DE1758781B2 - Process for the production of unquenched cast steel blocks in rectangular molds - Google Patents

Description

On ·, desiccating material for the process The molding used after the connection consists of a fine-grained heat-resistant material or refractory Materia !, an organic or inorganic binder and / or an organic fibrous material including a porous material and / or a heat-resistant material fibrous material.

As fine-grained, heat-resistant material, for example, quartz, SiO., Or materials with a content of more than 90 "" SiO. "Brick powder with a high aluminum oxide content, burnt Magnesium oxide, periododite, aluminum oxide, corundum, solid slate. Perlite and lapilli used.

Thermosetting synthetic resins and water glass are used as organic or inorganic binders used.

Organic fibrous materials or porous materials are, for example, ellulose, waste paper. Materials containing cellulosic fibers, pulp, hammered paper, powdered coke and cereal pulp used.

Al <= heat-resistant fibrous materials for example asbestos, rock wool, inorganic fibers, mineral wool and glass wool are used.

The above components for the heat insulating material can be, for example, in the following Quantity ranges are mixed with one another:

1. 75 to 90 percent by weight of one or more substances from the silicon oxide group. Crystals or materials with a content of more than 90 "" SiO ". less than 15 weight percent Paper pulp or paper waste, 5 to 18 percent by weight of thermosetting synthetic resins or Water glass and less than 3 percent by weight asbestos, mineral wool, rock wool or glass wool.

2. 85 to 95 percent by weight of one or more substances from the group of brick powder with high Aluminum oxide content, burnt magnesium oxide, periodotite. Aluminum oxide or corundum, and 5 to 15 percent by weight of a thermosetting resin or water glass.

3. 85 to 95 percent by weight of one or more substances from the group of expanded shale, perlite, or Lapilli. less than 15% by weight of one or more coke powder, sawdust, cereals or their powder, 5 to 18 percent by weight of thermosetting synthetic resin or water glass, and less than 3 percent by weight asbestos, mineral wool, rock wool or glass wool.

In the case of the mixtures given above, the fittings should preferably have the following properties:

Mixtures

Specific «weight
(in g cm-)

porosity

1 0.85 b ,, 0.96 45 to 60 2 1.2 to 1.3 35 to 40 3 0.8 until 0.9 40 to 60

The advantages of the method according to the invention are illustrated in the following example.

example

Two opposite side surfaces of a mold were completely made in a thickness of 20 mm lined with a heat-insulating material, on the long sides up to 100 mm below the upper edge of the mold. The heat insulating material used for this consisted of 50 percent by weight Brick powder with a high alumina content (with an average grain size of less than 0.5 mm) 42 percent by weight corundum (with an average grain size of less than 0.5 mm) and 8 percent by weight Binding agent! (Water glass). The specific weight was 1.45 and the porosity 35.8%. The block of choppy cast steel (with 0.13% carbon and 0.36% manganese) was poured into place made of steel from below. The following table lists the properties of a ingot produced by the method according to the invention and one produced in a conventional manner Compared to the cast ingot.

Distance (in mm) Thickness of the firm skin (in mm) According to the invention Tubular produced in the outer zone According to the invention from the top from the mold wall procedure shaped gas inlet procedure of the ingot measured 125 no Conventional Γ3 Conventional no 100 procedure 60 procedure no upper part 150 275 49 no no 200 210 31 no no 250 164 28 no no 500 127 30th no no 750 48 31 no very little 1000 37 47 very little little 1250 38 many little 1500 53 - many little 1750 69 many 1900 . many Lower part - many

For this purpose 2 sheets of drawings

Claims (1)

