KR100245044B1 - Method for manufacturing rolling roll - Google Patents

Abstract

The present disclosure relates to a method for manufacturing a hot rolled roll composed of two or more different materials and used for hot rolling a metal material. The present invention allows the hollows of the outer material 14 of the pre-made hot rolled rolls and the hollows of the upper and lower molds 22a and 22b to be arranged in a straight line to be connected to each other, and through the common hollow part, the melting electrode 20. By melting and solidifying the melt, the hot rolled rolls of different materials are manufactured, thereby simplifying the construction of the manufacturing apparatus and making the same products repeatedly under the same conditions without a moving mechanism, thereby increasing productivity. Since the external material and the core part are fused step by step, there is almost no difference in mechanical properties between the external material and the core material, thereby increasing the life of the product.

Description

Method for manufacturing hot rolled rolls of dissimilar materials using electrode melting casting

The present invention relates to a method for manufacturing a hot rolled roll, which is composed of two or more dissimilar materials and used for hot rolling a metal, and particularly, in the hollow part of the outer material of a prerolled hot rolled roll using an electrode melting method. The present invention relates to a method for producing a hot rolled roll for melting a core material by melting electrodes.

In general, hot rolled rolls require high hardness and crack resistance on the surface side of the hot rolling process and strength and toughness on the inner side to withstand high pressure. Therefore, whether the hot rolled roll can satisfy these mechanical properties is determined by the bonding state between two or more dissimilar materials.

Conventional hot rolling rolls are usually manufactured by applying an external material around the core material by using an electrode melting method or injecting molten metal of the molten external material around the core material.

As shown in Figure 1, the hot rolling roll by the molten metal injection method is produced by directly injecting the molten external material melted around the core material. The stationary stand 110 fixed to the movable unit 110 has a core part 112 of the hot rolling roll penetrated to one side thereof, and the stationary mold 114 is fixed to the outer peripheral surface of the core member 112 so as to be spaced apart from the core member 112. It is mounted in a fixed state with respect to 110. The upper side of the stationary mold 114 is coupled to the guide vessel 116 to act as a funnel, and each of the core material 112 and the stationary mold 114 is coupled to the induction coils 117 and 118, by induction current It generates a certain amount of heat between them to maintain a constant temperature during operation. Therefore, the molten metal of the outer material 119 material dissolved by the melting furnace is immersed in the injection furnace 120 in an appropriate amount, and the contained molten metal is injected into the guide container 116 by tilting the injection furnace 120. do. The molten metal injected into the guide vessel 116 covers the outer circumferential surface of the core member 112 of the inner space of the stationary mold 114, and moves the core member 112 downward in accordance with a gradually solidifying speed to produce a hot rolled roll of different materials. It can be produced.

However, in the conventional methods of manufacturing hot rolled rolls, in order to manufacture the hot rolled rolls of different materials, the moving mold or the core should be moved in accordance with the solidification speed of the external material, but it is difficult to control the exact solidification speed in the manufacturing process. In addition, there is a limit to the thickness of the external material to be applied. In addition, the molten metal is exposed to the outside before it is completely solidified as an external material of the hot rolled roll, which causes the molten metal to react with the ambient atmosphere to oxidize and to remain in the casting of the external material, thereby lowering the mechanical strength. There was a problem. Accordingly, the present invention has been made to solve the above problems, the object of the present invention is to provide a hot rolled roll manufacturing method for producing a hot rolled roll having a dissimilar material by using a simple manufacturing apparatus employing the electrode dissolution method.

1 is a configuration diagram of a manufacturing apparatus for explaining an example of a conventional hot rolling roll manufacturing method,

2 is a configuration diagram of a manufacturing apparatus for explaining a method for manufacturing a hot rolled roll according to the present invention;

Figure 3 is a perspective view showing a hot rolling roll manufactured by the method of manufacturing a hot rolled roll according to the present invention,

4 is a perspective view showing a hot rolled roll manufactured by the manufacturing method according to the present invention;

Figure 5 is a chart showing the hardness difference for each part of the hot rolled roll.

※ Explanation of symbols for main parts of drawing

12,100: Bottom plate 14,119: External material

16: cooling mold 18,108: power supply

20: melting electrode 22a: upper mold

22b: lower mold 30: hot rolled roll

30a: heat affected zone 32,102,112: heartwood

104: moving mold 106: melting electrode

110: fixed base 114: fixed mold

120: injection furnace 116: guide vessel

117,118: guide coil

Features of the present invention for achieving the above object is a method of manufacturing a hot rolled roll of different materials using the electrode melting casting method, the bottom plate is fixed to the bottom plate is connected to the wire from the power supply, the bottom mold having a hollow on the bottom plate Arranging; On the upper side of the lower mold, an outer material portion prepared in advance to have a hollow part is arranged so that the outer peripheral surface and the upper and lower end surfaces are in close contact with each other by a cooling mold, and an upper mold corresponding to the lower mold having a hollow is disposed on the upper surface of the cooling mold. Doing; And inserting a molten electrode connected from the power supply in the longitudinal direction into the hollow portion in which the hollows and the hollow portion communicate in the longitudinal direction, pouring molten slag so that the ends of the molten electrode are locked, and the molten electrode and the bottom plate from the power supply, respectively. Hot rolling roll manufacturing method comprising the step of applying a current to each other to face each other.

