CN1041330C - replaceable converter - Google Patents

Abstract

The present invention relates to a replaceable iron-smelting furnace for smelting steel by oxygen-top blowing or top-bottom composite blowing, which comprises a furnace casing, a backing ring and a drive device, wherein the furnace casing is suspended on the backing ring by flexible connecting rods; the backing ring is integrally and fixedly connected with the furnace casing by a spherical supporting device and a tilting pin. The present invention has the advantages of simple connecting mechanism, low manufacturing cost, safe and reliable operation, and convenient maintenance and replacement.

Description

replaceable converter

The invention belongs to a metallurgical furnace, and is particularly suitable for a steelmaking converter for oxygen top-blowing or top-bottom compound blowing for steelmaking.

The oxygen top-blown converter is the main method of steelmaking production at home and abroad. In order to increase production and reduce costs, for large-scale steelmaking plants, in order to realize the production method of two-blown two or one-blown one, replaceable converters are often used, that is, at the end of a furnace operation, the furnace body is replaced as a whole. The furnace body to be repaired that cannot continue to be blown is taken out from the support ring, moved to the furnace repair position, and then the furnace body prepared in advance is put into the support ring to continue blowing production. In order not to increase the lifting and transportation equipment capacity of the steelmaking workshop, a series of supporting auxiliary equipment is required when using the replaceable converter, such as: furnace changing car, furnace dismantling machine, movable support device, etc.

In 1984, "Stekmaking conference proceedings" introduced the convertible converter of Hu Jinggen Steelmaking of Mannesmann Steel Tube Company in Germany. The furnace is manufactured by Demark Company with two converters with a capacity of 220 tons and an annual steel output of 4.08 million tons. The furnace bottom is removable. The converter cap is water-cooled to prevent deformation. For the replaceable converter system, the fixing method of the converter body and the supporting ring is very important. Demark replaceable converter adopts thin steel tendons to lock the furnace and the support ring (see German patent 2905283). There are 4 steel tendons on both sides of the converter body, 2 gaskets and 1 load lug to fix the furnace body on the support ring superior. When replacing the converter, the converter to be replaced is disassembled from the supporting ring with a hydraulic device, and a new furnace is installed.

The tendons connecting the body of furnace and the support ring are flexible rods, and are shown in Fig. 3 and Fig. 4 of DE2905283.

The furnace shell and the supporting ring are connected by protruding blocks fixed on the furnace body, brackets and steel tendons on the supporting ring.

Demark’s exchange information stated that in order to prevent the relative slippage between the furnace shell and the support ring, two bearing pins are symmetrically installed at the bottom of the support ring on the trunnion side, and they are inserted into the two holes of the bracket. One pin is fixed, and the other can move in the axial direction, so that the furnace shell can slide freely during smelting, and the furnace shell and the supporting ring can be kept in a relative installation position.

Between the two pull rods on the left and right sides of the trunnion, a spherical bearing joint capable of radial displacement is installed respectively.

The above-mentioned prior art proposes bearing pins and spherical bearing joints, but there are no detailed illustrations, and there are obvious deficiencies. For example: the transverse force of the flexible rod (reinforcement bundle) connecting the support ring and the furnace shell is not reasonable enough, the installation alignment between the support ring and the furnace shell is difficult, and because one of the bearing pins is fixed, the other can move in the axial direction , which to some extent constrains the free displacement of the furnace shell thermal expansion.

The purpose of the present invention is to overcome technical problems such as the deflection displacement generated after the deformation of the furnace body and the difficulty in the installation of the support ring and the furnace shell, and specifically design the spherical support device between the support ring and the furnace shell and the tilting pin carried by the converter when it tilts.

Figure 1 of the replaceable converter of the present invention includes a converter shell, a support ring, a driving device, a blowing system, and the like. The furnace shell 1 and the support ring 2 are connected as a whole with a flexible rod device (steel tendon) 4, a spherical support device 5 and a tipping pin device 3. The furnace shell is composed of water-cooled furnace mouth, water-cooled furnace cap, furnace body bracket, movable furnace bottom and so on.

The spherical support device is a key part of the application of the convertible converter. The support ring and the furnace shell are tightly fixed through the spherical support device under the pre-tension of the flexible rod. Since the convertible converter shell and the support ring use four A group of eight flexible rods are connected, so four sets of spherical support devices are designed to be installed between two flexible rods respectively. The spherical support device is composed of three parts. The heat-resistant CrMO alloy steel is forged and processed after being welded with the support ring, and the surface of the support seat is heat-treated, and the heat-treated hardness is HB300-350. The hemisphere is installed between the supporting seat and the spherical seat. The upper plane of the hemisphere is in contact with the plane of the support seat, and the spherical surface is in contact with the spherical surface of the spherical seat. The hemisphere is made of heat-resistant CrMO steel and heat-treated as a whole. The hardness of the heat treatment depends on the volume and load of the furnace. The ball seat and the furnace shell support are welded as a whole. The ball seat is made of two parts and connected by bolts 8 to form a whole, which is convenient for installation and replacement. The spherical surface depth of the ball seat is half of the sphere and has been heat-treated. It is realized by a hemisphere, and the distance depends on the capacity of the furnace body and its deformation under thermal stress and the displacement angle of the supporting ring. The ideal distance is when the displacement angle between the furnace shell and the supporting ring is in the range of 5-8° Inside, so that the support seat does not touch the top of the ball seat. In order to overcome the misalignment between the supporting seat and the spherical seat due to manufacturing errors, the diameter of the supporting seat is appropriately larger than that of the hemisphere.

