DE2306898A1 - PROCESS FOR PRODUCING A PISTON RING WITH A RESISTANT SURFACE AGAINST WEAR AND EATING - Google Patents

Description

2305898

February 10, 1973 IG / ES

Hippon Piston In Go., Ltd.

Lo. 1-18, Uchisaiwai-eho 2-chom.e,

Ghiyoda-ku,

Tokyo / Japan

Process for the production of a piston ring with a surface that is resistant to wear and scuffing

The invention relates to a method for producing a piston ring with a piston ring that is resistant to wear and scuffing Surface, as well as a piston ring manufactured according to this process.

The invention aims at piston rings for internal combustion engines manufacture that are resistant to abrasion, wear and the like.

It is known that the compression ratio and the speed of rotation of the internal combustion engines have recently been markedly increased in order to be able to build more powerful motors. Accordingly, the piston rings in internal combustion engines are exposed to increased wear: they have to work under severe operating conditions, but still perform well. The amount of wear resistance tanaes on piston rings depends on a number of parameters, which include their ability to wear . withstand, that is, to withstand the abrasive action caused by small solid bodies of high hardness. But this also includes resistance to being eaten away. Therefore, in order to use piston rings in modern internal combustion engines,

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which have a highly effective wear resistance it. desirable both the resistance in terms of wear and tear as well as the resistance to erosion.

Various piston rings are already known which have increased wear resistance. These include piston rings, which are chrome-plated on the sliding surfaces (hereinafter referred to as chrome-plated piston rings). Piston rings are also known whose sliding surfaces have a molybdenum coating hereinafter referred to as molybdenum-coated piston rings.

However, the chrome plated piston rings have not been found to be satisfactory because chrome plating is an expensive one Method is, and also because such piston rings do not have sufficient resistance to seizure. In a similar way The piston rings coated with molybdenum are inadequate and have not been introduced to the market to any significant extent, because they have a relatively high price, they also have a low wear resistance.

This is why the chrome-plated or molybdenum-coated piston rings have not caught on because they do not have the ability to withstand high enough resistance to both wear and tear to oppose. However, these properties are required for piston rings when they are essentially wear-resistant meant to be.

The invention is based on the object of avoiding the above parts and of specifying a method for producing piston rings or piston rings ₉ by means of which piston rings are produced or piston rings are present which have adequate resistance to both wear and pitting. According to the invention, a piston ring is provided

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produced, on the upper TJinfangsf lache a multi-component alloy is applied, which gives the piston ring aasgezeichen properties in terms of wear and pitting. The multi-component alloy, with which the outer circumferential surface of the piston is coated, is produced by simultaneously ^{spraying about 30 to 95 c} ß> molten kolybdenum and about 5 to 70 fo a molten iron alloy onto the piston ring. The obtained coating contains an iron alloy, lolybdenum and combinations of iron alloy and molybdenum, and certain empty spaces.

One embodiment of the invention is shown in the drawing and is explained in more detail below. Show it:

1 and 2 are sectional views of piston rings, on which layers with the composition according to the invention are sprayed on or sprayed on.

3 is an enlarged, fragmentary, sectional view of a portion of the piston ring on which the liner is attached was sprayed on according to the invention.

For the production of piston rings, which have an increased resistance to wear, a layer or a coating is applied or deposited on the outer circumferential surface of the piston ring, into which 30 to 95 ^c ß> molten kolybdenum and 5 to 70 % of a molten iron alloy are sprayed at the same time and thus a surface is formed which is resistant to both wear and scuffing, this surface or the surface layer being iron alloy, molybdenum and compositions of iron alloy and molybdenum, and also voids.

if less than about 30 <} ί molybdenum is used, it turns out that the piston ring does not have the required hardness.

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On the other hand, if more than $ 95 molybdenum is knocked down it can be determined that there is a continuous drop in strength in the deposited layer and consequently a drop in wear resistance.

