EP4084918A1

EP4084918A1 - Method and device for directional crystallization of castings with oriented or monocrystalline structure

Info

Publication number: EP4084918A1
Application number: EP20859647.8A
Authority: EP
Inventors: Artur Wiechczynski; Marcin Lisiewicz; Lukasz PIECHOWICZ; Marcin DZIEDZIC; Marcin SZYC
Original assignee: Seco/Warwick SA
Current assignee: Seco/Warwick SA
Priority date: 2019-12-31
Filing date: 2020-12-15
Publication date: 2022-11-09
Also published as: PL432486A1; PL242831B1; WO2021137708A1; CN115135433A

Abstract

The subject of the invention is a method and a device for oriented crystallization of castings with a oriented or monocrystalline structure. The method is based on the fact that during the transfer of the mould (1) containing the alloy from the heating zone (5) to the cooling zone (7), the temperature of the mould surface (1) above CLT1 and below CLT2 of the crystallization front (14) is measured in real time in at least two points, using contactless temperature meters (9a, 9b), with at least one of the lowest points is located in the cooling zone. The device has at least two contactless temperature meters (9a, 9b) installed in the chamber (2), at least one (9b), the lowest, located in the cooling zone (7).

Description

Method and device for directional crystallization of castings with oriented or monocrystalline structure

The subject of the invention is a method and a device for oriented crystallization of castings with a oriented or monocrystalline structure.

The invention relates to the domain of casting production technology, in particular the treatment of molten mass in a casting mould by cooling it, and devices for such treatment, and may be applied in the production of castings from heat-resistant and creep-resistant alloys, especially in large-scale precision foundry for applications in the aviation or energy industry.

There are known methods of producing castings with oriented or monocrystalline structure using a two-chamber vacuum furnace, in which one of the chambers (upper chamber) is a heating zone, and the other (lower chamber) is a cooling zone. These methods consist of moving (extraction) a ceramic mould filled with liquid metal from the heating zone to the cooling zone, which takes place at a constant or variable speed according to a predetermined profile, called the mould extraction speed.

The most commonly used method of casting turbine blades with oriented or monocrystalline structure is the Bridgman method consisting of introducing a ceramic mould set on a cooled copper base into a heating zone, usually made as a resistance or induction heated graphite sleeve placed in a vacuum chamber, and then pouring the molten mass of the (heat-resistant and creep-resistant) superalloy from the crucible into a mould previously heated to a temperature higher than the liquidus temperature of the alloy, and moving the mould filled with liquid superalloy from the heating zone to the cooling zone through the opening of the thermal insulation partition, which is preferably a thermal barrier between both zones, with the heat removal from the surface of the form during this process through radiation, which takes place in the cooling zone below the thermal insulation partition, as a result of which a slow directional crystallization process takes place in the so-called

SUBSTITUTE SHEETS (RULE 26) the liquid-solid region of the alloy. A characteristic feature of this method is the use of the phenomenon of thermal radiation to cool the casting mould flooded with the alloy. The said mould is moved from the heating zone to the cooling zone at a predetermined, generally constant speed, regardless of the actual temperature gradient obtained in the process in the area of the crystallization front.

There are also known methods of increasing the temperature gradient in the area of the crystallization front by applying the convective heat exchange, using a stream of inert gas which is driected to the mould by means of nozzles located in the upper part of the cooling zone. Such a method is known, for example, from patent No. PL222793, the essence of which is that the cooling of the blade casting is carried out using at least one supersonic inert gas stream, with consumption per nozzle 0.5-2 g/s, which is directed to mould, in the area of crystallization of the blade casting.

The patent no. US7017646 describes the invention which relates to a method of producing castings with a oriented or monocrystalline structure characterized by significant differences in geometry and cross-section size. Cooling takes place with the use of noble gas, with nozzles arranged cylindrically below the partition between the heating and cooling chambers, in one plane. In a situation where a fragment of the ("irregular") casting with a thickness significantly different from the previous one enters the cooling zone, different cooling parameters are required for crystallization while maintaining the same directional or monocrystalline properties. In the said patent this is done by reducing or stopping the gas flow altogether while the irregular fragment is cooled. There is no temperature gradient measurement and therefore no dynamic control. The gas flow is only reduced or stopped and this is pre-programmed, which leads to the inability to make the process shorter.

