UA134683U - EXPENDITURE ELECTRODES FOR OBTAINING AN EMPTY INSTALLATION OF A FOLDED ALLOY ALLOY - Google Patents

Abstract

The expense electrode for obtaining a hollow ingot of an alloyed alloy by the method of electroslag remelting contains carbide inserts in the form of layers of grain-powder wire wound in a helical line on cylindrical metal shells, alternating with cylindrical layers of ring-shaped metal rings. Powder wire grains are modified with a nanodispersed titanium carbonitride powder with a nanoparticle size of 10… 100 nm and an optimum composition of 0.1… 0.2 from the volume of the modified material, with the nanodispersed powder bonded to the powdered wire grains with a liquid glass solution.

Description

The useful model belongs to the field of special electrometallurgy and can be used to obtain ingots of complex alloys by the method of electroslag remelting.

It is known that ensuring the high quality of large steel products of power and metallurgical engineering is traditionally associated with the homogeneity of the structure and chemical composition of the original forgings made from large ingots. But the known consumable electrodes, which are used to obtain ingots of complex alloy alloys, cannot guarantee obtaining a uniform fine-grained macro- and microstructure of the deposited multilayer ingot along its height. Therefore, the metal of large cast ingots cannot fully meet the ever-increasing requirements for the homogeneity of the structural material and, above all, for the homogeneity of the microstructure and isotropy of its physical and mechanical properties.

The closest analogue to the claimed useful model is a consumable electrode for obtaining a complex alloy ingot by means of electroslag remelting, containing carbide inserts, which is made in the form of a central cylindrical rod, and the carbide inserts are layers of grain-powder wire wound along a helical line on the mentioned central cylindrical rod, which alternates with cylindrical layers of ring metal rings and is connected to each other by pressing (Patent of Ukraine Mo 121525,

C220 1/02, 2017).

The presence of hard alloy inserts in the grain-powder wire of the known consumable electrode increases the strength and fatigue resistance of the resulting complex alloy ingot, but does not allow maintaining a sufficiently high plasticity, viscosity and crack resistance of the alloy matrix. During rolling, rolling, forging, impact and abrasive wear, hard alloy inserts break out of the alloy matrix, as a result of which its accelerated wear occurs, which leads to the destruction of products obtained from a complex alloy ingot. In addition, the known consumable electrode is limited in its use, it cannot be used to obtain a hollow ingot. To do this, it is necessary to drill a hole in a solid ingot. But for an ingot containing carbide grains, this is a very complex technological operation.

The useful model is based on the task of improving the design of the consumable electrode by making it hollow and modifying hard alloy grains

Powdered wire is a nanodisperse material to obtain a homogeneous fine-grained ingot microstructure, which has high plasticity, viscosity, and crack resistance, as a result of which the quality of the complex alloy and its physical and mechanical characteristics increase.

The task is solved by the fact that in the consumable electrode for obtaining a hollow ingot of a complex alloy by the method of electroslag remelting, containing hard alloy inserts in the form of layers of grain-powder wire wound in a helical line on cylindrical metal rings, which alternate with cylindrical layers of ring metal rings and bonded together by pressing, according to a useful model, powder wire grains are modified with nanodispersed titanium carbonitride powder with a nanoparticle size of 10...100 nm and an optimal composition of 0.1...0.2 by volume of the modified material, while the mentioned nanodisperse powder is bonded to powder wire grains with a solution of liquid glass.

Under the action of the modifier, a large number of crystallization centers are formed on the surfaces of hard alloy grains. During melting, hard alloy grains are detached from the electrode, pass through a slag and metal bath, and during movement from the crystals formed from crystallization centers, a plastic shell is formed on the surface of hard alloy grains, which in in a liquid bath grows with the crystals of the ingot matrix. The proposed consumable electrode makes it possible to obtain a hollow ingot with uniformly distributed modified hard alloy grains and a plastic fine-grained matrix, which reliably holds the grains during the technological process of processing and during operation of products obtained from a hollow ingot of a complex alloy.

When the size of nanodispersed particles of titanium carbonitride is less than 10 nm, their intensive oxidation and the formation of large agglomerates (aggregation) begin to occur, as a result of which the activity of grains as crystallization centers decreases, which negatively affects the formation of a finely dispersed structure. An increase in the size of nanodispersed particles above 100 nm leads to a deterioration of the physical and mechanical properties of the alloy.

