Manufacturing method of axisymmetrical parts like discs

FIELD: metallurgy.

SUBSTANCE: deformation of a peripheral part of a billet is performed by rolling with rolls at the superplasticity temperature in the deformation zone so that a sheet is formed. The central part of the billet is cooled down prior to rolling-off to the elastic deformation temperature. During the rolling-off process, the central part of the billet and the sheet subject to non-contact deformation is cooled down by action of a cooling medium on the central part. Cool-down of the sheet to its elastic non-contact deformation temperature is provided in a zone adjacent to the central part. Between the specified zone and the deformation zone, an intermediate zone is formed, in which temperature obtains an average value between elastic deformation temperature and superplasticity temperature and/or values close to the specified average value. In the rolling-off process, cooling medium pressure is increased with expansion of the cooled zone of the sheet. Intermediate zone temperature is maintained.

EFFECT: improving quality of manufactured parts and enlarging technological capabilities of their manufacturing method.

3 cl, 6 dwg, 7 ex

 

The technical field to which the invention relates.

The invention relates to the field of treatment of metals and alloys by pressure, in particular to methods of rotationally symmetrical parts such as disks from hardly-deformed multiphase heat-resistant alloys, including titanium and Nickel alloys. The invention can be used in the aerospace industry in the manufacture of disks of gas turbine engines (GTE).

The level of technology.

Currently drives GTE, have to meet very high demands on dimensional accuracy and structure formed during deformation and subsequent heat treatment, are mainly manufactured through forging ways, similar to the method described in the patent [1]. In this form, the canvas simultaneously, the rim and the hub of the disc. The methods involve high energy costs and the need to have a powerful large press equipment.

Therefore, since the 60's of the last century to the present time, attempts are being made to provide a method of rotationally symmetrical parts such as disks from hardly-deformed multiphase (low plasticity) heat-resistant alloys, including titanium and Nickel alloys, for brevity called in this text the way�m the manufacture of parts such as disks, in which a cloth and rim are rolling out a tool in the form of rollers or rolls, as is done in the manufacture of railway wheels [2]. The implementation of these attempts in the known methods [3, 4], promoted the use of features of superplastic deformation (SPD), which, in turn, implies the existence of the original steel with specially trained for the SAP structure, as well as compliance in the deformation zone under the rollers required for the SAP temperature and speed conditions. To meet the temperature conditions of rolling in the methods [3, 4] is performed in a furnace, which supplied the mills are specially designed for these purposes [5]. The deformable workpiece has a Central and a peripheral part. The Central part of the billet used for preliminary design of the hub disc. In the implementation of the methods [3, 4] to the Central part of the sheeting is subjected to elastic or plastic deformation by means of CMM quills mill, and in the flattening process is not deformed or deformed only elastically. The peripheral part of the blank intended to form the blade and the rim is rolled by the rollers. Next, we will talk mainly about the painting, as it is with the web in conditions of superplasticity in the implementation of the known methods, there are several problems that require �of adresine.

These problems are related to the fact that in the process of rolling the formed fabric continues to be subjected to so-called non-contact deformation. Non-contact deformation of the blade occurs due to force action on the canvas from the neighbouring parts, loaded with the effort of rolling and pressing the CMM quills Central part of the workpiece. The fabric also feels the effects of various reactive, inertial forces and moments of forces. These efforts are sufficient to ensure that non-contact deformation was plastic, aided by a number of other factors. Namely, as a result of compression rollers, the web becomes more homogeneous in comparison with the roll part, and voltage flow of the alloy in the canvas become lower than in roll. In addition, the canvas, while in the furnace, is subjected, if it is not cooling, the influence of the same temperature, and roll out the portion of the workpiece. Plastic non-contact deformation extends from the deformation zone to the Central part of the workpiece, the spinning canvas and stretching it in the radial direction. As a result changes the structure of the fabric and on the surface of the canvas there is a relief in the form of a spiral ridges, due to the nature of the non-contact deformation, combining torsion� with stretching. The presence of pronounced relief entails using for finishing the surface of the already thin blade machining with removal of sufficient magnitude layer, which leads to perestiani load-bearing fibers of the fabrics, in the operation of the parts working in tension, and as consequence, to reduction of operational properties of details in General. To ensure the required performance properties of the workpiece during rolling should be almost finished painting parts requiring minimal machining. Whereas the Central part of the billet may be subjected to further machining to give it final shape and size of the hub of the disk.

Changes in the structure of the canvas caused by exposure to non-contact deformation, also in certain cases lead to severe negative consequences. These cases will be discussed in detail in the analysis of the disadvantages of the known methods.

Due to the mentioned circumstances occurs the main difference between the considered method of manufacturing parts made by the method of rolling railway wheels. Although when rolling railway wheels non-contact deformation of the canvas can also be the case, but it is usually due to the lack of the need to comply with high-temperature isothermal unloveable elastic, and it can be neglected.

In the manufacture of parts such as disks for the above reasons, the neglect of non-contact deformation becomes impossible. Known methods of manufacture of parts such as disks [3, 4] represent two opposite approaches to the problem associated with the occurrence of non-contact deformation of the canvas. Consider these methods in more detail.

