DD270931A1 - WEAR-RESISTANT BRASS ALLOY - Google Patents

Abstract

The invention relates to a wear-resistant brass alloy, in particular with pronounced wear resistance under sliding stress under elevated temperatures and with sufficient cold workability, which finds application in narrowed Haerteverten for the production of Ventilschaftfuehrungen of internal combustion engines. According to the invention, the object is achieved in that an alloy contains 57 to 58.6 mass% Cu, 1.4 to 1.8 mass% Al, 1.6 to 2.2 mass% Mn, 0.5 to 0.8 mass% Si, 0.4 to 0.6 mass% Pb, 0.5 to 0.8 mass% Fe, 0.2 to 0.4 mass% Sn, balance Zn and whose structures consist of more than 80% of b-mixed crystals, wherein the alloy is cold-formed by drawing.

Description

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Xitel of the Invention Wear-resistant brass alloy

Field of application of the invention

The invention relates to a "wear-resistant brass alloy, in particular with pronounced wear resistance under sliding stress under elevated temperatures and with excellent cold workability, which is used in the case of narrowed hardness values for the manufacture of valve stem guides of internal combustion engines.

Characteristic of the known technical solutions

Some copper-based alloys have a pronounced wear resistance "With the advancement of the state of leohnik it is therefore endeavored this copper-based alloys _t in ohemisoher and kristallographisoher Hinsioht to adapt each neuon technical tasks" Especially guides in the valve stem and valve seat rings of internal combustion engines, which are exposed to the action of hot Verbrennungegase, Meohanisoher and ohemisoher attack at high thermal stress simultaneously on the material ein · For this application, complex alloys were developed whose components are the combination of their properties to ensure the performance properties of the resulting component «

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For example, the addition of zinc to copper in the presence of mishoh crystal hardening is said to increase the strength of the alloy, and the formation of thin oxides of both metals through self-lubricating properties improves wear resistance. "Thus, tin and aluminum enhance alloy strength and wear resistance as well as the corrosion resistance · Low iron contents are "fine" while lead additives improve the machinability · Silicon and Hangan are the main carriers of wear resistance due to the formation of manganese siliols "To increase the hardness it is known to additionally alloy other metals, for example chromium and phosphorus (SB -AS 2 145 690) ·

Duroh adding more items has been tried, the stand · »

It is an alloy of this type which provides for the addition of niocel and tellurium (DE-AS 1 287 313).

Furthermore, an alloy is known in which, in addition to other alloy constituents, arsenic or beryllium is used or these elements are replaced by selenium and sulfur or zirconium or titanium (DE-OS 1 558 466j DE-OS .1 558 467).

Such complex alloys are metallurgically so dominate. At least special-purpose processes or sintering processes are necessary for their production.

Despite the improvement in the Versohlesselfsassen, which have roughened the described measures, these materials meet the demands that modern engine construction demands on them, nioht · It has therefore been proposed to increase the wear resistance of Vontilsohaftführungen La manufacturing process duroh extrusion molding (DE-OS 558 470} DB-OS 1 558 471)

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In order to enable a cold deformation of the semifinished product duroh flowing or duroh a Kalibrierzug "the Zuscumensetzung the alloys is chosen so that they are at least at room temperature in the pO " area *

In addition, it was assumed that / Q shares in the mold promoted especially the trumpet-shaped widening of valve guides, their proportions were limited to έ 30 % (OS-OS 1 558 470). This influence was to be compensated by extrusion molding.

On the other hand, the high pC content of the alloy leads to difficulties in the hot processing of alloys and requires special measures during the extrusion process.

Object of the invention

The aim of the invention is to develop a wear-resistant brass alloy which, on the one hand, does not require any NaOH division in the case of valves produced therefrom and, on the other hand, considerably increases the running time of the internal combustion engine.

Explanation of the essence of the invention

The invention has for its object to provide a brass alloy with pronounced wear resistance under sliding stress at elevated temperatures, the processing should be easily möglloh on modern extrusion presses for further processing optimum temperature and cold at room temperature is sufficiently cold to be processed on continuous drawing machines to be able to ·

According to the invention, the object is achieved in that an alloy contains 57 to 58.6 mass% Ou, 1.4 to 1.8 mass% Al, 1.6-2.2 mass% Mn, 0.5 to 0, 8 Hasse- * Si, 0.4 to

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0.6 mass- £ Pb, 0.5 to 0.8 mass-Te, 0.2 to 0.4 mass-S6 Sn, remainder Zn, and of which more than 80 pounds of isohacrite portions are present *

It is also essential to the invention that the alloy is durably cold-formable. "

Ausführungsbeiepiel

The invention will be explained in more detail below with reference to an example. The following compositions of the alloys are significant for the production of valve bushings for internal combustion engines!

Example 2

Out 57.5 mass-56

example 1 58.3 mass £ W Out 1.41 It Old 1.61 Il Mn: O ₁ , 65 Il Sit 0.49 W Pb t 0.71 η Fet 0.29 W Sn: rest Zn:

Old Mn: Sit Pbt Fet Sn t Zn:

1.52 1.99 0.74 0.46 0.68 0.37 remainder

η η

N M If H

81 %

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The alloys mentioned in Examples 1 and 2 can be cold-drawn to finished dimensions on continuously operating drawing machines and are therefore suitable for a large-scale production process. «

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Claims (2)

claims 1. Wear-resistant brass alloy, in particular with a high compressive wear resistance under elevated temperatures, characterized in that an alloy contains 57 to 58 * 6 M & sse-Ji Ou, 1.4 to 1.8 mass-Al, 1.6 to 2.2 mass * Mn, 0.3 to 0.8 mass * Si, 0.4 to 0.6 mass * Fb, 0.5 to 0.8 mass * Fe, 0.2 to 0 , 4 mass- * Sn, remainder Zn and whose structure consists of more than 80 % of η mixed crystals · 2 · Brass alloy according to claim 1, characterized in that the alloy is cold-formable by a drawing operation.