RU2605017C1 - Method of producing cast dispersion-hardening ferrite-carbide steel - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of a cast dispersion-hardening ferrite-carbide steel for manufacture of cast molds of hot deformation, molds for die casting under pressure and forging dies for solid-liquid forming. Steel 35L is melted. Obtained molten alloy is introduced with ferrotitanium and ferronickel with provision of chemical composition of the steel containing, wt%: carbon (C) 0.27-0.32, nickel (Ni) 0.7-0.9 and titanium (Ti) 5.8-6.2. Then the melt at the temperature of 1,500-1,520 °C is added with spent carbide ceramic-metal inserts of a cutting tool from alloys: type T5K6, T15K6, T5K10, T21K8, TT7K12, TT8K6, TT10K9, TT20K9 and T30K4 containing titanium carbides (TiC), tantalum carbides (TaC), tungsten carbides (WC). Melt is held at this temperature for 30 minutes to provide dissolution of included in the hard-alloy inserts cobalt binder and uniform distribution of carbides in the melt. Obtained melt is poured into a chill mold with further cooling to produce steel castings. Steel castings have the following chemical composition, wt%: carbon (C) 0.27-0.32, titanium (Ti) 5.8-6.2, nickel (Ni) 0.7-0.9, cobalt (Co) 0.02, titanium carbides (TiC), tantalum carbides (TaC) tungsten carbides (WC) 0.5-1.5 %, iron (Fe) - the rest.

EFFECT: provided is production of a steel with fine-grain structure and uniform distribution of carbides in a ferrite matrix without formation of casting cracks.

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Description

The invention relates to the field of metallurgy engineering, and in particular to the field of production and use of foundry materials, can be used in the manufacture of hot-formed die casting dies, injection molding dies, forging dies for solid-liquid stamping (Avtoforge dies), alloys based on copper and others

Known [1] heat-resistant die steels of the martensitic class for hot deformation of 3X2V8F, 4X4SVMF (DI-22), 5X3V3MFS (DI-23), 4X5MFS, etc.

The disadvantage of [1] martensitic steel stamp steels is their use in the manufacture of a press tool only in a forged state. The limited use [1] of martensitic class steels for the manufacture of a cast press tool is associated with the formation of casting cracks during the crystallization of castings under accelerated cooling. In addition, during the operation of hot deformation dies as a result of heating the engraving to a high temperature (900 ° C), polymorphic α↔γ transformations occur, which leads to structural phase hardening and a decrease in the resistance of a press tool made of martensitic steel.

Known [2] is the experience of manufacturing cast forging dies for the process of solid-liquid stamping of bronze and brass, Avtoforzh dies at the KAMAZ Foundry of steel 4Kh3V2F2M2SKh.

The disadvantage [2] is that Avtoforge dies (weighing up to 60 kg) are obtained by casting in expensive zircon molds, manufactured using sophisticated technology by hot curing using environmentally harmful phenol-formaldehyde resins as a binder. In this case, slow cooling during crystallization of the castings leads to the formation of a coarse cast structure, which leads to reduced performance in comparison with forged dies.

A promising way to obtain a highly resistant cast press tool with a fine-grained structure and the absence of structural phase hardening due to the exclusion of α↔γ transformation is the use of austenitic carbide or ferritocarbide steels.

Known [3] austenitic-carbide steel of complex chemical composition 20X20H18TZYUFMBR, wt. %: carbon - 0.17-0.23; chrome 14.1-18.2; nickel - 17.0-19.0; titanium - 2.0-3.0; boron - 0.002-0.02; vanadium - 0.9-1.5; molybdenum - 0.8-0.9; aluminum - 1.2-1.5; niobium - 0.1-0.15; cerium - 0.04-0.05; iron is the rest.

The disadvantage [3] are the large economic costs, the scarcity of alloying elements and technological production difficulties.

The closest to the essence of the claimed invention, the prototype is an economically alloyed suspension cast alloy precipitation hardening ferritocarbide die steel [4], the steel contains, weight. %: carbon 0.27-0.32, titanium 5.8-6.2, nickel 0.5-0.9, titanium carbide (TiC) 0.5-1.5, iron rest, and may also contain traces up to 0.05% manganese, 0.15-0.17% silicon and ≈ 0.03% sulfur and phosphorus. Titanium carbide is introduced in the form of a powder with a particle size of up to 10 μm into the ladle or into the melt stream during the pouring of steel into a cooled metal mold. Titanium is introduced into the proposed steel in an amount of 4 wt. % to create a ferrite matrix, which is formed in the Fe-Ti system at the specified amount of Ti [5]. About 1 wt. % goes to create TiC, and 0.8 - to form a phase type Ni ₃ Ti.

The disadvantage [4] is the need to use expensive powder TiC carbides.

The objective of the invention is to develop a method for producing cast dispersion hardening ferritocarbide steel by utilizing spent carbide metal-ceramic inserts of cutting tools from alloys of the type: T5K6, T15K6, T5K10, T21K8, TT7K12, TT8K6, TT10K9, TT20K9 TiKa TKa and TK20K4 T30 tantalum (TaS), tungsten (WC).