A method of manufacturing parts such as disks [3] includes the local shaping by rolling a billet having a Central and a peripheral part made of a multiphase hard alloy prepared for the SAP structure. The local shape of the workpiece is carried out under conditions of superplasticity at temperatures lying in the range above 0.4 TPLwhere TPL- the melting point of the alloy, but below the temperature of collective recrystallization and strain rates lying in the range 10-2...10-3with-1. The Central part of the billet is formed by compressing the CMM quills, and the canvas is by means of rolling of the rollers. In this specific effort on the part of the tool, CMM quills and rollers, q, is selected from the conditions:

σsH>qσsD(1) ,

KσsAnd>q,(2)where

σsthe flow stress of workpiece material in a deformable Central to start rolling out and the peripheral parts of the workpiece;

σsH- deformation resistance in already subjected to the deformation of the Central part of the billet before rolling and cloth;

σsthe deformation resistance of the tool material at the temperature of deformation of the workpiece;

K - empirical coefficient equal to or less than 2.

The method also includes heat treatment of the workpiece which is carried out with heating above or below the temperature of dissolution of the second phase or allotropism modification of the matrix depending on formed during rolling of the microstructure.

In accordance with the above relation (1) plastic deformation of the workpiece in already subjected to the deformation of the parts of the workpiece, including non-contact plastic deformation of the canvas should be suppressed. The voltage in the Central part of the billet and the canvas, and the canvas with the start time of its formation must be reduced to values at which under the influence of the available effort was possible only elastic or elastic-PLA�genetic deformity. In the latter case, the degree of plastic deformation must be so small that the plastic component can be neglected. In the method [3] compliance with the above ratio is achieved by cooling the Central part of the workpiece and the blade by passing the cooling medium through the channels in the CMM quills and the Central part of the workpiece with sufficient for such cooling, the pressure of the cooling medium, resulting in a required increase of the deformation resistance of the Central part and the blade. However, the larger the diameter of the blade, the harder it is to cool it with the achievement of all the leaf temperature elastic deformation due to the limited technological capabilities of cooling equipment. Of course, here we are talking about rather high temperatures, in particular of the order of 400-450°C for titanium alloys and 600-750°C for Nickel alloys, but which is sufficient to reflect the level of the effective forces non-contact deformation was elastic. However, even when using powerful cooling equipment and associated with its operation costs of electricity cannot be cooled to the required temperature all the painting, especially the painting of large diameter, located in the furnace, which is maintained at a high temperature is required for the SPD, in particular of the order of 900-950°C for titanium�s alloys and 950-1100°C for Nickel alloys. When rolling a leaf of the large diameter parts were attempted to be used for blade cooling jet of coolant, protecting it from cooling, the deformation zone and nerazgadannoi part of the workpiece fixture type umbrella, but they failed due to the considerable complexity of this procedure in comparison with the admission of cooling due to the impact of the cooling medium to the Central portion of the workpiece.

Thus, the technological possibilities of the method according to the patent [3] in the part of the blade cooling are limited. To the full extent they can be realized only in the manufacture of small diameter.

However, even if we allow for the possibility of cooling the fabric to such an extent as to meet the relation (1), in accordance with the same ratio front cooling must be sharply braked before the deformation zone under the rollers. Of course in the canvas there is a sharp boundary between the area with the temperature of the elastic deformation and the zone temperature superplasticity in the deformation zone, which contributes greatly to the low thermal conductivity of heat-resistant alloy. Hereinafter these areas for the sake of brevity we will call respectively rigid and plastic zones. During the deformation, in such considerable temperature gradient in the fabric occur resp�public for a considerable amount of internal macronutrient, also referred to as zonal or stresses of the first kind [6]. To eliminate a considerable amount of zonal voltage only heat treatment without repeated plastic deformation, it is not possible [6]. Residual stresses were found in the fabric components made by the method [3], when cutting cloth cutter into individual strips for manufacturing the samples needed for further research. After cutting were visually observed distortion (warping) of strip form.

Residual zonal voltage may occur when operating details. It is known that particularly dangerous tensile residual stresses, as they are, adding to the tensile stresses from external loads, can lead to destruction of the part even when a small external loads [6]. It is also known that residual stresses are particularly dangerous in the products of low plasticity of alloys [6]. All observed may be attributed to the GTE discs and methods for their manufacture and use.

It can be concluded that, in addition to limited technological capabilities in parts blade cooling, quality parts made in the method [3], does not satisfy the requirements that apply to discs HDT, due to the occurrence in detail in its manufacture for a considerable amount of zonal stress.

further developed a method of manufacture of parts such as disks from blanks made of multiphase alloys capable SPD [4], including the rolling of the workpiece with control of temperature and strain rate in the temperature-speed interval superplasticity rolled and heat treatment details. The method involves the flattening process temperature control in the canvas so that non-contact deformation also occurred in the conditions of superplasticity. Speed non-contact deformation is supported by the corresponding speed SPD range of values of strain rate directly in the hearth under the rollers.

Method [4] proposes to allow non-contact deformation of the blade and is useful to use it. This approach, as mentioned above, is the exact opposite of the approach proposed by the previous method [3].

