generally carried out by hot extrusion, that is, by raising the temperature in a solid state to increase plasticity, and recently cold extrusion of small parts has also become popular. However, both have considerably high deformation resistance.

By the way, attempts are being made to form a slurry state in the coexistence of solid and liquid obtained by stirring a molten metal or alloy under cooling, but the extrusion process has not yet reached the practical stage, and there are no references in the literature. I can't find it.

In other words, for extrusion processing in a semi-molten state, it has been proposed to supply a semi-molten material into a container in advance and extrude it. This corresponds to heating it in a soaking furnace and charging it into a container, but in any case it is not designed to be heated inside the container.

Therefore, the extrusion plunger tip directly comes into contact with the hot material and is subjected to the processing force for extruding it, so it has a significant disadvantage in terms of material quality.

Furthermore, since there is still insufficient development of a sensor for detecting the solid phase ratio of a material in a semi-molten state, that is, a solid-liquid coexistence state, there is no control means necessary to obtain a proper molded product by extrusion processing.

When trying to extrude the metal or alloy material or metal matrix composite material in the semi-molten state described above, 1. The temperature of the material is much higher than in the case of hot extrusion processing, so the high temperature material in the semi-molten state is If you try to process it directly with a plunger chip, the first problem is the material of the plunger chip, 2. In order to obtain a homogeneous molded product, it is necessary to perform extrusion processing at a certain solid phase ratio, and It is also essential for the stability of the solid phase; if the solid phase rate is too high, it will solidify in the die and become impossible to extrude, and if it is too low, there will be disadvantages such as breakout at the exit of the die. 3. In order to perform extrusion processing with a constant solid phase rate, it is possible to detect the solid phase rate, feed it back to the heating device, and control the solid phase rate of the workpiece. The phase ratio sensor is not found, 4
Semi-molten materials in a solid-liquid coexistence state tend to grow crystals over time and become coarse. However, when the entire material is heated to a high temperature, the leading edge and the trailing edge of the material tend to deteriorate due to the elapse of extrusion processing time from the leading edge to the trailing edge. Problems pointed out include the fact that the crystal grain size differs at the rear end, making it impossible to obtain a homogeneous molded product, and if the extrusion time becomes too long, the crystals become coarser, making it impossible to obtain a molded product of good quality. Ru.

(Means for Solving the Problems) In the present invention, a material made of a solid metal material or a metal matrix composite material is charged into an extruder container, and heated to reach a solid-liquid coexistence temperature region immediately before an extrusion die. Then, by applying a preset pressure corresponding to the flow or deformation characteristics in this solid-liquid coexistence state to the extrusion cylinder, a semi-molten molded body is extruded from the extrusion die,
When extruding metal that is cooled and re-solidified at the exit of an extrusion die, the heating temperature of the material in the extruder container is adjusted according to the fluctuation of the load pressure in the extrusion cylinder with respect to the set pressure. A metal extrusion control method, which is characterized in that the extrusion speed of a semi-molten compact extruded from an extrusion die is limited according to the adjustment range of material heating temperature. be.

The above configuration of the present invention is based on the following knowledge.

The extrusion material can be charged into the container as a mixed material or a heated material, because the extrusion molding process is carried out using a die, so the extrusion material is heated to reach a predetermined solid phase ratio just before the die entrance. If so, it is sufficient to heat the extrusion die. Since the part of the material that comes into contact with the plunger tip is not directly heated, it does not reach a high temperature and will not cause any problems with the material of the plunger tip.

The heating means disposed close to the entrance of the extrusion die may be either induction heating or resistance heating.

The material inserted into the extrusion container in a solid state is processed by an extrusion cylinder at a set pressure, and at the same time is heated by a heating means near the extrusion die to a semi-molten state. The set pressure for extruding a material in a semi-molten state can also be determined from the relationship between extrusion pressure and solid phase ratio using the material and extrusion ratio as parameters, or it is best to determine this by trial extrusion.

-As an example, Cu-15%8! Figure 1 shows the relationship between solid phase ratio and extrusion pressure for hemetal.

Next, a specific example of an apparatus suitable for carrying out the extrusion control method according to the present invention is shown in FIG.

In Fig. 2, 1 is an extrusion plunger, 2 is a plunger tip, 3 is an extruder container, 4 is a raw material, 5 is a heating means, 6 is an extrusion die, 7 is a die holder, 8 is a sleeve, and 9 is a heating means. 5 power control device, 10
is a hydraulic system, 11 is a pressure transducer, 12 is a hydraulic piping, 13
1 is an extrusion cylinder, 14 is a molded product extruded in a semi-molten state, and 15 is a cooling zone for cooling and resolidifying the molded product.

