SU910822A1 - Process for modifying aluminium-based high-silicon alloys - Google Patents

Description

The invention relates to foundry. namely, methods for modifying aluminum-silicon alloys.

One of the main requirements for high-silicon alloys derived from aluminum is et-. with improved performance properties and improved machining -. bridges of cast products from these alloys. In order to achieve the above requirements, in the manufacture of aluminum-silicon alloys, the operation of modifying the various materials was obtained.

There is a method of modifying high-grade aluminum alloys by introducing hexachloroethane and phosphorous copper l into the melt.

The disadvantage of this method of modification is the formation of large inclusions of aluminum phosphide with m. Pl. 18 ° C, which are insoluble in neither solid nor liquid state.

By machining the products, these inclusions are partially crumbled to form pores, which absorb moisture from the air and make hydrogen phosphorus. Hexachloregane, when modified, is an aluminum alloy degasser. Because of its low melting point and volatility, it burns out before the start of the process of dissolving phosphorous copper, and therefore has little effect on the phosphorus inclusions removal process.

The closest in technical essence to the present invention is the method of modifying aluminum alloys with carbides of certain metals 2.

15

Known carbide-containing. modifiers are rather weak modifiers.

The purpose of the invention is to improve the mechanical and operational properties of cast

20 high-silicon aluminum alloys.

This goal is achieved by the fact that according to the method of modifying high, 1 aluminum-based alloys. including the introduction of modificat a into the melt of carbide-containing, in the melt powdered calcium carbide with a grain size of 3-10 mm in an amount of 0.6-0.8%. from the weight of the charge. When PS is added to oshkoobraznogo calcium carbide in aluminum foil in the melt, one finds a change in the shape and size of the primary phases and the morphology of the eutectic component, which entails an increase in the durability of molded products, by nqpHMep pistons fsied diesel engines. The proposed values of the fractional composition of calcium carbide of 3-1O mm are chosen experimentally and are optimal. For high-silicon aluminum alloys, tfichem 3 mm lower hedel is accepted from the condition that the introduction of a finer fraction of modifier tfi leads to partial volatilization and ignition , and the top is 1 ohm; because the calcium pieces are more coarse, the 4-factor oxidizes and does not completely dissolve. The choice of modifier quantity is determined by numerous samples and is the optimal value. At the same time, the input of 0.6–0.8% he9) bs1v calcium from the weight of the mixture satisfies the requirements of the modal structure of alloy structures: the grinding of 1 primary crystals of silicon, the thinning of the diffusion of aluminum-silicon eutectic, the increase of their strength characteristics. When entering the amount of modi fi cation ea below the lower limit, coarsening of the primary silicon crystals, intermetallic compounds is observed, the aluminum-silicon eutectic is formed as a structure of a coarse conglomerate, and when introduced into the amount above the upper limit, a partial modification of the structure occurs, which leads to uneven properties over the section, which leads to uneven properties over the section, which leads to uneven properties over the section, which leads to uneven structure modification, which leads to uneven properties over the section, which leads to unequal properties over the section, which leads to uneven structure, which leads to uneven structure, which leads to uneven properties over the cross section. The high-silicon aluminum alloy AK18 is molded and ipo is modified with various amounts of the modifier proposed. A number of experimental industrial heats and testing of their mechanical properties were carried out. The table shows the properties obtained by testing the AK18 alloy. Limit of rogenicity of alloys of ori fi ortofimate for powdered calcium carbide. E s burns at 3-5 kgf / mm, beats, fna in action on O, 1 kgf / mm, hardness at 40 yd. HB The use of a new modifier gives “a significant economic effect when modifying high-silicon aluminum alloys.

Phosphor copper with a phosphorus content of 8.5-1O% in the form of tiles

Powdered calcium carbide fraction 3-1О mm

Also

0.2

78

80

0.2

0.27

115

Oh 3

121

0.24

108

80

0.21 Formula 3 on the line and Method of modifying high-silicon alloys based on aluminum, including the introduction of a carbide-containing modifier into the melt, characterized in that, in order to improve the mechanical and operational properties of cast high-silicon aluminum alloys, powder is introduced into the melt - 9 2 were calcium carbide with a particle size of 3-10 mm in the amount of 0.6-O, 8% by weight of the mixture. Sources of information are taken into account in the examination 1. Patent of England N 9477О2, cl. C 7 A, 1964. 2. B. I. et al. / Joining of aluminum deformed fuses. M., Metallurgists, p. 63-65,

Claims (1)

Claim A method of modifying high-silicon aluminum-based alloys, comprising introducing a carbide-S holding modifier into the melt, characterized in that, in order to increase the mechanical and operational properties of the cast high-silicon aluminum alloys, porous 10- calcium calcium carbide with a grain size of 3-10 mm in the amount of 0.6-0.8% of the weight of the mixture.