DE1758998B2 - Method of making a metal gu body - Google Patents

Description

Casting of simple low carbon steel, low alloy steel or femtic or martensitic stainless steel is used.
35 The different types of activated charcoal required for a

The present invention relates to a method of use in the method according to the invention for producing a metal casting by being suitable, and the metals for which the casting of molten metal in a while driving is particularly suitable are in the patent of the cooling of the casting and during the Entry 15 58 268 described in detail. With regard to the casting of the metal surrounded by activated carbon, their porosity is the preferred activated carbon standard shell mold according to patent 15 58 268. th those with a specific surface area of wine of the French patent 13 05 025 is at least 500 m ² / g and in particular from 1000 to the Teaching taught that the liquid metal containing 1600 m ² / g.

To surround the casting mold with a mass, which can furthermore be advantageous according to the invention

carbonaceous material. As carbon-containing 45, if you work so that the activated carbon is a material of the well-known cast shot and graphite particle size has such that the entire main flaky and flaky form is used as well as material through a sieve with a mesh size of unspecified materials that one which essentially passes through 0.55 mm, but has a substantial carbon content and a relatively high thermal conductivity through a sieve with a mesh size of 0.105 mm. The 50 is essentially withheld.
Use of activated charcoal as a protective substance is here. It is assumed that the favorable condi-

but not provided, but the measure in conditions that in the present invention Special cases, the mold is obtained together with the process, the rinsing or heat carbonaceous material. the removal of air from the permeable material

The use of activated carbon now creates a 55 rial of the shell shape and out of the cavity of the Improvement over the use of other casting models through the gaseous combustion coals in such a process. The products of carbon are to be attributed. the The extent of this improvement is greater, the more the carbon is burned during the more the moldings are introduced to surface flaws oxida-burning and lasts during the Gietiven Origin, for example, from the formation of scars on the inside and the cooling of the casting and decarburization, suffer. The procedure is new.

of particular value in the manufacture of castings. It is envisaged that the in the process of

of metals, the ceramic damage used against such surfaces present invention are very sensitive, such as casting mold normally after conventional simplifications Steels with a low carbon content, 65 can be manufactured, this process being alloyed Steels and many stainless steels from the ren when the shell mold is fired one ferritic and martensitic type. Output stage of typically a temperature in

In the process described in the main patent, the range from 950 to 1100 ° C. is included. At the previous

3 4

lying method can be a bowl shape, optionally. The particle size distribution of the

rend it is still hot from burning, activated charcoal was turned in so that through a sieve with

Coal are embedded in such a way as a shell shape with a clear mesh size
with surrounding activated carbon to form, which then on

the desired temperature is heated. It is often- 5 ^from °> ^{54 to} °> ³⁷ n ™ ⁴³ ° / ° of ^the particles,

maize is most suitable that this temperature is from 0.37 to 0.25 mm 45% of the particles,

is essentially the same as the one in which the "" .. _{nii ino,.} , _T .,. _e "" _ri j

Shell shape is fired, because then for the two ^from ° ^{'25 to} °> ¹⁸¹ ^ ^{10 / o the Teuchen} ™ ^d

Firing method of the same furnace used 0.18 to 0.15 mm 2% of the particles

can. In addition, according to the present io

Procedure possible to go through the normal duration of the firing.

shortening the time of the shell shape, because the process The refractory container was then

the hardening during the reheating in lenform and the surrounding activated carbon in

Presence of carbon continues. baked in an oven at 1050 ° C for 15 minutes.

It is generally undesirable to allow the cooling to take place 15 a few seconds after removing the fire

the shell shape with the surrounding activated carbon, solid container from the furnace was melted

if the metal has already been cast, more than necessary steel of the composition given below

agile to delay so that the surrounding active for the production of castings in the mold

Amount of coal preferably poured on the to achieve. Left before removal from the mold

of the subject matter of the invention required minimum * o to cool to room temperature. The steel used

worth it. This minimum value depends on the following composition:

a number of factors including by weight percent

for example the size and shape of the mold and carbon maximum 0.45

the metal to be cast, but is used in every _.... , _{n £ n}

special case easily without unnecessary attempts ^- 5 Smcium maximum 0.60

it's correct. There are different options available- Manganese maximum 1.00

bar to ensure the insulating effect of the shell shape and nickel a maximum of 0 40
to counteract the caking of the coal,

such as the use of an inert chromium maximum 0.25

Extender, which in a mixture with the carbon 30 molybdenum a maximum of 0.15

has a higher thermal conductivity, or “,. , _n , _n

Whirling the baked carbon, given ^Rupter maximal u, ju

if after an initial static period, un-sulfur 0.05 maximum

using a cold, inert gas, phosphorus max. 0.05

for example from cold carbon dioxide. In addition, 35

out can work at lower metal and ^remainder iron

Cup mold temperatures than commonly used possible in certain cases when pouring the total content of nickel, chromium, molybdenum be. and copper exceeds a value of 0.80 weight

The invention is not by the following at 4 ° percent.

games explained. The cast bodies obtained had a

_H. ,, Pen formation-free, bright surface and a uniform

^{D lbpiei} moderate distribution of carbon.

A ceramic cup mold was made by applying successive layers of a 45 in substantially the same manner as the pre-slurry of sillimanite with such a base, except that it was of a particle size that it could be passed through a sieve with a Hch - First burning, still hot state in activated carbon th mesh size of 0.075 mm, not embedded through it at room temperature. The molten hen, in hydrolyzed ethyl silicate solution and a steel, was a few seconds later in the mold sanded with sillimanite particles poured through a sieve 5o, and the mold and cast body with a mesh size of 0.37 were allowed to cool to room temperature without Pass the carbon 0.175 mm through it, remove it on a wax model. Again, the castings were made with each slurry layer free from flaking, but the test was allowed to freeze upon application of the next. It was found that in places a slight surface finish a total of six layers of slurry had taken place.
brought and the coated wax model to “. · 1 ο
the solidification of the last coating in a warispi
dried with airflow. The wax model was This example describes the production of a casting by treating it in a steam autoclave, whereby it should be examined whether it was removed from the mold, after which the shell casting quality through the mass or the thickness of the transverse mold was placed in an oven for 1 hour 1050 ° C cut is influenced if after the invention was fired. is worked according to the procedure.

The shell mold was then removed from the oven. The model consisted of a 50.8 mm

Taken and transferred to a refractory container, dice and a 25.4 3.1 mm strip that attached

where they are up to about 1 cm from the edge of the filler 65 the opposite sides of a 6.45 cm ² -In-

was surrounded with activated charcoal. The active cast were arranged. To this model was

Coal was a type of coal that was built up by pyrolysis of a ceramic shell shape, this after

Coconut shells was manufactured and commercially available. Removal of the model for 1 hour at 1050 ° C

and then fired again at 1050 ^° C. for 15 minutes while it was embedded in activated carbon in the manner described in Example 1.

The shell mold with the activated carbon surrounding it was removed from the oven and shortly thereafter molten steel of the same composition as in Example 1 was poured into the mold. the The shell mold and the activated carbon surrounding it were allowed to cool to room temperature before the strip and egg Cast was removed from the mold. All io the surfaces

Claims (4)

1 2 a shell mold is produced, in conventional claims: Licher way, burned and after removing the mold from the furnace in the activated carbon. 1. Method of making a metal casting- dips. The metal is usually made without a delay body by pouring in molten tion then poured into the mold, and you Metal in a during the cooling of the casting leaves casting body and mold, while it is of carbon body and during the pouring of the metal are surrounded by substance, cool down to a temperature, Ceramic bowls surrounded by activated carbon - which is below the minimum value at which a casting mold according to patent 1558268, characterized by exposure to air that has a negative effect, that io would ben before pouring. of the melt, the shell shape with which it is surrounded benden activated carbon burned and the melt led to the present invention, found that one is poured into the still hot mold. improved results, especially in terms of 2. The method according to claim 1, characterized in avoiding decarburization, characterized by a mode that the activated carbon can receive a specificization of this process. see a surface of at least 500 m ² per. One proceeds here in such a way that, in the case of a VerGramm, one has to go through to manufacture a metal cast body 3. The method according to claim 2, characterized in that the activated carbon has a specific gram of the cooling of the cast body and during the see surface of 1000 to 1600 m ² per ao of the pouring of the metal with activated carbon gram . ceramic shell mold according to patent 15 58 268 4. The method according to any one of claims 1 so that before pouring the melt, the to 3, characterized in that the active shell shape with the surrounding activated carbon has a particle size such that it burns and the melt in the still hot form all of the material is poured through a sieve with a magnet. width of 0.55 mm passes through it, but it has been found that the inventive through a sieve with a mesh size of procedure in addition to the above pre-0.105 mm is essentially retained. part of avoiding decarburization continues also allows an improved flow of the metal in thin cross-sections. The present invention is preferred for the