SU1035085A1 - Cast iron - Google Patents

Abstract

A CAST IRON containing carbon, silicon, manganese, chromium, nickel, aluminum, vanadium, copper, titanium and iron, characterized in that, in order to improve the wear resistance of the iron and its structure. tours and hardness across the section in thin-walled castings, it additionally contains barium in the following ratio of components, # wt.%: 2.9-3.5 Carbon 1.8-2.6 Silicon 0.6-1.0 Manganese 0.15 -0.45 Chromium 0.1-0.4 Nickel 0.005-0.020 Aluminum 0.07-0.30 Vanadium 0.5-1.2 Copper. 0.03-0.08 Titanium 0.005-0.020 Barium Else Iron

Description

e:: l

about

00 SP The invention relates to metal, in particular, to the search for the composition of cast irons for the production of friction castings. Known cast iron l containing components in the following ratio May.%: Carbon 2.8-3.3 Silicon 0.5-1.2 Manganese 0.5-0.8 Cerium 0.04-0.08 Yttrium 0.02-0, 07 Iron Rest In the cast state, a known cast iron has a flexural strength of 48-55 kgf / mm. The disadvantages of this iron are low flowability, bone wear, heat resistance and a high tendency to chill. Closest to the invention of the technical nature and achievable result. is iron-containing 2, wt.%: Carbon 2.9-3.5 Silicon 1.8-2.6 Manganese 0.4-0.8 Chromium 0.15-0.40 Nickel 0.1-0, 4 Aluminum 0.005–0.020 Vanadium 0.1–0.3 Cerium 0.005–0.020 Copper 0.02–0.30 Titanium 0.03–0.10 Iron Else The known cast iron has sufficiently high strength when stretched to 2V kgf / mm and It is not inclined to the formation of chillings in thin sections of the branches obtained in sandy forms. However, known cast iron does not provide the required structure for the cross section of thin-walled chill castings. In the outer, rapidly cooled surfaces of castings, adjacent to the chill mold, interdendritic graphite and primary cementite are observed in the cast iron structure, which makes it difficult for the castings to run. On the inner surface of the casting, made by the core, in the cast iron structure there is about 20% of ferrite, which is not allowed for important parts, in particular of the sleeves of internal combustion engines. The purpose of the invention is to increase the nosostability of the cast iron and level its structure and hardness along the section in thin-walled castings. The above purpose is achieved in that the cast iron containing carbon, silicon, manganese, chromium, nickel, aluminum, vanadium, copper, titanium and iron additionally contains barium with the following ratio of components, wt.%: Carbon 2.9-3, 5 Silicon 1.8-2.6 Manganese 0.6-1.0 0.15-0.45 Nickel 0.1-0.4 ALUMINUM 0.005-0.020. 0.07-6.30 Vanadium Copper 0.5-1.2 Titanium 0.03-0.08 Barium 0.005-0.020 Iron Rest Carbon content (2.9%) and silicon, (1.6%) is based on the fact that in the structure of cast iron there was no eutectic cementite and alloy I had a good fluidity. The upper limits for carbon (3.5%) and silicon (2.6%) are set, based on the fact that the cast iron crystallizes without liberating ferrite during the process of cooling the casting. The lower limit of the chromium content is 0.15%, nickel is 0.1%, titanium is 0.03%, vanadium 0.07% is set, so that the cast iron has the required strength and wear resistance, and the upper limit is 0.45 %, 0.4%, 0.08%, 0.3% in order to obtain a cast structure without the formation of primary carbides of these elements. The content of 0.0050, 02% of aluminum and bari is due to the fact that these elements produce a modifying effect, reducing supercooling during crystallization and that safer, change graphite and improve its shape. It is known that an increased amount of copper leads to an increase in the tendency of iron to perlite formation. Perlite metal base causes an increase in wear resistance, leveling of hardness and the structure of differential castings. The lower limit of the copper content (5%) is established from the need to obtain the required wear resistance and leveling the structure and hardness over the cross section of the castings. An increase in the copper concentration above 1.2% does not lead to a further increase in these properties. An additional barium input of 0.0050, 02% enhances the modifying effect of aluminum and retains it for a longer time. Due to the high cooling rates in the known alloy, cementite and ferrite are formed in various casting zones. The reason for the formation of ferrite is the interdendritic graphite of supercooling. The addition of barium to the alloy at the proposed ratio of ingredients ensures due to an effective graphitizing effect, firstly, by eliminating primary cementite, secondly, by improving the shape of graphite (eliminating its interdendritic form — heptirating the metal matrix. Barium in the range of 0.005–0.02% reduces the amount of supercooling during eutectic crystallization from 7 to 3–3.8 This is due to the formation of a large number of complex barium oxysulfides serving Additional crystallization centers of stable eutectics. Barium not only eliminates chill, improves the shape of graphite. This action of barium helps to align the structure over the section of thin-walled chill castings, and consequently, the properties of the material. to increase the wear resistance of cast iron more than 1.5 times.

