BG51113A1 - Aluminum-based casting alloy - Google Patents

Abstract

The alloy is used for making parts operating at high temperatures, especially for internal combustion engines. It has a low coefficient of thermal expansion and high mechanical properties at elevated temperatures. It contains in wt.%: silicon 10-13, copper 0.8-1.8, nickel 0.3-1.3, magnesium 0.8-1.3, manganese 0.01-0.6, zirconium 0.02-0.2, iron 0.4-0.9, titanium 0.05-0.4, zinc 0.1-0.9, chromium 0.02-0.4, vanadium 0.02-0.2, molybdenum 0.01-0.15 and the rest is aluminum.

Description

The invention relates to non-ferrous metallurgy and aluminum-based casting alloys used for the manufacture of parts operating at high temperatures and internal combustion engines.

A known foundry alloy based on aluminum, solder

dry, wt.%: Silicon 11.0-13.0 Copper 0.8-1.5 Nickel 0.8-1.3 Magnesium 0.8-1.3 Aluminum the rest

Impurities : no more than: D θ 710 30 0.7 Zinc 0.2 Manganese 0.2 Titanium 0.01 /I/.

Mechanical properties of the alloy are as follows: Strength limit, kgf/mm ² at temperature:

20°C ' 20-25

150°C 18-23

250°C 10-15

Tverdoet /nV/ at:

20°C 90-110

150°C 70-90

250°C 35-40

Coefficient of thermal expansion /20-200°0/·Ι0θ· city ¹ - 20.5-21.5.

An increase in the power of the internal combustion engines leads to the burnout. worn out and failed pistons made of splag of reduced composition. The reason is low heat resistance of the alloy, decrease in hardness at full /Х0-200°C/ temperatures, besides the alloy has low corrosion resistance.

The closest to the proposed alloy in terms of technical essence and achievable result is the well-known foundry alloy based on aluminum, containing, wt./:

Silicon 10-12

Copper 0.8-1.8

Nickel 0.8-1.3

Magnesium 0.8-1.3

Manganese 0.2-0.6

Zirconium 0.02-0.2

Deleuzeau 0.4-0.9

Titanium 0.05-0.4

Zinc 0.21-0.9

Vanadium 0.02-0.2

Aluminum alloy /2/.

However, the known alloy has an insufficiently low coefficient of thermal expansion and insufficiently high mechanical properties at room and elevated temperatures.

The purpose of the invention is to reduce the thermal expansion coefficient and quench the mechanical properties at room and ambient temperatures.

Для доставчие postаЕленной цели an aluminum-based cast alloy containing silicon, copper, nickel, magnesium, manganese, zirconium, iron, titanium, zinc and . vanadium, additionally contains chromium and molybdenum in the following ratio of components, wt./:

Silicon 10-13

Copper 0.8-1.8 Nickel ι 0.8-1.3 Magnesium : 0.8-1.3 Manganese 0.01-0.6 Zirconium 0.02-0.2 Celezo 0.4-0.9 Titanium 0.05-0.4 Zinc 0.1-0.9 Chrome 0.02-0.4 Vanadium 0.02-0.2 Molybdenum 0.01-0.15 Aluminum the rest.

Addition of molybdenum in the alloy leads to grain grinding, which increases hardness, strength and load-bearing elongation. Increase in molybdenum content by more than 0.15%. leads to the formation of large intermetallics, which reduces the workability of the alloy. A decrease in the content of molybdenum less than 0.01$ reduces the modifying effect, that is, the improvement of mechanical properties is not observed.

Introduction of chromium in an alloy - improves the exchangeable properties and reduces the tendency of the casting to form cracks. An insignificant amount of chromium in an alloy /0.02-0.4^/ provides an increase of 10-20;» strength and hardness of the alloy while maintaining the values of relative elongation and impact viscosity. Chromium in quantity. 0.02-0.4$ provides a reduction in the coefficient of thermal expansion. Increase in hardness and strength of the alloy when chromium is introduced due to the formation of a triple phase бгч ζ>ί ₄ . With a chromium content of less than 0.02$, mechanical properties do not improve, as such content is insufficient for the formation of a triple phase, and chromium is in solid solution. The maximum content of chromium in the alloy /0.4$/ determined by the ztectic point in the system α£-0^ at. at a temperature of 661.2°C. With increased chromium content, more than 0.4?» a solid phase is formed, which loses weight 4

5111?

Shaet casting properties eplava.

... When the content of silicon in the melt is reduced by less than 10%, the hardness is sharply reduced and the linear expansion increases, an increase in the content of silicon more than 13% leads to the precipitation of an excess phase of silicon, which worsens the conditions of mechanical processing of products from this alloy.

Copper introduced into the alloy for increased heat resistance. With a copper content of less than 0.8%, no improvement in mechanical properties is observed. An increase in the copper content of the alloy above 1.8% reduces the corrosion resistance of the alloy.

Likel increases the ultimate strength of the ZEtectic sheet. A decrease in the nickel content of less than 0.8% does not affect mechanical strength, and an increase of more than 1.3% leads to overexpenditure of deficit/abundance of metal without improvement of strength properties.

