WO2012175271A2

WO2012175271A2 - Use of a hot gas corrosion-resistant ductile alloy

Info

Publication number: WO2012175271A2
Application number: PCT/EP2012/059585
Authority: WO
Inventors: Albrecht Geissinger; Simon Schmittinger; Pavlo Saltikov
Original assignee: Robert Bosch Gmbh
Priority date: 2011-06-21
Filing date: 2012-05-23
Publication date: 2012-12-27
Also published as: WO2012175271A3; CN103620072A; EP2726638A2; JP2014522450A; DE102011077893A1; JP5774215B2

Abstract

The invention relates to the use of a hot gas corrosion-resistant ductile alloy, containing 36 to 39 wt.-% nickel, 20 to 23 wt.-% chromium, 0 to 0.12 wt.-% carbon, 0 to 1 wt.-% manganese, 1.3 to 2.2 wt.-% silicon, 0 to 0.5 wt.-% aluminum, 0.03 to 0.5 wt.-% lanthanum, 0 to 0.03 wt.-% sulphur, 0 to 0.03 wt.-% phosphorus, and 0 to 0.5 wt.-% copper, remainder iron, the sum of all components not exceeding 100 wt.-%, as a material for glow tubes of sheathed glow plugs for compression-ignition engines and other components that are exposed to high temperatures and corrosive gases.

Description

Description title

The invention relates to the use of a hot gas corrosion resistant ductile alloy in components exposed to high temperatures and corrosive gases. For example, the alloy can be used as a material for the manufacture of glow plugs of glow plugs. Glow plugs are used for the cold start of

Diesel engines are used and are exposed to high temperatures and corrosive gases.

On glow plugs high demands are placed on the heating rate and the annealing temperature. Glow plugs with a metallic glow tube typically reach annealing temperatures in the range of about 1000 ° C to 1050 ° C, with higher temperatures are possible for a short time. Despite the high annealing temperatures, the material used must have good creep resistance, so that the glow tube remains dimensionally stable and does not bend. The position of the glow plug to the

Injection jets are important for the optimal ignition of the fuel. Therefore, a deformed glow plug would result in uneven combustion with increased pollutant emissions when used in an internal combustion engine. In addition, the glow plugs are exposed to corrosive gases in the combustion chamber, which can attack the material of the glow tube. A corroded glow tube can no longer prevent the ingress of air, water and other substances and leads to the destruction of the resistor element contained and thus to the failure of the glow plug. To withstand the high temperatures and the corrosive gases are used for the glow tubes

Nickel-based alloys with very high nickel contents of over 50 wt .-% used.

Such a glow tube is known, for example, from DE 10 2009 000 751 A1. It is made of a nickel base alloy by a forming process (deep drawing) or by extrusion of a compound from a metal powder or by metal powder injection molding. In addition to the application in glow plugs components are made

hot gas corrosion resistant alloys used in other applications, especially in the automotive field as spark plugs for internal combustion engines, in

Exhaust gas turbochargers, in protective tubes for sensors. In heating technology, these alloys are used to manufacture ignition electrodes and various sensors.

Nickel-base alloys are very expensive because of the high price of nickel and, depending on the composition, have adverse processing properties.

For example, the alloy NiCr25FeAIY has an excellent oxidation or

Corrosion resistance and also a high creep resistance, but can be processed only to a limited extent in forming processes. Components such as a glow tube can not be made of this alloy by e.g. Deep drawing can be made. There must be other, more elaborate manufacturing methods used. The alloy NiCr23Fe, on the other hand, is easy to shape. Due to their lower oxidation and

However, creep resistance is not something made of this alloy for all

Applications in conjunction with corrosive gases and very high temperatures suitable.

From EP 21 15 179 B1 a nickel-chromium-silicon alloy with a reduced nickel content of less than 42 wt .-% is known, which has a high oxidation resistance and

Creep resistance has.

Disclosure of Invention According to the invention, the use of a hot gas corrosion resistant ductile

Alloy containing 36 to 39 wt .-% nickel, 20 to 23 wt .-% chromium, 0 to 0.12 wt .-% carbon, 0 to 1 wt .-% manganese, 1, 3 to 2.2 wt. % Silicon, 0 to 0.5 wt% aluminum, 0.03 to 0.5 wt% lanthanum, 0 to 0.03 wt% sulfur, 0 to 0.03 wt% phosphorus, 0 to 0.5 wt .-% copper, balance iron, the sum of all components does not exceed 100 wt .-%, as a material for glow tubes of glow plugs for

Compressor engines and other components that are exposed to high temperatures and corrosive gases proposed. Such an alloy is offered under the material number 1 .4888 (X10NiCrSiLa38-22). To improve the long-term properties of the material, in each case one or more of the elements cerium, yttrium, zirconium, hafnium, titanium can be alloyed with up to 0.5% by weight.