In tab. D shows the chemical composition of cast iron.

To obtain the studied alloys, three compositions of the proposed cast iron are melted. The lower, middle and upper levels of the components are maintained (Table 1J. Melting is carried out in an acid-lined induction furnace. Cast iron pigment LK2, LKD, vanadium scrap is used as charge material pig iron, ferroalloys of manganese, silicon, nickel, chromium. The charge materials are loaded into the furnace, the melt is overheated to –1450 ° C. Aluminum and barium, in the form of silico barium,%: Si 60; Ba 10 Fe, the rest and alloy,%: Si 70, A1 10; Fe rest in a molten cast iron at 1360-14 00 C. To ensure uniform dissolution of the ligatures and distribution of the alloying elements in the melt, it is allowed to stand for 10 minutes prior to release.

The consumption of ligatures to obtain boundary limits for the concentrations of aluminum and barium in cast iron is 0.07–0.28% by weight of the metal. Liquid metal is poured into a chill mold to produce castings for SMD-BO engine sleeves. Mechanical machining of castings is carried out in a common flow. Samples for

Analysis of the hardness and structure of the cast iron is cut directly from the cast. The ultimate tensile strength on the base is 5 {, 1,. In 1 out of our 30-32 gtgagtlivok, JlBie flSpCT vjHB is distributed to | compress; c0- Vryy1vl pf load 750 needles per ball; , d | 1s1mee9S 1 5 ml, Mikrostr uk1; hooray in the case of a vision of a hell "1" by the myth of the microscope. Eid; Ioso; Toykrst;

0 is determined by the cP mass tPgHW „.. from the dry traction platform at a specific load of 12 kgf / cm and a sliding speed of 1.2 m / s. Wear resistance is assessed by the weight method 5 in rpeiMMax, referred to ioOO and mileage.

In tab. 2 shows the properties of the investigated compositions of cast iron.

0 As can be seen from the table. 2, in a known alloy, the hardness in castings varies from the wall of the chill mold to the inner surface obtained upon contact with the core from 251 to 187 HB. The increase in the concentration of copper leads to a decrease in the amount of ferrite on the inner surface of the casting, obtained from the rod and leveling the hardness. On the outer surface, chill molds, known

In the alloy, there is about 5% cementite, and in the proposed alloy composition with increasing copper concentration, there is no cementite. The core of the thin-walled chill casting has

five

same hardness and structure.

The alignment of the structure and hardness over the cross section of a thin-walled chill casting leads to an increase in wear resistance. In addition, an increase in copper concentration and an additional barium input leads to the alignment of the structure and hardness over the cross section of a thin-walled chill casting, which causes an increase in

5 wear resistance of the alloy.

The expected economic effect from the implementation of the proposed invention in a household is 500 thousand rubles.

Table 2

251

Famous

241

229

Predgg gage-yp

229:

Continued table. 2

187

0.04

229

0.035

207

229

0.020

217 0.025 211

Claims (1)

PIG IRON containing carbon, silicon, manganese, chromium, nickel, aluminum, vanadium, copper, titanium and iron, characterized in that, in order to increase the wear resistance of cast iron and smooth its structure ·. rounds and cross section hardness in thin-walled castings, it additionally contains barium in the following ratio of components, "wt.%: Carbon Silicon Manganese Chrome Nickel Aluminum Vanadium Copper. Titanium Barium Iron