The method covered by the patent US10082032 is the most extensive and has the most potential of influencing the formation of the macro-and microstructure of the casting as it takes into account various methods of process control, such as: mould speed control, cooling gas flow rate control, molten mass temperature control, which are carried out on the basis of temperature measurement using thermocouples. However, the patent relates only to the production of equiaxial castings, and the measurement method used, i.e. placing the thermocouples in the

SUBSTITUTE SHEETS (RULE 26) heating zone and cooling zone, is an indirect measurement in the cooling zone, not directly related to the temperature of the cooled mould and the temperature gradient in the area of the crystallization front, but dependent on many other factors, such as: the weight of the mould with the crystallizing superalloy, dimensions and geometry of the mould, distance of the thermocouple from the surface of the cast element, pressure in the furnace, etc. The result of such measurement is difficult to directly link to the temperature on the mould surface, or in inside it.

Patent No. US5197531 describes a method of measuring the temperature gradient in the area of the crystallization front by means of thermocouples placed directly on the mould. However, the applied method requires time-consuming, manual assembly of special thermocouples on a ceramic mould. The need to manually assemble the thermocouples, usually using ceramic adhesives, and to connect them to the measuring system of the furnace means that a cold mould should be placed in the furnace, i.e. at a temperature close to the ambient temperature, and then, after installing the measurement system and obtaining the appropriate vacuum level in the furnace, the mould must be slowly heated to operating temperature. Such a temperature measurement solution makes it impossible to place a preheated mould in the furnace, which is a common industrial practice in serial production. The need to place a cold mould in the furnace significantly extends the process, extends the pumping of the furnace to achieve a working vacuum, and requires heating the mould in the heating zone, as flooding the cold mould may result in mould cracking and cause casting defects in various forms. Therefore, such forms and measurements are made only in test castings.

A common disadvantage of the mentioned solutions is the lack of continuous and fully automatic control of the actual temperature gradient in the area of the crystallization front allowing for high-performance, large-scale and fully automatic production in industrial conditions, regardless of the geometry and size of the cross-section of the cast items. Due to the lack of such control of the temperature gradient in the area of the crystallization front in the described solutions, difficulties may arise in ensuring high efficiency of the process while maintaining stable and optimal cooling conditions of the superalloy-filled mould, especially when casting blades of variable cross-sectional size and chord length.

SUBSTITUTE SHEETS (RULE 26) Known are devices for producing castings, in the form of a cylindrical vertical chamber placed in a vacuum casing, separated by a heat-insulating screen with a central opening between the heating and cooling zone. In the vacuum chamber, above the heating zone, there is a device for melting the alloy and pouring its molten mass into the casting mould, and in the cooling zone, nozzles can be installed to supply the cooling agent, mostly cooled inert gases, to the surface of the casting mould, which is transferred from the heating zone to the cooling zone near the nozzles.

A common disadvantage of the known devices is the difficulty in providing stable optimal casting mould heating and cooling parameters containing the molten mass to form a oriented and monocrystalline casting structure over the entire height of the casting mould.

The aim of the invention is to develop a method and a device implementing this method, allowing to optimize the production of castings with a oriented or monocrystalline structure by minimizing the crystallization time in vacuum foundry furnaces and reducing the percentage of defects through dynamic, automatic control of the mould extraction speed based on continuous and contactless measurement of the temperature gradient in the area of the crystallization front.

A method of directional crystallization of castings with a oriented or monocrystalline structure including transferring a ceramic casting mould to the heating zone, placed on a crystallizer connected with a vertical up-down drive mechanism, filling the mould with molten alloy from a crucible, moving the filled mould from the heating zone to the cooling zone, until the casting crystallisation process is completed, which is separated from this mould after the process, according to the invention is characterised in that during the transfer of the mould with the alloy from the heating zone to the cooling zone, the temperature of the mould surface above CLT 1 and below CLT2 of the crystallisation front is measured in at least two points, using contactless temperature meters. At least one of the lowest points is located in the cooling zone, and the temperature gradient value of these points (ACLT = CLT 1 - CLT2) is analysed by the PLC or other system in the

SUBSTITUTE SHEETS (RULE 26) feedback loop between the temperature gradient measurement system and the mould drop mechanism and / or mass or volume flow regulators that regulate the inert gas flow rates when gas blowing supports the mould cooling process. The real-time instantaneous temperature difference value is used to dynamically adjust the mould transfer speed from the heating zone to the cooling zone and / or to regulate the flow rate or gas mixture composition.

