JPS58104113A - Intermediate charging type walking beam type heating furnace - Google Patents

Abstract

PURPOSE:To charge steel ingots smoothly through an intermediate charging port for charging of hot steel ingots into a walking beam type ingot heating furnace provided with said inlet by maintaining the conveying level of an ingot conveyor provided in the outside part of the intermediate charging port lower than the surface of the stationary hearth in the heating furnace. CONSTITUTION:In a walking beam type ingot heating furnace provided with a stationary hearth 4 and movable hearths 8, 9, cold steel ingots M1 are charged through a charging inlet 2 at the tail of the furnace and hot ingots M2 are charged through an intermediate charging port 5 of the heating furnace. After the ingots are heated to rolling temp. in the furnace, the ingots are discharged through a discharge port 12. In charging the ingots M2 through the port 5, the level of rolls 6 for conveying the ingots is made lower than the level of the ingot supporting surface of the hearth 4 in the heating furnace. In the stage when the ingots M2are charged through the port 5, the ingots M2 are charged smoothly onto the hearth 4 in the heating furnace without colision of the preceding end thereof against the side surface of the hearth 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intermediate charging type walking type heating furnace, and is intended to smoothly charge materials to be heated through an intermediate charging port.

The continuous heating furnace is used to process bloomed steel billets (slabs, blooms, etc.).
Billet 1. g) Or in order to hot-roll steel billets, etc. extracted from a continuous casting machine, the steel billets, which have been turned into cold steel billets, are charged from the bottom side of the heating furnace and placed under pressure in the longitudinal direction of the furnace. Through the transfer cycle of the movable hearth, the material is alternately transferred to the movable hearth and the fixed hearth, and is sequentially transferred to the extraction side, and while being transferred into the furnace, the steel pieces are reheated to the target temperature by a burner, and then transferred from the extraction port. This is to be carried out to a rolling mill for the subsequent process.

In the intermediate charging type walking type heating furnace, the temperature of the hot steel billets charged in the middle is the same as that between the furnace bottom charging port and the extraction port in normal heating furnace operation. An intermediate charging port is provided at a position approximately equal to , thereby rationalizing the heating of the hot steel slabs, and enabling operations to alternately or only perform one or the other of charging the furnace bottom and intermediate charging of the steel slabs.

1 and 2 show the above-mentioned strain heating furnace developed by the present inventors, the former being a longitudinal sectional view and the latter a plan view with the ceiling of the furnace cut away. In these figures, 1 indicates the heating furnace body, 1a#li' the ceiling of the furnace, 2 the furnace bottom charging port, 5 the intermediate charging port, and 12 the extraction port. 4 indicates a fixed hearth;
8.9 is a movable hearth divided into two in the longitudinal direction of the furnace. The movable hearth reciprocates in parallel and up and down directions with respect to the fixed hearth, and if we focus on one point on the hearth surface, it forms a rectangular loop, but the intermediate charging port 5 is located at the tip of the movable hearth 8 on the butt side. It is installed halfway up the furnace wall, facing directly to the reciprocating locus of the reciprocating motion. Further, on the outside of the furnace wall of the intermediate charging port 5, there is a roller table 6, and a charging calf that can freely move forward and backward on the roller table.
Four-ra tables 15 and 16 are provided to the furnace tail charging inlet 2 and the extraction port 12. Reference numeral 3 denotes a billet charging device installed at the bottom of the furnace, which includes a plurality of protruding rods that penetrate the furnace wall and protrude into the furnace. Reference numeral 11 denotes a discharger, which is installed on the furnace wall on the opposite side of the furnace head from the extraction port 12, facing the furnace opening 12m.

