RU2141885C1 - Method for making wear resistant percussion action members - Google Patents

Abstract

FIELD: breaking, disintegrating hard materials in ferrous and non-ferrous metallurgy, possibly manufacture of wear resistant percussion-action members such as hammers (beaters) of hammer breakers. SUBSTANCE: method comprises steps of placing base of carbon steel product into casting mold; pouring high manganese steel at rate 7 -14 kg/min for forming wear resistant layer of product with thickness 10-40 mm; providing steel temperature at beginning and at termination periods of steel casting equal respectively to (1440-1460) C and (1420-1440) C; heat insulating casting molds and soaking product in it for 5-8 hours; cooling product in air until temperature of environment. Steel of wear resistant layer includes carbon (0.9-1.1)%, manganese (11-15)%, silicium (0.9-1.1)%. Steel may include in addition vanadium - (0.3-0.6)%, chrome and nickel - no more than 0.1%. EFFECT: enhanced structure and strength of products. 2 cl, 1 tbl

Description

 The invention relates to crushing, grinding of solid materials in the ferrous and non-ferrous metallurgy and can be used for the manufacture of wear-resistant impact products, for example, hammers (beat) hammer crushers.

There is a method of increasing the wear resistance of hammers, described in the article of the journal "Metallurgy and heat treatment of metals" N 4, 1974 C. 68-71 - an analogue consisting in the fact that the hammer is made by casting from Hadfield steel, the hammer is cast into a mold, the parts obtained are cut off, heated to t = 1100 ^o C and held at this temperature for 30 minutes. However, the method has disadvantages: the need for a technological operation for heat treatment of products and the high cost of the product.

 A known method of increasing wear-resistant products (application N 96-104058, which is published in the Bulletin of inventions N 12, 1998, volume 1 - prototype). The "base" of the hammer is installed in the mold, after which Hadfield steel is poured, then the mold is coated with heat-insulating material and can withstand no more than 10 hours at ambient temperature.

 The disadvantage of this method is that it does not indicate the technological modes and it has not been worked out.

 An object of the invention is to reduce energy costs, increase wear resistance and reduce costs.

The technical result is achieved by the fact that in the method of manufacturing shock products, comprising installing a carbon steel product into a mold “base”, forming a wear-resistant layer by pouring high-manganese steel into a mold, coating the mold with a heat insulating material, holding the product in the mold under a heat insulating material and then cooling it in air to ambient temperature, in which the mold and the "base" of the carbon steel product is heated to 500 - 800 ^o C, and to form a wear-resistant layer use steel containing 0.9-1.1% carbon, 11.0-15.0% manganese, 0.9-1.1% silicon, which is poured at a speed of 7.0-14.0 kg / min until a layer is formed a thickness of 10-40 mm, while the temperature of the steel is maintained between 1440-1460 ^o C and 1420-1440 ^o C at the beginning and end of casting, respectively, and the exposure of the product in the form under heat-insulating material is carried out for 5-8 hours.

 Various versions of models and foundry molds were designed and manufactured in order to determine the most optimal parameters (sizes and shapes) of the "base", which ensure the formation of a high-quality clad layer on the working surface of the hammers.

 At the same time, various patterns of arrangement of the “foundations” in the forms were varied: horizontal and two vertical — with the hammer earring up and down. The latter option turned out to be the most acceptable and rational.

 Steel of wear-resistant material was smelted in an induction furnace (IST-16) with a magnesite crucible. Tractor tracks made of steel 110G13L served as the charge for smelting wear-resistant material. Its chemical composition is given in table No. 1.

The mixture was melted under the main slag. After the initial filling was completely melted, the melting slag was removed, the FeSi and FeMn metal were deoxidized and carburized by a shallow electrode fight. The metal mirror was protected by crosstalk of the new main slag. When the melt reached T = 1600 ^° C, FeV metal was alloyed, slag was removed and the metal was poured into a ladle. The final deoxidation in the ladle was carried out with aluminum and silicocalcium.

 Smelting was carried out in accordance with the technological task. The chemical composition of the charge components are given in table No. 1.

Smelting order:
Load the trucks (115 kg). After complete melting, measure the temperature (1500 ^o C). When the set temperature is reached, remove the slag. If the temperature has reached 1500 ^o C, then introduce ferrosilicon (0.6 kg) and electrode battle (0.150 kg) into the melt. Introduce manganese (2.4 kg).

 Insert ferrovanadium (1.68 kg) into the melt.

The release of metal at a temperature of 1600 ^o C.

 Casting.

The temperature of the casting 1420-1460 ^o C.

 In order to remove gases, either pieces of silicocalcium (0.25 kg) or a silico-calcium tape (0.15 kg) should be added to the bottom of the bucket.

 The calculation is made for 120 kg.

Before casting, the chill molds (or molds) must be warmed to a temperature of 600 ^o C.

 As a result, the prototypes, which were subsequently successfully tested under the conditions made together with standard hammers, had a microstructure similar to the Hadfield steel reference structure, which underwent the usual additional heat treatment. The tested samples did not undergo additional heat treatment separately, and it was actually combined with the casting process. Thus, in the developed process, an additional production operation with expensive energy costs was virtually eliminated.

 Metallographic analysis showed that the structure of the samples is cast, having a dendritic structure. The microstructure consists of martensite, residual austenite and carbides, the distribution of carbides in the structure is uniform.

 The resistance of experienced hammers is 3 times higher than standard hammers.

Claims (2)

1. A method of manufacturing a wear-resistant impact products, including installation of a carbon steel product base into a mold, forming a wear-resistant layer by pouring high-manganese steel into a mold, coating the mold with a heat insulating material, holding the product in a mold under a heat insulating material, characterized in that the mold and the body of the product carbon steel is heated to 500 - 800 ^o C, to form a wear-resistant layer using steel containing 0.9 - 1.1% carbon, 11.0 - 15.0% manganese, 0.9 - 1.1% silicon, which flooded at a speed of 7.0 - 14.0 kg / min until a layer with a thickness of 10 - 40 mm is formed, while the temperature of the steel is maintained between 1440 - 1460 ^o C at the beginning and 1420 - 1440 ^o C at the end of pouring; heat-insulating material is produced within 5-8 hours, after which the product is cooled in air to ambient temperature.  2. The method according to claim 1, characterized in that for the formation of a wear-resistant layer, steel is used, containing an additional 0.3-0.6% vanadium, not more than 1.0% chromium and not more than 1.0% nickel.

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