If less than 5 $> iron alloy is deposited, the strength in the layer of precipitation decreases, thus also the wear resistance, but if the deposit contains more than 70 $ of the iron alloy, the correct mutual mixture of iron and molybdenum will not occur in this layer which, however, is necessary to ensure the improved resistance to wear and seizure in piston rings.

One of the most important advantages of the manufactured according to the invention Piston ring consists in the firm connection between the precipitated metal particles in the coating and the piston ring body underneath, so that the Separation of the extremely hard, solid particles in the coating Ehicht pressed down to a minimum during the rubbing and sliding movement on the 6-counter body of the piston ring will. As a result, the abrasion on the opposing body is by itself .. Any separating particles are also reduced, and a piston ring is obtained that is highly resistant to wear.

By comparison, known piston rings have a Molybdenum layer was deposited, usually an extremely low strength, on the order of • 450 kg per cm. This unfavorable property is due to poor or loose bonding between the pest body particles returned in the deposited layer, with the result that the resistance to wear is low.

In the method or piston rings according to the invention causes • or. facilitates the presence of particles on the high Temperature located iron alloy in the molten, the

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Precipitation forms metal that. firm bond of Layer to the underlying piston ring body and improves the alloying ability of the molybdenum particles and the Iron alloy particles during the formation of the precipitated Layer or the coating. As a result, there is a uniform structure of rigid bonds, with the difficult binding or adhesion of the molybdenum particles is overcome, which is bound and bound by the total alloy (alloy combination) of iron alloy and molybdenum be firmly supported. This is illustrated in FIG. 3, the molybdenum particles 1 and the composite alloy 2 shows, where Ite tere a compound or combined Alloy of the iron alloy and molybdenum is.

In Fig. 3, the iron alloy particles are 3 and the voids 4 · as well as the embedding material A shown.

The entire coating formed by precipitation thus forms or effects an improved, more rigid and firm bond has a higher dielectric strength in the layer, however also a higher wear resistance compared to known piston rings.

Furthermore, the coating according to the invention is also a better lubricating effect due to the voids 4, Fig. 3, achieved, which serve to keep the lubricant in the deposited Layer to be deposited between the material particles. This effect also occurs with the known piston rings that are coated with molybdenum. In addition, the composite alloy is the piston ring coating according to the invention from the iron alloy, furthermore from a composition of iron alloy and molybdenum, from molybdenum particles and the voids and includes shallow pits formed on the iron particles because of the difference in hardness between the iron alloy particles and the molybdenum particles and because of the resulting differences

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Wear effect on iron alloy particles and molybdenum particles marry, are educated.

The increase in resistance to seizure in the invention ■ piston rings according to the invention is furthermore covered by an anti-friction iron oxide film achieved on a surface part of the "'iron alloy particles during the formation of the precipitated Coating is molded. The iron oxide film has an extremely low coefficient of friction, which results in an increased Y / resistance against seizing. Similarly, molybdenum oxide is formed on the molybdenum particles, thereby increasing the resistance further is achieved against erosion «,

Aas the foregoing it can be seen that the present invention can produce an improved piston ring, in which a composite alloy coating is present, the Tsen by 'Spr & the liquid material is obtained, which 30 Ms 95 includes i> molybdenum and from 5 to 70 ^c /> iron alloy, the Coating covers the "G-guiding surface of the piston ring. This composite alloy coating formed in this way consists of iron alloy particles (particles), of further particles from the combination of iron alloy and molybdenum, and also of molybdenum particles and voids. Such a piston ring has an increased resistance to wear as well as against erosion, namely because of the structural properties peculiar to the layer as well as the characteristic values of the individual particle components and finally because of the interrelationship of the particles from different constituents or materials in the deposited layer.

Can different carbon steels be used in the manufacture of the piston ring according to the invention _? z. B. a 13-chromium stainless steel or 13 ^ .Chrom containing stainless steel. According to a further embodiment of the invention

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is considered essential that the selected iron alloy the property is supposed to have, that in this case the entire downcast Coating a hardness above HRG 25 (according to the fiockwell measurement) to have. The production of piston rings by the process according to the invention can be seen from the following examples emerged.

example 1

A conventional steel piston ring was provided on its outer circumferential surface with a shaft-shaped coating applied by means of median impact of molten material, which coating has a thickness of 3 dm. The layer was formed by simultaneously spraying 50 Jo molybdenum and 50 # molten carbon steel, with 0.8 fa carbon content, onto this outer surface of the piston ring. The coated circumferential surface of the piston ring has a tensile strength of 1950 kg / cm and a Rockwell hardness of 40.

This layer can be applied to the outer circumferential surface of the piston ring as in the cross-sections according to Pig. 1 and! Ig. 2 can be seen, dejected v / ground.

Example 2

A commercially available piston ring made of steel was provided on its outer circumferential surface with a 0.3 mm thick coating of molten metal deposited in layers. The film was prepared by simultaneously spraying of 80 io molten molybdenum and 20 $ 13 of molten / ° chromium-containing stainless steel of the piston ring surface. The coated circumferential surface of the piston ring shows a tensile strength of 1820 kg / cm and a Rockwell hardness of 40.

This layer can be deposited on the piston rings with a distribution or structure that can be seen in FIGS. 1 and 2, or it can also be deposited differently, depending on the individual case. According to the invention , see Pig. 2, here A is the sprayed layer, B the sliding surface, C a furrow.

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Even if the method according to the invention or the method according to the invention Piston ring discussed in the context of a layer of deposited composite alloy such composite alloy or the coating of it includes corresponding modifications, see above that this composite alloy also has rigid oxides, nitrides, carbides, silicides, sulfides and fluorides or theirs Elements a. Depending on the individual case, the inventive Teaching similar or equivalent process steps or compositions are used.

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Claims (1)

February 10, 1973 ΐα / Eö Process for producing a piston ring with a surface that is resistant to wear and scuffing Nippon Piston Hing Go., Ltd. Claims ^ Method for producing a piston ring or the like with more resistant to wear and galling surface, characterized in that equilateral> gescxiiuolzenes molybdenum and from 5 to 70 ° fo an iron alloy is sprayed on as f or sprayed onto the sliding surface of the Xolbenringkörpers 50 to 95 i, wherein the iron alloy is selected so that the sprayed-on layer has a hardness of about HRC 25 (Rockwell hardness 25) or more, so that the layer formed consists of a mixture of particles of this iron alloy, particles of an iron alloy and molybdenum formed alloy! and molybdenum particles and that the surface parts of the layer are oxidized to iron oxide and molybdenum oxide or contain this oxide, and that this layer also has voids. 2. The method according to claim 1, characterized in that the iron alloy and the molybdenum in approximately equal proportions by weight be splashed. 3. The method according to claim 1, characterized in that as Iron alloy a carbon steel is used. 309835/1091 4. The method according to claim 1, characterized in that " stainless steel is used as the iron alloy. 5 .. The method according to claim 3, characterized in that a steel with 0.8 fo carbon is used as the carbon steel. 6. The method according to claim 4 _5, characterized in that the stainless steel used is one with 13 "/ <> chrome (13-chrome steel). 7. Hach one of the methods according to claim 1 to 6 manufactured piston ring, characterized in that the dielectric strength its coating layer is about 1800 kg / cm. 8. Piston ring according to one of the preceding claims, characterized in that a coating layer contains about 80 fo molybdenum and about 20 $ iron alloy, 9. piston ring or the like, in particular according to one of the preceding claims, characterized in that its metallic base body has a layer of solidified Efiederschlagsmetall, which has about 30 to 95 fo molybdenum and 5 to 70 fa of a molten iron alloy, such that the layer has a Rockwell hardness of 25 or more, and that in this layer there is a mixture of epidemics which consist of this iron alloy, also an alloy consisting of this iron alloy and molybdenum, and of molybdenum, that the surface parts of the layer in 3? orm of iron oxides and molybdenum oxides are present, and that voids are also present in the layer. 309 835/109 1