DE102013106635A1 - Conduit element for the exhaust system of a motor vehicle - Google Patents

Abstract

Proposed is a line element (2) for the exhaust system of a motor vehicle with internal combustion engine, with at least one flexible conduit part (3), preferably bellows. The line element (2) is characterized in that the flexible line part (3) at least partially in a first steel with a Mo content ≥ 4% or ≥ 6% and with an N-share between 0.3-0.6% or between 0.18-0.25%, preferably a grade 1.4565 or 1.4547 grade steel. Further proposed is a decoupling element (1) for motor vehicles with internal combustion engine and a related use of steel with a Mo content ≥ 4% or ≥ 6% and with an N-fraction between 0.3-0.6% or between 0.18 -0.25% is formed, preferably a steel of the grade 1.4565 or 1.4547.

Description

The invention relates to a line element for the exhaust system of a motor vehicle with internal combustion engine, which line element at least one flexible conduit part, preferably a metallic corrugated hose or bellows, according to the preamble of claim 1. In the context of this description, the term "exhaust system" includes not only exhaust pipes, but explicitly also exhaust gas recirculation lines, unless specified otherwise.

Moreover, the invention relates to a decoupling element for motor vehicles with an internal combustion engine, preferably for exhaust pipes or exhaust gas recirculation lines, according to the preamble of claim 4, and a use of certain materials according to claim 6.

For decoupling (EKE), which are used in exhaust systems of motor vehicles with internal combustion engine to decouple vibrations induced by the engine of other components of the exhaust system, are usually stainless austenitic steels, preferably so-called standard austenite, z. As the materials 1.4301, 1.4541 or 1.4571 used. On the one hand, line elements used in this area must withstand high thermal loads due to the temperature of the exhaust gas flow passed through and, on the other hand, have to be particularly resistant to corrosion at least on their outside, since such line elements, when used in or on motor vehicles, absorb moisture and other corrosive media, in particular brine, are exposed.

It is therefore known from the prior art, at least in the outer region of line elements for the exhaust system of a motor vehicle nickel base materials, eg. B. 2.4856, use. As a result, a particularly good corrosion resistance is achieved, but has the disadvantage that nickel base materials over the standard austenites mentioned above are many times more expensive.

Since the corrosion resistance of standard austenites, for example 1.4571, is not sufficient for certain applications, in many applications an intermediate solution is desirable in which the price as well as the corrosion resistance of the material is between the respective values for the materials 1.4571 and 2.4856. In order to remedy this situation, steel manufacturers have in the past become active and have developed their own alloys and filed for industrial property rights. These include Special Metals' Incoloy 864 and Incoloy 865 materials and Allegheny's 332Mo and 334Mo materials.

In this context, however, has proved to be disadvantageous that the price-performance ratio of the mentioned steel developments Incoloy 864/865, 332Mo and 334Mo is relatively unfavorable. Due to the strictly limited supply situation, there were again and again in the past, price increases or delivery problems.

The invention has for its object to provide a conduit element or a decoupling element of the type mentioned above, which is characterized in that it can be formed from a worldwide and possibly obtainable by more than one steel manufacturer alloy, the price of which is approximately in the middle between the prices for the materials 1.4571 and 2.4856, whereby the corrosion resistance should be clearly better than with the material 1.4571. In this way, the disadvantages mentioned above with regard to the procurement situation, the production costs and the corrosion resistance should be avoided.

The above object is achieved by a line element with the features of claim 1 and by a decoupling element with the features of claim 4 and a use with the features of claim 6. Advantageous further developments are the subject of dependent claims.

An inventive line element for the exhaust system of a motor vehicle (motor vehicle) with internal combustion engine, with at least one flexible conduit part, preferably in the form of a bellows, is characterized in that the flexible conduit part at least partially in a first steel with a Mo content ≥ 4% or ≥ 6% and is formed with an N content of between 0,3-0,6% or between 0,18-0,25%, preferably a grade 1.4565 steel or a grade 1.4547 grade steel. Here, "Mo content" denotes the molybdenum content and "N content" the nitrogen content of the steel. According to the invention, both the Mo content and the N content are relatively high.

An inventive decoupling element for motor vehicles with internal combustion engine, preferably for exhaust pipes or exhaust gas recirculation lines, is characterized by a line element according to the invention.