Magnesium in a zvtectic alloy in the range of 0.8-1.3% strengthens it due to the presence of magnesium-containing phases of the 6Υ type. When the magnesium in the alloy decreases, the hardening phase does not burn, the mechanical properties of the casting do not improve, an increase in the magnesium content leads to embrittlement of the alloy.

(~ Manganese in the alloy improves the structure, improves heat resistance. A decrease in the manganese content in the alloy of less than 0.01% does not result in positive alloying, an increase in the manganese content of more than 0.6% leads to the formation of inter-thallide phases /Mts H& !ξ>ί., which reduces the mechanical properties of the alloy.

...Zirconium refines the enamel structure, improves mechanical and anti-corrosion properties. A decrease in zirconium content of less than 0.02% does not increase the corrosion value of the plate, an increase of more than 0.2% leads to peremodification, which negatively affects the strength of the casting.

iron in alloy has a similar effect

51115 nickels and partially replaces it, however, an increase in its content more than 0.9$ worsens the casting. properties of the alloy, reducing the iron content to less than 0.4% reduces heat resistance.

Titanium exerts a strong modifying influence on the structure of the alloy, especially when paired with zirconium. Titanium completes the mechanical properties of the alloy, increases heat resistance.

The minimum titanium content is 0.05$, with a lower content of the modified effect, no modification effect is observed, an increase in the titanium content of more than 0.4% leads to deterioration of the mechanical properties of castings.

Introduction to the alloy of zinc is called not to bypass the improvement of cast alloys, moreover, zinc stabilizes the solid solution of elements in aluminum, which improves the mechanical properties of the alloy. An increase in the zinc content in the alloy more than 0.9$ causes liquidation, which reduces the heat resistance of the alloy, a decrease in zinc concentration less than 0.10$ does not have a positive effect on the properties of the alloy.

Vanadium introduced into the alloy in the amount of 0.02-0.2$, which provides an improvement in the alloy's mechanical and casting properties.

For testing the proposed alloy, compositions were prepared, the chemical composition of which is shown in Table I.

51117

Table I

Component Content of components, wt.$ 3 suggested splage composition 3 known alloy composition I ά 3 4 5 Silicon 10.0 10.9 11.5 12.3 13.0 11.0 Copper 1.8 1.3 1.2 1.0 0.8 1.5 Nickel 0.8 0.85 1.0 1.3 1.05 1.0 Magnesium 1.3 1.1 1.05 0.8 0.97 . 0.95 Manganese 0.01 0.23 0.60 0.46 0.30 0.4 Zirconium 0.02 o,n 0.15 0.2 0.05 0.1 Iron oh,4 0.65 0.7 0.71 0.9 0.8 Titanium 0.05 0.1 0.14 0.22 0.4 0.1 Zinc 0.10 0.4 0.5 0.8 0.9 0.6 Chrome 0.02 0.32 0.21 0.4 0.08 - Vanadium 0.02 0.15 0.09 0.11 0.2 0.1 Molybdenum 0.15 0.05 0.01 0.1 0.08 - Aluminum ost ost ost ost U ost ost

. Tests of the tested compositions of the proposed splzvz were carried out on castings in several samples. The resulting test of the proposed. the alloy in comparisons with the known given in table 2.

Table 2

Properties Alloy

Proposed News

I 2 3 4 .5 6 Strength limit 9 kgf/mm at tempera- tours: 20°C 31Λ 32.0 31.8 33.1 32.0 28.0 150°C 26.9 28.0 27.1 28.4 27.9 24.1 250°C 21.0 20.8 22.9 22.0 22.0 18.0 Terdost HΙ 5 at: 20°C 135 120 125 140 135 100.0 15O°C PO 100 PO PO P5 90 200°C 85 90 88 80 85 70

Coefficient of thermal expansion /20-200°0/

S ⁶ city 17 L 17.6 Ι7,Ι„17.3 17.1 19.6

Thus, as can be seen from Table 2, the ultimate strength of the braze increased to 30 kgf/;,!./, the coefficient of thermal expansion decreased to 18*10 ^о град"^or to 5/3 $, the hardness of the alloy increased to 10 $.

Claims (1)

FORMULA OF INVENTIONS An aluminum-based cast alloy containing silicon, copper, nickel, magnesium, manganese, zirconium, iron, titanium, zinc and vanadium, distinguished by the fact that, in order to reduce the coefficient of thermal expansion and increase the mechanical properties at room and elevated temperatures, it additionally contains chromium and molybdenum in the following ratio of components, wt.£: Silicon 10-13 Copper 0.8-1.8 Nickel 0.3-1.3 Magnesium 0.8-1.3 Manganese 0.01-0.6 Zirconium 0.02-0.2 Iron 0.4-0.9 Titanium 0.05-0.4 Zinc 0.1-0.9 Chrome 0.02-0.4 Vanadium 0.02-0.2 Molybdenum 0.01-0.15 Aluminum the rest Sources of information, consideration at expertise: