Method and device to produce shell from two materials and produced shell

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy and may be used to manufacture a bimetallic shell made of circular external and internal shells. On a casting base (1) with inlet (4, 11) and outlet channels (5, 6, 12, 13) there are two moulds installed to form two casting spaces. The first casting space (7) is limited by the upper side of the base, the internal wall (3) of the first mould and the external wall (8) of the second mould. The second one - by the upper side of the base, the external wall (8) of the second mould and the internal wall (9) of the second mould. Liquid metal is poured by a siphon method in one of the casting spaces (7, 10). The external wall (8) of the second mould is raised to open the first shell metal crust hardened on it. The liquid metal is poured by the siphon method in another casting space. External and internal shells are connected by diffusion welding or joint hardening of forming materials.

EFFECT: invention provides for the higher efficiency and reliability of the shell production method.

19 cl, 3 dwg

The invention relates to the field of metallurgy and, in particular, to the manufacture of shells of the two materials, that is, of parts, consisting of two fixedly connected concentrically parts of ring shape, made of two different materials and is fixedly connected to each other.

In industries associated with the use of the reactor, subjected to the action of pressure, including in the nuclear and petrochemical industries, such shells are used as component parts tanks reactors or of the pressure compensators. These shells can be fabricated by welding two initially separate shells, each of which is made using a specific method, or one of the shell and the strip placed on the surface of the shell. The outer shell can be performed, for example, low carbon steel 16MND5 and inner shell is made of austenitic stainless steel type 304L initially in the form of a strip.

The outer shell of mild steel can be obtained by forging and inner shell made of stainless steel, as indicated above, to perform in the form of a strip that is secured by welding on the inner surface of the outer shell. Not restrictive inner diameter of the inner shell can be from 2 to 9 meters, height could reach 2 to 5 meters while the thickness of the sides may be approximately from 50 mm to 600 mm for the outer shell and from 5 mm to 100 mm for the inner shell.

It is relatively easy to implement solution is still not optimal, as this is a lengthy process. For the shell of the reactor core having the above dimensions, welding and quality control of welding can take from 5 to 10 weeks this time, which varies depending on the internal dimensions of the shell and the desired thickness of the weld. The weld quality must be carefully checked, and it depends on the criteria used for the control.

Object of the invention is to provide a method of manufacture of such shells of two materials with higher performance and absolute reliability.

The task is solved in the method of manufacturing shells of two materials consisting of an annular outer shell and an annular inner shell, welded to each other and both shells are made of different materials, containing, according to the invention, the stages at which:

- carry out the siphon casting and solidification of the outer shell in the foundry space, the foundry base, a first wall of the mold located on the casting base, and is arranged to move up the outer wall of the second mold located at the specified base and concentric with the first mold;

- Sain�you have specified roaming the outer wall of the second ingot mold so to open the hardened crust on it outer shell;

- carry out the siphon casting and solidification of the inner shell in the foundry space, the specified peel the outer shell, which is pre-hardened to drag the outer wall of the second mold, and a fixed inner wall of the specified second mold, wherein the welding of two shells is due to the diffusion of material between the surfaces of these sides that come in contact with each other during solidification;

- and if necessary produce forging and/or machining of the node is made up of those welded shells.

Specified outer wall of the second mold can be lifted after solidification of the outer shell.

You can start to raise the specified outer wall of the second mold when casting the outer shell is complete, but its solidification is not over yet.

You can start to raise the specified outer wall of the second mold when casting the outer shell is not yet complete.

You can greasing the interface between the outer sidewall and the outer wall of the second mold.

It is possible to carry out forced cooling of the inner wall of the second mold.

The outer shell can be run from carbon steel and vnutrennyaya - stainless steel.

The object of the invention is also a device for the manufacture of the shell of two materials consisting of an annular outer shell and an annular inner shell, welded to each other and both shells are made of different materials according to the invention the device comprises:

foundry basis for siphon casting;

- the input channel and the output channels for the molten metal intended to be used as the material of the outer shell, made in the specified radix, in this case, these output channels are communicated with the first foundry space bounded by the upper side of the base, the inner wall of the first mold and the outer wall of the second mold;

- the input channel and the output channels for the molten metal intended to be used as the material of the inner shell, made in the specified radix, in this case, these output channels are communicated with the second foundry space bounded by the upper side of the base, the specified outer wall of the second mold and the inner wall of the second mold;

- and means for lifting specified inner wall of the second mold in a vertical direction, allowing access to the hardened inner surface of the outer shell and enter �e in contact with the liquid metal, designed for use as the material of the inner shell.

