EA016324B1 - Babbit alloy - Google Patents

Abstract

The invention relates to metallurgy, in particular, to materials used in sliding bearings working in special-purpose conditions under large and impact loads with high sliding speeds. The invention is aimed at enhancing wear ability and increasing life time thereof. The task is solved by using a proposed babbit alloy for manufacturing and repair inserts of sliding bearing comprising copper, silicon, antimony, iron, aluminium and tin with the following component ratio. wt%:

Description

The invention relates to the field of metallurgy, and in particular to materials operating in sliding bearings for critical purposes under high and shock loads at high sliding speeds.

The material intended for such products should have high wear resistance, a low coefficient of friction between the shaft and the bearing, have sufficient ductility for better fit to the shaft surface; hardness sufficient for the liner as a shaft support, but not causing strong wear of the shaft itself; have the ability to retain lubricants. To do this, it should consist of a soft base with solid inclusions evenly distributed in it.

Bearing alloys are known, called babbits, for example B16, used for the manufacture of bearings it has the following composition, wt. %:

antimony 15.0-17.0 copper 1.5-2.0 tin 15.0-17.0 lead the rest [1,2,3].

The disadvantage of this alloy is its high lead content, high brittleness and reduced wear resistance.

The closest in technical essence to the claimed alloy is B-83 babbit GOST 1320-74 of the following composition, wt. %:

antimony 10-12 copper 5.5-6.5 lead 0.3 - 0.35 tin 82.0 - 84.0

The disadvantages of this alloy include the high content of expensive tin, the presence of lead and insufficient wear resistance.

The objective of the present invention is to improve the operational properties of babbitt, primarily, wear resistance and service life of the sliding bearing while maintaining the remaining high characteristics.

The problem is solved in such a way that aluminum, silicon and iron are additionally introduced into the babbit alloy containing tin, antimony and copper in the following ratio of components, wt. %:

copper 2.5-4.5 silicon 2.0-3.3 antimony 5.0 - 7.0 iron 0.2 - 0.5 aluminum 7.0 - 8.0 tin 79.0-81.0

The given ratio of components provides a combination of high mechanical, casting and operational properties of the proposed alloy.

Comparative analysis with the prototype shows that the claimed technical solution differs from the known one by the presence of new components, namely aluminum, silicon and iron, a decrease in the tin content, and also the absence of lead, which indicates that the proposed technical solution meets the novelty criterion.

As an example, smelting of alloys is carried out, the chemical composition of which is given in Table 1. Table 1. The chemical composition of the alloys

No. Type of alloy Component Content Chemical composition, % 8p 8b Si B 81 A1 Re one Famous B-83 middle 83.0 11.0 5.7 0.3 - - - 2 Proposed lower 79.0 7.0 2,5 0,0 3.3 8.0 0.2 3 Proposed upper 81.0 5,0 4,5 0,0 2.0 7.0 0.5

The smelting of alloys was carried out in an electric furnace using a known technology. The following materials were used as charge materials: GOST 860-75 tin, GOST 1089-82 antimony, GOST 859-2001 copper, GOST 2169-69 silicon, GOST 11036-75 iron, GOST 11069-2001 aluminum.

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Aluminum helps to increase the corrosion resistance and wear resistance of the alloy due to the formation on the surface of the part of the protective layer containing oxide L1 ₂ 0z or other, more complex oxides containing aluminum. The silicon content in the selected range of 2.0-3.3% provides the necessary hardness and wear resistance of the alloy and slightly increases its heat resistance. Iron is necessary to stabilize the alloy.

________ Sample _______ B-83 GOST1320-74 babbit (average percentage composition of components) Suggested alloy (lower limit of component content) _______

The proposed alloy (the upper limit of the content of components)

Studies of the strength properties of the investigated materials were conducted. According to the methods described in [4], the Brinell hardness (HB) of the samples was determined, and the compressive strength was also determined. The research results are presented in table. 2.

Table 2. Strength properties of babbit materials

Strength, MPa __________110___________ __________110___________

110___________ __________89___________ __________95___________

93___________ __________106___________ ___________105___________

103

Hardness, HB

30.1

30,0

29.9

24.4

25.9

25.5

28.8

28.5

28.2

The table shows that the Brinell hardness and, accordingly, the compressive strength, for samples of the proposed alloy is much less than for samples of babbit B-83 GOST 1320-74, which reduces shaft wear in sliding bearings.