Cooling, which are the elastic deformation, is carried out only in the Central part of the workpiece. In the area of blade cooling is carried out with an intensity that allows you to maintain speed non-contact deformation of the fabric, with the result thin places over low voltage currents, in the range of speeds of the SAP. In some cases, particularly when the grain size in the initial billet is equal to or exceeds 20 μm, the temperature of the fabric is maintained at temperature � the deformation zone under the rollers and even higher.

In the manufacture of prototypes of rotationally symmetrical parts made from titanium and Nickel alloys, the canvas due to the cumulative effects of core and non-contact deformation atenalol fairly evenly within the tolerance on the thickness. When cutting the fabric details on the individual samples of the residual zonal stress was observed. However, on the surface of the parts, especially parts made from a more ductile titanium alloy, was the formation of a pronounced spiral relief.

The main disadvantage of the method revealed in the result of the study of the microstructure of the blade parts produced on the way from Nickel alloy. Namely, the painting was discovered unacceptably large number of micropores (see Fig.4, a). As you know, increased porosity is a structural defect that is observed in many alloys after SPD [7]. The exception here may be, are titanium alloys, in which this defect is practically not observed. In addition, the development of porosity in the SAP noticeable impact deformation scheme is the density of micropores after the precipitation is much less than after stretching at identical temperature-rate conditions of deformation. The volume fraction of micropores in tension increases monotonically with the degree of deformation, reaching � the time of the destruction items 3-5% [7]. The origin and growth of micropores in the SAP occurs in the same pattern as in creep when creep is due to the ZSE [8]. The micropores are generated, first, in areas with a high density of surface (assuming the surface of the grains) of energy, which are the joints three and four grains with high angle boundaries. Secondly, the pores nucleate at locations with high stress concentration, such as protrusions at the grain boundaries and inclusions in the interphase boundaries [8]. In Nickel alloys, inclined at LDS stretching to the pore formation, such inclusions are particles of γ' and δ phases.

Non-contact deformation of the fabric during rolling is carried out mainly by tension, while the degree of non-contact deformation accumulates and reaches a considerable value, especially in the manufacture of large diameter. Both of these factors in the method [4] can cause dangerous amounts of micropores, which can lead to the destruction of the workpiece is made of a Nickel alloy, in the process of deformation or to make the item unserviceable. Here it should be noted that porosity is the most dangerous for the details of the type of turbine engine disks, since they are operated at elevated temperatures. Even a small porosity when operating in the so - �x conditions to accelerate the development of creep and destruction of the part.

Technological possibilities of the method according to the patent [4] as well as the technological possibilities of the method according to the patent [3] are limited but, in contrast to the method [3], used in relation to manufacture of parts materials. Given the fact that Nickel alloys, due to their high heat resistance, particularly suitable for the manufacture of disks of modern gas turbine engines, it can be stated that very limited technological capabilities of the method according to the patent [4]. Given the nature of Nickel alloys, to expand the technological capabilities of the method according to the patent [4] is not possible.

Noted shortcomings of the known methods of manufacture of parts such as disks [3, 4] slowed down implementation in the industry is quite economical technology that uses the technique of rolling leaf rollers, what inspired you to pursue a thorough develop in this direction and led to the establishment of the proposed method.

Given the great similarity of features of the claimed method according to technical essence and even on the result achieved by the features of the method according to the patent [3], a method according to the patent [3] is selected as the closest analogue is the prototype of the claimed method.

Disclosure of the invention and justification of the newness and materiality of the inventive method.

The object of the invention is to increase ka�society of manufactured parts and the expansion of technological capabilities of the method.

The technical result of the invention providing a solution to the problem is to exclude the possibility of occurrence when rolling out a sharp boundary between rigid and plastic zones in the fabric, and consequently in the decrease of the zonal level voltages to values that you can address them during heat treatment details.

Another technical result of the invention is to implement the possibility of blade cooling during rolling of large diameter parts, down to the details of the maximum diameter that can be accommodated in the working space of the furnace.

In addition, in the invention remains inherent parts that are manufactured according to the method prototype, in the absence of the canvas unacceptably large number of micropores, regardless of the material fabricated component. There was also a decrease of the bump on the fabric surface due to a significant decrease in degree of non-contact plastic deformation.

All technical results are achieved with a single set of techniques of ways, among which is the new reception regulated blade cooling.

The claimed method of rotationally symmetrical parts such as disks having Central and peripheral portions of the workpieces, made of hardly-deformed multiphase splavo� prepared for superplastic deformation structure includes the deformation of the peripheral portion of the workpiece by rolling rollers at a temperature superplasticity in the deformation zone under the rollers with the formation of a cloth, and heat treated parts, in addition, the Central part of the billet and subjected to non-contact deformation of the blade is cooled by exposure to the cooling medium to the Central portion of the blank, and the Central part of the billet before rolling the fabric is cooled to a temperature of elastic deformation.

The proposed method differs from the known fact that the canvas is cooled to a temperature non-contact elastic deformation in the zone, coupled with the Central part of the workpiece to form between this area and the deformation zone under the rollers, the intermediate zone, where the temperature takes the average between the temperature of the elastic deformation and temperature superplasticity or values close to the average value, over time increase the rolling pressure of the cooling medium acting on the Central portion of the blank, expanding the area of the canvas, cooled to a temperature of elastic deformation, while maintaining the intermediate zone with the temperature values.

