JP2735675B2 - Cooling method in cast iron machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a cooling method in a cast iron machine for manufacturing a pig iron by successively pouring molten iron into a large number of endlessly moving molds, and cooling and punching. It is about.

[Prior art] Conventionally, molten iron is sequentially injected into a large number of molds that move endlessly, and the molten iron is cooled and removed from the mold. (5-20m distance conversion) After air cooling, solidified shells are stably formed on the surface layer by soft water spraying from the mold upper surface and medium cooling water spraying, then completely solidified by strong water spraying and cooled to the mold release temperature. It is common.

 This gradual cooling is primarily for safety: preventing steam explosions.

Ensuring quality of pig iron: Prevent deterioration of the surface layer of pig iron and non-uniform internal structure.

This is for reasons such as.

For this reason, cooling in a conventional cast iron machine requires a relatively long air cooling (cooling) time after injecting hot metal into a mold. Therefore, (a) a reduction in mold life: the mold is similar to a pig iron. , The longer the contact time with the hot metal, the easier it is to wear and the shorter the service life.

(B) Decrease in production capacity: Since the speed of the cast iron machine must be reduced in order to sufficiently perform direct cooling by water spray having a large cooling effect, a decrease in production capacity is inevitable.

There are problems such as.

In particular, in the case of casting pig iron, it is required to have a good surface layer in addition to the components and to have a structure in which the developed graphite is evenly distributed. There is a problem that it is difficult to say that productivity is sufficient, and that the securing of the surface layer texture required by the pig iron is not necessarily sufficient in terms of efficiency. (Reference technology JP-A-61-159245).

[Problems to be Solved by the Invention] The present invention advantageously solves the problems of the conventional cast iron machine, particularly its cooling, and extends the useful life of the mold while ensuring safety. Another object of the present invention is to provide a cooling method in a cast iron machine which ensures the quality of the surface properties of the pig iron, the distribution of graphite development, etc., and greatly improves the productivity.

[Means for Solving the Problems] According to the present invention, after pouring hot metal into a mold that moves endlessly, at the initial stage of air cooling, water spray cooling is started from the back side of the mold at the initial stage of air cooling. This is a cooling method for a cast iron machine, wherein water spray cooling is started from an upper surface side of a mold.

In the present invention, after injecting hot metal into a mold of a casting machine, before water spray cooling from the upper part of the mold, i.e., water spraying is started from the back side of the mold to the lower surface of the mold while the upper surface side of the mold is air-cooled, thereby preventing the mold temperature from rising. Promotes cooling from the lower surface of the hot metal through

As a result, the life of the mold can be extended by lowering the mold temperature; the center temperature of the mold can be reduced, and the life of the mold can be extended by about 20%.

The surface texture and internal structure of the pig iron can be improved; by strengthening the cooling from the lower surface of the hot metal, the solidification of the hot metal proceeds smoothly from the lower part, and a uniform structure with well-developed graphite is obtained.

In addition, since cooling can be promoted by cooling from the lower surface of the hot metal, the air cooling time on the upper surface side of the mold can be extended to further improve the surface texture. (If the air cooling time is shortened and the hot metal surface layer is solidified early by sprinkling cooling from the upper surface side, the surface layer cracks due to the generation of a chill layer and the partial ejection of graphite that is bent out inside, which significantly deteriorates the appearance).

Since cooling can be performed from the back side of the mold, the cooling effect is large, so that the mold moving speed can be increased and the production capacity can be improved.

And the like.

[Embodiment] One embodiment of the present invention will be described below together with an example of a cast iron facility for carrying out the present invention shown in FIGS.

In Figure 1, 1 is tiltable in torpedo car for conveying and accommodating the molten iron M _i from the blast furnace, while pre-treated to Izuku machine 3.

2 is Izuku gutter is intended for injection into the mold 4 to move in the arrow B direction by the hot metal M _i to be arranged in an endless Izuku machine 3 drives M _o from torpedo car 1.

Reference numeral 5 denotes a soft water sprinkler disposed above the upper surface of the mold 4 which moves endlessly, 6 denotes a medium cooling water sprinkler disposed behind the same, and 7 denotes a strong cold water sprinkler further disposed behind the same. in these water spray devices supply pipe, the flow (pressure) adjusting the valve, via a pump or the like, is connected to a supply source or the circulation pit W _p of the cooling water W. Since it is necessary to make cooling water into fine water droplets in soft watering, it is preferable to use clean water in order to prevent nozzle clogging. 8 is mold 4
In sprinkler system disposed on the back side down, into a mold 4 slightly rearward of the molten iron M _i injection position, the upper surface of the mold 4 begins sprinkling cooling from the initial stages of air A, the mold 4
The rear surface of the mold 4 can be spray-cooled immediately before the middle cooling water spray device 6 on the upper surface side.

Reference numeral 9 denotes a water collecting hopper which collects water from the water spray cooling device 8 on the rear surface side of the mold 4 and the water spray from the middle cold water spray device 5 on the upper surface of the mold while preventing the water from splashing. which it is introduced into the circulation pit W _p via the sedimentation tank by gathered pump P the formed inclined groove 10 of the pit 11 through circulating used as cooling water. 12 is a water collecting hopper to collect sprinkling (water) from Tsuyohiya sprinkler system 7, the cooling water W collected here is recycled as cooling water is introduced into the circulation pit W _p via the sedimentation tank by a pump P You.

