JPH01180745A - Method for cooling die - Google Patents

Abstract

PURPOSE:To extend the service life of a die by providing an enclosure for storing a cooling water on the upper face of a die, setting the enclosure of the working face side of the die higher than a non-working face side and performing the flow control of the cooling water. CONSTITUTION:A die 1 is clamped at the specified position of the press bed 4 for forging and an enclosure 6 is provided on the upper face of the die 1. In this case, the height of the enclosure 6 of the work face 8 side of the die 1 is set higher than a non-working face 9 side by the specified amt. The flow is thus controlled at the forging time of a hot slab so that a cooling water is flowed out of the non-working face 9 side only and at non-forging time the flow control is performed so that the cooling water is over-flowed from both sides of the work face 8 and non-work face 9. Consequently the cooling of the die 1 can be performed optimum without watering a cooling water on the hot slab and the service life of the die 1 is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cooling a hot forging die.

(Prior art) Hot slabs used in the hot rolling process generally have a thickness of 100 to 3
The 001 layer has a width of about 600 to 2200x, and is heated to a required temperature (for example, 1200° C.) in a heating furnace or reheating furnace, and then hot rolled.

By the way, recently, the width of the hot slab has been reduced by up to several hundred B by forging the hot slab in the width direction immediately after the above-mentioned heating, and then the width of the hot slab has been reduced by a maximum of several hundred B. For example, a system is being implemented that allows the width dimensions of continuously cast slabs to be integrated and arranged in a timely manner, while producing hot rolled steel sheets with a wide variety of final shapes in a timely manner.

Therefore, extending the life of the forging machine molds used in such systems and reducing the number of replacements will not only reduce mold costs, but also improve the smooth flow of the manufacturing process after continuous casting. This is an important element in ensuring that

Therefore, the mold is made of a wide variety of materials, and due to economic constraints, it is necessary to choose between a material that is difficult to break but whose life span is limited by the progress of deformation and wear, and a material that can withstand deformation and wear to a certain extent but is easy to break. What you do is - boat fishing. and,
Naturally, cooling the mold generally extends its life, so cooling the mold is performed.

(Problems to be Solved by the Invention) By the way, if the mold can be cooled even during forging, the life can be further extended, but there are the following problems.

That is, in the method of water cooling by supplying cooling water directly from above the mold, the hot slab is also sprayed with cooling water.

In this case, if the cooling water is uniformly applied to the hot slab, the temperature of the hot slab will drop and the processing temperature in the subsequent process will drop, so the extraction temperature in the heating furnace should be lower than the desired temperature. This will increase fuel costs.

On the other hand, if the cooling water is applied unevenly, the end surface a and both sides of the upper surface of the hot slab S will be cooled, especially as shown in FIG. Since the hardness increases more than that of other parts, non-uniformity in mechanical properties such as tensile strength and shape will occur.

In the first place, even in the process of simply rolling a hot-rolled steel sheet, there is a problem with the difference in cooling conditions between the center of the sheet and the edges (the edges are lower). end a,
Since a device may be installed to heat portion b, it is necessary to avoid further enlarging the temperature difference between the center and end portions of the hot slab due to water cooling of the mold.

Therefore, at present, cooling is not performed during forging, and as shown in Fig. 5, after the preceding hot slab S leaves the mold 1, until the following hot slab S enters the mold 1 Cooling water is sprayed diagonally toward the mold 1 from water cooling nozzles 2 disposed above and behind the mold to cool it.

By the way, the time required for forging a hot slab in the width direction using a die is about 60 to 90 seconds, which is longer than rolling.

On the other hand, as a rolling line, 30 to 40 hot slabs are processed in one hour, so considering the rolling steps before and after, the time to inject cooling water into the mold is about 10 seconds with the method described above. In some cases.

Therefore, the conventional water cooling method was unable to sufficiently cool the mold, and was insufficient in terms of extending the life of the mold.

Although it is possible to extend the cooling time by internally water-cooling the mold, the piping work when replacing the mold becomes complicated, so it takes a long time to replace the mold, and work efficiency decreases. invite.

The present invention aims to provide a mold cooling method that can solve these problems.

(Means for Solving the Problems) The present invention provides a cooling method for a hot forging die for forging a hot slab in the width direction, in which cooling water is stored over as wide a range as possible on the upper surface of the die. At the same time, the height of the enclosure on the processed side of the mold is higher than the height of the enclosure on the non-processed side (and during forging, cooling water is allowed to overflow only on the non-processed side of the die). This is a cooling method for a mold, the gist of which is to control the amount of cooling water supplied to the enclosure so that the cooling water overflows both the processed surface side and the non-processed surface side of the mold during non-forging.

