SU1700087A1 - Cast iron - Google Patents

Abstract

This invention relates to metallurgy, in particular to wear-resistant cast irons. The purpose of the invention is to increase the mechanical and operational properties. The proposed cast iron contains, wt%: carbon 2.2-3.2; silicon 1.2-1.6; manganese 1.5-2.7; chromium 2.1-3.5; titanium 0.1-0.3; vanadium 0.6-1.2; aluminum 0.01-0.03; niobium 0.08-0.7; molybdenum 0.13-0.6; boron 0.02-0.14 and iron else, 2 tab.

Description

(L

WITH

The invention relates to metallurgy, in particular, to the search for wear-resistant chuguns working under conditions of cavitation-erosion wear.

Known wear-resistant cast iron containing wt.%:

Carbon

Silicon

Manganese

Chromium

Nickel

Iron

2.4-3.5 1.4-2.2 0.5-1.5 1.0-1.7 0.2-0.7 Else

This cast iron has unstable mechanical properties.

Known cast iron of the following chemical composition, wt.%:

Carbon3.3-3.8

Silicon0.7-1.2

Manganese 0.1-0.3

Chromium

Nickel

Molybdenum

Magnesium

Copper

Cerium

Iron

0.1-0.3

3.5-4.0

0.3-0.5

0.04-0.06

2.5-3.0

0.02-0.04

Rest

Known cast iron has an unstable hardness (340-444 HB) and low cavitational-erosion resistance.

Closest to the offer is cast iron containing, in wt.%:

Carbon

Silicon

Manganese

Chromium

Titanium

Vanadium

Aluminum

2.6-3.5

1.2-1.8

0.3-0.8

0.2-0.5

0.1-0.4

0.1-0.25

0.1-0.2

IronErest

As a technological impurity, the well-known cast iron can contain up to 15 wt.% Of phosphorus and DoO, 15 May,% of sulfur.

The structure of known iron in 25 mm diameter castings is pearlite-valuable, and the mechanical and operational properties are as follows:

Strength at

bending, MPa 700-780

Hardness НВ400-550

Uda roostoych and howl

cycles 600-800

Cavitation erosion resistance

mg / m2 gs140-165

The coefficient of wear resistance Ka1-1,05

The disadvantages of the known cast iron are low mechanical properties.

The purpose of the invention is to increase the mechanical and operational properties.

The goal is achieved by the fact that carbon, silicon, manganese, chromium, titanium, vanadium, aluminum and iron containing carbon additionally contains niobium, molybdenum and boron in the following ratio, wt.%:

Carbon2.2-3.2

Silicon1,2-1,6

Manganese 1.5-2.7

Chrome 2.1-3.5

Titan0,1-0.3

Vanadium 0.6-1.2

Aluminum 0,01-0,03

Niobium 0.08-0.7

Molybdenum 0,13-0,6

Bor 0.02-0.14

IronErest

The analysis of the proposed cast iron shows that at the moment there are no known technical solutions for which these differences would have been reflected. In addition, these symptoms are necessary and sufficient to achieve a positive effect. This allows us to conclude that these differences are significant. The additional introduction of niobium, molybdenum into the cast iron and its modification with boron provides a significant increase in mechanical properties.

The additional introduction of niobium is due to its high doping capacity and the increase in microhardness, mechanical and operational properties while maintaining impact resistance. Its effect begins to manifest itself with a concentration of 0.08 wt.%, And with an increase in its content of more than 0.7 May. % homogeneity of structure and stability of mechanical properties are reduced.

Molybdenum strengthens the matrix, increasing wear resistance, hardness and performance properties. The concentration of molybdenum is up to 0.13 wt.%. The hardness, strength, wear resistance and heat resistance of cast iron are insufficient, and as the concentration of molybdenum increases to more than 0.6 wt.%, The impact resistance and plastic properties decrease,

Boron in the amount of 0.02-0.14.% Introduced as an effective modifying additive that enhances uniformity.

5 structure, eliminating the structure of the formation of interdendritic graphite, contributing to an increase in strength characteristics and the limit of endurance during bending.

0 When the boron concentration is up to 0.02 wt.%, The modifying effect appears weakly, and when the boron concentration increases to more than 0.14 wt.%, The metal waste increases, the metal boundary between the metal matrix is reduced and the mechanical and operational properties of the iron in the castings decrease. .

The presence of titanium in the cast iron in an amount of 0.1-0.3 wt,% micro-alloying matrix

0 with titanium carbides and refractory inclusions, changing its nature, improves the distribution of graphite in non-metallic inclusions, increases the wear resistance, density and tightness of cast iron, its compatibility with corrosive media. When the concentration of titanium is up to 0.1 wt.%, The increase in wear resistance and corrosion resistance are insignificant, and with an increase in its content by more than 0.3 wt.%

0, plastic properties, flexural strength and impact resistance are reduced.

Chromium (2, 5 wt.%) And vanadium (0,6–1,2 wt.%) Are the main alloying components that provide enhanced caitazisno-zrozionnye properties. As their concentration increases above the upper limits, the strength problem decreases. at bending, and at concentrations

0 less than the lower limits - hardness and operational properties are insufficient,

Aluminum serves as a deoxidizing and modifying additive, and the manganese concentration is increased to 1.5-2.7 wt.%, Which

5 increases the austenite content and reduces the concentration of the pearlite component, increasing cavitation-corrosion resistance. An increase in the manganese content of more than 2.7 wt.% Causes an increase in the concentration of cementite, strengthens the structure and reduces the tensile strength in bending and impact resistance.

For example, iron smelting is carried out in an electric arc furnace. The alloying of cast iron with chrome X98, ferrous molybdenum FMO1, ferrovanadium FVd2, ferromanganese FMN75 and ferroniobium FN658 is produced in an electric furnace at 1760–1780 K, and modification by ferrotitanium FTiZOB, ferroblem PB2 and ferroaluminium and wrought iron; produced in dry liquid glass molds to obtain 30 mm samples, process step samples and wear-resistant castings.

In tab. 1 shows the chemical compositions of the cast irons of the experimental heats, and Table 2 shows their mechanical and operational properties.

Cavitation-erosion resistance is determined on hydroabrasive plants with an average speed of hydro-abrasive flows of 75 m / s.

As can be seen from the gab. 2, the mechanical and operational properties of the proposed iron are significantly higher than the known.

Claims (1)

Formula of Invention Cast iron containing carbon, silicon, manganese, chromium, titanium, vanadium, aluminum and iron, characterized in that, in order to improve the mechanical and operational properties, it additionally contains molybdenum niobium and boron in the following ratio of components, "ac.%: Carbon 2.2-3.2 Cre km1,2-1,6 gLarganets 1.5-2.7 Chrome 2.1-3.5 T hten0,1-0,3 Vkkadmyy0,5-1,2 Aluminum 0,01-0,03 Molybdenum 0,13-0,6 Niobium 0.08-0.7 Bor 0.02-0.14 Iron Else. Table 1