The objective is achieved by the fact that with this method, the inventive cast dispersion hardening ferritocarbide steel can be obtained, for example, in the following way.

After the melting of 35L steel, ferrotitanium and ferronickel are introduced into the melt to ensure the chemical composition of the steel containing, by weight. %: carbon (C) 0.27-0.32; nickel (Ni) 0.7-0.9 and titanium (Ti) 5.8-6.2. Then, spent carbide ceramic-metal inserts of a cutting tool from alloys of the type: T5K6, T15K6, T5K10, T21K8, TT7K12, TT8K6, TT10K9, TT20K9, and T30K4 containing titanium carbides (TiC), tantalum are introduced into the melt at a temperature of 1500-1520 ° C. ), tungsten (WC), followed by exposure at this temperature for 30 minutes, providing dissolution of the cobalt binder entering the carbide inserts and uniform distribution of carbides in the melt. Then carry out the casting of the obtained melt into a chill mold, followed by cooling to obtain steel castings, while the steel castings has the following chemical composition, wt. %:

carbon (C) 0.27-0.32;

titanium (Ti) 5.8-6.2;

nickel (Ni) 0.7-0.9;

cobalt (Co) 0.02;

carbides: titanium (TiC), tantalum (TaC), tungsten (WC) 0.5-1.5%;

iron (Fe) - the rest.

Due to the accelerated cooling of castings when pouring the obtained steel melt into a chill mold, a fine-grained structure is formed with a uniform distribution of carbides in the ferrite matrix without the formation of casting cracks.

The presence of Ni in the alloy allows the use of dispersion hardening regimes with the formation of fine particles of the Ni ₃ Ti type, which provide an additional increase in hardness and abrasion resistance of the press tool.

The present invention satisfies the criteria of novelty, since when determining the level of technology no means were found that are inherent in signs identical (matching in the function performed by them and in the form of performing these signs) to all the signs listed in the claims, including the purpose of the application.

The inventive method has an inventive step, because it has not been identified technical solutions having features that match the distinguishing features of this invention, and the popularity of the influence of distinctive features on the specified technical result is not established.

The claimed technical solution can be implemented for the production of hot-formed die casting dies, injection molds, forging dies for hard-fluid stamping (Avtoforge dies) of copper-based alloys, etc., while solving the environmental problem of disposing of carbide metal-ceramic cutting inserts tool. This meets the criterion of "industrial applicability" presented to the invention.

Used sources

1. L.A. Poznyak, Yu.M. Skrynchenko, S.I. Tishaev - Stamped steels. - M.: Metallurgy, 1980 - 240 p.

2. AC No. 1108126 of the USSR, MKI C22C 38/26. Stamped steel. Authors: M.S. Kolesnikov, E.N. Kornienko, L.A. Alabin et al. Posted on 04/15/84. Bull. No. 30.

3. AC No. 1724723 of the USSR, MKI C22C 38/26. Stamped steel. Authors: M.S. Kolesnikov, L.V. Troshina et al. Posted on 02/03/91. Bull. No. 26.

4. Patent "Suspension cast dispersion hardening steel" No. 2487958 C2 MP K C22C 38/14, C22C 33/04. Authors: I.O. Leushin, E.V. Panfilov, M.S. Kolesnikov, V.I. Astashchenko, R.A. Bikulov, S.V. Kalistov, N.V. Salamashkina. Application No. 2011109290/02 of 03/11/2011. Published on July 20, 2013. Bull. No. 20.

5. Hansen M., Anderko K. The structure of double alloys. - M.: Metallurgizdat, 1962 - 574 p.

Claims (2)

1. A method of producing a cast precipitation hardening ferritocarbide steel, comprising the melting of 35L steel, introducing ferrotitanium and ferronickel into the obtained melt, ensuring the chemical composition of the steel, containing, wt.%: Carbon (C) 0.27-0.32, nickel (Ni ) 0.7-0.9 and titanium (Ti) 5.8-6.2, then the spent carbide metal-ceramic inserts of a cutting tool from alloys containing titanium carbides (TiC) and tantalum are introduced into the melt at a temperature of 1500-1520 ° C ( TaS) and tungsten (WC), followed by exposure at a given temperature for 30 minutes, ensuring which dissolves the cobalt bond included in the carbide inserts and uniformly distributes the carbides in the melt, after which the melt is cast into a chill mold and then cooled to obtain steel castings, while the steel castings have the following chemical composition, wt.%:
carbon (C) 0.27-0.32;
titanium (Ti) 5.8-6.2;
nickel (Ni) 0.7-0.9;
cobalt (Co) 0.02;
carbides: titanium (TiC), tantalum (TaC), tungsten (WC) 0.5-1.5%;
iron (Fe) - the rest. 2. The method according to p. 1, characterized in that the spent carbide metal-ceramic inserts of a cutting tool from alloys of the type T5K6, T15K6, T5K10, T21K8, TT7K12, TT8K6, TT10K9, TT20K9 and T30K4 are introduced into the melt.