Preferably, the distance of the lower temperature measurement point in the cooling zone from the next one located above it is at least 25 mm, and the distance of the lower temperature measurement point from the horizontal thermal insulating partition is at least 20 mm.

Preferably, the measuring points are located above and below the area of impact of the inert gas stream.

Preferably, contactless temperature meters operate on the basis of any technology for analysing the thermal radiation emitted by the surface of the mould, preferably pyrometric or thermal imaging.

A device for the production of castings with an oriented or monocrystalline structure, comprising a vacuum chamber comprising a crucible for melting the melt and pouring the molten mass into a casting mould mounted on a cooled crystallizer and moved vertically in the up-down direction by means of a drive mechanism, and the vacuum chamber has a heating zone and a cooling zone separated by a horizontal thermal insulating partition in the form of a disc with a central opening, and according to the invention, it is characterized in that at least two contactless temperature meters are installed in the vacuum chamber, with at least one located at the lowest point in the cooling zone.

Preferably, an annular gas collector with gas ejectors supplying inert gas streams with a rate set by flow regulators is mounted in the housing of the cooling zone.

Preferably, the lowest contactless temperature meter is located in the cooling zone at a distance of at least 25 mm from the next meter arranged above it.

Preferably, at least one contactless temperature meter is provided in the heating zone.

SUBSTITUTE SHEETS (RULE 26) Preferably, contactless temperature meters in a device with an installed gas manifold are arranged in such a way that the lower one is below the plane of the cooling gas supply nozzles, and the other above the plane, so that the area where the inert gas stream flowing from the annular nozzles impacts the gas manifold is located between the meters.

Preferably, contactless temperature meters, such as pyrometers or thermal imaging cameras, operate based on the analysis of thermal radiation emitted by the mould surfaces

An unquestionable advantage of the invention is the option of using it in industrial conditions for high-performance and large-scale production of turbine blades to achieve the maximum possible furnace throughput, energy efficiency of the process while maintaining the required macro and microstructure of the casting.

Thanks to the use of continuous and automatic control of the temperature gradient in the area of the crystallization front, it is possible to carry out the process in the shortest time and with the required macro- and microstructure of the casting, regardless of the geometry and size of the cross-section of the cast items. Thanks to the use of contactless temperature measurement, it is possible to use the method according to the invention on an industrial scale, in every process. The method according to the invention does not require the use of specially prepared moulds and time-consuming procedures of installing measuring sensors on the mould.

The embodiments of the invention are illustrated in figures, where fig. 1 shows the furnace in longitudinal section with the mould in the upper position completely in the heating zone, fig. 2 shows detail A of fig. 1 showing the position of the meters in the variant in which the upper the meter is located in the heating zone, fig. 3 shows the furnace in longitudinal section with the mould in the middle position, i.e. partially in the heating zone, partially in the cooling zone, fig. 4 shows detail B of fig. 3 showing the position of the meters, in the variant in where the upper meter is in the heating zone, fig. 5 shows a detail of the furnace with the mould in the middle position in the variant where the upper meter is in the cooling zone, fig. 6 shows the furnace in longitudinal section with the mould in the lower position completely

SUBSTITUTE SHEETS (RULE 26) in the cooling zone, fig. 7 shows detail C of fig. 6 showing the position of the meters in the variant where the upper meter is located in the heating zone. fig. 8 shows a separate cooling chamber with an annular gas manifold with gas ejectors in a perspective view, fig. 9 shows a longitudinal section of the heating zone and cooling zone with a mould containing a bar-shaped casting of variable diameter, fig. 10 shows a casting in the form of a bar of variable diameter, fig. 11 shows a longitudinal section of a heating zone and a cooling zone with a mould containing a turbine blade casting of variable shape, fig. 12 shows a casting in the form of a variable geometry turbine blade.