The cold steel billet is sent through the roller table 15 in the direction of the arrow from the furnace tail charging inlet 2 to the tail end of the fixed hearth in the furnace M! It is charged as shown in . The cold steel billets are: In this example, billet and billet, which are charged when there are two billets. After charging the cold steel billet to the tail end of the fixed hearth, the charging guides 1 and 1-5 are activated, and the cold steel billet Ml' is deflected by the projecting rod of the VCIi1M and placed onto the tail end of the movable hearth 8. move it. When this state is reached, the movable hearth 8 can be lowered, moved laterally to the left in the drawing, raised (at this time, moved laterally to the right (at this time, the steel pieces also move to the right), and lowered (the pieces are moved to the fixed hearth). 4), the cold steel slabs are conveyed to the furnace head side.When the steel slabs are charged from the furnace bottom charging port, the split movable hearths 8 and 9 are integrated. The steel billet is then reciprocated and transported from the furnace bottom to the furnace head, during which it is heated by the burner.The heated steel billet conveyed to the furnace head is pushed out by the charger 11. From the extraction port 12 to the table roller 6
is carried out to the next process.

The hot steel billet is charged into the furnace through the intermediate charging port 5. The pigeons are loaded into the furnace with the heated billet on a roller table 6 and pushed by a charging calf, sliding over a fixed hearth. At this time, the movable hearth 8.9 stops at a position slightly lower than the fixed hearth surface, for example, by about 10 to 50 degrees, and closer to the head of the hearth in its reciprocating locus. It went down a little. Kt
6゜Yu*A##M1g,: Will+□8,9□To avoid collision'.

However, there are some problems with this intermediate charging, one of which is that the tip of the charged billet gets stuck in the hearth, making it difficult to charge. This will be explained with reference to FIGS. 3 and 4. As mentioned above, this walking hearth type heating furnace has fixed hearths and movable hearths arranged alternately, and hot billets M! When charging the movable hearth into the furnace, lower the movable hearth so that it is slightly lower than the fixed hearth. Also, between the movable hearth,
The movable hearth can move in a rectangular loop! Therefore, the heated material charging path 20 extending from the charging port 5 into the furnace has unevenness and gaps, and the intermediately charged steel billet has a fine surface. The tail end is pushed by the charging calf as it enters the entrance. Billet charging is also done at the bottom of the furnace, but in this case the roller table 15
The conveyance level of the steel pieces is slightly (10 to 50 points) higher than the surface of the hearth. This 1. In this case, while the center of gravity of the steel billet is on the table roller side, the billet moves 10 to 50 cm above the bottom of the hearth which protrudes from the tip of the table roller, and the sliding resistance is zero. When the center of gravity of the steel billet moves away from the tip of the tape rule roller and toward the furnace side, the billet falls forward using the tip of the table roller as a fulcrum, and the tip of the billet comes into contact with the hearth. However, since the hearth is flat, the pressed steel pieces can easily enter the furnace. However, this is not the case at the intermediate charging port.

That is, as shown in FIG. 3, if the billet island is intermediately charged in a situation where the billet conveyance level of the table roller 6 is slightly higher than the fixed hearth surface, the level of the conveyance path in the furnace will be slightly higher than the fixed hearth surface. As in the case, the billet can be charged with no resistance while the center of gravity of the billet is on the roller table 6, but when the center of gravity of the billet moves from the tip of the roller table to the furnace, the billet is loaded as shown in Fig. 4. It is tilted forward and hits the edge of the fixed hearth with a protruding tip. If the tip of the steel billet is on the fixed hearth when it is tipped forward, it will come into contact with the fixed hearth surface, similar to the case on the butt side, but as it moves forward, the tip will slide on the fixed hearth surface, After passing through the gap G, it passes over the movable hearth and collides with the edge of the next fixed hearth as shown in the figure.

If this condition occurs, further charging will be impossible.
Forcibly pushing in will damage the edges of the fixed hearth.

The present invention aims to improve these points, and is characterized by having fixed and movable hearths, and also having a charging port for the material to be heated in the middle of the furnace, so that the material to be heated can be heated from the intermediate charging port. When charging the heating material into the furnace, the movable hearth is lowered from the fixed hearth and the material to be heated is supported by the fixed hearth. The material transport level is set to be lower than the level of the heated material supporting surface of the fixed hearth. FIG. 5 shows an example thereof.