13 head sprinkler system, P _i is stamped from the mold 4, driven by the drive unit M _1, pig iron falling on the pivotable swivel conveyor 14 by the drive unit M _2, 15 is Katazuku P _i and the turning Apron sprinkler to cool conveyor 14, or
16 is a pallet, 17 is a pallet sprinkler, and 18 is a pig iron carrier.

In the present invention, after injecting a molten iron M _i in the mold 4, in the mold upper surface, conventional naturally cooled by air cooling the range A of the same first hot metal injection position, then soft water spray, a cool water spray, Tsuyohiya watering Cool in the order of
Of are also characterized by performing water spray cooling from the back side, in this embodiment, water spray cooling from the back surface side of the mold 4, during injection of the molten iron M _i to the mold 4 hot metal M _i
In addition, the position where there is no concern of direct contact with the splash, that is, the upper surface side of the mold 4 is started from the initial stage of the air cooling, and is finished just before the start of the medium cooling water spray cooling from the upper surface of the mold 4.

This is because the upper surface side of the mold 4 is naturally cooled by air cooling, and the surface layer is satisfactorily generated by cooling by soft water spraying, and at the same time, water is sprayed on the back surface of the mold and indirectly cooled through the mold to solidify from the hot metal lower surface. This is because the formation of the shell is effectively performed, and the development of graphite and its uniform distribution structure are obtained in a synergistic manner.
If the internal structure is generated stably, it is hardly affected by the subsequent cooling. ).

The amount of water sprayed from the back side of the mold 4 for this purpose depends on the cooling conditions on the top side of the mold 4, the material of the mold 4,
Mold shape dimensions, pig iron size dimensions Mold moving speed,
Differs depending hot metal component hot metal temperature, etc., should be set in consideration of these conditions, there is also inclined to increase or decrease the are that, usually, at 0.3~1.0m ³ / min approximately, the watering As a region, the distance from hot metal injection to die release is 20 to 40
% Is sufficient.

The present invention was implemented in the example of the cast iron equipment shown in FIGS.

Table 1 shows the implementation conditions in this embodiment together with the conventional example.

The results of manufacturing about 150,000 tons of casting pig iron under the conditions of the present invention shown in Table 1 are shown in Table 2 in comparison with the conventional example (the results of the conventional example are set to 100 to show the improvement effect of the present invention. ).

In the present invention, since the back surface of the mold is spray-cooled, the cooling effect is large, the mold moving speed can be increased, and the yield of non-defective products can be improved as described above, so that the production capacity of non-defective products can be improved by about 20%. Was completed.

In the present invention, on the upper surface of the mold, air cooling, soft water spraying, slowly cooling to form a good surface layer without holes, and water spray cooling the mold back surface to stably solidify from the lower surface of the hot metal through the mold back surface. Since the shell could be formed, it was possible to obtain a pig iron having an internal structure in which the developed graphite was uniformly distributed without lowering the mold moving speed, and it was possible to improve non-defective product yield of the pig iron by about 20%.

In the present invention, since the mold back surface is cooled, the average speed of the mold can be reduced by about 100 ° C., and the life of the mold can be improved by about 10%.

It should be noted that the present invention is not limited to the above-described embodiment, but changes the conditions of implementation as necessary.For example, the target pig type can be applied not only to casting pig iron but also to steelmaking pig. It is. The cooling on the mold upper surface side is preferably air-cooled, followed by soft watering → medium cooling watering → strong cooling watering, but it is not indispensable to clearly separate the molds. The cooling conditions on the top side of the mold and the conditions for water spray cooling from the back side of the mold are controlled by the output of the pump, the operation of the flow rate (pressure) adjustment valve, etc. Depending on the conditions, it is also considered to enable automatic control so that high-quality pig iron can be obtained with high productivity, safely and at low cost, in addition to the control of these conditions.

[Effect of the Invention] In the present invention, the cooling from the upper surface side of the mold is sprinkled from the back surface of the mold, thereby extending the life of the mold to reduce the molding cost and improving the surface texture and the internal structure to improve the product quality. This has the effect of improving the retention and, at the same time, improving the productivity of the pig iron.

[Brief description of the drawings]

FIG. 1 is a partial schematic cross-sectional view showing an example of a cast iron facility for carrying out the present invention, and FIG. 2 is a schematic cross-sectional view taken along the line II 'of FIG. M _i ... hot metal, W _p ... circulation pit W ... cooling water, 1 ... torpedo car 2 ... cast iron gutter, 3 cast iron machine 4 ... mold, 5 ... soft sprinkler 6 ... medium cold sprinkler, 7 ... strong cold sprinkler 8 ... mold backside sprinkler device 9 ... water collecting hopper, 10 ... inclined grooves 11 ... pit, 12 ... water collecting hopper 13 ... head sprinkler system, 14 ... turning conveyor 15 ... apron sprinkler P ... pump, M _0, M ₁ , M ₂ … drive

Claims (1)

(57) [Claims] 1. After pouring hot metal into a mold that moves endlessly, at the initial stage of air cooling, water spray cooling is started from the back side of the mold, and then water spray cooling is started from the upper face side of the mold. Cooling method in a cast iron machine, characterized by starting.