A use according to the invention relates to the use of steel with a Mo content ≥ 4% or ≥ 6% and with an N content of between 0.3-0.6% or between 0.18-0.25%, preferably one Steel of grade 1.4565 or 1.4547, for the manufacture of components for a Conduction element or a decoupling element for the exhaust system of a motor vehicle with internal combustion engine, preferably for a flexible conduit part, most preferably bellows.

The applicant has determined in extensive experiments that specifically the materials 1.4565 and 1.4547 mentioned meet the requirements formulated above. According to the knowledge of the applicant and these materials have not been used for line elements or decoupling elements for the exhaust system of motor vehicles, especially not used there, flexible, thin-walled line parts, because the appropriate suitability has not been recognized.

The proposed materials offer a significantly increased corrosion resistance at comparatively low additional costs compared to standard austenites. For this reason, components made from them last longer, which on the one hand increases customer satisfaction and on the other hand helps to save resources by avoiding scrap.

The proposed materials, in particular 1.4565, are known per se, but are hardly used nowadays. What is new in any case is their use proposed in the present application.

A first development of the conduit element according to the invention provides that the flexible conduit part is formed in multiple layers with an inner layer and an outer layer and optionally additional intermediate layers. It can be provided that at least the outer layer of the flexible pipe part is formed in the first steel to increase specifically in this area, the corrosion resistance to external harmful effects.

Another development of the conduit part according to the invention can provide that the inner layer is formed in a second steel, because in relation to the inner layer, the corrosion resistance often plays only a minor role. In the said second steel may be a steel with a relatively low nickel content, as it is for example in the DE 10 2007 060 133 A1 is disclosed. Alternatively, in particular the inner layer can also be formed in another material, for example in a standard austenite, preferably 1.4301, 1.4541 or 1.4571. The same applies in principle also to any intermediate layers.

A further development of the decoupling element according to the invention provides that there at least one further component, preferably an outer component, most preferably a surrounding the flexible conduit part braid or knitted sheath, is formed in the first steel to selectively increase the corrosion resistance at low additional cost ,

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing.

1 shows partially and in longitudinal section an inventive decoupling element with a conduit element according to the invention;

2 shows partially and in longitudinal section a multi-layered flexible conduit part; and

3 shows results of a salt bath dipping test for different types of steel.

1 shows schematically and in longitudinal section a decoupling element 1 for motor vehicles with internal combustion engine, preferably for exhaust pipes or exhaust gas recirculation lines. Reference symbol AS denotes that within the decoupling element 1 guided exhaust flow, while reference LA the longitudinal axis of the decoupling element 1 indicates. The decoupling element 1 is rotationally symmetrical with respect to the longitudinal axis LA formed.

The decoupling element 1 includes a conduit element 2 , Which in the present case as a largely flexible conduit part in the form of a bellows 3 is trained. Furthermore, the decoupling element comprises 1 in a manner known per se, a radially inside the bellows 3 arranged inner component 4 , For example, a winding tube or liner, as well as a radially outside of the bellows 3 arranged outer component 5 For example, a mesh or knitted sheath. The joint connection of bellows 3 , Inner component 4 and outer component 5 takes place terminally in the area of end sleeves 6 , For example, by welding and / or pressing. An inventive decoupling element 1 however, is by no means limited to the embodiment described above by way of example.

The bellows or the flexible conduit part 3 is presently formed in a special metallic material of the grade 1.4547 or 1.4565, so that the flexible conduit part 3 has a suitable for automotive applications in the exhaust gas corrosion resistance, without this being associated with a significant disadvantage in terms of manufacturing costs and / or the procurement situation. In principle, other components of the decoupling element 1 , in particular the outer component possibly coming into contact with corrosive media 5 and / or the end sleeves 6 be formed in one of the aforementioned materials. Especially for the internal component 4 , but also for other components of the decoupling element 1 with the exception of the flexible line part 3 However, other materials may be used in the present invention, for example, the already mentioned standard austenite or so-called low-nickel materials, as in DE 10 2007 060 133 A1 disclosed.

2 shows schematically and in longitudinal section a special design of the flexible conduit part 3 as with the decoupling element 1 according to 1 can be used.

