SU1090750A1 - Cast iron - Google Patents

Abstract

CAST IRON, predominantly for castings, containing carbon, silicon. manganese, vanadium, antimony and iron, characterized in that, in order to increase the tensile strength, wear resistance and stabilize the hardness in castings with wall thickness of 20-60 mm, it additionally contains molybdenum and copper in the following ratio of components, wt. %: 3.0-3.4 Carbon 1.6-2.2 Silicon 0.01-0.04 Manganese 0.15-0.35 Vanadium 0.08-0.12 Antimony 0.1-0.4 Molybdenum 0.8-1.2 Copper Rest Iron

Description

The invention relates to metallurgy, in particular, to the development of cast iron for castings operating at significant loads and under conditions of friction. Known cast iron fl, containing, wt.%: Carbon 3.2-3-3.8 Silicon1.6-2.3 Manganese, 0.6: -1.0 Nickel, 0.8-1.4 Molybdenum, 0.2-0.5 Chrome, 0.15- 0.45 Sulfur Up to 1 PhosphorDo 0.3 However, the specified cast iron has low strength and wear resistance depending on the thickness of the casting sections. The closest to the invention in its technical essence and the achieved result is cast iron 2j, containing, wt.%: Carbon 3.0 -3.4 Silicon 1.6-2.2 Manganese 0.005-0.04 Vanadium0.15-0.45 Antimony0.15-0.25 IronErestal Well-known cast iron incorporates a complex of elements (silicon antimony, vanadium, manganese), stabilizing and alloying the carbide phase of the alloy, which provides a sufficiently high mechanical properties of the material. However, the use of a known alloy for the production of castings with a difference in wall thickness from 20 to 60 results in a different structure and, as a result, significant differences in strength and wear resistance over the section of the part. The aim of the invention is the noBbf reduction of the tensile strength at stretching of the scientific research institute, the wear resistance and the stabilization of hardness in castings with a thickness of 20-60 mm. This goal is achieved by the fact that cast iron predominantly for castings containing carbon, silicon, manganese, vanadium, antimony and iron additionally contains molybdenum and m with the following ratio of componeite, wt,%: Carbon 3.0-3.4 Silicon 1.6-2 , 2 Manganese 0.01-0.04 Vanadium 0.15-0.35 Antimony 0.08-0.12 Molybdenum 0.1-0.4 Copper 0.8-1.2 Iron Rest Entering copper and molybdenum into the vessel promotes the hardening of cast iron in a metastable system during the period of the zhektepoidnogo transformation, stabilizes the structure, reduces the influence of temperature factors. talization and additionally alloy the metal base, contributes to the strength and durability of the material. Example. To study the structure and properties of the proposed material, the cast iron of three compositions containing the main components at three LEVELS low, medium and high, as well as a well-known alloy with an average level of ingredients, is smelted. Chemical compositions of cast iron are presented in table. 1. Cast iron is smelted in an induction furnace using a low-manganese blend: metallized pellets, vanadium, molybdenum ferroalloys, silicon, electrolytic copper, and crystalline antimony. To test for mechanical properties and wear resistance, samples are cast into a dry sand mold with a diameter of 30 mm. The study of the phase composition and hardness of the material is carried out on a specially made stepped plate with a thickness of 20, 40 and 60 mm. The hardness measurements are carried out on a sample cut in half according to the scheme shown in the drawing. The wear tests were carried out on an MT-2M friction machine with a load of 1-2 kg / cm and a sliding speed of 1.2 m / s. The test results are presented in Table. 2. As can be seen from the table. 2, the proposed cast iron has increased wear resistance and mechanical properties, as well as a more uniform hardness in sections of various thicknesses. In the central part of the casting of a known alloy with a wall thickness of 40 and 60 mm, 10-15% and 45-55% of ferrite are formed, respectively. In the alloy of the proposed composition, the structure is completely pearlitic, regardless of the sample thickness. The dispersion of perlite in the known alloy is in the range of 0.5-2.0 µm, depending on the thickness of the sample. In the alloy of the proposed composition in the range of 0.7-1.2 μm in the whole investigated volume of the step sample. The limits of the content of the components are established on the basis of obtaining a favorable combination of properties and structure of cast iron. The lower limits of the carbon content (3.0%) and silicon (1.6%) are due to the need to obtain a metal matrix without ledeburite inclusions, the upper one (C - 3.4%, Si - 2.2 G) is limited to obtaining a pearlite matrix with no ferrite more than 2%. The lower limit of the content of antimony (0.08%) guarantees the production of pearlite base of iron, the upper (0.12%) is associated with obtaining a structure without eutectic cementite. The content of vanadium (0.15-0.35%), copper (0.8-1.2%, and molybdenum (0.1-0.4%) is chosen from the conditions of the structure stabilization in the cross sections of casting of various thickness and the maximum hardening of metal bases. The optimum composition of the alloy contains,%: carbon 3.2, silicon 2.0, manganese 0.02, vanadium 0.25, copper 1.0, antimony 0.1, molybdenum 0.25Production techniques for cast iron consists of melting high-carbon metallized pellets of the ferroalloy silicon (75% Si), molybdenum (45%, Mo), and vanadium (45% V) melted in. Electrolytic copper and antimony are introduced into the ladle before pouring The value of additives is calculated on the basis of an average level of silicon, copper and antimony absorption at a level of 85-95%, vanadium and molybdenum at a level of 70-80%. The proposed composition of cast iron is most effectively used for the manufacture of castings operating under conditions of wear and heavy loads. For example, the brake drums of heavy vehicles. The environmental effect of the implementation of the invention will be 120 thousand rubles per year. Table 1

eatable

Average 3.2 2, .0 0.02 0.25 0.1 0.25 1.0

Upper 3.4 3.2.20.040.35 0.120.4 1.2

Table

Continued table. 2

Claims (1)

PIG IRON, mainly for castings containing carbon, silicon, manganese, vanadium, antimony and iron, characterized in that, in order to increase the tensile strength, wear resistance and stabilize hardness in castings with wall thicknesses of 20- ^ 60 mm, it contains molybdenum and copper in the following ratio of components, wt.%: Carbon Silicon Manganese Vanadium Antimony Molybdenum Copper Iron 3.0-3.4 1.6-2.2 0.01-0.04 0.15-0.35 0.08-0.12 0.1-0.4 0.8-1.2 Rest 4-ίί Z & / 4/7 12 ^