The task is also solved in the following cases:

because of the expansion zone, cooled to the temperature of the elastic deform�tion, followed through the automatic control system, which uses the temperature sensor having the ability to move and measuring the temperature at the border of this zone, for example a pyrometer, the amount of movement which is used as a feedback signal;

- rolling is carried out with a cooled rollers.

In the present method, unlike the prototype method, it is proposed to cool to a temperature at which the possible non-contact elastic deformation, not the whole sheet, but only a part, namely, the area of the canvas, coupled with the Central part of the workpiece, called as it was made above a hard area to form between the deformation zone with a temperature superplasticity - plastic zone, hard zone, intermediate zone, where the temperature takes the average between the temperature of the elastic deformation and temperature superplasticity or values close to the mean. The intermediate zone with such temperatures effectively prevents the occurrence of a sharp boundary between rigid and plastic zones and accordingly, the occurrence of zonal stress. It is also proposed that in the process of rolling out to increase the pressure of the cooling medium to larger expansion capabilities hard zone. Without the extension or with a weak extension of the rigid zone under �leniem much stronger overall heating of the intermediate zone will be warm and it will set the temperature, close to the temperature in the furnace. In this case again there is a sharp boundary between rigid and plastic area, but unlike the prototype method is the plastic area to spread outside of the deformation zone.

However, to increase the pressure of the cooling medium so that the hard area is not completely blocked intermediate zone. Otherwise there may be a sharp boundary between rigid and plastic zones, and between the hard area on rolled canvas and plastic zone of deformation, as in the prototype method.

Because of these features, associated with the presence of a common heating, the pressure of the cooling medium must be increased in accordance with the condition of creating and maintaining the intermediate zone, as such, and the conditions of preservation in the intermediate zone of the above temperatures.

At the beginning of the sheeting to comply with the required conditions, the pressure of the cooling medium is increased by insignificant and mild, with a hard area, increasing from zero, will be correspondingly very small. With a sharp increase in pressure of the cooling medium due to the low thermal conductivity of heat-resistant alloy of the intermediate zone can also occur abruptly, causing the occurrence of significant magnitude zonal stress. Especially in the initial time lag�and stored cooled impact the Central part of the workpiece. In other words, you must stand and give an opportunity to form an intermediate zone. Taking a tough area at the initial time is zero, experimentally or through modeling or through thermal calculation with respect to

- cooling generated at the beginning of the rolling by the pressure of the cooling medium required for cooling the Central part of the billet to a temperature at which the possible elastic deformation of the Central part - Pinitial;

- temperature in the deformation zone;

- General heat;

- coefficient of thermal conductivity of alloy;

- thickness

you can determine the time for the formation of the intermediate zone. Or that has the same physical meaning, determine approximately the size of the intermediate zone. In the future, the size of the intermediate zone can be considered constant under the assumption that the boundary between the hard and the intermediate zone temperature will maintain its value, namely the value that is created under the influence of pressure Pearly.Such an assumption is quite true, as the front cooling is distributed from the Central part of the workpiece - if you increase the pressure of the cooling medium temperature in a tough area in the vicinity of the Central part is expected to decrease, but at the same�military will increase the radius of the blade and the boundary between rigid and intermediate will increasingly move away from the source of cooling.

Also, through simulations or experimentally determined dimensions of the plastic zone deformation zone associated with the contact patch of rollers. Typically, the size of the plastic zone with consideration of the sheet thickness exceeds the size of the contact patch, where the conjugate surface of the workpiece and the working surface of the roller, approximately 3-5 times. The cooling of the rollers the size of the plastic zone is smaller than in the case where the rollers are cooled. Remaining after deduction of intermediate size and plastic zone of the cloth is a tough area, expands, reaching to the end of the sheeting, as shown by the experiments, approximately half of the canvases and more.

It should be noted that the accuracy of determining the size of the zones of the invention. Necessary conditions to obtain the technical results provided by the invention are the fact of existence of the intermediate zone and the rigid extension of the zone to maintain this existence.

In addition, when extending rigid zones are most of the cloth will deform elastically, and is guaranteed to be elastic, since the temperature in that part of the hard zone, which is located closer to the Central part of the workpiece will be reduced to values significantly less than required. Constant level of cooling may not protect�tit cloth from the emergence of non-contact plastic deformation in case of accidental increase affecting the painting effort as these efforts are, as already noted, is a complex character and not always amenable to audit and control.

It is recommended to follow the rigid extension of the zone and to control the cooling process of the canvas. Adjustable value in this process, as the invention is the pressure of the cooling medium acting on the Central portion of the workpiece. And regulate the pressure during the entire time rolling, increasing simultaneously with the increase of the diameter of the canvas.

For management purposes, the process of cooling of the blade can be used the pressure dependence of the cooling medium from the time of rolling. The dependence can be determined by simulation and presented in a graph. The dependence can be represented in the form known from the course of mathematical physics graphs of functions corresponding to a given cooling character. So in particular, it can be graph exponential functions of the formP=Pnachewhere t is the time of rolling, Δ is a constant that takes into account the possibility of cooling equipment (compressor output), Rinitial- the pressure of the cooling medium required for cooling before rolling Central�the second part of the workpiece to a temperature where possible elastic deformation of the Central part. In some cases, particularly when rolling out parts of small diameter, this can be the graph of a linear function.