Embodiment 1

A device comprising a vacuum chamber 2 in which a crucible 6 is positioned for melting the alloy and pouring the molten mass into a casting mould 1 mounted on a cooled crystallizer 3 and moved vertically up-down by means of a drive mechanism 4. The vacuum chamber has a heating zone 5 and a cooling zone 7 separated by a horizontal thermal insulating partition 8 in the form of a disk with a central opening, the heating zone 5 being formed by a graphite muffle 19 with an inducer 17 separated by a thermal insulating layer 18. The cooling zone 7 has a cooled casing in the form of a tubular water jacket 13. Two contactless temperature meters 9a and the lowest 9b are installed in the vacuum chamber. The above device is used to produce bars with a round cross-section and a diameter of to 14 mm, where the diameter changes stepwise from 8 to 14 mm in ½ of the bar length. The bar is shown in fig. 9 and 10. For production, ceramic, shell moulds were used, prepared by the lost wax method, with a wall thickness of 10 mm +/- 1 mm. The preheated casting mould 1 is placed in the vacuum chamber 2 of the furnace, on the crystallizer 3 cooled with water, using the drive 4 it is transferred to the heating zone 5 under the crucible 6. The heating zone 5, the cooling zone 7, and the crucible 6 are located in the vacuum chamber 2. The ceramic mould 1 in the heating zone 5 is heated to a temperature of 1 ,510°C, which is higher than the liquidus temperature of the alloy. In the crucible 6, the CMSX-4 nickel superalloy is melted, and after it is heated to a temperature above the liquidus, i.e. 1,510°C,

SUBSTITUTE SHEETS (RULE 26) it is poured into the ceramic mould 1 , and then the mould 1 is extracted, i.e. it is transferred from the heating zone 5 through opening in the horizontal thermal insulating partition 8 to the cooling zone 7. The transfer is performed by the drive system coupled with the logic controller of the device in the speed range of 2-6 mm/min. The surface temperatures of the mould 1 in the heating zone 5 and the cooling zone 7 are measured continuously by means of two contactless temperature meters 9a and 9b. In this example, these are pyrometers coupled to the furnace logic controller. The upper pyrometer 9a is located 3 cm above the upper surface of the thermal insulating partition 8, while the lower pyrometer 9b is located 8 cm below the upper pyrometer 9a. The instantaneous value of the temperature difference between the pyrometers 9a and 9b is compared with a set value of 240°C, which corresponds to a temperature gradient value at the crystallization front of 30°C/cm. The logic controller of the furnace continuously changes the mould 1 transfer speed in order to maintain the highest possible mould 1 transfer speed in the range of 2 to 6 mm/min, while preventing the temperature gradient from dropping below the set value. For the conditions used (casting process in the example without gas), this speed is 4 mm/min. When part 101 of the mould 1 with a cross-section increased from 8 to 14 mm is transferred to the cooling zone 7, the longitudinal temperature gradient on the mould 1 is reduced, which is detected by contactless temperature meters 9a and 9b and the PLC smoothly reduces the mould 1 extraction speed to 2.8 mm/min. After the fragment 101 with the increased cross-section has passed through the area where the melt crystallization occurs, the temperature gradient value measured by the pyrometers 9a and 9b begins to increase again and the logic controller smoothly increases the extraction speed of the mould 1 to a value of 4.2 mm/min. In the method used, castings of 10 bars with a round cross-section, with a monocrystalline structure meeting the requirements of the aviation industry, were obtained, while at the location of a sharp increase in the cross-section, there were no defects in the structure, and the desired microstructure refinement was maintained. Throughout the process, the mould 1 extraction speed was within the set limit of 2-6 mm/min and was smoothly adjusted to the changing cross-sections of the cast sample. The process was carried out in a vacuum, at a pressure in the chamber of approx. 1 x10- 3 mbar.

SUBSTITUTE SHEETS (RULE 26) Embodiment 2:

The device is as in embodiment 1 , where immediately below the thermal insulation partition 8, on the circumference of the housing 13 of the cooling zone 7, there is an annular gas collector 11 with radially arranged gas ejectors 12. The nozzles of the gas ejectors 12 are directed towards the centre of the cooling zone 7. Each ejector is connected to a mass flow regulator 16 regulating the flow rates of the inert gas. Everything is connected to the PLC.