According to 2 is the flexible conduit part 3 multi-layered and has an inner layer 3a as well as an outer layer 3b on. Between the inner layer 3a and the outer layer 3b may be arranged one or more intermediate layers, which in 2 are not shown. The two block arrows in 2 symbolize on the one hand on the outside situation 3b acting harmful influence (SE), for example in the form of corrosive media, such as moisture and / or brine, for example, by the seasonal use of road salt. The other block arrow TE symbolizes the first on the inner layer 3a acting temperature influence of the exhaust stream AS, wherein the temperature influence TE due to the intimate connection of the inner layer 3a and the outer layer 3b of course also in the area of the outer layer 3b is effective.

In the embodiment according to 2 is now preferably only the outer layer 3b , which is directly exposed to the harmful influence SE, formed in the material 1.4565 or 1.4575. The inner layer 3a On the other hand, it may preferably be made in another material, such as one of the standard austenites mentioned or a low-nickel material, in order to achieve a cost optimization in the production. The same applies to any intermediate layers (not shown).

3 shows graphically the result of a salt bath dip test, testing tape samples of various specified materials over 60 cycles and at a temperature of 650 ° C. After the tape samples were heated in an oven at 650 ° C for 30 minutes and then cooled for 10 minutes, salt water immersion was carried out for 1 minute in a 5% road salt solution. The abscissa indicates the residual wall thickness measured as a percentage of the original strip thickness. The ordinate shows the alloy surcharge payable on purchasing the materials shown in euros per kg (as of January 2011).

As the presentation in 3 can be easily seen, cut the materials proposed in the present invention 1.4547 and 1.4565 in terms of corrosion resistance (highest possible residual wall thickness) even better than the mentioned in the introductory part special steel developments Incoloy 864/865 and 332Mo / 334Mo. With regard to the alloy surcharge, which should be as small as possible, they are at least to be regarded as equivalent to the special steel developments mentioned. In comparison with the standard austenite 1.4571, there is likewise a markedly increased residual wall thickness with only a slightly increased alloying addition. Only the nickel base material 2.4856 mentioned at the beginning cuts even better with regard to the remaining wall thickness, but has a value added by more than a factor of 2 for the alloying addition.

In particular, the material 1.4565, but in addition also the material 1.4547, is thus particularly suitable for the use indicated above in the field of automotive exhaust systems. In particular, the material 1.4565 is long known per se, but not for applications in the field of exhaust systems or for the production of decoupling elements.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007060133 A1 [0016, 0024]

Claims (6)

Conduit element ( 2 ) for the exhaust system of a motor vehicle with internal combustion engine, with at least one flexible conduit part ( 3 ), preferably bellows, characterized in that the flexible conduit part ( 3 ) is formed at least in part in a first steel with a Mo content ≥ 4% or ≥ 6% and with an N content of between 0.3-0.6% or between 0.18-0.25%, preferably one 1.4565 grade or 1.4547 grade steel. Conduit element ( 2 ) according to claim 1, characterized in that the flexible conduit part ( 3 ) in several parts with an inner layer ( 3a ) and an outer layer ( 3b ) is formed, and that at least the outer layer ( 3b ) is formed in the first steel. Conduit element ( 2 ) according to claim 2, characterized in that the inner layer ( 3a ) is formed in a second steel with a relatively low nickel content, preferably as disclosed in DE 10 2007 060 133 A1, or in a standard austenite, preferably the material 1.4301, 1.4541 or 1.4571. Decoupling element ( 1 ) for motor vehicles with internal combustion engine, preferably for exhaust pipes or exhaust gas recirculation lines, characterized by a line element ( 2 ) according to one of the preceding claims. Decoupling element ( 1 ) according to claim 4, characterized in that at least one further component of the decoupling element ( 1 ), preferably a flexible conduit part ( 3 ) surrounding woven or knitted sheath ( 5 ), is formed in the first steel. Use of steel with a Mo content of ≥ 4% or ≥ 6% and with an N content of between 0.3-0.6% or between 0.18-0.25%, preferably 1.4565 or 1.4565 steel 1.4547, for the manufacture of components for a conduit element ( 2 ) or a decoupling element ( 1 ) for the exhaust system of a motor vehicle with an internal combustion engine, preferably for a flexible line part ( 3 ), most preferably bellows.

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