(Function) When the temperature of the material is raised to reach the expected solid phase ratio in a semi-molten state, extrusion begins. Then, it is extruded at a preset speed.

Note that if the output of the heating means is insufficient for the set extrusion speed, the extrusion pressure will naturally increase with an increase in the solid fraction. Therefore, the output of the heating means is increased.

Finally, if the output of the heating means is excessive, the solid phase ratio will become small and the extrusion pressure will drop, so the output of the heating means is reduced.

As described above, extrusion processing at a constant speed and a constant solid phase ratio can be achieved. There is no need to use a solid phase rate sensor here, and the relationship between solid phase rate and extrusion pressure is used. As mentioned above, the material is locally heated near the extrusion die in the extrusion container 3, so compared to the conventional method of heating the entire length of the material in a soaking furnace, the heating time is extremely short and there is almost no grain growth. .

In this invention, the extrusion pressure is set by determining σ from the deformation characteristic curve (σ to fs curve, σ is deformation stress, deformation resistance, or flow stress, and fs is solid phase fraction) of the semi-solid material, and using this, the extrusion ratio, and The extrusion pressure P0 can be calculated theoretically from
0 may be determined.

When charging the raw material into the extrusion container 3, it may be an electrical material, but it is preferable to use a warm material that has been soaked and preheated in advance. The material charged into the extrusion container 3 is set as described above and is pushed by the plunger tip 2 toward the extrusion die 6 at an extrusion pressure P0. Here, the heating means 5 set in the immediate vicinity of the extrusion die 6 locally heats the tip of the material 4, that is, the portion in contact with the extrusion die 6.

As described above, as shown in the extrusion operation control sequence shown in FIG. 3, extrusion molding is carried out at a constant speed with a set solid fraction. Since the molded product 14 extruded from the extrusion die 6 is in a solid-liquid coexistence state, it is cooled in the cooling sozone 1 immediately after the die.
5 is provided, and the molded body 14 is cooled and re-solidified.

The amount of cooling is determined by the extrusion speed, extrusion solid fraction, and extrusion ratio, but the extrusion solid fraction and extrusion ratio are constants and are functions only of the extrusion speed. Moreover, since this speed is constant except for changes in speed due to insufficient heating capacity, it can be easily controlled.

(Example) (1) Setting of extrusion force Figure 4 shows the σ~fs curve when Cu 10%-Al1 was extruded at an extrusion ratio of -7.

The inner diameter of the sleeve 8 is DIIl [11 Set the hole diameter of die 6 to d Then, the extrusion ratio=D2/d2.

D = 200 dishes, d = 75.6 d In other words, in order to perform extrusion processing with Cu 10%-Af gold alloy fs = 0.5 at extrusion ratio = 7, σ = 0.7 kgf from Fig. 4.
/mm2, so 2 tf. Therefore, the output of the extrusion cylinder 13 is 22 t.
The hydraulic pressure P0 of the extrusion cylinder 13 is set so that f.

(2) The heating material is slightly smaller than the inner diameter of sleeve 8 (200 m) (19
8 aa), insert it into the extrusion container 3, and apply hydraulic pressure P to the extrusion cylinder 13. , thereby applying an extrusion force of 22 tf to the material. Next, when electric power is applied to the heating device 5 installed near the die, the temperature of the material near the entrance side of the die 6 rises, the solid phase ratio eventually reaches 0.5, and extrusion is started. At this time, there is a slight gap between the sleeve 8 and container 3 and the material, so the softened material flows backward through this gap, but the temperature of the material and container behind the heating device is lower than the material. The temperature does not reach a high enough temperature to cause it to flow, and the material that flows into the gap eventually solidifies, resulting in a seal that prevents the high-temperature material near the heating device from coming into contact with the outside air and prevents the material from oxidizing. .

At this time, the heating device is set to about 60% of its normal maximum capacity.

(3) Setting of extrusion speed The set value v 0 (m/s) of the extrusion speed v (m/s) is determined as follows. FIG. 5 shows the relationship between temperature T and solidus fraction f8 of Cu 10%-Aj2 alloy, where Ts is the solidus temperature and TL is the liquidus temperature. From the same figure, f, = 0.5
The corresponding temperature is 605°C. That is, assuming that the charging temperature of the material is 25°C, a temperature increase (=ΔT) of 605-25=580°C is required to make f, = 0.5.

In 22, the physical properties of Cu 10%-Af gold alloy are specific heat C#
1000 J/kg -k heat of fusion q= 390X 1
Since the density ρ = 3.3 kg/m', the amount of heat required to raise the temperature of ΔT per unit volume is Q = ρC・Δ
T + pg-fs (J/m3) = 3.3X10'X
580+3.3X390X103X0.5=2.56X
10'J/m'-2,6X 10'J/m3. Therefore, if the extrusion speed is v (m/s) and the cross-sectional area of the material is S (m"), the amount of heat per second w (h) to be provided by the material is W = QSv (J
/s) = QSv(W/), and it becomes.

However, the output w' of the heating device is not entirely consumed in heating the material, but is also transferred to surrounding objects such as the sleeve 8, the die 6, the die holder 7, etc. This heat loss varies depending on the size and structure of the machine, the thermal conductivity of its constituent members, heat transfer between constituent members, etc., but in this device, the amount of heat per second that enters the material is approximately W'i 0. 5 W', so if the output of the heating device -' is 50000 (W), then W
= 50000X0.5 = 25000 (W)
Therefore, the extrusion speed v Cm/s) is Q=2.6X
10"J/m', S = tt xo, 2"xl/4
'= 0.03 m'', so V # 0.3 m/s. This is the set speed v0.

(4) Control Next, start the extrusion cylinder at a constant speed of set speed v0. At that time, the temperature T (for example, 605°C for Cu 10%-A2 alloy) of the material on the input side of the die 6 corresponds to the assumed solid phase fraction fs (for example, fs = 0.5).
If not, the material floe 5tress
Since is larger than the initially set value, the extrusion force increases, and as a result, the hydraulic pressure P loaded on the extrusion cylinder becomes greater than the set hydraulic pressure P0. Therefore, by increasing the heating output -', the temperature increase rate of the material becomes faster and the predetermined temperature, that is, the predetermined solid phase ratio can be obtained. However, there is not enough room in the heating device, so the heating output -' is increased If this is not possible, by decreasing the set speed v0 and reducing the amount of heat required for temperature increase, the material temperature can be increased and a predetermined solid phase ratio can be obtained.
If the hydraulic pressure P is lower than the set hydraulic pressure P0, the material temperature T is high (the actual solid fraction is smaller than the predetermined solid fraction), so this can be dealt with by reducing the output of the heating device. do. According to the control flowchart shown in FIG. 3 above, the hydraulic pressure P is measured and compared with the set hydraulic pressure P0, and depending on whether the p - PaO difference is positive or negative, this is fed back to the heating device or the hydraulic system of the extrusion cylinder. Control of the main extrusion process can thereby be achieved.

(Effects of the Invention) According to the present invention, heating means that responds to fluctuations in temperature by raising the temperature of the material charged into the extruder container to a semi-molten state, particularly in the vicinity of the extrusion die, and setting the extrusion pressure. An appropriate extrusion speed is set by controlling the extrusion rate, thereby stably extruding the semi-molten state.

[Brief explanation of drawings]

Figure 1 shows Cu-15%8! A graph of the relationship between the extrusion pressure and solid phase ratio of hemlock, Fig. 2 is an explanatory diagram of an extrusion device suitable for carrying out the extrusion processing control method of the present invention, Fig. 3 is an extruder operation control sequence diagram, Fig. 4 is the solid phase ratio-extrusion pressure correlation diagram of the Cu 10%-82 alloy in extrusion Hizaki 7, and Figure 5 is the Cu 10%-8! It is a solid phase ratio-temperature correlation diagram of an alloy. 3... Extruder container 4... Raw material 5... Heating means 6... Extrusion die 9... Heating means power supply control device 11...
・Pressure converter 13... Extrusion cylinder 15...
・Cooling zone Figure 1 0.3 0.4 E Lang Zhao Figure 3 Figure 4 Solid phase ratio

Claims (1)

[Claims] 1. A material made of a solid phase metal material or a metal matrix composite material is charged into an extruder container, heated to reach a solid-liquid coexistence temperature range immediately before the extrusion die, and A semi-molten compact is extruded from an extrusion die by applying a preset pressure corresponding to the flow or deformation characteristics in a liquid coexistence state to an extrusion cylinder, and is cooled and re-solidified at the exit of the extrusion die. A method for controlling metal extrusion processing, the method comprising: adjusting a material heating temperature in an extruder container in accordance with fluctuations in load pressure in an extrusion cylinder with respect to a set pressure during metal extrusion processing. 2. Metal extrusion processing control in the method according to claim 1, characterized in that the extrusion speed of the semi-molten compact extruded from the extrusion die is limited according to the adjustment range of the material heating temperature. Method.