SU1406203A1 - Cast iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the manufacture of cylinder liners, etc. The purpose of the invention is to improve machinability and corrosion resistance. New cast iron contains components in the following ratio of May.%: C 3.53-3.91; Si 4.19-4.52} Mp 7.21-7.85; Cr 0.8-0.9; W 0.6-0.9; Ca 0.3-0.5; 5 0.5-0.8 and Fe - the rest. Additional input into the composition of cast iron Ca and Bb provided an increase in corrosion resistance by 1 times, and an improvement in workability by cutting by 1.37-1.42 times. 2 tab.

Description

The invention relates to metallurgy, in particular, to the development of the composition of WWII iron for casting cylinder liners.

ditch, etc .:

The purpose of the invention is to improve machinability and corrosion resistance.

The lower and upper limits of carbon and silicon are chosen based on the conditions for obtaining the optimal amount of graphite in individual castings of cylinder liners for automobile engines and preventing their outer surfaces from being whipped off during the centrifugal casting. The limits of the content of manganese are chosen, on the basis of the preservation of the unstable austenitic-martensitic structure of the metal base, which is capable of self-strengthening during wear and tear due to the phase transformations of austenite to martensite,

The chromium content in the proposed iron is in the range of 0.8-0.9%, which makes it possible to increase the corrosion and abrasive resistance of the iron by obtaining wear-resistant carbides in the structure. A further increase in chromium content leads to an increase in hardness and a deterioration in the workability of cylinder liners.

The tungsten content in the range of 0.6-0.9% provides for obtaining in the microstructure a small, needle-shaped form, uniformly distributed in the metal base of carbides, which increase the ability of cast iron to resist corrosion and abrasive wear. The increase in the amount of tungsten, especially in combination with the upper limit of the manganese content, leads to a sharp deterioration in the machinability,

I

Calcium content within

0, 5% provides for obtaining in the iron the optimal amount of graphite, reducing the amount of carbides and the hardness of the iron, which leads to an improvement in the workability of its cutting. At the same time, when calcium is introduced into cast iron, graphite is more uniformly distributed in the microstructure and more compact in shape. This contributes to the preservation of high corrosion and abrasive resistance and increases the mechanical properties. Introduction to cast iron-antimony in the amount of 0.5-0.8%

o

50

five

0

five

0

five

0

five

significantly increases its corrosion resistance, having a positive effect on the wear resistance of cast iron during sliding friction with lubricant containing abrasive,

In the proposed iron, the content of sulfur and phosphorus should not be higher than 0.1-0.2%.

Iron smelting was carried out in induction. Furnaces with a basic lining, alloying elements in the form of ferromanganese, ferrosilicon, ferrochrome, ferro-tungsten were introduced at 1380-1420 ° C into the pig iron melt, and the ferromanganese was added 15 minutes before the end of the smelting to prevent the manganese from burning out. Calcium silicide in powder form and Su-3 antimony with a grain size of 3–8 mm were introduced during casting directly into the ladle.

In order to obtain the proposed iron, six mixtures of ingredients of the proposed chemical composition and known iron were smelted. The chemical composition of the melted iron is presented in table. 1, and data on the mechanical properties and the results of known and corrosion tests are given in Table. 2

The wear tests were carried out on a SMC-2 friction machine with sliding friction with a lubricant containing an abrasive in the amount of 10% by weight of the lubricant. Tests for corrosion resistance were carried out by the weight method in a 20% aqueous solution of sulfuric acid for 40 hours.

The relative durability of the cutting tool was determined for VK-3 drills,

As can be seen from the table. 2, the addition of Ca and 8b to cast iron provides an improvement in machinability by 1.37-1.42 times and corrosion resistance by 1.25-1.35 times.

Claims (1)

Invention Formula Cast iron containing carbon, silicon, manganese, chromium, tungsten and iron, characterized in that, in order to improve machinability and corrosion resistance, it additionally contains calcium and antimony, in the following ratio of components, wt.%: 3.53-3.91 4.19-4.52 7.21-7.85 0.8-0.9 0.6-0.9 0.3-0.5 0.5-0.8 Rest table 1 Proposed 13.53 3.64 3.78 3.91 3.61 Proposed 7.21 7.41 7.64 7.85 7.53 0.8 0.8 0.9 0.9 0.8 0.6 0.8 0.8 0.9 0.7 0.3- 0.3 0.4 0.5 0.5 0.6 0.8 0.8 table 2