In the device in this embodiment, samples are produced as in embodiment 1 . The ceramic mould 1 in the heating zone 5 is heated to a temperature of 1 ,510°C, which is higher than the liquidus temperature of the alloy. In crucible 6, the CMSX-4 nickel superalloy is melted, and after it is heated to a temperature of 1 ,510°C, i.e. above the liquidus, it is poured into the ceramic mould 1 , and then the mould 1 is extracted, i.e. it is transferred from the heating zone 5 through an opening in the horizontal thermal insulating partition 8 to the cooling zone 7, while in the cooling zone 7 there is a device for supplying cooling gas streams in the form of an annular gas collector 11 equipped with two gas ejectors 12 for one single sample 10. From these ejectors, arranged radially on the circumference of the cooling zone 7 and inclined at an angle of 10° to the horizontal plane, an argon stream is directed at supersonic velocity onto the mould 1 , and at the same time the vacuum pump system operates in such a way that the pressure in the furnace is maintained at 0,16 bar abs. The amount of argon flowing into the annular gas collector 11 is controlled by a mass valve coupled to the furnace's PLC, in the range of 40-400 Ndm³/min. The displacement of the mould 1 is carried out by a drive system with a slide drive 4, coupled to the PLC of the device with a constant speed of 6 mm/min. The surface temperatures of the mould 1 in the heating zone 5 and the cooling zone 7 are measured continuously by means of two contactless temperature meters (pyrometers) 9a and 9b coupled to the furnace PLC. The upper pyrometer 9a is located 3 cm above the upper surface of the thermal insulating partition 8, while the lower pyrometer 9b is located 8 cm below the upper pyrometer 9a. The instantaneous value of the temperature difference between the pyrometers 9a and 9b is compared with a set value of 400°C, which corresponds to a temperature gradient value at the crystallization front of 50°C/cm. The PLC of the furnace continuously regulates the amount of cooling gas (argon) flow so as to prevent the

SUBSTITUTE SHEETS (RULE 26) temperature gradient from dropping below the set value while maintaining a constant extraction speed of 6 mm/min. When a part of the mould 101 with a cross- section increased from 8 to 14 mm is moved to the cooling zone 7, the longitudinal temperature gradient on the mould 1 is reduced, which is detected by contactless temperature meters 9 and the PLC increases the cooling gas flow, in the described embodiment by 80% of the initial flow. After the sample fragmentwith the increased cross-section moves through the area where the alloy crystallization takes place, i.e. through the area where the cooling gas stream impacts the mould 1 , the temperature gradient value measured by pyrometers 9a and 9b begins to increase again and the PLC lowers the cooling gas flow to the minimum ensuring the set temperature gradient is maintained. In the method used, castings of 10 bars with a round cross-section, with a monocrystalline structure meeting the requirements of the aviation industry, were obtained, while at the location of a sharp increase in the cross-section 101 , there were no defects in the structure, and the desired microstructure refinement and the angle of deviation of the casting axis from the direction [0 0 1 ] were maintained. In the described embodiment, the mould 1 extraction speed was 6 mm / min throughout the process.

The subject of treatment may be items other than the item shown in embodiments 1 and 2 in figures 9 and 10. Figure 11 shows the process for a mould shaped in a different variant, i.e. for the item of fig. 12 simulating the shape of a variable geometry turbine blade.

Embodiment 3

The system of dynamic control of the transfer speed of the mould 1 from the heating zone 5 to the cooling zone 7 operates continuously during the process in a closed feedback loop between the temperature gradient measurement system in the area of the crystallization front 14 based on the continuous measurement of the temperature of the mould 1 surface using contactless temperature meters 9a and 9b in at least two measuring points located in the cooling zone 7, and the mould lowering mechanism, i.e. the drive 4 of the crystallizer 3, on which the mould 1 filled with superalloy is placed. The PLC analysing the instantaneous value of the temperature difference (ACLT = CLT1 - CLT2), dynamically controls the transfer speed of the mould 1 placed on the crystallizer 3 from the heating zone 5

SUBSTITUTE SHEETS (RULE 26) to the cooling zone 7 in order to maintain the programmed temperature difference ACLT of the cast items 10 or their specific section 101 guaranteeing the shortest possible time and maintaining the required macro- and microstructure of the casting, regardless of the geometry and size of the cross-section of the cast items

10.

Embodiment 4

The system of dynamic control of the flow rates of the inert gas components operates continuously during the process in a closed feedback loop between the measuring system of the temperature gradient in the area of the crystallization front 14 based on the continuous measurement of the temperature of the mould 1 surface using contactless temperature meters 9a and 9b in at least two measuring points located in the cooling zone 7, and mass flow regulators 16 regulating the flow rates of the inert gas components. The PLC analysing the instantaneous value of the temperature difference (ACLT = CLT 1 - CLT2), dynamically controls the flow rates of the inert gas components while maintaining a constant mould transfer speed from the heating zone 5 to the cooling zone 7 in order to maintain the programmed temperature difference ACLT of the cast items 10 or their specific section 101 guaranteeing the shortest possible time and maintaining the required macro- and microstructure of the casting, regardless of the geometry and size of the cross-section of the cast items 10. By changing the value of the flow rate of inert gas components, it is possible to affect the value of the heat flux density received from the mould surface in the area of the crystallization front 14, which can be represented by the following relations: q = a (T_m - ^Ta) a = a_r + a_c where: q - heat flux density, a - total heat transfer coefficient, a_r - radiation heat transfer coefficient, a_c - convective heat transfer coefficient,

