SU944746A1 - Method of hardening multilayer shell moulds - Google Patents

Description

(5) METHOD OF STRENGTHENING MULTILAYERED ENCLOSURE

one

The invention relates to foundry, in particular, to the hardening of multilayer shell molds, produced by melted models, for any casting nomenclature.

The closest to the invention is a method of hardening multilayer shell molds produced by melted models, including fluidizing the dusting material, JQ introducing into it for layering, dusting the model block, sealing the drainage material around the model block after the fluidization stops, removing the model block, , 5 ka from dusting material and the subsequent layer-by-layer solidification of the form 1. "

The known method does not protect the binder, increase the strength of the shell and reduce the time. solidification of the suspension due to the short residence time of the model FORM

block in an unliquerated dusting material for 120 -.

Claims (1)

The increased consumption of the suspension is due to the fact that with a slight exposure of the model block in the non-liquefied dusting material, i.e. under conditions of incomplete hardening of the suspension, there is not a sufficiently strong connection between the suspension and the embedded grains of dusting material. When the model block is removed from the dusting material, a part of the grains is pushed out of the slurry. it does not harden and has (albeit insignificant) the ability to push out solid filler grains embedded in it. Some of these grains are separated from the coating by their own weight. In this case, a part of the suspension may be carried away with the grains thus separated. All this increases the consumption of suspensions. The same reasons explain the lower strength of the coating. An increase in the hardening time of the suspension is associated with a decrease in the intensity of mass transfer of the solvent in the open air. The aim of the invention is to save the binder, to increase the strength of the forms and to reduce the time it takes to cure. This goal is achieved by the fact that according to the method of hardening multi-layered shell molds, including fluidizing the dusting material, introducing a model block for layered dusting, sealing the dusting material around the model block after fluidization stops, fluidization resuming, removing the model block from the dusting material The mold hardening, the full curing operation of each layer is carried out in a compacted dusting material. The intensity of hardening of the coating in the non-liquefied dusting material increases due to the force of the capillaries between the grains of the dusting material adjacent to the surface of the core of the solvent from the suspension, so that the layer of dusting material plays the role of a sponge. Example. A model block, made in a conventional, cast in a casting process, using an ethyl silicate binder, is immersed in the volume of the slurry, removed from it and introduced into a fluidized bed of dusting material. The boiling is then stopped; the dusting material is compacted around the block, which is kept in the non-liquefied material — DO is completely cured; then the fluidization of the dusting material is resumed and the model block is removed. Hardening of the suspension in the volume of the non-liquefied filler takes place throughout the hardening process. The buoyant forces of the fluidized material are compensated for by the forces exerted by the bulk pressure of the dusting material on the casing. In the cut, a much larger amount of grains of dusting material adheres to the suspension, since in 6 each they are excluded from the coating under the action of their own weight. This provides an increase in the strength of the shell, since the stress state of the bonds between the suspension and the filler grains is in equilibrium. Comparative data on hardened multilayer forms according to the proposed method and known, are given below. For the manufacture of compared multilayer shell molds produced by melted models. Quartz sand was used as a dusting material. Ambient temperature The total curing time of each layer according to the proposed procedure is min, and according to the known min. The thickness of each layer of the shell was taken 1.1-1.9 mm. The total thickness of the shell is 6.3-8.9 mm, whereas in a known manner the shell with a thickness of 5.5-6.5 mm was strengthened. At the same time, the strength of the proposed shell mold is (5-7NPA MPa and known (3-6) - 10 MPa. The implementation of the proposed method will reduce the defect on shell destruction by increasing strength and increasing labor productivity by reducing the suspension hardening time. Formula of the invention ; eni Method of hardening multilayer shell molds obtained by melted models, including fluidization of dusting material, the introduction of an outer model block, compaction of dusting material around the model block after do not stop fluidization, re-fluidize, remove the model block from the dusting material and layer-by-layer solidify the mold. 59t «7 6 6 characterized in that, the sources of information in order to increase the strength of the molds, taken into account in the examination reducing their curing time, 1. Casting on melted patterns, complete curing of each layer is monogrammed. Engineering monograph. Edited by They exist in compacted dusting of Ya.I. Shklennik and V.A. Oeerova M., material. Mechanical Engineering, 1971, p. 235.,