Table 1

In Table 1 is a comparison of the elongation at break between the nickel alloys NiCr25FeAIY, NiCr23Fe and the proposed alloy for use in glow tubes with the material number 1 .4888. The data are taken from the DIN standards "DIN 17750: 2002-09" and the data sheet "Cronifer 40B Material Data Sheet No. 4051 March 2010 Edition". Despite the reduced nickel content, the alloy with the material number 1 .4888 has a high elongation at break and can be processed well by forming.

This alloy has a high oxidation resistance and a good creep stability at the annealing temperature. The alloy is ductile and can easily be transformed like NiCr23Fe.

The glow tube is formed from this alloy by means of a forming process. Used in the glow plug according to the invention permanent annealing temperatures of up to 1050 ° C and short-term up to 1 100 ° C are possible. The alloy is resistant to the in

Combustion chamber of an internal combustion engine present corrosive influences and remains dimensionally stable even at high temperatures.

The hot gas corrosion resistance of alloy no. 1.4888 is inferior to that of NiCr23 Fe and NiCr25 FeIlY alloys.

Due to the advantageous properties of the alloy with the material number 1.4888 such as temperature resistance and corrosion resistance as well as the easy formability, it is also suitable for other components that are exposed to high temperatures and corrosive gases. Conceivable further uses for the alloy arise, for example, as spark plugs for internal combustion engines, exhaust gas turbocharger, protective tubes for Sensors and in heating technology for ignition electrodes in oil burners or gas burners as well as for flame sensors.

Advantages of the invention

The glow tube made of the alloy with the material number 1 .4888 has a high temperature resistance up to 1 100 ° C. Without any restrictions on the service life, a maximum annealing temperature of 1 100 ° C and a high afterglow temperature of 1050 ° C can be achieved. The glow tube is furthermore resistant to the corrosive influences present in the combustion chamber of an internal combustion engine. This ensures that the resistance element enclosed by the glow tube is also protected and prevents premature failure of the component. Furthermore, the glow tube has a good resistance to deformation. This ensures a good ignition of the fuel mixture and thus a uniform combustion with low emissions when using the glow plug in an internal combustion engine.

Although NiCr25FeAIY fulfills the corrosion resistance requirements of the currently widely used nickel-based alloys, the material costs are very high due to the high nickel content. All previously used alloys have in common is the high nickel content, and thus a high material price.

The alloy proposed for use in a glow tube shows good

Properties with reduced nickel content and facilitates the manufacture of the glow plug by its formability. The alloy with the material number 1.4888 can be easily formed by forming processes such as extrusion, drawing, deep drawing and other processes.

The advantages mentioned can also be transferred to other uses of the alloy, such as spark plugs for internal combustion engines, exhaust gas turbochargers, protective tubes for sensors and ignition electrodes and flame sensors in heating technology.

Brief description of the drawings

Fig. 1 shows an embodiment of the glow plug according to the invention. Embodiments of the invention

In Fig. 1, the inventive use of the alloy with the material number 1 .4888 is shown as a material for the glow tube 4 of a glow plug 1 1. The

Shunt plug 1 1 comprises the glow tube 4, which encloses a resistance element 12, a housing 5 and electrical connection devices in the form of a round plug 10.

The resistance element 12 enclosed by the glow tube 4 comprises a heating coil 1 on the side facing the combustion chamber of an internal combustion engine and a control coil 3 on the side facing the circular connector 10. The remaining interior in the glow tube 4 is filled with an electrically insulating heat conducting powder 2 such as, for example, magnesium oxide powder , The heating coil 1 has a nearly

temperature-independent electrical resistance, while the electrical resistance of the control coil 3 increases with increasing temperature. In the cold state of the

Resistance element 12, the electrical resistance of the control coil 3 is low and it can flow a large current through the heating coil 1. As a result of the following heating, the resistance in the control coil 3 increases and the current flow decreases. In this way, the temperature in the glow tube 4 is controlled independently of external control devices. It is also conceivable, however, an embodiment without control coil 3, in which the temperature is controlled in other ways, such as with an external control device.

