SU1305192A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the production of iron castings operating under conditions of hydroabrasive wear. The purpose of the invention is to increase the flexural strength, microhardness of the matrix, its hardenability and the improvement of operational durability during hydroabrasive wear. Cast iron contains, wt%: C 2.4-3.0, Si 0.2-1.0, Mp 0.8-2.6, Cg 18.7-27, Mo 0.2-0.6, V 0.2–0.5, Ni 0.5–1.0, Nb 0.42–1.4, Sb 0.07–0.2, titanium nitrides 0.05–0.2 and iron - the rest, Entering Nb, Sb and titanium nitrides into the composition of the cast iron provides an increase (Ec from 960 to 1220 - 1310 MPa, an increase in hardenability by 1.7-2.1 times, the microhardness of the matrix by 7-9% and an improvement in the operational durability of 1.7- 2.4 times. 2 tab. (L

Description

The invention relates to metallurgy, in particular, to the development of a composition of white wear-resistant cast irons intended for the manufacture of parts operating under hydroabrasive wear conditions, impellers, cylinder bushings and other parts of pumps.

The purpose of the invention is to increase the flexural strength, microhardness of the matrix, its hardenability and fO improvement of the operational durability at hydroabrasive wear.

The choice of the boundary limits of the components is due to the following.

Additional introduction of niobium in t5 in an amount of 0.42–1.4 wt.% Micro-ligates and hardens the metal base, crushes the structure, blocks defects of the crystalline structure, reduces segregation, increases the stability and uniformity of the structure and mechanical properties, which ensures increased wear resistance, strength and other properties in castings. When the

and an increase in manganese concentration of more than 2.6 wt.% decreases casting properties, increases segregation and reduces the stability of the structure and properties, and at concentrations of carbon more than 3.0 wt.%, silicon more than 1.0 wt.% and manganese less than 0.8. wt,% structure in castings becomes coarse, its wear resistance and stability of mechanical properties are reduced.

The content of alloying additives (chromium. 18.7–27 wt.%, Nickel 0.5–1.0 wt.% -, molybdenum 0.2–0.6; vanadium 0.2–0.5 wt.%) Is determined experimentally and limited to the limits below which microhardness, strength properties, hardenability depth and wear resistance are insufficient, and above which structure stability, dynamic strength and other properties in castings are reduced.

Titanium nitrides (0.05–0.2 wt.%) Are effective modifying agents that reduce the niobium structure to up to 0.42 wt.% Of micro- and increase the mechanical properties of the alloying effect; wear resistance, bo, substantial hardening of metal- At a concentration of up to 0.05 wt.% of the molar base, the discriminating effect does not show a weakness of hardness and properties in bo, and at a concentration of them more than castings are low. At a concentration of nio-30 of 0.2 wt.%, They are not completely dissolved — b more than 1.4 wt.% Decreases in the matrix, the concentration and stability of the mechanical properties of non-metallic inclusions and the dissimilar properties of cast iron in the castings are increased. . the heterogeneity of the structure that leads to

reduction of wear resistance and mechanical injection of antimony in the amount of 0.07–35 — properties of cast iron in castings. 0.2 wt.% Increases the hardness, wear resistance of the matrix, hardenability, microhardness of the matrix, its stability in castings, which ensures a reduction in hydroabrasive wear and an increase in mechanical properties. The content of antimony was taken from a concentration of 0.07 wt.%, With which an increase in the stability of hardness and wear resistance in castings was observed, and the furnace was released at 1480–1500 ° C and was limited to a concentration of 0.2% by weight; microalloying and in which there is a decrease in the solubility of antimony in a metal base and a decrease in dynamic strength and stability of the structure and properties of cast iron.