Most expedient to carry out the cooling of the blade by choosing to control the cooling process noted above exponential dependence. It involves a very slight increase in pressure of the cooling medium at the beginning of the sheeting, which is particularly favorable for the occurrence of the intermediate zone and, accordingly, to exclude the possibility of occurrence of zonal stress. At the end of rolling is quite a sharp increase in pressure provides a more rapid increase in hard areas and thus required compensation for the effects of heating, which increases with the diameter of the cloth, especially in the process of rolling out the details of a large diameter.

The value Δ can be set empirically. But it is possible to determine and calculated by using the dependence and some known data. This calculation is shown below in the section describing the Implementation of the invention."

It is also advisable to monitor the extension of the rigid zone, a time-dependent rolling and pressure of the cooling medium, by using the automatic control system, which includes a temperature sensor, having�th the possibility of moving and measuring the temperature at the boundary of the rigid zone, for example a pyrometer, similar to the sensor described in the description of the utility model [11]. In this case, as the feedback signal using the magnitude of the displacement sensor. As the control unit of the cooling process can be used by the host PC.

Due to the lack of the need for intensive cooling of the entire leaf, as in the prototype method, the technological capabilities of the method is greatly enhanced, which ensures the production of parts of different diameters, including details of the maximum diameter that can be accommodated in the working space of the furnace.

In addition, the cooling of the rolled portion of the drive guarantees obtaining in the minimum volume of grain size and consequently a more uniform structure, which undoubtedly will have a positive effect on the mechanical properties of the part.

The above arguments demonstrate the existence of causal relationships between features of the method and the technical results, the receipt of which is provided by the present invention.

The combination of features of the claimed method differs from the set of attributes of known method of manufacture of axisymmetric parts type disks according to the patent [3], which indicates the novelty of the proposed method.

To prove the essential featur�th the proposed method let us return to consideration of features of the method according to the patent [4], where non-contact deformation of the blade is plastic and is carried out in the temperature superplasticity conditions. This fabric may not be cooled, moreover it can even be heated, briefly discussed above and in more detail described in the specification of the patent. In the disclosed method, the cooling fabric is required, and the intensity of cooling increases. While in the staging area of the canvas where the temperature takes the average between the temperature of the elastic deformation and temperature superplasticity or values close to the mean, there is a change in the mechanism of plastic deformation, namely in the process of deformation occurs by the movement of grain boundaries and the deformation of the grains themselves, unlike the ZSE during superplastic deformation.

In the manufacture of parts made of Nickel alloys due to the change of deformation mechanism cease to be provided for the initiation of intergranular damage in the form of micropores. Given the fact that in a tough area of the canvas is only elastic deformation, one can state that the decrease in leaf area, which can give rise to pores, at least two-thirds in comparison with the method according to the patent [4]. But in the plastic zone, where non-contact deformation is carried out at a temperature near�Oh to temperature superplasticity, the possibility of a dangerous number of pores is excluded due to a significant reduction in the degree of non-contact plastic deformation.

Due to a significant reduction in the degree of non-contact plastic deformation during the manufacture of parts made of any alloys significantly reduces the relief surface of the canvas, the result for final machining can be used methods of machining with the removal of a small surface layer. In some cases this treatment may not be necessary. These circumstances cause a marked improvement in the quality of rolled out details.

It is recommended that the rolling of the cooled rollers. This technique will further reduce the size of areas where non-contact deformation in superplastic conditions. Here we should note the obviousness of this additional intake of the inventive method, as in the known methods it is used primarily for other purposes, namely, for increasing the durability of the rollers.

These arguments show that all the signs-the techniques of the claimed method, are new compared to the characteristics of the prototype method and has significant differences from the techniques of the known methods.

Brief description of the drawings and other g�epicheskih materials.

Fig. 1 is a diagram of rolling details type disk;

Fig. 2 shows a block diagram of process control blade cooling;

Fig. 3, 4 shows the graphs that can be used to control the cooling process of the canvas;

Fig. 5 shows the microstructure of samples cut from a part made of Nickel alloy Inconel 718 by the proposed method;

Fig. 6 shows the microstructure of samples cut from a part made of Nickel alloy Inconel 718 by the method protected by a patent [4].

For rolling parts can be used with the device type of mill, is protected by the patent [5]. Fig. 1 shows only a separate part of the camp, necessary for the explanation of the scheme rolling.

For implementing the method is used, the workpiece 1 was prepared for superplastic deformation structure. POS. 2 denote its Central part, item 3 - the canvas in the process of rolling out. The Central part 2 to start rolling deformed by compression in the plastic or elastic, or elastic-plastic (with a very small degree of plastic deformation field through the CMM quills 4, 5. Rolling the blade 3 is carried by two pairs of rollers 6, 7, 8, 9. Using these same rollers, the workpiece 1 is rotated. The workpiece 1, the sleeve 4, 5 and the forming rollers 6, 7, 8, 9 is located� in the furnace 10. Cooling the Central part of the billet and paintings done by passing the cooling medium through the channels 11, 12 in the CMM quills and channel 13 in the Central part of the workpiece. Position 14 marked the temperature sensor is a pyrometer. The pyrometer is movable. To enable the measurement of leaf temperature sensor 14 in the wall of the furnace is a slot 15, a closed quartz glass. POS. 16 marked the solenoid valve mounted on the compressor (Fig. not shown), by which regulates the pressure of the cooling medium is compressed air flowing through the channels 11, 12, 13 acting on the Central portion of the workpiece 2 and the blade 3. The valve 16 is associated with the block of management of process of cooling of the blade (see Fig. 2) in the flattening process.

