SK120997A3 - Refractory moulding for revolving hearth furnaces - Google Patents

Abstract

In revolving hearth furnaces for annealing cylindrical or tubular materials (5), these materials are set into semicircular radial recesses that prevent them from rolling sideways. In time, wear causes these recesses to work themselves into the refractory material, so that the materials to be annealed sink down and the surface available for heating is reduced. As wearing down progresses, quality problems may result. In addition, the availability of known furnaces is reduced, since they must be repaired from time to time. To solve these problems, a moulding (3) is disclosed in which the semicircular recess (6) is shaped at the top of a bulge (7) whose cross-section tapers towards its top.

Description

FIRE - RESISTANT SHAPE FOR THE QUARRY FURNACE

Technical field ¹

The invention relates to a refractory shaped part for lining the bottom of a carousel furnace with cylindrical or tubular annealed articles which lies in a partially circularly shaped support of the shaped part in the longitudinal direction of the annealed material.

BACKGROUND OF THE INVENTION

For annealing, resp. heating of steel preforms, event. billets or other semi-finished products, in addition to Carousel ovens are also used in the pusher furnace, in which the preforms are deposited by a charging device, for example a charging manipulator, at the bottom of the carousel furnace and then removed after being passed through the furnace in the hot state for further processing.

In the annealing of the cylindrical or tubular annealed articles, a partially circularly shaped bearing is radially running in the fire-resistant floor plate of the carousel furnace in order to prevent the annealed articles from moving sideways on the floor plate.

At least for the re-laying of the floorboard, according to the state of the art, ready-to-use refractory molded parts are used, which have a comparatively high durability compared to the floorboards to be struck.

Due to the thermal differences between the annealed cold-deposited products and the hot refractory lining in the region of the partially circular-shaped bearing, there is a progressive wear of the floor lining and / or the lining. so that the touch zone under the annealed products on the surface is cracked and the annealed products sink over time into the floor lining due to the deepening of the deposition. .

With such continued wear, the floor lining is not only weakened; it also destroys, but there is also a loss of quality on the annealed products, as the increasingly smaller volume of the annealed products exceeds the furnace bottom and is available for direct heating through the atmosphere in the furnace or the furnace. thermal radiation. Thus, uneven heating passes through the cross-section of the annealed products. when producing tubes from solid cylinders, radial deviations of the mandrel may occur on the punching press or the punching machine.

The described mechanism can reduce the efficiency of the furnace and the heating rate of the annealed products, so that annealing times may have to be extended if necessary. A new lining of the floorboard and the associated longer shutdown of the carousel furnace is necessary when the preforms drop into the floorboard so that the insertion manipulator can no longer grasp and remove them.

When annealing a cylindrical blank with a diameter of about 200 mm, e.g. a maximum wear of 50 mm is allowed, which is achieved after about two years with known adjustment methods.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to provide a refractory welded part for unloading the floor of carousel ovens for cylindrical and tubular annealed products, which can increase the furnace readiness and improve the annealed product quality.

This object is achieved by placing the projection extending on the upper side facing the annealed articles in the longitudinal direction of the annealed articles, which extends above the bottom of the carousel furnace and has a tapering front cross-section upward.

With the protrusion according to the invention, with the upper partially circularly shaped bearing, the wear path of the refractory material under the annealed articles is substantially increased, without impermissibly exposing the circumferential side surfaces of the annealed x products by dropping to the floor lining. In this way, the readiness of the furnace, e.g. the service life of the fireproof lining is almost doubled, while at the same time ensuring a more even heating of the annealed products and thus a corresponding improvement in quality or simplification of further processing. Thus, e.g. when processing preforms on a punch press or punch machine, the risk of side running of the punch mandrel is substantially reduced.

The lateral sides of the projection have an angle between about 3Ô and 60 ° to the horizontal. With such an arrangement of the lateral sides, the exerted thermal stress and shear force can be dissipated optimally into the interior of the molded part without causing more cracking.