It may contain cooled from the inside of the mandrel surrounded by the inner wall of the second mold.

The mold may contain a lucrative extension.

The outer wall of the second mold may include means for lubricating the border section with the outer metal shell.

The object of the invention is also the shell of two materials consisting of an annular outer shell and an annular inner shell, welded to each other and both shells are made of different materials according to the invention the shell is made using the method described above.

The outer shell may be made of carbon steel 16MND5, and the inner shell may be made of 304L stainless steel.

The shell can be a part of the tank of a nuclear or petrochemical reactor.

The shell can be a part of a pressurizer of a nuclear reactor.

From the foregoing it is clear that the invention is achieved by providing simultaneous or almost simultaneous curing of two hollow ingots of the shape and composition of which correspond to the shapes and composition of the two components of manufactured shells of two materials. Hardening the outer side of the ingot, forming the inner shell, PR�comes directly on the inner side of the ingot, forming an outer shell, or Vice versa, and their connection occurs by diffusion welding or joint solidification forming their materials.

The invention will be more apparent from the following description with reference to the accompanying drawings.

Fig.1 schematically shows an installation for implementing the method in accordance with the invention, a front view in section;

Fig.2 shows the same installation during the solidification of the outer shell;

Fig.3 shows the same installation after complete solidification of the outer shell and in the course of solidification of the inner shell.

Fig.1 shows an example of a device in accordance with the invention, used for the manufacture of the shell of two materials. As major elements in the first place, it contains a foundry basis for 1 siphon casting for casting ingots of circular shape that is slightly tapered in the presented example. This base 1 in the present example includes in its Central portion, the cap 2 is essentially cylindrical in shape, protruding in relation to the rest of the base 1.

The first mold is partially limited metal cylindrical wall 3, which is installed on the base 1 and the lower portion which covers the base 2, the upper side of which forms the bottom of the first molds�. The first wall 3 of the mold may if necessary be cooled from the outside by the circulation of a fluid medium, or may not be cooled. The inner side of the first mold 3 is intended to ensure solidification of the outer part of the shell. For this purpose, the base 1 comprises an inlet channel 4 for liquid metal (e.g., 16MND5 low carbon steel), coupled with a not shown Central gate, i.e. with a vertical channel, intended for the passage of molten metal resulting from the filling of the bucket, where regulate its temperature and its composition. Input channel 4 is divided into a number of output channels (of which in the figures shows two channels 5, 6) facing the upper side of the cap 2 and allow the liquid metal to place in different places of the annular casting space 7 bounded on the outside by the first wall 3 of the mold.

The second mold is limited to the upper side of the cap 2 of the base 1, while the other two concentric metallic cylindrical walls 8, 9 limit between the annular space 10, intended for molding the inner part of the shell. For this purpose, the base 1 comprises another input channel 11 for liquid metal (e.g., 304L austenitic stainless steel), coupled with the other Central gate (not shown) than that of the Central�tion of the gate, feeding the above-mentioned input channel 4. Preferably this other input channel 11 is divided into a number of output channels (two channels 12, 13 to the rear of the plane of the section shapes as input and the channel 11 shown in the figures by dashed lines). They open onto the upper surface of the cap 2 and allow the liquid channel to pass into the annular casting space 10, limited by the walls 8, 9 of the second mold.

According to the invention a feature of this second mold is that it is the outer wall 8 which separates the two foundries space 7, 10 (and, therefore, forms an inner wall of the first mold), is movable in the vertical direction to the team in accordance with the conditions, which will be discussed below. This mobility provide lifting means not shown, controlled by the operator or an automatic device. The inner wall 9 of the second mold may be fixed or removable.

The installation complements the cooling system of the internal wall 9, limiting the second mold. For example, this cooling system may consist of a mandrel 14, which is cooled internally by the circulation of a fluid medium (e.g. water), as described in documents FR 2525131, FR 2543031, FR 2676670 or FR 2676671. The bar 14 comes into contact with the inside�Rennie wall 9, limiting the second mold, to ensure its cooling and its retention during use of the installation.

Preferably in the upper parts of the casting spaces 7, 10 installation contains also a profitable extension arms 15, 16, i.e. ring-shaped parts made of heat-resistant material positioned on the stationary walls of the moulds:

- on the inner side of the first mold 3;

and on the inner wall 9 of the second mold.