A block diagram of the control process of cooling of the blade 3 (Fig. 2) includes the control unit 17, which is used as the control computer. The control unit 17 is connected with the actuator, which performs the role of the electromagnetic valve 16 connected to the compressor. The feedback signal is input to the control unit with adjustable temperature sensor 14. The signal conversion by the displacement sensor, reflecting the rigid extension of the zone, directly connected with the time of rolling, the signal on the cat�rum monitor the pressure increase of the cooling medium, is performed in the control unit 17. The control unit, temperature sensor, actuating mechanism included in the instrumentation, which supplied the mills for rolling parts such as disks [5].

The implementation of the invention.

Also as other well-known methods [3, 4], knowing the alloy, which is made a part, and structural condition, particularly the grain size, the workpiece 1, determine the temperature and speed conditions of the sheeting, and further taking into account the strain rate determine the time of rolling of t. Also determine the pressure of the cooling medium Pinitialrequired for cooling the Central portion 2 of the workpiece to a temperature at which before you start rolling it will have elastic deformation. The required dimensions of the intermediate zone are determined experimentally or by simulation taking into account the effect of cooling on the one hand, the temperature in the deformation zone on the other hand, the General heat conductivity coefficient of the alloy, the thickness of the fabric. Also, through simulations or experimentally determined dimensions of the plastic zone with the possibility of cooling rollers. The net result was found in the sizes of the dimensions of the finished blade is determined by the size of the hard zone at the end of the sheeting, i.e. the limit of its expansion and d respectively�pressure P conneeded to cool the area of the canvas that size.

The workpiece 1 is heated in a separate furnace and then transferred to the already heated furnace for rolling mill or heated together with the furnace of the mill.

The Central part 2 to start rolling deformed by compression in the plastic or elastic, or elastic-plastic region through CMM quills 4, 5. In the last two cases the Central part of the billet immediately after placing in the oven begins to cool by exposure to the cooling medium. In any case, before rolling out the Central part of the billet is cooled to a temperature of elastic deformation, with a corresponding pressure of the cooling medium Pearly.

In the process of rolling increases the pressure of the cooling medium acting on the Central portion of the workpiece, tracking a rigid extension of the zone from zero to the identified limit of its expansion.

To control the cooling process, use a graph of the pressure of the cooling medium from the time of rolling. Fig. 3 presents some of the mathematical graphs that can be used to control the cooling process of the fabric: a, b) graphs of exponential functions; graph linear functions; Fig. 4 presents a plot of the simulation results. In all graphs the abscissa axis occludin�is the time value of the sheeting, the ordinate is the pressure of the cooling medium, and at t=0, are deposited pressures required for cooling the Central part of the billet before rolling. Here it should again be noted that when the automatic process control using charts seem appropriate. But it does not exclude the implementation of management and without the use of graphs, namely by simply tracing the margins of the rigid zone.

As already noted, it is most advisable to increase the pressure of the cooling medium according to the schedule exponential functions (curves a, b), namely:P=Pnache. Curve 6 represents a graph blade cooling parts of a larger diameter. As can be seen from the comparison of two graphs exponential functions with increasing diameter of the part of the cooling intensity increases.

The value of Δ can be determined as follows:

As a rule, for blade cooling when rolling part having a maximum diameter which can be placed in the working space of the furnace, the possibility of cooling equipment fully utilized. For example, a part made of titanium alloy, has a Maxi�exponentially diameter of 800 mm. The time of rolling is 60 min. Maximum pressure of the cooling medium generated by the compressor Pmaxis 0.8 MPa. The pressure required for cooling the Central part of the billet before rolling, Pinitial=0.5 MPa.

Based on the given data, compute Δ:

0,8/0,5=e60Δ

ln 1,6=60Δ

0,47=60Δ

Δ~0,008 MPa per minute.

Found a guide value Δ takes into account the possibility of a specific cooling equipment. It can be used in cases of rolling of parts with different diameters, using the same cooling equipment.

The cooling process of the canvas, as the deformation process, including maintaining the temperature superplasticity in the deformation zone under the rollers, as already noted, is subject to control and management, which uses the instrumentation of the mill [5].

After rolling the workpiece is subjected to heat treatment by known modes [3, 4, 6]. The heat treatment serves to relieve the internal stresses of various kinds, arising in the process of its formation.

Specific examples of the method using the new method of cooling fabric Prishtine parts such as disks of titanium alloy VT9, having a chemical composition, in mass%: Al 5,9; Zr 2,1; Mo 3,0; Si 0,2; else Ti and Nickel alloy Inconel 718, having a chemical composition, in % by weight: From 0.05; Cr 19; 3,1 Mo; Fe 18; Al of 0.5; Ti 1,0; Nb 5,1; else Ni.