The wear resistance of the alloys was evaluated according to the results of the wear of the samples when tested on a MI-1M friction machine designed to test materials for friction and wear, with a kinematic scheme of peripheral sliding friction with coverage of a rotating shaft.

The tests were carried out in the presence of lubricant (turbine oil ТП 22С ТУ 38.101821-2001). The sample was tested at a load of 19.6 MPa and was paired with a counterbody (steel 40X). During sliding friction, the counterbody in the form of a disk rotates, and the sample in the form of a block is motionless. The total test time for each sample was at least 25 hours. The wear of the samples was determined every two hours of testing during running-in and every five hours in steady state, and was estimated by weight loss by weighing with an accuracy of 10 ^-4 g. The results of comparative tests of known and claimed alloys are given in table. 3.

Table 3. The results of comparative tests of the known and claimed alloys

No. Sample Load, P, MPa Time, ΐ, 4 Depreciation, t, g Sliding Speed, V, m / s Wear rate, μg / km Wear rate V, mg / h Coefficient of friction to one 2 3 4 5 6 7 8 nine one Babbit B-83 GOST1320-74 19.6 2 0.0017 1.68 142 0.85 0.032-0.009 19.6 2 0,0003 1.68 16.7 0.1 0.009-0.008 19.6 5 0,0004 1.68 thirteen 0.08 0.008 19.6 5 0,0003 1.68 10 0.06 0.008 19.6 5 0,0004 1.68 thirteen 0.08 0.008 19.6 5 0,0003 1.68 10 0.06 0.008 19.6 5 0,0003 1.68 10 0.06 0.008 2 The proposed alloy (lower limit of the content of components) 19.6 2 0.0043 1.68 358 2.15 0.051-0.010 19.6 2 0.0000 1.68 0 0 0.010-0.009 19.6 5 0.0000 1.68 0 0 0.009-0.008 19.6 5 0.0000 1.68 0 0 0.008 19.6 10 0.0000 1.68 0 0 0.008 19.6 10 0.0000 1.68 0 0 0.008 19.6 fifteen 0.0000 1.68 0 0 0.008 3 The proposed alloy (the upper limit of the content of 19.6 2 0.0040 1.68 333 2.0 0,050-0,010 19.6 2 0.0000 1.68 0 0 0.010-0.009 19.6 5 0.0000 1.68 0 0 0.009-0.008

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The table shows that in the steady state in the samples of the inventive alloy, wear was not detected even for a period of time ten times longer than the period for which wear was detected for the sample from B-83 babbit, which suggests that the wear of the samples from the claimed the alloy is at least an order of magnitude smaller than that of a sample of B-83 babbit.

The results shown in tables 2 and 3 indicate that the proposed alloy has an optimal combination of mechanical and operational properties. Thus, the proposed alloy in comparison with the prototype has higher properties and meets the task during development. In addition, the absence of lead improves its environmental performance.

The proposed alloy will be widely used at gas transportation enterprises, for example, at Belgazenergoremont Beltransgaz OJSC for repair of plain bearings of the GPA STD-4000 gas pumping unit, as well as at other enterprises using bearings operating in difficult conditions.

The used literature [1.] E.I. Marukovich, M.I. Karpenko. Wear resistant alloys. Moscow., Engineering, 2005 p.52.

[2.] D.F. Gelin. Metallic materials. Directory. Minsk., Higher School, 1987, p. 353360.

[3.] D.O. Slavin. E.B. Steiman. Metals and alloys in chemical engineering and apparatus engineering. Moscow., Mashgiz, 1951, p. 437-440.

[4.] Elyutina O.P. Practical issues in metal testing. - M., Metallurgy, 1978. 277 p.

Claims (1)

CLAIM Babbit alloy containing tin, antimony and copper, characterized in that it is additionally introduced aluminum, silicon and iron in the following ratio of components, wt.%: copper 2.5-4.5 silicon 2.0-3.3 antimony 5.0-7.0 iron 0.2-0.5 aluminum 7.0-8.0 tin 79.0-81.0 Eurasian Patent Organization, EAPO Russia, 109012, Moscow, Maly Cherkassky per., 2