The function of these lucrative extensions 15, 16, the principle of which is well known in the field of casting of ingots from molten metal, is to slow down the solidification of metal in the front area so that in this zone as long as possible a supply of liquid metal, which can nourish the axial part of the ingot to ensure its maximum possible uniform solidification. Indeed, the crust solidified, formed from opposite walls of the mold, can grow unevenly and connect with each other prematurely, forming, thus, a "bridge" that holds more liquid metal. During the solidification of the metal will shrink and leave voids, called "shrinkage sinks" that can adversely affect the quality of the ingot and produced products. In the case of shells, manufacturing�supported in the framework of the invention, these shrink holes are especially undesirable because of the shell in the future are or almost are not subjected to plastic deformation, which could shrink holes close. A supply of liquid metal held a lucrative extension, allows you to power the Central part of the ingot during solidification and to avoid the formation of bridges, which are the cause of shrink holes, or melt these jumpers after their formation.

Fig.2 shows an installation during the casting and solidification of the outer shell 17 of carbon steel. In the device through the inlet 4 pour carbon steel in the liquid state, and it penetrates in the foundry space 7, limited by the inner wall of the first mold 3 and the outer wall 8 of the second mold.

Shown in Fig.2, the sidewall 17 is in the stage of solidification, and on the walls of the first mold is formed by solidifying crust 18.

Fig.3 shows an installation during the casting and solidification of the inner shell of stainless steel. After raising the cylindrical wall 8, which was shared by two foundries space 7, 10, to open the solidified crust of the outer shell 7, through the inlet 11 pour stainless steel in the liquid state. It penetrates in the foundry space 10, which is limited outside of�ichikai 17 and the other wall 9, limiting foundry space 10 of the second shell. It hardens on a wall 9, which is cooled by the mandrel 14 and the inner surface of the outer shell 17. The temperature of the two metals (solidifying shell 17 and the liquid metal 18 designed to receive an inner annular shell) chosen at the time of molding the inner shell to the chemical and metallurgical diffusion between carbon steel and stainless steel occurred intensively on the boundary or on the boundary of the section was a joint solidification. Thus, you get great quality curing two sides due to the phenomenon of diffusion welding or joint solidification.

After complete solidification of stainless steel 18 first remove the mold 3 and the wall 9 of the second mold and get the desired workpiece shells of two materials, ready for forging and/or machining to obtain the final shells of the possible operations after heat treatment.

Preferably, to facilitate the ascent of the wall 8 separating the two foundries space 7, 10, without damaging the surface of the shell 17, it is possible to equip her side, intended to enter into contact with the outer sidewall 17, lubrication means, such as channels discharge oil facing surface�of the wall, similar to that used for moulds of continuous casting of steel, or channels for injection of gas under pressure making fast separation wall 8.

Above has been described a case where for molding the inner shell of stainless steel waiting until it fully hardens the outer shell 17. However, in the framework of the invention and can not wait for this fully cured, and make the rise of cylindrical wall 8, then casting stainless steel 18 until the solidification of the outer shell 17 is not yet fully ended. Enough of the hardened crust is formed on the wall 8, was solid enough to not be damaged from the movement of the wall 8 and to withstand the pressure that it exerts stainless steel 18 during casting. The advantage of this solution is the possibility of casting, while the inner surface of the outer shell is at a relatively high temperature, which increases the intensity of the mutual diffusion of metals. Due to this even better is the grip between the two sides.

Similarly, you can start lifting cylindrical wall 8, and then molding the inner shell to complete the molding of the outer shell 17 when the solidification of the outer shell 17 has progressed sufficiently so that the hardened crust on the cylindrical�th wall 8 was quite thick and solid and able to withstand moving wall 8 and the pressure of liquid metal 18, injected for forming the inner shell. Hardening of the outer shell 17 can continue even when the wall 8 is in motion.

In comparison with known prior to the present technology, the present invention avoids the phase welding of stainless steel strips and testing welds that provides a gain in time of at least 5-10% for large manufacturing two-component shells. For example, but is not limited to this time may be 5-10 weeks from the total production time, which can last for a hundred weeks.

The manufacture of the shell of two materials goes through the process of obtaining a two-component hollow ingot.

The mold, allowing the production of such a shell is mainly made of cast iron, with internal removable device made of cast iron or of steel. Stage forging and/or circular rolling allows to obtain the preform, which essentially has a two-component finite length of the shell and a minimum thickness enabling the next phase of machining. Finally, the phase of the mechanical treatment is carried out to translate two component shells from the state of the workpiece in the condition of the finished part with the given dimensions.

The invention has been described for the case of the manufacture of shells of the two materials, i.e. �W carbon steel for the outer part and stainless steel for the inner part. But, of course, this example is not limiting, and it is possible to use other materials. Similarly, the order of magnitude of the dimensions that were given as examples, not limiting.

In the framework of the invention the annular shells 17, 18 can be cylindrical, truncated cone, may be of rectangular or other section.

