SU778926A1 - Method of surface alloying of castings - Google Patents

Description

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This invention relates to ferrous metallurgy, in particular, to foundry production.

There is a known method of hardening the surface of a metal, including the deposition of 5 alloying layers on the surface of a mold or rod and pouring the metal in a protective atmosphere or vacuum flj.

However, the surface layer when using this method is obtained 10 insufficient thickness, and the operating conditions of a number of castings, in particular refrigeration plates, require an increase in the doped layer to 8-10 mm.

The purpose of the invention is to increase the cpo-t5 of the service life of castings by increasing the thickness and quality of the surface alloyed layer.

The goal is achieved by the fact that collectors are installed in the molds from the working surface of the casting and within 5-60 s from the moment of the start of pouring in it, a vacuum of 5-10 is created - I-IO mm Hg

Under the action of the vacuum created in the obviation of the submerged metal, the poured metal impregnates the coating to a much greater depth, since the rate and depth of filtration of the melt significantly increases through the pores of the coating.

according to Darcy's law). As a result, the depth of the resulting doped surface layer increases to 8-10 mm, which leads to an increase in the service life of the castings.

Creating a vacuum in the collector for less than 5 s from the moment of the start of pouring does not provide high-quality impregnation (filtration) of the coating due to the short duration of the effect. An increase in the evacuation time of more than 60 s does not lead to an increase in the quality of the doped layer, since by this time the doping process is over.

When vacuum in the collector is less than mm Hg. a sufficient pressure differential is not created and, therefore, a high-quality coating impregnation is not provided. Increased dilution above mm Hg. leads to the destruction of the walls between the pores of the coating, erosion of local volumes of the coating, the creation of heterogeneities and, thus, deterioration of the quality of the doped layer.

On the surface of the mold, the dimensions of 500x4005450 mm, from which the collector is molded, are applied a coat of thickness of 9-10 m.

37789264

Claims (1)

Contains as a filler a fer-Formula of the invention of ROHEUM. When casting with gray iron (Tzdd) in the SOE collector. The method of surface doping is given by a vacuum of 1 lm Hg. castings, including application on the treatment of 30 s. Parallel to the working surface of the casting mold, casting of the extrusions without the use of a collar; coatings from alloying materials and rarefaction. 5 liters (of elements), the molten metal is poured. During the subsequent metallographic metal into the casting mold and according to the ROM study, it is established that the subsequent crystallization of the metal with The proposed method increases by the depth of dilution, about tl and bina of the doped layer up to 8-10 mmch with the fact that (at 2-3 mm without using it). Increasing the thickness and quality of the surface of the obtained doped layer of the just-doped layer, cutting, gas pores and shrinkage joints is maintained for 5-60 s. there are no wines in it. The doped layer of the projecr is from filling, and its magnitude is connected with the metal of the casting. is 5; 10 - I-IO mm Hg. Thus, the application of the method ,, It increases the thickness of the received-. , „„ „„ „„ „„ .- „„ ,. : -S S si z i „p„ „, .. p, method in the manufacture of refrigeration blast furnace slabs allow to increase- „1. French patent 1469183, their service life is 1.7-2.0 times. cl. At 22 C, 1967.