CN1015000B - Zn-base alloy for making holder of bearing entity - Google Patents

Abstract

The present invention relates to zinc base alloy for making a rolling bearing entity keeper and other abrasion resistant structural members, which is composed of 25 to 35% of Al, 0.1 to 1.5% of Cu, 0.005 to 0.15% of Mg, 0.5 to 5.0% of Pb and Zn as the rest. Titanium salt modification treatment and metal type or centrifugal casting are adopted, and the zinc base alloy can also be shaped by a press casting or liquid forging method. The strength, the plasticity and the tenacity of the zinc base alloy by a casting through heat treatment. The strength sigma b of the zinc base alloy is greater than or equal to 441 N/mm<2>, and the elongation rate delta of the zinc base alloy is greater than or equal to 14%. The impact tenacity alpha of the zinc base alloy is greater than or equal to 75 J/cm<2>. The zinc base alloy has good cutting processability, and the abrasion resistance of the zinc base alloy is superior to the abrasion resistance of lead brass.

Description

Zn-base alloy for making holder of bearing entity

The present invention is a kind of zinc base alloy, is used to make rolling bearing body retainer and other abrasion-proof structure part.

The mobile bearing entity retainer is the abrasion-proof structure part in the rolling bearing.It bears the wearing and tearing and the impact of rolling body at work, requires it to have the certain deformation ability during running in bearings again, so require material to have high intensity and wear resistance and enough plasticity and toughness.That use is more at present is leaded brass ZHPb59-1, and its shortcoming is the low (σ 〉=245N/mm of intensity ²), wear no resistance, especially to consume a large amount of copper, the material cost height, the fusing energy consumption is big.Make the rolling bearing body retainer with zinc base alloy Alloy instead of Copper alloy, not only can save the copper of a large amount of costlinesses, shortage, reduce starting material and manufacturing cost, and intensity, wear resistance, the work-ing life that can improve retainer.Present widely used zinc base alloy ZnAl127, the intensity height, wear resistance is good.Under the sand mold casting condition, its tensile strength is 400～441N/mm ²But because the copper-rich phase ζ phase (CuZn that distributes along crystal boundary is arranged in the alloy structure ₃) exist, in use, crackle easily from the junction germinating and the expansion of ζ phase and crystal grain, causes intercrystalline fracture, so its plasticity low (unit elongation is 3～6%), (impelling strength is 31～54J/Cm to poor toughness ²).The existence of ζ phase is simultaneously also handled to solid solution aging and is brought difficulty.The thermal treatment process that external recommendation is used for ZnA127 is a furnace cooling after being incubated 3 hours under 320 ℃, though handle the plasticity of back alloy raising is arranged, but still obvious deficiency, and intensity reduces significantly.Its machinability is relatively poor in addition, so ZnA127 can't satisfy the performance requriements of holder of bearing entity to material.Chinese patent application number is " a kind of Zi-Al-Co-Mn alloy for bearing " document of 85105072, frictional coefficient reaches the bigger shortcoming of grinding spindle amount more greatly when being used as bearing metal at the ZnAl127 alloy, by changing alloying constituent and content, the microstructure that makes alloy is the polyphase structure that discrete distribution hard point, the hard point is to be base with compound MnA16, solid solution a spot of other element.Therefore the hard point because of discrete distribution in the tissue, reduced friction area, improved lubricating condition, reduced the frictional coefficient of fricting couple piece and, and self is wear-resisting, zinc base alloy is applied to preferably on the wearing pieces such as bearing shell, axle sleeve the wearing and tearing of axle journal.But, owing to contain manganese, and constituent content such as copper, magnesium is higher, formed the bigger rich manganese phase hard point of fragility in the alloy structure, inclined to one side glomerocryst circle of magnesium elements and one deck magnesium film is arranged again at grain surface, and still exist the copper-rich phase ζ phase that distributes along crystal boundary in the tissue, cause the plasticity of alloy and toughness to reduce that (unit elongation is less than 3%, and impelling strength is 19～25J/cm ²) can not increase substantially its plasticity and toughness with heat treating method, so can not be used to make holder of bearing entity and other is to plasticity and the higher abrasion-proof structure of toughness reguirements.

