SU1010153A1 - High-tensile cast iron - Google Patents

Abstract

HIGH-STRENGTH CAST IRON containing carbon, silicon, marga5 ti (. V nits, copper, magnesium, cerium to iron, differing in that, in order to reduce oxidation resistance while maintaining its mechanical and mechanical properties, it additionally contains aluminum at the following ratio of ingredients, weight. %: s, 2-s, e Carbon 2.3-, 0 Silicon O, 2-0.4 Manganese 0.03-0.07 Magnesium 0.2.5 Copper 0.01-0.05 Cerium 0.5 -O, 9 Aluminum Rest Iron §

Description

SP

co Isobregnation relates to metal1, namely to high-strength cast iron compounds, and can be used in the production of complex difference-thickness coatings with high and equal strength, ductility and satisfactory machinability. High-strength cast iron with spherical graph, known in the foundry industry , silicon, manganese, magnesium, copper and aluminum. These cast irons have a complex chic composition and sufficient strength in massive sections of castings. However, they do not provide the stability of the properties of high-strength cast iron at higher concentrations of sulfur (more than 0.02%) and have a high tendency to foam formation High-strength cast iron l 1 containing ingredients in the following ratio, weight,% Carbon 3.2-3, Silicon , 0.1–1.5 Manganese 0.1–1.2 Magnesium O, 03–0, O8 Copper 0.5–1.0 Aluminum1.5–3.0 Iron Others This cast iron, due to the content of magnesium in it, produces spherical graphite when sulfur is contained in the initial alloy no more than 0, O2%. At high concentrations of sulfur in the initial alloy for spheroidal ation grafi Ta required increase sotserzhani ma audio to 0.1%. However, the compact form of graphite is not achieved. A higher concentration of aluminum and copper leads to foaming in thick combinations of castings, as well as reduced technological properties, in particular, fluidity. The content of manganese in such limits leads to the appearance of structurally free carbons, which, in turn, reduces the ductility and makes machining difficult. The reduced concentration of KEZOMN does not provide for the production of castings with a cross section of up to 10 mm without cement. All this leads to unstable properties of castings. The closest to the proposed technical essence and the achieved result is high-strength cast iron of the following chemical composition, weight. Carbon 2.8-3.2. . Silicon 1.7-2.4 Manganese 0.1-0.4 Copper 0.1-1.0 Cerium 0.01-0.1 Magnesium 0.03-0.15 Iron Other The disadvantage of the known cast iron is low scaling resistance. This goal is achieved by the fact that high-grade iron, containing carbon, silicon, manganese, copper, magnesium, cerium and iron, additionally contains aluminum in the following ratio of components, wt.%: Carbon 3.2-3.6 Silicon 2.3-3 , 0. Manganese 0.2-0.4 Copper 0.2-O, 5 Magnesium 0.03-0-07 Cerium 0.01-0.05 Aluminum 0.5-0.9 IronEstal Iron contains, as an impurity, in wt.%: Phosphorod 0.10 Cerado 0,06 Magnesium provides nodular graphite and high mechanical properties. With a content of less than 0.03% in the structure, plate inclusions of vermicular graphite are observed. Entering magnesium more than 0.07% is not rational, since the form of graphite worsens, the modifier consumption and the amount of harmful outgassing during smelting increase. Cerium in amounts of 0.01-0.05% helps to obtain the correct spherical shape of graphite in castings with significant fluctuations of the harmful sulfur impurity in the initial melt up to 0.06%. The lower limit of the cerium content (0.01%) is due to the need to obtain nodular graphite in castings. The upper limit (0.05%) is limited due to the possibility of over-modifying effect. Cerium also contributes to the reduction of pigment in the pig iron. To obtain a high ductility of the alloy, the manganese content in it is limited in the range of 0.2-S, 4%. An increase in the silicon concentration (2.3–3, O%) promotes the crystallization of the alloy according to a stable diagram of the state of rs without structurally free carbides. The lower limit for silicon (2.3%) is set, based on the requirements for eliminating chill in castings. When the silicon content is more than 3%, the spherical shape of graphite deteriorates and the ductility of the alloy decreases. Aluminum reduces the formation of cementite in the alloy structure. Concentrations of aluminum less than 0.5% do not provide high and stable strength and plastic characteristics. The top aluminum target is limited to 0.9%. The practice of working with aluminum-containing cast irons shows that when the aluminum content is more than 0.9%, the technological properties of the oil flow rate noticeably improve, and the tendency of the melt to froth increases, resulting in the use of such cast iron in the manufacture of thin wall castings is not possible. The favorable combination of strength and ductility of the alloy is achieved by a reduced copper content ranging from 0.2-0.5%. The concentration of sulfur impurities up to 0, O5% and phosphorus of 0.10% is established, based on the need to ensure the spherical shape of graphite and to obtain higher and more uniform mechanical properties in complex differential castings. The structure of the proposed cast iron has a ferrite-perlite metal matrix and compact spherical inclusions of graphite. Example. To obtain high-strength cast iron, 3 compositions of the proposed alloy are smelted with the lower, upper and average content of components, as well as a known alloy with an average content of components. The melting is carried out in a 40 kg induction furnace with an acid A-flue. The following materials are used as charge materials: cast iron, own return, ferroalloys of magnesium, cerium, aluminum. The content of sulfur impurities is 0.05%, phosphorus - 0, lD%. After overheating of the metal to 1420 ° C, the cast iron is modified with magnesium, cerium, mepa and aluminum using appropriate ferroalloys. Investigation of properties is filled in a raw form with a complex sample, which includes a stepped slab with a wall thickness of 5 to 4 mm and wedge samples, which are used to evaluate the tendency-casting of foaming and rinse. In tab. 1 shows the chemical properties of the alloys. In tab. 2 shows the mechanical. properties of alloys. As can be seen from the table. 2, the proposed alloy has a higher fluidity, lower tendency to foaming, has a stable plasticity at the sulfur content in the initial melt. Scaling is determined by the difference in mass of the sample before and after aging at 90 ° C for 4 hours. Techniques for preparing the proposed alloy may include: preparing a melt in an acid electric arc furnace or a duplex process cupola electric furnace and subsequent modifying with magnesium and aluminum , copper, cerium. The most rational application areas of the proposed alloy are the loaded parts of tractors and automobiles. The expected economic effect is 87 thousand rubles. ° Table 1

1 Known 3, OO 2, O5 0.25 0, O9 O, 55 - 0.055

Proposal3, 22.3 0.2 0.03 0.2 0.5 O, 01 th

3.42.55 O, 3 0.05 0.35 0.7 0, OZ

3.63, O 0.4 0.07 0.5 0.9 0.05

1 Known

Note: In the numerator d columns are given

plasticity fluctuations, in the denominator - the average value.

table 2

0.5-1.5

Claims (1)

HIGH-STRENGTH IRON, containing carbon, silicon, manganese, copper, magnesium, cerium and iron, characterized in that, in order to increase the scale resistance while maintaining the drinking and mechanical properties, it additionally contains aluminum in the following ratio ingredients weight.%: Carbon 3.2-3.6 Silicon • 2.3-2.0 Manganese 0.2-0.4 Magnesium 0.03-0.07 Copper 0.2 * 0.5 Cerium 0.01-0.05 Aluminum 0.5-0.9 Iron Rest _n »SU„ „1010153 1 1010153