Common to all examples is that the rolling is performed by using a rolling mill for rolling SRD-800, similar to that given in the patent [5]. The maximum diameter of the part which can be placed in the working space of the furnace mill is 800 mm. the Central part of the billet is deformed in the elastic-plastic region (the degree of plastic deformation was 2%). The Central part of the billet and the canvas was cooled by passing the cooling medium is compressed air through the channels in the CMM quills and the Central part of the workpiece. For passing compressed air used compressor, in which the maximum pressure of the cooling medium in the channels was 0.8 MPa. In all examples, the cooling process was carried out according to a pre-selected schedule and was controlled by an automatic control system, composed of a temperature sensor having the ability to move and track the hard boundaries of the zone.

The examples do not limit the capabilities of the proposed method in respect of parts made from other garorock�x alloys in particular of heat-resistant Nickel alloys 79 EC, EP 742. In addition, parts can be fabricated using other more powerful mills with a large working space of the furnace, or alternatively, using a less powerful mill than the mill SRD-800. Cooling in the case, when in the Central part of the blanks no hole, can be performed by passing the cooling medium only through the channels in the CMM quills.

Identification of some other rolling conditions noted below for each group of examples, helped among other things to demonstrate the technological capabilities of the method in terms of cooling depending on the diameter of the roll out details, and the ability blade cooling using a variety of graphs of the dependence of the pressure of the cooling medium from the time of rolling, including a simple graph of a linear relationship.

Examples№№1, 2, 3, 4, 5 relate to the manufacture of parts made of titanium alloy VT9.

Common to this group of examples is that billet had prepared for superplastic deformation structure with the same average grain size ~8-10 μm. A peripheral portion of the workpiece is deformed with a strain rate of 10-2...10-3with-1The temperature in the deformation zone under the rollers at 950°C.

Examples # 1 and # 2.

About�slip for sample No. 1, 2, is rolled out detail with a diameter of 600 mm. the Diameter of the Central part of the billet of 120 mm leaf Thickness 20 mm. the Temperature in the Central part of the billet before rolling out 450°C. the pressure of the cooling medium required for cooling the Central part of the billet before rolling, Pearly.=0.4 MPa. The time of rolling of 45 min. the size of the deformation zone about 90 mm, about 50 mm fall on the canvas, the rest of the deformation zone does not apply to rolled peripheral portion of the workpiece. The size of the intermediate zone provided determine, in its temperature in the range 650-700°C to about 60 mm. Approximate size of the hard zone(600-120)/2-(50+60)=130 mm. Pressure required to maintain the ratio of hard and intermediate zones at the end of the sheeting

Pcon=0,7 MPa.

In the flattening process when extending rigid zone, the temperature in the Central part of the workpiece and part of the hard zone is cooled down to 300-350°C. the Temperature at the boundary between the hard and the intermediate zone is maintained at 450°C.

In example No. 1, the cooling fabric was on schedule according toP1=PNache1tΔ,Fig. 3, curve a. Values� Δ was ~0,008 MPa / minute (see the calculation given above)

In example No. 2. cooling was carried out according to the schedule of the linear function of Fig. 3, V.

P2=0,7 t2+PNach

Thus regardless of the type of the graph is observed due to the use of the same alloy and size details of the equality:

t1=t2

PNach=PNach

PCon=PCon

Comparing the results of rolling and cooling of the fabric parts with a diameter of 600 mm, made according to the methods described in examples 1 and 2 we can conclude that the graph of a linear function gives a more abrupt increase of the pressure of the cooling medium. The larger the diameter of the part, the more sharply will increase the pressure of the cooling medium, and therefore the blade will be sharper the temperature gradient. This, in turn, will result in some increase of the zonal stress is definitely much smaller than in the prototype method, but to produce parts of higher quality, besides having a large diameter is preferable to cool the blade, using graph exponential functions or a special chart based on the simulation results. Examples No. 3, 4, 5

Total for sample No. 3, 4 5 is unrolled detail with a diameter of 800 mm. the Diameter of the Central part of the billet 150 mm leaf Thickness 18 mm. Pressure, cooled�her environment necessary for cooling the Central part of the billet before rolling, Pinitial=0.5 MPa. The time of rolling of 60 min. the Pressure of the cooling medium at the end of rolling of the Pcon=0.8 MPa. The ratio of sizes of plastic and intermediate zones of the canvas is the same as in example No. 1. The size of the hard zone a few more, because big is the diameter of the part.

In example No. 3, the cooling fabric was on schedule according toP3=Pnachande3Fig. 3, curve b.

The value of Δ was ~ 0,008 MPa per minute.

In example No. 4, the cooling fabric was on schedule, built according to the simulation results, Fig. 4.

Also regardless of the type of the graph is observed due to the use of the same alloy and size details of the equality:

t3=t4

PNach-PNach

PCon-PCon

In example No. 5 in contrast to the examples No. 3 and 4, the rolling was carried out with a cooled rollers.

The longest hard zone was observed in the fabric parts made in example No. 5 by the use of cooled rollers and reducing the size of plastic zone.

Item�, manufactured according to examples 1-5 were subjected to heat treatment.

Heat treatment was in the double annealing of parts:

1. The first annealing was carried out at a temperature of 950°C for 2 hours, followed by cooling in air;

2. The second annealing was carried out at a temperature of 530°C for 6 hours, followed by cooling in air.

Examples Nos. 6, 7, relate to the manufacture of parts made of Nickel alloy Inconel 718.

