SU1700086A1 - Cast iron - Google Patents

Abstract

Disposal relates to metallurgy and can be used in the manufacture of machine tools. The goal is to increase wear resistance, tensile strength and hardness. New cast iron contains, in May.%: C 3.4-3.8; S 15-2.0; MP 13.5-2.2; N1 0.06-0.35; A 0.08-0.26; Ca 0.003-0.02; Ce 0,015-0,05; Mo 0.03-0.07; chromium carbonitride 0.06-0.41; Over 0,003-0,01; Zr 0.05-0.3; Fe - the rest. Additional input into the composition of the proposed iron Zr allows to increase HB by 1.01-1.05 times, OB by 1.16-1.22 times and reduce wear by 1.41-1.62 times. 2 tab.

Description

The invention relates to metallurgy, in particular to the development of cast iron compositions for castings used in machine tools.

The purpose of the invention is to increase wear resistance, tensile strength and hardness.

The choice of the boundary limits of the content of components in the pig iron of the proposed composition is due to the following.

Zirconium at a content of 0.05-0.3 wt.% Stabilizes perlite, increases its spheroidization, increases hardness and wear resistance, their stability during operation and the operational resistance of cast parts. With an increase in zirconium concentration of more than 0.3%, its segregation begins to appear, the form factor of graphite decreases, and at a concentration of up to 0.05 wt.%, The hardness and wear resistance of castings decrease, and plate-like perlite predominates in castings with a dispersity of 1.0 1.0 1.4.

The introduction of chromium carbonitrides in the amount of 0.06-0.41 wt.% Crushes the structure of perlite, graphite inclusions, increases hardness, wear resistance, tightness and operational durability. At a concentration of up to 0.06 wt.%, Wear resistance, dispersion of the structure and operational durability are insufficient, and at chromium carbonitrides concentration of more than 0.41 wt.%, The coefficient of friction increases, the form factor of graphite decreases, impact-fatigue and operational durability.

An additional introduction of barium in the amount of 0.003-0.01 wt.% Crushes the structure of cast iron in the castings, increases the hydraulic density of the castings, the shape factor of graphite and provides an increase in wear resistance and operational durability. At a concentration of up to 0.003 wt.%, The dispersion and stability of the structure and hardness are insufficient, and at a barium concentration of more than 0.01 wt.%, The technological

cl

with

x |

v

v

ABOUT

properties, hydraulic density and operational durability.

The introduction of calcium contributes to the separation of grain boundaries and the spheroidization of graphite. At a calcium concentration of up to 0.003 wt.%, The dispersity of graphite decreases, the mechanical and operational properties. At a calcium concentration of more than 0.02 wt.%, The stability of the structure and properties decreases, the characteristics of wear resistance and impact fatigue life decrease.

Nickel in the amount of 0.35 wt.% As an affective additive strengthens the metal base and reduces the viscosity of the cast iron, reduces the threshold of cold brittleness and the tendency of the cast iron to form cracks, increases wear resistance and operational durability. When the nickel concentration is less than 0.06 wt.%, Its effect is insignificant. Increasing its concentration by more than 0.35% reduces the form factor of graphite, wear resistance and operational durability.

The carbon and silicon content in the proposed iron is selected taking into account the practice of manufacturing wear-resistant parts with increased hardness values and operational durability. As their concentration increases above the upper limits, the stability of the structure and toughness and the characteristics of the elastic-plastic properties decrease, and when the concentration of the lower lower levels decreases, the fluidity decreases, eutectic cementite is released, the bulge increases, which leads to a decrease in fracture resistance, plastic properties and operational durability .

Aluminum in the amount of 0.08-0.26 wt.% Has a deoxidizing, micro-doping and stabilizing effect, contributing to a decrease in the content of non-metallic inclusions and an increase in hardness and wear resistance. When the concentration of aluminum is up to 0.08 wt.%, The deoxidizing, microalloying and stabilizing effect is insufficient, and when the concentration of aluminum is more than 0.26 May. % decreases the hardness of the castings, the relative wear resistance and the operational resistance.

The content of the main modifying components (magnesium 0.03-0.07 wt.% And cerium 0.015-0.05 May.%) Ensures melt degassing and spheroidization of graphite and perlite and increasing the strength, elastoplastic performance properties. Sulfur increases chill. Fragility, reduces shock fatigue doping

ness therefore, it is excluded from cast iron.

The manganese content is increased to 0.5-2.1 wt.% And is limited by concentrations, below which high spheroidization of pearlite is not achieved, and a significant increase in wear resistance, and the content of cementite and chilliness increases above the upper limit, increases

brittleness, reduced structural stability and plastic properties, impact-fatigue and operational durability.

The iron melts are conducted in induction furnaces. Overheating of the melt during smelting is 1450-1480 ° C. Cast iron is used as the charge materials. cast iron pom, waste electrical steel, steel chips, return your own

production, carburizer (pitch coke), chromium carbonitrides, nickel, ferrochrome, ferrosilicon zirconium with manganese s6cCsMr40, ferromanganese, ferrosilicon, silicobarium, silicocalcium, ligatures

type ZhKMKBa, nitrogen. The content of magnesium in ligatures is 6-9 wt.%, Barium 4.8-9.3 wt.%, Cerium 3.5-6 wt.%. The ligature is fractionated to a fraction of 4–20 mm. Microalloying with chromium carbonitride, ferrosiliconium zirconium with manganese and ferromanganese is carried out in a melting furnace. Modification of cast iron with spheroidizing LMGUR, silicobarium, silicocalcium and ferrosilicon is carried out in foundry

buckets.

Parts of machine tools, wear-resistant castings, process samples and test specimens are cast from modified cast irons.

In tab. 1 shows the chemical compositions of high-strength cast irons of the experimental heats. The determination of the content of components in the cast iron was carried out by methods of differential chemical analysis. Shock

viscosity is determined on samples of 10x10x55 mm with a Y-shaped notch.

In tab. 2 shows the data on the mechanical cone and structure characteristics

cast iron experienced melts in castings. Mechanical tests are carried out by standard methods, and analysis of the structure of cast irons according to GOST. The operational reliability is determined on dry test stands.

training in tandem with synthegran.

As follows from the table. 1 and 2. Additional input into the composition of the proposed zirconium iron, as well as nitrogen, chromium in the form of chromium carbonitrides allows to increase the wear resistance, strength and hardness of HB.

Claims (1)

Invention Formula Cast iron containing carbon, silicon, manganese, nickel, aluminum, calcium, cerium, magnesium, barium and iron, characterized in that, in order to increase wear resistance, tensile strength and hardness, it additionally contains zirconium and chromium carbonitrides in the following the ratio of components, wt.%: Carbon3,4-3,8 0 Silicon Manganese Nickel Aluminum Calcium Cerium Magnesium Karbokmtridy chrome Barium Zirconium Iron 1.5-2.0 0.5-2.2 0.06-0.35 0.08-0.26 0,003-0,02 0,015-0,05 0.03-0.07 0.06-0.41 0.003-0.01 0.05-0.3 Else Table Note. In composition 1 iron, 0.20% by weight of chromium and 0.02% are additionally contained. nitrogen. table 2