1 2 be influenced by so !! that the Blocki.or Claim: after the mold has been removed, it is kept warm, will. Procedure for the hersial unquenched pas- For the professional world it was so far taken for granted ner steel blocks in rectangular molds, that 5 to achieve a quenching effect; characterized in that two relatively cheap heat transfer '. erhalin ^ Sw between opposite side surfaces of the co- molten steel and the walls de Killen had to manufacture completely with a heat-insulating Ma-Form. It follows that be lined material. so a prejudice against using one ίο heat-insulating material was available. The proposed genen cover hood !! should only be the radiation serve to protect. The invention was therefore the task The basis is to create unquenched cast steel blocks with a uniform cast skin and the gas It is known that in the case of calm cast steel 15 inclusions in the outer zone are largely reduced both the mold head and the whole mold adorn. completely or partially with heat insulating Surprisingly it was now possible to determine who Materials to be lined. It is also the case that when using a thermal insulation known that unites the pouring of unsmoothed layer of a heat insulating material Steel during solidification within the mold 20 forms solid cast skin of uniform thickness, which a considerable volume of carbon monoxide gas has a low strength. This is achieved through this. forms is. Part of this gas is used during the solidification of the heat insulating Solidification in the molten state including lining of contacting molten steel forms so-called blowholes. The rest of the gas hesitates by preventing the steel from getting its If the molten steel in the atmosphere 25 suddenly heats up to the inner wall of the mold the end. Some of these voids are carried over inside the steel. It was also found that compensate for the shrinkage of the unquenched steel block that occurs in the unquenched cast steel block Cast steel locks, so that the shrinkage primary cavities reduced in an advantageous manner resulting cavities or blowholes can be avoided if the formation of the cast skin in can be. In this way, a high mold results from the fact that the heat yield is influenced when rolling ur.jeruhigt poured insulating lining the entire area of Steel blocks, at low cost, two opposing side surfaces of the expenditure. Form covered. The unrestrained according to known methods The invention therefore relates to a method for Cast steel blocks, however, have the disadvantage of producing unquenched cast steel blocks in on that the solid cast skin, in contrast to the rectangular mold, which is characterized impure steel in the middle of the block is a layer that has two opposite sides made of Unquenched cast steel represents and the surfaces of the molds are completely insulated with more uniform heat Thickness is. At the same time occur in the material to be lined. Outer zone with primary cavities and segregations. 40 In the following description, some important The thickness of the solid cast skin comprises those preferred embodiments of the method Area of the outer zone in which no voids of the invention on the basis of the drawings in detail available. A thickness of explained is considered to be optimal. 25 to 35 mm. The thickness in the upper part of a fig. 1 shows a side sectional view of a Bach's customary process was unsettled Steel blocks, however, is usually several places from unquenched cast steel blocks; hundred mm, while the thickness in the lower area F i g. FIG. 2 is a top plan view of the FIG. 1 ge of the block is about 10 mm. An unevenly pointed mold; The thickness of the solid cast skin has a negative effect. 3 is a graph showing the on the rolled steel, and in particular, 50 Curve A represents the thickness of the casting skin, which by means of If it is steel sheet. the method according to the invention is obtained, When producing unquenched cast steel while curve 5 represented the thickness of the cast skin So far, a prejudice against undressing represents, which is achieved by means of the known method 4 molds with heat-insulating material. In which will; German patent specification 577 693 is, for example, 55 F i g. 4 shows the tubular gas inclusions in a method and a mold for improving the block cross-section as in the known method described by unquenched cast steel that occur; is characterized in that the mold above F i g. 5 shows the tubular gas inclusions in as a radiation protection a conclusion with a bad block cross-section as in the method according to the thermally conductive inner surface. The present with a 60 invention. heat-insulating material lined heat- When carrying out the method according to the hoods in the upper area of the steel block, the invention is as shown in FIGS. 1 and 2 shown, Temperatures during the solidification on a molded piece 2 made of heat-insulating material! at Maintain an elevated level in order in this way to remove the two mutually opposite side surfaces 3 to avoid shrinking whispers. Arranged in the 65 of a mold 1. The fittings out German patent specification 608 556 is a method the heat-insulating material can also be described older, in which the elimination of deoxinative is arranged on the side surfaces 4 of the mold 1 dation slag from the liquid block core.