Common to this group of examples is that billet had prepared for superplastic deformation structure with the same average grain size ~4-5 μm. A peripheral portion of the workpiece is deformed with a strain rate of 10-3...10-4with-1the temperature in the deformation zone under the rollers at 950°C. Unrolled detail with a diameter of 600 mm. the Diameter of the Central part of the billet was 120 mm leaf Thickness 20 mm. Pressure of cooling medium required for cooling the Central part of the billet before rolling, PNach=0.4 MPa. The time of rolling was 60 min. the Pressure of the cooling medium at the end of the rolling amounted to PCon=0,75 MPa.

In example 6, the cooling was carried out according to the schedule of dependence ofP6=Pnachande6 Fig. 3, curve a.

Match the graphs in examples # 1 and # 6, including the coincidence of values of Pinitialbecause of the Central hard part and the leaf area of the workpiece Nickel alloy was cooled to a higher temperature compared to the billet of the same size made of titanium alloy, namely: the Central part of the billet Nickel alloy at the beginning of the sheeting was cooled to a temperature of 650°C. Approximately the same as in example No. 1, was the ratio of the areas of the canvas.

In the flattening process when extending rigid zone, the temperature in the Central part of the workpiece and part of the hard zone is cooled down to 500-550°C. the Temperature at the boundary between the hard and the intermediate zone is maintained at 650°C.

In example No. 7 rolling was carried out without cooling of the blade by the method protected by a patent [4].

Parts made according to examples 6, 7, were subjected to heat treatment.

Heat treatment consisted of the following:

1. High-temperature annealing at a temperature of 1000°C for 1 hour, followed by cooling in air;

2. Aging at a temperature of 750°C for 15 hours, followed by cooling in air.

A visual inspection of all parts produced according to examples 1-6, it was revealed the absence of the expression�tion of the relief on the surface of the canvas, to resolve of which would need removing significant layers of material during the cutting process. The dimensions of the parts were within the specified tolerance.

When cutting the fabric into separate samples for further studies of the residual zonal stress was observed.

Samples cut from various areas of the fabric parts made according to examples 6, 7 Nickel alloy according to the proposed method and the method according to the patent [4] were subjected to studies by optical and electronic microscopy. The results showed the absence in the former case, samples of the pores, whereas in the second case in the samples of observed clusters is quite large then. The results are shown in Fig. 5, 6.

Thus, as a final conclusion it can be stated the fact that the use of new techniques allows to overcome the disadvantages of the known methods [3, 4] and that the claimed method of rotationally symmetrical parts such disks can be used in industrial applications for the manufacture of turbine engine disks.

Sources of information taken into consideration:

1. U.S. patent No. 3519503, IPC C22F 1/10, 1970

2. Bibik G. A. et al. Production of railway wheels, Moscow: Metallurgiya, 1982. 232 p.

3. RF patent №2119842, IPC WC 1/32, 1998

4. RF patent №2254195, IPC VN 1/04, 2005

5. P�the awning of the Russian Federation No. 2134175, IPC VN 1/00, 1999

6. Novikov I. I. Theory of heat treatment of metals: proc. for higher education institutions. 4-e Izd. M.: Metallurgy, 1986. S. 110 to 121).

7 Kaibyshev O. A. Superplasticity of industrial alloys, Moscow: Metallurgiya, 1984. P. 32-35).

8. The Čadek Th. Creep of metallic materials/Tr cheshek. M.: Mir, 1987. 304 p.

9. Bronstein I. N., Semendiaev K. A. Handbook of mathematics for engineers and students of technical colleges. 13-ed. fixed. M.: Nauka, 1986. With a 179.

10. Bird Engineering mathematics John / Pocket guide per. s angl. M.: Publishing house "Dodeca-XXI, 2008. With 70-76.

11. RF patent (utility model) No. 121181, IPC VN 1/02, 2012

1. A method of rotationally symmetrical parts such as disks having Central and peripheral portions of the workpieces, made of hardly-deformed multiphase alloys prepared for superplastic deformation of the structure, including the deformation of the peripheral portion of the workpiece by rolling rollers at a temperature superplasticity in the deformation zone under the rollers with the formation of a cloth, and heat treatment parts, the Central part of the billet and subjected to non-contact deformation of the blade is cooled by exposure to the cooling medium to the Central portion of the blank, and the Central part of the billet before rolling the fabric is cooled to a temperature of elastic deformation, otlichalis�, the belt is cooled to a temperature non-contact elastic deformation in the zone, coupled with the Central part of the workpiece to form between this area and the deformation zone under the rollers of the intermediate zone, where the temperature takes the average between the temperature of the elastic deformation and temperature superplasticity or values close to the average value, over time increase the rolling pressure of the cooling medium acting on the Central portion of the workpiece, with the area of the canvas, cooled to a temperature of elastic deformation, while maintaining the intermediate zone with the temperature values.

2. A method according to claim 1, characterized in that carry out the monitoring of the extension zone of the workpiece is cooled to a temperature of elastic deformation, with the help of automatic system containing a temperature sensor, which is movable and measuring the temperature at the boundary of the specified area, such as a pyrometer.

3. A method according to claim 1, characterized in that the rolling is carried out with a cooled rollers.



 

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