In the present invention, the height of the enclosure refers to the lowest height portion when the upper ends of the enclosure are not on the same horizontal plane.

(Function) The mold cooling method according to the present invention is a method for cooling a hot forging mold for forging a hot slab in the width direction, in which cooling water is applied to the upper surface of the mold over as wide a range as possible. In addition to providing a storage enclosure, the height of the enclosure on the processed side of the mold is set higher than the height of the enclosure on the non-processed side by the required amount, and during forging, cooling water overflows only on the non-processed side of the die. When not forging, the amount of cooling water supplied to the enclosure is controlled so that the cooling water overflows on both the processed and non-processed sides of the mold. The mold can be cooled without applying cooling water to the hot slab, whether forging or non-forging.

(Example) The present invention will be described below based on the example shown in FIGS. 1 to 3.

The mold 1 is transported, for example, to the upper part of the press body by a crane or the like, and then suspended by a hook 3 protruding from the upper part of the press body by an elevation device disposed in the press body, and placed in advance in the elevating position of the mold 1. The press head 40 that is being moved is lowered to a predetermined hanging position, is firmly fixed by the clamp 5 at the predetermined height position, and is used for forging work.

Therefore, in the present invention, an enclosure 6 is provided on the upper surface of the mold 1, and the enclosure 6 is located above the press head 4 and at a position that does not hinder the lifting and lowering of the mold 1. The mold 1 is cooled by supplying cooling water from the provided cooling water supply pipe 7.

Therefore, it is preferable to install the enclosure 6 over as wide a range as possible on the upper surface of the mold 1, as shown in FIG. 1, in view of the cooling effect from the upper surface.

Further, in the present invention, the height of the enclosure 6 is made different between the processed surface 8 side and the non-processed surface 9 side of the mold 1. That is, in the embodiment shown in FIGS. 1 and 2, the machined surface 8
The height of the side enclosure 6 is compared to the height of the non-processed surface 9 side.This difference in height is the difference in the amount of cooling water between forging and non-forging. , during forging, the mold 1 vibrates in the width direction of the hot slab S (several tens of SPM, amplitude 10
(approximately 0 to 300 W), the change in the cooling water level in the enclosure 6 is taken into account when determining the amount.

By doing so, when the amount of cooling water supplied from the cooling water supply pipe 7 into the enclosure 6 is small, the cooling water overflowing from the enclosure 6 is only on the non-machined surface 9 side, and on the other hand, when the amount of cooling water is large, the cooling water overflows from the enclosure 6. , the cooling water overflowing from the enclosure 6 is on the unprocessed surface 9.
It will overflow not only from the side but also from the machined surface 8 side.

Incidentally, the upper end of the enclosure 6 is disclosed in this embodiment as having a sawtooth shape. This is because the amount of cooling water overflowing from the enclosure 6 changes depending on the installation position of the cooling water supply pipe 7, the amount of cooling water, or the vibration of the mold 1, which changes the water surface height during forging or non-forging. This is to prevent

It should be noted that the shape of the upper end of the enclosure 6 is of course not limited to the sawtooth shape as disclosed in this embodiment, but if other shapes are adopted, the above-mentioned effects should be taken into consideration when determining the shape. is desirable.

The present invention installs the above-described enclosure 6 on the upper surface of the mold 1, and during forging, supplies enough cooling water from the cooling water supply pipe 7 to overflow only the non-processed surface 9 of the mold 1. At this time, an amount of cooling water is supplied so that the cooling water overflows not only from the non-processed surface 9 but also from the processed surface 8.

Therefore, when the upper end of the enclosure 6 is shaped like a saw blade, the height h2 of the enclosure 6 on the non-processed surface 9 side is reduced as shown in FIG.
Even if is higher than the height h4 on the machined surface 8 side, the same effect can be obtained if the height of the valley bottom part of the saw blade surface on the non-processed surface 9 side is lower than the height h3 of the valley bottom part on the machined surface 8 example. You will get it.

Therefore, according to the method of the present invention, during the forging of the hot slab S, there is no need to water-cool the hot slab S by pouring cooling water on it, and the entire surface of the mold 1 can be effectively water-cooled when not forging.

