SU1357455A1 - Wear-resistant cast iron for casts - Google Patents

Abstract

The invention relates to metallurgy, in particular to the search for wear-resistant cast irons for castings operating under conditions of abrasive wear, for example, cast balls, grinding media and rollers. The purpose of the invention is to increase the hardenability and stability of hardness in castings. Proposed cast iron contains, wt%: carbon 2.5-3.5; silicon 0.8-2.4; manganese 0.3-1.5; vanadium 0.05-0.5; titanium 0.05-1.23; phosphorus 0.06-0.75; sulfur 0.02-0.12; boron 0.0.1-0.12; zirconium 0.05-0.23; aluminum 0.04-0.09; copper 0.02-0.05; chromium and / or molybdenum carbonitrides 0.06-0.18; iron - the rest. The hardenability of the proposed cast iron during air quenching is 121-131% compared with the MF-25. 2 tab. S. (L SA JV 4 JV

Description

The invention relates to metallurgy, in particular, to the search for wear-resistant cast irons for castings operating under conditions of abrasive wear, for example, cast balls, metal, rollers and rollers.

The purpose of the invention is the formation of hardenability and stability of hardness in castings.

The proposed wear-resistant cast iron contains components in the following ratio, wt.%:

Carbon2.5-3.5

Silicon0.8-2.4

Manganese 0.3-1.5

Vanadium0.05-0.5

Titan .. 0.05-1.23

. Phosphorus 0.06-0.75

Sulfur0.02-0.12

Bor0,01-0,12

Zirconium 0.05-0.23

Aluminum0.04-0.09

Copper0.02-0.05

Carbonitrides of chromium and / or molybdenum Q, 06-0.18 IronEstal

Cast iron may contain as an impurity up to 0.2 wt.% Nickel.

Additional introduction of zirconium in an amount of 0.05–0.23 wt.% Crushes the cast iron structure in castings, increases hardenability during air quenching, crack resistance and structure stability in castings and after their heat treatment, which provides an increase in the stability of hardness, wear resistance and operational properties. When the concentration of zirconium is up to 0.05 wt.%, The stability of the structure and hardness in the cast balls is insufficient, and when the concentration of zirconium is more than 0.23 wt.%, The crack resistance and impact resistance decrease,

Aluminum in the amount of 0.04–0.09 wt.% Has a deoxidizing and stabilizing effect, contributing to a decrease in the content of non-metallic inclusions and an increase in the stability of hardness and wear resistance. When the concentration of aluminum to 0.04 wt.%. the deoxidizing and stabilizing effect is insufficient, and with an increase in the aluminum concentration of more than 0.09 wt.%, the hardness of the castings and of the calcivability decreases.

Copper with a content of 0.02–0.05 wt.% Increases the hardness and wear resistance, their stability in

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the process of operation. With an increase in the copper concentration of more than 0.05 wt.%, The graphitizing effect begins to appear, a. at a concentration of up to

0.02 wt.% Reduced hardness and wear resistance of castings.

Chromium and / or molybdenum carbonitrides micro-alloy the metal base, strengthen the matrix, increase its hardness, hardenability and their stability. The lower limit of their concentration is taken from the content (0.06 wt.%), At which there is a noticeable increase in the hardenability of castings of balls with a diameter of 90-120 mm, and the upper one is limited by a concentration (0.18 wt.%), Above which the stability of hardness decreases and crack resistance.

The carbon, manganese, and silicon contents are derived from experience in the production of wear-resistant castings of balls with increased hardness and wear resistance.

Microalloying additives (vanadium 0.05-0.5 wt.%, Boron 0.01-0.12 wt.% And titanium 0.05-1.23 wt.%) Increase the hardness and hardenability of wear-resistant castings. Their lower limits are due to the low stability of the hardenability of wear-resistant castings at lower concentrations, while at higher concentrations, the characteristics of impact resistance, crack resistance and 5 deflection are reduced.

Phosphorus (0.06–0.75 wt.%) And sulfur (0.01–0.12 wt.%) Have a bleaching effect, increasing the hardness of castings and the characteristics of wear resistance and hardness. With an increase in the phosphorus concentration of more than 0.75 wt.% And sulfur of more than 0.12 wt.%, The characteristics of toxicity and impact resistance decrease, the heterogeneity of the structure and hardness of cast iron in the castings increases.

P and mery Conducted smelting iron-known and the proposed formulations using limiting and foundry iron, scrap iron, ferroalloys and ligatures, mp emogo iron ,, ferrophos ferrovanadium, ferrochrome azotiro- g bathrooms and ferromolybdenum is introduced into the melting furnace, and ferrotitanium, complex ligatures SDR-30 SCR-50 and modifying additives are placed in a ladle before pouring the melt from

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Temperature is not less than 1400 C.

ovens. From micron-alloyed iron cast technological samples, samples and castings of grinding bodies and balls. Filling temperature of casting molds is 1340-1370 С,

Table 1 shows the chemical compositions of wear-resistant cast irons in a number of heats. The content of ingrains in the cast iron is determined by standard methods of quantitative differential chemical analysis.

Table 2 shows the mechanical and technological properties of wear-resistant cast irons of experienced bottoms. The stability of hardness in the castings of balls with a diameter of 90 and 120 mm is carried out after their normalization from a temperature of 860 - 880 C. When testing for crack resistance and hardenability, gray cast iron is used as a reference.

СЧ25, Wear resistance and hardness of cast irons are determined according to GOST. As an abrasive material when tested for wear, electrocross is used with grit No. 16-P with a relative moisture content of 0.12-0.14%,

As can be seen from the table. 2, the proposed wear-resistant cast iron has higher calcined values.

bridge and wear resistance and more stable hardness than the known.

Claims (1)

Invention Formula Wear-resistant cast iron for castings containing carbon, silicon, manganese, vanadium, titanium, phosphorus, sulfur, boron, and iron, which is characterized by the fact that, in order to increase the flexibility and stability of hardness in castings, it additionally contains zirconium, aluminum, copper, chromium and / or molybdenum carbonitrides in the following ratio, wt.%: 25 Compiled by N. Shepitko. Editor N. Rogulich Tehred M. Khodanych Proofreader A. Obruchar 5972/25 Circulation 605 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Table 2, .1