SU1735419A1 - Alloy on the basis of aluminium - Google Patents

Abstract

The invention relates to alloys based on aluminum used for the manufacture of wear-resistant parts operating at temperatures up to 400 ° C. The aim of the invention is to increase thermal stability, which is achieved by the additional content of cerium, chromium, iron and bismuth nitrides. Alloy based on aluminum contains, wt%: silicon 1.1-6.0; copper 4.1-9.0; tin 1.0-2.9; lead 0.1-1.3; titanium 0.03-0.6; boron 0.002-0.05; cerium 0.1-0.5; chromium nitrides 0.02-0.32; iron 0.02-0.8; bismuth 0.002-0.005; aluminum else. The alloy has the following properties: Vickers hardness 520-551 MPa: tensile strength at 250 and 400 ° C, respectively 130-142 and 98-112 MPa; thermal stability during thermal cycling (before cracking) at 250 and 400 ° C; C, respectively, 80-97 and 38-47 cycles; friction wear resistance at 250 and 400 ° C, respectively 72-83 and 85-109 mg / m2 gs. 2 tab. cl

Description

The invention relates to metallurgy, namely, aluminum-based alloys used for the manufacture of wear-resistant parts operating at temperatures up to 400 ° C.

The aim of the invention is to increase thermal stability.

The goal is achieved by the fact that an aluminum-based alloy contains tin, lead, silicon, titanium, copper, boron, as well as cerium, chromium nitrides, iron and bismuth in the following ratio, wt.%:

Tin1.0-2.9

Lead 0.1-1.3

Silicon1,1-6,0

Titanium0.03-0.6

Copper 4,1-9,0

Bor0,002-0,05

Bismuth 0.002-0.005

Chromium nitride 0.02-0.32

Iron0.02-0.8

Cerium0,1-0,5

Aluminum Else

The addition of chromium nitrides improves heat resistance, shredding the structure and increasing wear resistance. When the concentration of chromium nitrides to 0.02 wt.% Grinding the structure and improving wear resistance and thermal stability

VI from the next

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insufficient. With an increase in the concentration of chromium nitrides of more than 0.32 wt.%, The homogeneity of the structure, the stability of wear resistance, thermal stability and mechanical properties decrease.

Cerium has a modifying effect on the structure, improves the casting and technological properties of the alloy, increases the shape factor of silicon precipitates in the structure and thermal stability. The modifying effect of cerium and an increase in the shape factor of silicon precipitates in the structure and thermal stability of the alloy begins to show with a cerium concentration of 0.1 wt.%. The upper limit of the concentration of cerium is due to an increase in the carbon monoxide and an increase in the content of non-metallic inclusions in the structure, which reduces the mechanical properties and thermal stability.

The additional introduction of iron in an amount of 0.02–0.8 wt.% Provides hardening of the alloy and an increase in its hardness and thermal resistance, and also allows the use in melting of the alloy not only pure metals, but also ferroalloys. However, with an increase in the iron content of more than 0.8 wt.%, The structure is enlarged, the coefficient of friction and wear under friction at 250-400 ° C increase.

The lower limits of the content of the alloying components are increased to concentrations (silicon 1.1 wt.%, Copper 4.1 wt.%), Providing structure hardening and improving heat resistance. The upper limit of the lead content is reduced to 1.3 wt.%, Since its higher concentrations reduce the thermal resistance, hardness, and wear resistance of the alloy.

The tin content (1.0-2.9 wt.%) Corresponds to the optimum concentration, and the lower concentrations of copper and boron are increased to 4.1 and 0.002 wt.%, Which is due to the low wear resistance characteristics and the thermal resistance of the alloy at lower concentrations. At boron concentrations greater than 0.05% by weight, the structure homogeneity and antifriction properties of the alloy are reduced.

Bismuth was introduced to reduce the coefficient of friction and increase wear resistance, technological and mechanical properties of alloys. At a bismuth concentration of up to 0.002 wt.%, Thermal resistance, wear resistance and mechanical properties are reduced. With an increase in bismuth concentration of more than 0.005 wt.%, Technological and strength properties and wear resistance are reduced at 250-400 ° C.

To test the proposed alloy, the compositions were prepared as follows. Copper M1 and aluminum AB91 are introduced into a graphite crucible of an induction open furnace, melted under a flux layer. Then, the melt is deoxidized and microligrated with ferrosilicon FS75 and ferrocerium FCI1 IM with stirring. Tin, chromium nitrides, lead and bismuth are then sequentially introduced. After soaking for 2-3 minutes at 750-760 ° C, the melt is poured into dry forms to obtain billet sleeves, process samples and samples for mechanical testing.

In tab. Figures 1 and 2 respectively show the chemical composition of the tested compositions of the proposed alloy and their properties in comparison with the known alloy.

As can be seen from table 2, the proposed alloy exceeds the well-known thermal resistance, mechanical properties at elevated temperatures and wear resistance.

Claims (1)

Alloy based on aluminum, containing silicon, copper, tin, lead, titanium and boron, characterized in that, in order to improve thermal stability, it additionally contains cerium, chromium nitrides, iron and bismuth in the following ratio of components, wt.% : Silicon1.1-6.0 Copper 4,1-9,0 Tin1.0-2.9 Lead 0.1-1.3 Titanium0.03-0.6 Bor0,002-0,05 Cerium0,1-0,5 Chromium nitride 0.02-0.32 Iron0.02-0.8 Bismuth 0.002-0.005 Aluminum Else table 2 -j with SP . Thermal resistance is determined by the number of cycles of thermal cycling before the occurrence of cracks on castings such as bushings.