It is also possible to carry out molding of the inner shell 18 and outer casting shell 17, if install cooling facilities, providing initial forced cooling of the inner shell 18. Also, as mentioned above for the inverse case, molding of the outer shell 17 can be realized on the inner sidewall 18, which have fully or partially hardened or is in the process of casting.

1. A method of manufacturing shells of two materials consisting of an annular outer shell (17) and an annular inner shell (18) being welded to each other and both shells are made of different materials, characterized in that:
- carry out the siphon casting and solidification of the first shell (17, 18) in the foundry space (7, 10), foundry limited basis (1), the first wall (3, 9) of the mold located on the casting base (1) and wall (8), made with the possibility of moving up located based on the specified�and (1) and concentrically with the wall (3, 9) of the mold,
- raise a specified movable wall (8) so as to open the hardened crust on it first shells (17, 18),
- carry out the siphon casting and solidification of the second sidewall (18, 17) in the foundry space, indicated by the cortex of the first shell (17, 18), which is pre-hardened for movable wall (8) and a stationary second wall (9, 3) of the mold, wherein the welding of two shells is due to the diffusion of material between the surfaces of these shells, come in contact with each other during curing or co-curing,
- if necessary produce forging and/or machining of the shell of two materials formed by the specified welded shells.

2. A method according to claim 1, characterized in that the first sidewall is annular outer sidewall (17).

3. A method according to claim 1, characterized in that the first sidewall is annular inner sidewall (18).

4. Method according to one of claims.1-3, characterized in that the specified movable wall (8) raise after solidification of the first shell (17, 18).

5. Method according to one of claims.1-3, characterized in that the specified movable wall (8) begin to rise, when first casting shells (17, 18) is completed, wherein the solidification is not over yet.

6. Method according to one of claims.1-3,�lichudis, that specified movable wall (8) begin to rise, when first casting shells (17, 18) is not yet complete.

7. Method according to one of claims.1-3, characterized in that lubricate the interface between the first sidewall (17, 18) and a movable wall (8).

8. Method according to one of claims.1-3, characterized in that the injected gas under pressure to the interface between first sidewall (17, 18) and a movable wall (8).

9. Method according to one of claims.1-3, characterized in that carry out forced cooling of the same and/or another of the walls (3, 9) of the mold.

10. Method according to one of claims.1-3, characterized in that the outer shell (17) made of a carbon steel and an inner shell made of stainless steel.

11. Device for the manufacture of the shell of two materials consisting of an annular outer shell (17) and an annular inner shell (18) being welded to each other and both shells are made of different materials, characterized in that it contains:
casting base (1) for siphon casting, with inlet channel (4) and output channels (5, 6) for liquid metal intended for use as the material of the outer shell (17), made in the specified radix (1), the specified output channels (5, 6) communicated with the first casting space (7) limited to the upper stronyasvane (1), the inner wall of the first mold (3) and outer wall (8) of the second mold, and the input channel (11) and output channels (12, 13) for liquid metal (18) intended to be used as the material of the inner shell, made in the specified radix (1), the specified output channels (12, 13) communicated with the second casting space (10), limited by the upper side of the base (1), the specified outer wall (8) of the second mold and the inner wall (9) of the second mold,
- means of lifting the specified outer wall (8) of the second mold in a vertical direction, allowing access to the hardened inner surface of the outer shell (17) and introduce it into contact with liquid metal (18), which is the material of the inner shell.

12. The device according to claim 11, characterized in that it comprises means of cooling the inner wall (9) of the second mold, such as a cooled internal mandrel (14) surrounded by the inner wall (9) of the second mold.

13. The device according to claim 11 or 12, characterized in that said mold contain profitable extension arms (15, 16).

14. The device according to claim 11 or 12, characterized in that the outer wall (8) of the second mold includes means for lubricating the border section with the metal outer shell (17).

15. The device according to claim 11 or 12, characterized in that the outer wall (8) second� the mold includes means for forcing gas under pressure at the boundary section with the metal outer shell (17).

16. Shell of two materials consisting of an annular outer shell (17) and an annular inner shell (18) being welded to each other and both shells are made of different materials, characterized in that it is manufactured by a method according to one of claims.1-10.

17. The shell according to claim 16, characterized in that the outer shell is made of carbon steel 16MND5, and the inner shell is made from 304L stainless steel.

18. The shell according to claim 16 or 17, characterized in that it is a detail of the tank of a nuclear or petrochemical reactor.

19. The shell according to claim 16 or 17, characterized in that it is part of a pressurizer of a nuclear reactor.