T_m - mould surface temperature,

T_a - temperature of the cooling zone,

SUBSTITUTE SHEETS (RULE 26) u - linear gas velocity at the surface of the cooled workpiece, p - pressure, d - characteristic dimension of the cooled part, h - gas dynamic viscosity coefficient, c_p - specific heat capacity of gas,

K, a, b, c, d, e, f - constants with a value greater than 0

Embodiments 3 and 4 describe the situation for the solution variant in which there are two meters and both are mounted below the insulating partition 8. This does not exclude other variants, including the one in which e.g. one of the meters is located above the thermal insulation partition in the heating zone.

SUBSTITUTE SHEETS (RULE 26)

Claims

Patent claims

1. A method of direction crystallization of castings with an oriented or monocrystalline structure comprising transferring to the heating zone a ceramic casting mould placed on a crystallizer connected with a vertical up- down drive mechanism, filling the mould with molten alloy from a crucible, moving the filled mould from the heating zone to the cooling zone, until the casting crystallisation process is completed, which is separated from this mould after the process, characterized in that while the mould (1) containing the alloy moves from the heating zone (5) to the cooling zone (7), the temperature of the mould (1 ) surface is measured in real time above CLT 1 and below CLT2 of the crystallization front (14) in at least two points, using contactless temperature meters (9a, 9b), with at least one of the lowest points located in the cooling zone and the temperature gradient value at these points (ACLT = CLT 1 - CLT2) is analysed by the PLC or other system in the feedback loop between the temperature gradient measurement system and the mould lowering mechanism and/or mass or volume flow regulators (16) which regulate the inert gas flow rates when its blowing aids the mould (1) cooling process, and the instantaneous value of the temperature difference determined in real time is used to dynamically adjust the rate of mould (1) transfer from the heating zone (5) to the cooling zone (5) and / or to adjust the flow rate or gas mixture composition.

2. The method according to claim 1 , characterized in that the distance of the lower temperature measurement point (9b) in the cooling zone (7) from the next one located above it is at least 25 mm, and the distance of the lower temperature measurement point (9b) from the horizontal thermal insulating partition (8) is at least 20 mm.

3. The method of claim 1 , characterized in that the measuring points (9a, 9b) are located above and below the area of impact of the inert gas stream.

4. The method of claim 1 , characterized in that the contactless temperature meters (9a, 9b) operate on the basis of any technology for analysing the thermal radiation emitted by the surface of the mould (1 ), preferably pyrometric or thermal imaging.

SUBSTITUTE SHEETS (RULE 26)

5. A device for the production of castings with an oriented or monocrystalline structure, comprising a vacuum chamber comprising a crucible for melting the melt and pouring the molten mass into a casting mould mounted on a cooled crystallizer and moved vertically in the up-down direction by means of a drive mechanism, and the vacuum chamber has a heating zone and a cooling zone separated by a horizontal thermal insulating partition in the form of a disc with a central opening, characterized in that in the vacuum chamber (2) at least two contactless temperature meters (9a, 9b) are installed, with at least one (9b), the lowest, is located in the cooling zone (7).

6. Device according to claim 5, characterized in that an annular gas collector (11) with gas ejectors (12) supplying inert gas streams with a flow rate set by flow regulators (16) is mounted in the housing of the cooling zone

7. The device according to claim 5 or 6, characterized in that the lowest contactless temperature meter (9b) is located in the cooling zone (7) at a distance of at least 25 mm from the next meter arranged above it.

8. The device according to claim 5 or 6, characterized in that at least one contactless temperature sensor (9a) is located in the heating zone.

9. The device according to claim 6, characterized in that the contactless temperature meters (9a, 9b) are arranged in such a way that the lower one is under the plane of the gas ejectors (12) of the annular gas collector (11), and the second is above the plane, so that the area of impact by the inert gas stream flowing from the gas ejectors (12) is located between the meters (9a, 9b).

10. Device according to claim 5 or 6, characterized in that the contactless temperature meters (9a, 9b) such as pyrometers or thermal imaging cameras, operate based on the analysis of thermal radiation emitted by the mould (1) surfaces

SUBSTITUTE SHEETS (RULE 26)