As already mentioned, the individual moldings are inserted into the floor lining so that the camber goes in the longitudinal direction of the annealed articles, radially to the rotary axis of the bottom of the carousel furnace.

Alternatively, block-shaped stones without a protrusion can be positioned between adjacent shaped parts in the radial direction. a correspondingly formed fire-resistant ramming material with the same surface. Though they can be caused by increased pressure loads, eventually. Increased wear of the individual moldings according to the invention, but on the other hand, by providing the furnace atmosphere or radiated heat with free access to all peripheral surfaces of the annealed products in the areas where they lie, the continuous furnace performance can be increased.

The radius of the partial annular fit may be smaller than the radius of the annealed articles to further shape the shaped workpiece. This will result in a linear two-point load at the lateral edges of the bearing, causing some premature wear in this area, which however leads to an increase in the surfaces of the annealed articles to be heated. Such an effect also occurs when the annealed cold annealed products are increased in diameter after being heated, thereby increasing the load on the side edges of the bearing.

The basic arch width at the bottom of the furnace will not be more than the diameter of the annealed products. This avoids the formation of side bridges which reveal the annealed products on the sides.

Depending on the diameter of the annealed products, the size of the furnace and the resulting weight of the molded parts, two or more protrusions can be provided. storage, so that the re-setting of the floor lining is simplified.

The moldings according to the invention consist of highly wear-resistant refractory materials and can be manufactured industrially, for example, by ramming, casting, vibration or pressing.

The invention is illustrated in the drawing by way of example and details are set forth in the drawing. They are:

Summary of the Invention

Fig. 1 Original shaped part for unloading of carousel furnaces for cylindrical annealed products,

Fig. 2 shows the wear pattern of the shaped part according to FIG. 1

Fig. 3 Molded part according to figure a

Fig. 4 shows the wear pattern of FIG. Third

DETAILED DESCRIPTION OF THE INVENTION

The molded part according to FIG. 1 according to the prior art consists essentially of a block stone 1 with two partially circularly shaped bearings which extend longitudinally with the annealed products.

When annealing the cylindrical billets, the wear pattern according to FIG. 2, wherein the partially circular-shaped bearing 2 and the annealed articles thereof sink down into the fire-resistant lining. The wear curves are shown to decrease the annealed products by 10 mm each.

The molded part 3 according to FIG. 3 also consists of an approximately cuboid base body 4 with a partially circular shaped bearing 6 lying in the longitudinal direction of the annealed articles 5.

The recesses 6 have protrusions 7 on the upper side, the sides 8 of which enclose an angle of about 45 ° with the horizontal.

The wear shown in FIG. 4 makes it possible to recognize that, in contrast to the prior art, the wear depth can be greatly increased without unacceptably exposing the peripheral surfaces of the annealed articles 5. Thus, at a wear of 50 mm, the original molding 1 corresponds to the exposed angular range as set to molded part 3 according to the invention, after wear. 90 mm.

Claims (6)

Fire-resistant molding for lining the bottom of a carousel furnace for cylindrical or tubular annealed articles with one partially circular shaped annealed support extending in the longitudinal direction of the annealed articles, characterized in that the support (6) extends on the upper side facing the annealed the article (5) in the longitudinal direction of the annealed articles (5) has a protrusion (7) that rises above the bottom of the carousel furnace and has a tapering cross-section upwards. Molded part according to claim 1, characterized in that the flanks (8) of the projection (7) enclose an angle between 20 and 80 °, in particular between 30 and 60 °, with the horizontal. Molding according to claim 1 or 2, characterized in that the projection (7) extends radially to the rotary axis of the bottom of the carousel furnace. Molding according to one of Claims 1 to 3, characterized in that the radius of the partially circular-shaped bearing (6) is smaller than the radius of the annealed articles (5). Molded part according to one of Claims 1 to 4, characterized in that it has a plurality of protrusions (7) or bearings (6). Molded part according to one of Claims 1 to 5, characterized in that it consists of beaten, cast or pressed refractory material. '