In Fig. 5, the same parts as in Figs. 1 to 4 are given the same reference numerals, so 4 is a fixed hearth, 8 is a movable hearth, 5Fi intermediate charging port, 6 is a roller table, and pigeons are This is a hot billet that is charged in the middle. In the present invention, the heated material conveyance level of the heated steel piece tb heated material island conveying roller table 6 is set to the boiling point shown in the figure.
The surface of the fixed hearth 4 of the conveyance path 20 should be the same as the surface of the fixed hearth 4. Or: 1: 1 - Fix the table conveyance level: Set it lower than the fixed hearth surface. When the levels are the same, the slab island slides on the surface of the fixed hearth 40 immediately after entering the furnace, the movable hearth 8 passes over it, and then slides on the next fixed hearth surface, and so on. The center of gravity of the billet does not move forward even if it leaves the tip of the roller table because it is at the same level.
Maintain the same horizontal position as at the beginning. Therefore, the tip of the steel piece will not collide with the side edge of the protruding fixed hearth. When the conveyance level of the roller table is set lower than the level of the entrance passage into the furnace, when the steel pigeon is charged from the intermediate charging port, its tip first moves to the fixed hearth on the furnace wall side, which forms part of the intermediate charging port 5. Raise (
For this purpose, the lower surface of the intermediate charging port 5 is sloped as shown by the dotted line 21), and the billet is charged into the furnace with the tip lifted up, and the center of gravity of the billet is located on the intermediate charging port 5 side. hearth 4
When it leaves the steel piece, it falls forward, but it is supported by the 4 groups of fixed hearths 4 with nine protruding steel pieces, and the tip of one piece does not collide with the side edge of the fixed hearth 4 from which it protrudes, as shown in FIG. P-Latte, 1 The difference between the transport level of Pull 6 and the level of entrance into the furnace interior is about +3 to -5 degrees. Note that +3■ is within the manufacturing difference range of -, and the design is 0 to -5 cabinets.

The intermediate charging billets are placed correctly in the furnace and inserted into the loading passage 20.
It is necessary to align the center line of the billet with the center line of the steel billet and load it at right angles to the direction of conveyance in the furnace.If the billet deviates from this state in terms of position or angle, conveyance will be hindered, and the spacing between billets may not be as expected. This causes problems such as difficulty in uniform heating. To prevent this, it is effective to widen the charging passage 20 and use its centering effect to regulate the charging position. The conveyance level of the roller table 6 is set to be below the billet support level of the charging path 20 with some consideration. Further, both the fixed and movable hearths are covered with bricks, but the fixed hearth portions forming the charging path 20 are made of wear-resistant material because the material to be heated slides thereon. In the present invention, the fixed hearth on the side of the intermediate charging port 5 also serves as a pivot point for the material to be heated, so it is preferably reinforced with heat-resistant metal or the like. In the heating furnace shown in Figures 1 and 2, the movable hearth is divided into 8.9 parts with the intermediate charging port as the border.
This enables efficient operation by operating only the movable hearth 9 on the extraction side in the case of intermediate charging, but for simple transport and heating purposes, these may be integrated into a walking type heating furnace. In addition to the walking hearth type shown in the figure, the present invention can also be applied to a walking beam type.

As explained above, according to the present invention, intermediate charging of the material to be heated can be reliably performed without causing problems such as difficulty in charging due to collision of the tip with the hearth, and is extremely effective.

[Brief explanation of the drawing]

Figures 1 and 1s2 are a schematic longitudinal view and plan view of a walking type heating furnace to which the present invention is applied, Figures 5 and 4.
The figure is an explanatory diagram of the problem that occurs during intermediate charging, and FIG. 5 is an explanatory diagram of the main part of the present invention. In the drawing, 1 is the main body of the heating furnace, 4 is a fixed hearth, 8.9 is a movable hearth, 5 is an intermediate charging port, 1 is a material to be heated, and 6 is a conveyance device. Applicant: Nippon Steel Corporation (and one other person) Patent attorney: Minoru Aoyagi - Figures 2 and 5

Claims (1)

[Claims] The furnace is equipped with a fixed and movable foot hearth, and also has a charging port for the material to be heated in the middle of the furnace.When charging the material to be heated into the furnace through the intermediate charging port, the movable hearth is replaced with the fixed hearth. In a walking heating furnace in which the material to be heated is supported by the fixed hearth,
An intermediate charging type walking heating furnace characterized in that a material conveying level of a conveying device provided outside the intermediate charging port is set to be lower than the level of the heated material supporting surface of the fixed hearth.