Hereinafter, with reference to the accompanying drawings to explain the configuration and operation of the present invention.

As shown in FIG. 2, the manufacturing apparatus for manufacturing hot rolled rolls is connected to the bottom plate 12 for fixing molds by connecting wires from the power supply unit 18 and to close the external material 14 during operation. Current is applied through the cooling mold 16, the core mold manufacturing molds 22a and 22b, and the power supply unit 18, and a consuming electrode 20 for manufacturing the core portion of the hot rolled roll is provided. Doing.

The bottom plate 12 is preferably configured to have the same width as the cross sectional area of the hot rolled roll to be produced, and is connected to the power supply unit 18 so that current can be applied to the power supply 18 extending from the power supply. The lower mold 22b is arranged on the upper surface of the bottom flat plate 12, and the lower mold 22b has a hollow having the same shape as a part of the core portion of the hot rolled roll to be manufactured. On the upper side of the lower mold 22b, a cylindrical outer portion 14 prepared in advance is disposed with a hollow therein, and a cooling mold 16 is disposed on the outer circumferential surface and the upper and lower end surfaces of the outer member 14. It is in close contact. Cooling mold 16 has a cooling water passage (not shown) therein is divided into a multi-stage structure inside the cooling mold 16, and serves to cool the heat transferred to the outer material 14 during the manufacture of the hot rolled roll, As the cooling method, water cooling is mainly used. The cooling mold 16 can be detachably implemented to be detachable to the outside. In addition, an upper mold 22a corresponding to the lower mold 22b is disposed on the upper end surface of the cooling mold 16. Like the lower mold 22b, the upper mold 22a has a hollow having the same shape as a part of the core portion of the hot rolling roll. Of course, the upper mold 22a may be replaced with a movable mold to move up and down. In addition, the hollow portions of each of the lower mold 22b, the outer member 14, and the upper mold 22a have the same cross-sectional area and extend in the vertical direction, and lead wires from the power supply 18 to this common hollow portion. The connected melting electrode 20 is disposed.

Therefore, the melting electrode 20 is inserted into the common hollow portion and the molten slag is poured so that the lower end of the melting electrode 20 is locked, and then the current from the power supply is supplied to the power supply 18. It is applied to the melting electrode 20 through. Thus, the flow of current is interrupted by the liquid slag injected between the bottom plate 12 and the melting electrode 20, and thus Joule heat is generated at the end of the melting electrode 20, thereby dissolving the electrode. Heating and dissolution begin. As a result, the dissolved electrode metal has a water droplet shape and causes internal impurities to move toward the surface due to its high surface area. This impurity reacts with the slag component while passing through the molten slag to remove impurities. Thus, only the high purity molten metal is integrated at the bottom to form a pool of a certain shape (solid) is one-way solidification in the upper direction. As a result, the solidified layer accumulates upward through the hollow portions of the lower mold 22b, the outer material 14, and the upper mold 22a as time passes, thereby obtaining a hot rolled roll of a desired dissimilar material.

By this process, the hot rolling roll 30 as shown in Figure 3 is produced, the hot rolling roll 30 is the inner peripheral surface of the outer material 14 is fused with the core 32 by the melting electrode and the outer material And the heat-affected portion 30a due to electrode dissolution at the joint surface of the core material. In addition, Figure 4 shows the parts of the mechanical properties of the hot rolled rolls manufactured in this way, A is a change in hardness according to the conventional method and B is a change in hardness according to the present invention. As shown in Fig. 4, it can be seen that the hot rolling roll according to the present production method has a slightly different hardness difference than the conventional method.

As described above, the present invention arranges the hollow of the outer material 14 prepared in advance and the hollow parts of the upper and lower molds 22a and 22b in a straight line so as to communicate with each other, and through the common hollow part, the melting electrode 20. It is possible to remove the segregation phenomenon at the joining between metals with high segregation by making the hot rolls of different materials by solidifying and accumulating the melt of the material, and controlling the crystal structure by controlling the cooling rate. There are no restrictions on the materials to be used. In addition, since the configuration of the manufacturing apparatus is simpler and the same product can be repeatedly manufactured under the same conditions without a moving mechanism, the productivity is increased, and the core part is gradually fused to the external material, as shown in FIG. 5. Since the mechanical characteristic difference such as hardness existing between the external material and the core material is changed gently, there is an effect of increasing the life of the product.

Claims (2)

In the manufacturing method of hot rolled rolls of dissimilar materials using the electrode melting casting method, Fixing a bottom plate connected to the conductors from a power supply and disposing a lower mold having a hollow on an upper surface of the bottom plate; On the upper side of the lower mold, an outer material portion prepared in advance so as to have a hollow part is disposed in close contact with the outer circumferential surface and the upper and lower end surfaces by a cooling mold, and corresponds to the lower mold having the hollow on the upper surface of the cooling mold. Placing the upper mold; And Insert a molten electrode connected to the lead from the power supply in the longitudinal direction in the hollow portion in which the hollows and the hollow portion communicate in the longitudinal direction, pour the molten slag so that the end of the melting electrode can be locked, and the molten electrode from the power supply And applying a current to each of the bottom plate and the lower plate to face each other. The method of claim 1, And the cooling mold is detachably attached to the outside of the outer material to dissipate heat from the outer material.

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