By the way, in the method of the present invention, there is a concern that the amount of cooling water for cooling the mold 1 during non-forging will be larger on the non-processed surface 9 than on the processed surface 8, but if the amount of cooling water on the processed surface 8 is insufficient, If this is the case, you can replenish the amount of cooling water with another water cooling nozzle as shown in Figure 4, or use an enclosure 6 as shown in Figure 2.
The inside is divided into a processed surface 8 side and a non-processed surface 9 side by a partition plate 10,
If you adopt a method such as reducing the amount of cooling water during forging and supplying the cooling water only to the non-machined surface 9 side, and increasing the amount of water during non-forging to actively supply the cooling water to the machining surface 8 side. good. In such a case, if the cooling water supply pipe 7 is configured with a double pipe, etc., the cooling water supply can be used more reliably.

In addition, although this embodiment discloses that the enclosure 6 is integrally formed with the mold 1, there may be cases where the machined surface 8 of the mold 1 is cracked, deformed, or worn, and this surface is cut and reused. It may be possible to make it removable by bolting or the like.

By the way, the peak height on the processed surface 8 side is 80 m, the valley height is 501 m, the pinch of the saw blade is 6011 m, and the peak height on the non-processed surface 9 side is 7011 m, and the trough height is 20 m. , enclosure 6 with saw blade pitch of 60m is molded into mold 1 (top surface area 5000cm)
During forging, cooling water is supplied from the cooling water supply pipe 7 at a rate of 301/min to the mold 1 having the structure shown in FIG. Cooling water overflows only to the non-processed surface 9 of the mold 1 to cool it, and when not forging, 25017 m1n of cooling water is supplied to flood not only the non-processed surface 9 of the mold 1 but also the processed surface 8. and cooled. When forging work was performed using the same type of die under these conditions, the surface temperature of the machined surface 8 of die 1 was 570°C.
There is little difference in that the internal temperature rises to 250°C with the conventional cooling method shown in Figure 5, but according to the present invention, the internal temperature rises to 250°C with the conventional cooling method, as shown in Figure 5. The temperature was 220°C.

Note that instead of cooling by overflowing the cooling water from the enclosure 6 as in this embodiment, the mold 1 is provided with a plurality of through holes in the vertical direction, and the cooling water supplied to the enclosure 6 passes through these through holes. The mold 1 may be cooled by doing so.

In addition, in order to solve the problem that even if the water volume is increased during non-forging, the water level rises and it takes some time for the cooling water to overflow to the machined surface 8 side, the sensor predicts the slab coming out and increases the water volume just before the slab is pulled out. It is even more effective if control is performed so that the machined surface 8 side is cooled immediately after the slab is removed.

(Effects of the Invention) As explained above, the mold cooling method according to the present invention is a method for cooling a hot forging mold for forging a hot slab in the width direction. In addition to providing a cooling water storage enclosure over a wide area, the height of the enclosure on the processed side of the mold is set higher than the height of the enclosure on the non-processed side by the required amount, so that only the non-processed side of the die is used during forging. Internal water cooling is As a result, the mold can be effectively cooled without connecting piping to the mold, and without spraying cooling water on the hot slab during forging or non-forging, and this improves the uniformity of the mechanical properties of the product. This means that the life of the mold can be extended without damaging it. Therefore, according to the present invention, the number of mold replacements is reduced, so that work efficiency can be improved, and other great effects are achieved.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the first embodiment of the method of the present invention, Fig. 2 is a sectional view showing the second embodiment, Fig. 3 is a perspective view showing another embodiment of the enclosure, and Fig. 4 is a forging. FIG. 5 is a perspective view showing a portion with non-uniform mechanical properties that occurs in a hot slab when cooling water is applied thereto, and FIG. 5 is an explanatory diagram of a conventional method. ■ is a mold, 6 is an enclosure, 7 is a cooling water supply pipe, 8 is a processed surface, 9 is an unprocessed surface, and 10 is a partition plate. Figure 1

Claims (1)

[Claims] (1) In a method for cooling a hot forging die for forging a hot slab in the width direction, a cooling water storage enclosure is provided on the upper surface of the die over as wide a range as possible, and the die is processed. The height of the enclosure on the face side is set higher than the height of the enclosure on the non-processing side, and during forging, cooling water is supplied to only the non-processing side of the die so that it overflows, and during non-forging, the enclosure height is increased by the required amount. A mold cooling method characterized by controlling the amount of cooling water supplied to the enclosure so that the cooling water overflows on both the surface side and the non-processed surface side.