The content of the main components (carbon 2.4-3.0 wt.%, Silicon 0.2-1.0 wt.% And manganese 0.8-2.6 wt.%)

Example. Experimental smelting of cast iron was carried out in an induction furnace using cast iron, cast iron, cast iron, silicon manganese, antimony, niobium, steel scrap, ferrochrome, titanium nitride powder, ferrovanadium, ferrosilicon, and other ferroalloys. Cast iron out

dosing agents. Cylindrical specimens with a diameter of 30 mm were cast from cast irons, technological samples with a maximum thickness of 500 mm and castings of pump parts were cast.

In tab. 1 shows the chemical composition of the known and proposed iron, Table. 2 - data on the stability of the structure, hardenability, mechanical and operational properties of cast iron.

determined by the practice of the production of white wear-resistant cast iron for thick-walled cast parts. By reducing the carbon content to less than 2.4. Wt.% And silicon below 0.2 us., 7,

and an increase in manganese concentration of more than 2.6 wt.% decreases casting properties, increases segregation and reduces the stability of the structure and properties, and at concentrations of carbon more than 3.0 wt.%, silicon more than 1.0 wt.% and manganese less than 0.8. wt,% structure in castings becomes coarse, its wear resistance and stability of mechanical properties are reduced.

The content of alloying additives (chromium. 18.7–27 wt.%, Nickel 0.5–1.0 wt.% -, molybdenum 0.2–0.6; vanadium 0.2–0.5 wt.%) Is determined experimentally and limited to the limits below which microhardness, strength properties, hardenability depth and wear resistance are insufficient, and above which structure stability, dynamic strength and other properties in castings are reduced.

Titanium nitrides (0.05–0.2 wt.%) Are effective modifying agents that reduce the structure of the 35-properties of cast iron in castings. 45 furnaces were manufactured at 1480-1500 С into casting buckets with microalloying and micro-

Example. Experimental smelting of cast iron was carried out in an induction furnace using cast iron, cast iron, cast iron, silicon manganese, antimony, niobium, steel scrap, ferrochrome, titanium nitride powder, ferrovanadium, ferrosilicon, and other ferroalloys. Cast iron out

35 - properties of cast iron in castings. 45 furnaces were manufactured at 1480-1500 С into casting buckets with microalloying and micro-

dosing agents. Cylindrical specimens with a diameter of 30 mm were cast from cast irons, technological samples with a maximum thickness of 500 mm and castings of pump parts were cast.

In tab. 1 shows the chemical composition of the known and proposed iron, Table. 2 - data on the stability of the structure, hardenability, mechanical and operational properties of cast iron.

313051924

As can be seen from the table. 2, proposed, so that, in order to increase the strength, cast iron has a higher depth of bending strength, microturbine hardenability and uniformity of the matrix, its hardenability

structure. High operational and improved operational durability under hydro-abrasive conditions, tee with hydro-abrasive wear,

wear is achieved by semi-it additionally contains niobium,

fine martensitic antimony and titanium nitrides with the following austenitic matrix with complex ratio of components, wt.%:

carbides. The optimum values of hardness, wear resistance and mechanical properties in cast products are achieved when the temperature is normalized from a temperature of 970.

Claims (1)

Invention Formula i Cast iron containing carbon, silicon, manganese, chromium, molybdenum, vanadium, nickel and iron, distinguishing titanium 2.4-3.0 0.2-1.0 0.8-2.6 18.7-27 0.2-0.6 0.2-0.5 0.5-1.0 0.42-1.4 0.07-0.2 0.05-0.2 Rest Table 1 Tensile strength with bending, MPa 960 Hardness, HRC 60 The stability of the structure,% 55 Wear resistance coefficient 8,6 Microhardness, H 5020 Worn cylinder liners at a pulp speed of 3 m / s, mg / cm. h58,6 Depth of calcination, mm 220 Operational (resistance, h 1400 1220 1250 1310 980 1050 64 65 67 60 63 90 94 97 56 370 430 470 230 84 13.2 13.6 14 8.8 11.6 5370 5450 5480 5130 5280 25.6 18.4 16.4 57.6 32.6 330 2380 3160 3420 1430 1960 Table 2 90 94 97 56 84 25.6 18.4 16.4 57.6 32.6 370 430 470 230 330