With the present invention, the relative position of the flexible rods connecting the furnace shell and the supporting ring is more accurate, and the force and deformation of the flexible rods are more reasonable during the prestress and expansion and deformation of the furnace body, and the flexible rods are pre-tightened to a certain value. , the support ring and the furnace shell will be reliably connected as a whole, and can prevent the relative displacement of the support ring and the furnace shell when the converter is toppled.

During smelting, the furnace shell works under the condition of up to 200-400°C. There is a temperature gradient not only in the height direction of the furnace body, but also in the surrounding and radial directions. Due to this temperature gradient, the different thermal expansions of the various parts of the furnace shell cause it to generate heat. Stress deformation, using the device of the present invention, can freely change the displacement angle with the support ring with the deformation of the furnace shell, so that the furnace shell and the support ring still maintain the tightness of the flexible rod when the prestress is tightened, and the converter maintains normal operation .

The tipping pin is another important part of the convertible converter, as shown in Figure 3, it is composed of a pin body 10 and a concave groove wear plate 11. Two tipping pins are respectively installed on the bottom of the support ring on the trunnion side and the upper part of the furnace shell support, and are used to transmit moment and force from other directions between the furnace shell and the support ring.

The pin body adopted in the present invention is integrally forged with heat-resistant alloy steel and formed through heat treatment, with a width of 600 millimeters and a thickness of 550 millimeters. The force-bearing surfaces on both sides of the pin body are processed into an involute shape to ensure good contact and uniform force. At the same time, it is easy to center and insert when replacing the furnace shell. The connection between the pin body and the support ring is a processing plane. There are bolts connected with the support ring on this surface to ensure sufficient pre-tightening force and shear strength. In order to facilitate the precise relative position of the pin body and the support ring after installation, two pin holes 14 for positioning are provided inside, and the installation accuracy of the pin body is realized by the positioning pins. The pin body is symmetrically installed on the bottom of the support rings on the sides of the two trunnions, and a pin body positioning groove is left at the contact part.

The concave grooves for inserting the tipping pins are arranged on the furnace shell supports on the sides of the two trunnions. Both sides of the trough body are equipped with wear-resistant plates bearing radial force. The wear-resistant plates are made of heat-resistant low-alloy steel. A stainless steel lining plate 12 is installed inside the wear-resistant plates to adjust the gap between the pin body and the grinding plate. The two plates are connected with the 13 grooved plates of the furnace shell bracket with high-strength bolts, and the connecting bolts should have sufficient pre-tightening force.

The size of the gap between the pin body and the grinding plate is the key to determine the normal use of the tipping pin, and directly affects the furnace replacement operation. When the gap is too large, the operation of the converter equipment will be affected by the large impact due to frequent start-up of the converter, and the components will be damaged prematurely. If the gap is too small, it will cause difficulty in alignment and affect the furnace replacement operation.

In addition to satisfying the torque transmission when the furnace body is tilted, the tilting pin also has the following advantages:

1. The gap between the pin body and the groove-shaped grinding block can be adjusted at will, so that the two tilting pins can be loaded at the same time when the furnace body is tilted. Once one is damaged, the other can still complete the torque transmission.

2. The stress condition of the flexible rod connecting the support ring and the furnace shell is improved, so that it will not be bent and deformed due to radial force and overturning moment.

3. The tipping pin not only transmits the tipping moment, but also bears the radial force from the weight of the furnace body.

4. Since the tipping pin is not axially fixed on the axis of the trunnion, the furnace shell can freely slide axially when expanding.

5. Due to the use of the involute tooth shape pin, it is easier to insert in the center when replacing the furnace shell, which facilitates the operation and saves time.

6. The new tipping pin device has simple structure, low manufacturing price, safe and reliable operation, and convenient maintenance and replacement.

7. The tipping pin device is suitable for replaceable converter equipment of various capacities without any trouble.

Example:

As an embodiment of the present invention: now the specific technical parameters of the 210t converter are listed:

Nominal capacity 210t,

The inner diameter of the furnace is 8000mm,

Furnace body height 11090mm,

The maximum working tilting moment is 245tm,

Freezer torque 725tm.

Description of drawings:

Figure 1 Schematic diagram of replaceable converter

Figure 2 Schematic diagram of spherical support device

Figure 3 Schematic diagram of the tipping pin structure

Figure 4 Schematic diagram of pin guide position

in:

1. Furnace shell

2. Support ring

3. Tilting pin device

4. Tendons

5. Spherical support device

6. Support seat

7. Hemisphere

8. Bolts

9. Ball seat

10. Pin body 11, concave groove wear-resistant plate 12, stainless steel lining plate 13, furnace shell bracket 14, pin hole

Claims (2)

1. A replaceable converter, including a furnace shell, a support ring, and a driving device. The furnace shell is suspended on the support ring by a flexible rod, and the support ring and the furnace shell are fixedly connected into one body through a spherical support device and a tilting pin. It is characterized by a. The spherical support device is composed of a support seat, a hemispherical body and a spherical seat. The support seat is installed on the lower cover of the support ring, the spherical seat is installed on the furnace shell, the hemispherical body is installed on the spherical seat, and the hemispherical body is in contact with the support seat. . b. The tipping pin is composed of a pin body fixed at the bottom of the support ring and a concave groove fixed on the furnace shell bracket. The bearing surface of the tipping pin is an involute curve, and the two tipping pins are respectively installed on the trunnion side . 2. The replaceable converter according to claim 1, characterized in that the spherical supporting device is made of heat-resistant steel and has been heat-treated, and the tipping pin is made of heat-resistant alloy steel.

Images