RU2001158C1 - Method of manufacturing articles from zinc-aluminiun alloys - Google Patents

Abstract

The invention relates to metallurgy. The method is carried out as follows. A melt of a given composition on zinc-aluminum sonic is poured into a mold, cooled to a solid state in the R mold. The casting is subjected to preliminary heat treatment (quenching, or normalization, or annealing) then deforms 6–99% at a temperature tt (t is the ectectoid transformation temperature t - the melting onset temperature), followed by cooling at a speed of 10-30 deg / s. Then the product is aged. The application of the method increases the logarithmic decrement (in absolute value) of products from CA 39 splice by 0.3 - 2.9%, from CA22 alloy by 0 , 5 - 6.3 from alloy CA15 - by 0.3 - 6.1% 1 tab.

Description

The invention relates to metallurgy, in particular, to a method for manufacturing articles of zinc-aluminum based spavas having high damping ability.

A known method of producing a damping zinc-aluminum alloy, including homogenization at a temperature below the melting point, but above 250 ° C for 5 minutes to 100 hours, cooling, cold plastic deformation of at least 5%, heating at a temperature of not higher than 250 ° C for 5 minutes - 100 hours cooling. The method is taken as a prototype.

The disadvantage of the prototype method is that it does not provide a sufficiently high damping ability of the alloy.

The purpose of the invention is to increase the damping ability of a zinc-aluminum alloy.

The goal is achieved by the fact that the method includes casting the melt into a mold, cooling it in a mold to a solid state, preliminary heat treatment (quenching, or normalization, or annealing), deformation of 6-99% at a temperature of: e (+ 5 ° C) -tcHO ° C) (where that is the eutectoid transformation temperature, tc is the melting onset temperature), cooling to room temperature at a rate of 10-300 deg / s, aging at a temperature not exceeding 250 ° C.

Significant differences are as follows. The proposed method differs from the prototype in the presence of hot (rather than cold) plastic deformation, which leads to grinding of the high-temperature o1 -, a - and / 3 phases (depending on the chemical composition), as well as the subsequent quick cooling after deformation, which fixes in comparison with a known process a more dispersed structure with a more developed interphase boundary. As the experiment showed, such a finely dispersed structure has a higher ability to dissipate the energy of mechanical vibrations (see table).

The method of preliminary heat treatment does not play a significant role in the formation of the final damping ability. The adoption of several methods of preliminary heat treatment is caused by a possible variety of technologies in the manufacture of various products. Methods of hot deformation can be different, for example: pressing (extrusion, extrusion), rolling, drawing, allowing to maintain the temperature of deformation above b.

Examples of specific performance.

Three alloys were taken: the eutectoid composition CA22 (aluminum 22.7%, the rest is zinc,

microadditives and impurities), hypoeutectoid

composition - CA15 (aluminum 15.3%, the rest

zinc, microadditives and impurities) and the hypereutectoid composition CA39 (aluminum 38.5%, the rest is zinc, microadditives and impurities).

The alloys were smelted in an open crucible. The melt was poured into metal molds. Castings after hardening were subjected to various preliminary heat treatments: CA15 ignition from 350 ° C,

CAA22 - normalization from 350 ° C, CA39 - hardening from 350 ° C, and then, after machining the castings to the desired size, heated to hot plastic deformation temperatures. Plastic deformation

was carried out by the simplest method for this method - by hydroextrusion method: CA39 alloy at 280, 320 and 445 ° C. CAA22 alloy at 280, 350, 410 ° С, CA15 alloy at 280.350 and 372 ° С Each

at each of the indicated temperatures, the alloy underwent deformation with a degree of 6, 33, 55, 99%. After hot plastic deformation, the preforms were cooled to room temperature at a rate of CA15-10,

CA22 - 300, CA39 - 100 deg / s, then subjected to aging at 70 ° C for 2 hours. The known treatment was carried out on the same alloys according to the regimes that coincided, where possible, with the proposed method: homogenization at. within 2 hours, air cooling, cold plastic deformation 55%, aging at 70 ° C for 2 hours

When assigning the temperature range of hot plastic deformation, it was assumed that the temperature excess tc

-10 ° C is dangerous due to the possibility of melting the alloy, and the heating temperature is lower

B5 ° C is not practical, because the monotekgoid transformation upon cooling, which plays a large role in increasing the damping ability of the alloys, may not occur. The degree of plastic deformation was determined by the formula (D-d) / D 100%, where D is the initial diameter of the workpiece. d is the final diameter of the workpiece. Maximum degree of plastic deformation

-99% is determined by the technical capabilities of the hydroextrusion method used. Samples were prepared from appropriate preforms to measure damping ability. The damping ability was determined by the torsional matrix method using the logarithmic decrement tests presented in

that d) at the amplitude of torsional vibrations} -5 - 105

Table results

From the table and the above treatment modes, it can be seen that a method involving hot plastic deformation with a degree of 6-99% (examples 1-4). forms a higher damping ability in zinc-aluminum alloys compared to the known method (example 5)

Obtained due to processing by the proposed method, the effect of increasing the damping ability will reduce vibration, noise of dynamically loaded products

(56) Japanese application No. 61-4414431, cl. C 22 F 1/10, 18/00. 1986.

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Claims (1)

The claims METHOD FOR PRODUCING PRODUCTS FROM ZINC-ALUMINUM ALLOYS, including preliminary heat treatment, plastic deformation and aging, characterized in that, in order to increase the damping ability of the alloys, an additional casting is carried out before the preliminary heat treatment Table continuation 4A22 35 (D 3.2 4.2 4.4 5.5 2T ABOUT-   80L b 8g 2 b | ; 71 I 3.5 | 7.4, 4.5 8.4 | 6.2 Ji 2.3 the melt into the mold, preliminary heat treatment is carried out by quenching, normalization or annealing, and plastic deformation is carried out at a temperature of te + 5 ... tc - 10 with a degree of 6 - 99%, followed by cooling at a speed of 10 - 300 deg / s where Te is the eutectoid transformation temperature, tc is the melting onset temperature, C.