Task of the present invention is: develop a kind of zinc base alloy that is suitable for making rolling bearing body retainer and other to the higher wear knots member of plasticity and toughness reguirements, this alloy strength height, wear resistance is good, enough plasticity and toughness are arranged, to the cast moulding method wide adaptability, excellent cutting performance can obviously improve the mechanical property of alloy by thermal treatment.

The present invention is that a kind of zinc-aluminium is the alloy of base, adds a spot of copper, magnesium, lead, cerium and other element and carries out alloying, and with titanium salt (K ₂TiF ₆) processing of going bad.For avoiding hard embrittlement compound phase occurring, do not contain manganese element in the alloy.ζ phase for preventing that grain boundary segregation from forming the magnesium film and distributing along crystal boundary reaches maximum solid solution strengthening effect again, so the strict content that limits copper and magnesium in the alloy ingredient.The raising of machinability and friction, lubrication realizes by adding lead element.The chemical ingredients of alloy (by weight percentage) is: Al:24～35%; Cu:0.1～1.5%; Mg:0.005～0.015%; Pb:0.5～5.0%; Ce:0～.5%(or mishmetal 0～1%), surplus is zinc and unavoidable impurities.

Advantage of the present invention is the intensity height (σ b 〉=441N/mm of alloy ²), plasticity good toughness (unit elongation δ 〉=14%, impelling strength a _k〉=75/cm ²), wear resistance is higher than leaded brass, and machinability is good, easily chip breaking, the workpiece surface finish height, material cost is low, and (lighter by about 40%) in light weight than leaded brass, the fusing power consumption is low, wide adaptability to cast moulding method, can under as cast condition, directly use, also can make the further highly malleablized of alloy, be applicable to be manufactured on rolling bearing body retainer and other abrasion-proof structure part of working below 120 ℃ by thermal treatment.

Embodiments of the invention:

With the A1-50%Cu master alloy crucible heat fused of packing into of preparation in advance, add the zinc that accounts for total amount 3/4ths again, fusing is heated to 600～720 ℃, with the titanium salt processing of going bad, adds magnesium, lead and remaining zinc more earlier.Alloy pours into and is divided into Al:24%, Cu:1.5%, and Mg:0.015%, Pb:0.5%, Ce:0.02%, surplus is Zn.Available alloy liquid directly pours into a mould rough casting or the cast alloy cast ingot is standby.Available centre spinning method cast form, 530～560 ℃ of teeming temperatures, centrifuge speed is looked the diameter of part size and is selected in 600～1200 rev/mins of scopes; Also can adopt sand mold, graphite mould, permanent mold casting, die casting or the cast form of liquid forging method.The alloy casting state microstructure is a polyphase structure, is made up of the interdendritic uneven eutectic structure of rich aluminium α phase dendrite (changing Zn-Al binary eutectoid through the solid-state phase changes rear section into).Foundry goods reheats to 300～360 ℃ of insulations and cools off in water after 4～12 hours, then ageing treatment.Alloy microscopic structure after the processing is the tiny and uniform granular (tissue of α+η+ζ) (granularity is less than 1um).

Claims (3)

1, a kind of zinc base alloy that is used to make rolling bearing body retainer and other abrasion-proof structure is characterized in that, by Al24～35%, Cu0.1～1.5%, Mg0.005～0.015%, Pb0.5～5.0%, Ce0～0.5% or mishmetal 0～1%, surplus are that Zn forms.

2, the manufacture method of the described zinc base alloy of claim 1 is characterized in that, adopts titanium salt K during alloy melting ₂TiF ₆The rotten processing, treatment temp is 600～720 ℃.

3, the heat treating method of the described zinc base alloy of claim 1 is characterized in that, 300～360 ℃ the insulation 4～12 hours after water-cooled, timeliness then.