Addition of a modifier in an amount less than 0.1 95 of the volume of the modified material reduces the stability of the physical and mechanical characteristics of the alloy. The content of the modifier more than 0.2 95 of the volume of the modified material complicates the technology of melting the ingot. Only the composition of 0.1-0.2 945 from the mass of the ingot improves the effect of titanium carbonitride and contributes to sufficient 60 modification of the hard alloy grains of the flux cored wire.

In addition, the structural and mechanical characteristics of the material in the hollow ingot are higher than in the solid ingot obtained by the closest analogue. This is due to the nature of the cooling of the hollow ingot, which is carried out from two sides (outside and inside), which leads to an improvement in the structure of the ingot matrix and its mechanical characteristics.

The use of a liquid glass solution for bonding nanodisperse material with hard alloy grains of powdered wire contributes to the increase of crystallization centers, which leads to the formation of a fine-grained structure of the ingot and has a positive effect on its physical, mechanical and technological properties.

The gradual formation of the consumable electrode by alternating cylindrical layers of grain-powdered wire with hard alloy grains modified with nanodispersed titanium carbonitride powder and cylindrical layers of metal ingots ensures a uniform distribution of hard alloy inserts throughout the volume in the fine-grained material of the hollow ingot, and this allows the consumable electrode to withstand a constant melting regime and ensures, during remelting, the production of a high-quality hollow ingot, in which hard alloy layers are evenly distributed throughout the volume in the fine-grained plastic matrix of the hollow ingot.

In Fig. 1 shows the proposed consumable electrode, in Fig. 2 - a section along AA of the construction of the consumable electrode presented in Fig. 1. The consumable electrode contains a central cylindrical shell 1, on which a grain-powder wire 2 consisting of hard alloy grains 3, on the surface of which a modifier in a shell 4 is applied, is wound along a helical line.

Two half-shells 5, secured with an arc tack b, cover a layer of wound grain-powder wire 2. The resulting structure is compacted by pressing 7. Adding successive layers of grain-powder wire and shells to the resulting structure allows obtaining the required diameter of the consumable electrode.

Example.

For the experimental verification of the proposed utility model, a central cylindrical rod made of 12 x 18N10T steel with a diameter of 30 mm and a length of 1000 mm was made. A grain-powder wire with a diameter of 3.5 mm with grains of tungsten carbide with a diameter of 1.6-2.5 mm was wound on it. A modifier was applied to the surface of hard alloy grains - nanodisperse powder of titanium carbonitride TI(SM), corresponding to TU U 24.6-2424050-001-2002, in the amount of 0.15 95

Zo from the volume of the modified material mixed on the liquid glass. Self-fluxing wear-resistant SNGN-55 powder was used as a powder. A metal rod was pressed onto a layer of wound grain-powder wire. A layer of grain-powder wire was again wound on the resulting custom. The process of building up alternating layers was continued until the outer diameter of the consumable electrode was 250 mm. The resulting consumable electrode was remelted by the method of electroslag technology on the A-550 furnace in a copper water-cooled crystallizer according to the following mode parameters: voltage 0-36 V, current 1I-600-700 A, feed speed of the consumable electrode m-0.05 m/min. The analysis of the research results showed that in the obtained ingot, hard alloy grains are evenly distributed over the volume in the form of concentric circles. The microstructure of the modified ingot is uniform, fine-grained; grain size is 0.1-1 mm. When casting without modification, the average grain size was 3-10 mm.

The use of the modifier ensured a stable homogeneous microstructure and isotropicity of its physical and mechanical properties.

Thus, the proposed consumable electrode ensures the formation of a hollow ingot of a complex alloy with increased mechanical and operational properties.

Claims (1)

USEFUL MODEL FORMULA Consumable electrode for obtaining a hollow ingot of a complex alloy by the method of electroslag remelting, containing hard alloy inserts in the form of layers of grain-powder wire wound in a helical line on cylindrical metal cores, which alternate with cylindrical layers of ring metal cores and are connected to each other by pressing, which is characterized by the fact that the powder wire grains are modified with nanodispersed titanium carbonitride powder with a nanoparticle size of 10...100 nm and an optimal composition of 0.1...0.2 by volume of the modified material, while the mentioned nanodispersed powder is bonded with powder wire grains with liquid glass solution.