The resistance element 12 is electrically conductively connected on one side to the glow tube 4. The other side is contacted by a connecting bolt 7. On the side of the connecting pin 7, the glow tube is partially received by the housing 5. The glow tube 4 is sealed against the housing 5 by a press connection. The

Sealing between the glow tube 4 and connecting bolt 7 is performed by a

Temperature-resistant elastomer seal 6. This seal 6 hermetically seals the interior of the glow tube from the atmosphere in the engine compartment. After closing the seal 6 residual amounts of H ₂ 0, N ₂ or 0 ₂ remaining in the glow tube 4 could react at high temperatures with the heating coil 1 or the control coil 3 and damage it. To bind these residues, the inside of the glow tube 4 can be coated with a getter material. This few μηη thick

Coating with, for example, aluminum or magnesium reacts during heating of the Glow tube 4 with the residual amounts of H ₂ 0, N ₂ or 0 ₂ in the glow tube 4. Additionally or alternatively, the getter can also be added to the Wärmeleitpulver 2 in small quantities.

The connecting bolt 7 extends through the housing and is connected at the end with the connecting device designed as a round plug 10. Between round plug 10 and the

Housing 5 is an insulating 9 arranged from a non-electrically conductive material. A seal 8 in the region of the insulating disc 9, for example made of elastomer seals the housing 5 of the glow plug against the environment. Furthermore, the hot gas resistant ductile alloy can also be used in spark plugs for

Gasoline engines are used. The alloy with the material number 1.4888 is particularly suitable as an electrode material for the center electrode.

The hot gas resistant ductile alloy can also be used as a protective tube for various sensors. Many sensors are sensitive to high temperatures or are easily attacked by corrosive gases. The protective tube made of the alloy with the material number 1.4888 envelops the sensor, for example a lambda probe or the flame sensor of an oil burner or gas burner, and protects it from the damaging environmental influences.

Due to its high oxidation resistance and creep resistance, the alloy is well suited as a material for ignition electrodes in heating technology.

Claims

Claims 1. Use of a hot gas corrosion resistant ductile alloy containing 36 to 39% by weight of nickel, 20 to 23% by weight of chromium, 0 to 0.12% by weight of carbon, 0 to 1% by weight of manganese, 1, 3 to 2 , 2 wt .-% silicon, 0 to 0.5 wt .-% aluminum, 0.03 to 0.5 wt .-% lanthanum, 0 to 0.03 wt .-% sulfur, 0 to 0.03 wt. -% phosphorus, 0 to 0.5 wt .-% copper, balance iron, the sum of all components does not exceed 100 wt .-%, as a material for components that are exposed to high temperatures and corrosive gases.

2. Use of a hot gas corrosion resistant ductile alloy according to claim 1, wherein the alloy each contains one or more of the elements cerium, yttrium, zirconium, hafnium, titanium with up to 0.5 wt .-%.

3. Use of a hot gas corrosion resistant ductile alloy containing 36 to 39 wt .-% nickel, 20 to 23 wt .-% chromium, 0 to 0.12 wt .-% carbon, 0 to 1 wt .-% manganese, 1, 3 to 2.2% by weight of silicon, 0 to 0.5% by weight of aluminum, 0.03 to 0.5% by weight of lanthanum, 0 to 0.03% by weight of sulfur, 0 to 0.03 Wt .-% phosphorus, 0 to 0.5 wt .-% copper, balance iron, the sum of all components does not exceed 100 wt .-%, as a material for glow tubes of glow plugs for compression ignition engines.

4. Use of a hot gas corrosion resistant ductile alloy according to claim 3, wherein the alloy each contains one or more of the elements cerium, yttrium, zirconium, hafnium, titanium with up to 0.5 wt .-%.

5. Use of a hot gas corrosion resistant ductile alloy containing 36 to 39 wt .-% nickel, 20 to 23 wt .-% chromium, 0 to 0.12 wt .-% carbon, 0 to 1 wt .-% manganese, 1, 3 to 2.2% by weight of silicon, 0 to 0.5% by weight of aluminum, 0.03 to 0.5% by weight of lanthanum, 0 to 0.03% by weight of sulfur, 0 to 0.03 % By weight of phosphorus, 0 to 0.5% by weight

Copper, balance iron, the sum of all components does not exceed 100 wt .-%, as a material for spark plugs for gasoline engines.

6. Use of a hot gas corrosion resistant ductile alloy according to claim 5, wherein the alloy each contains one or more of the elements cerium, yttrium, zirconium, hafnium, titanium with up to 0.5 wt .-%.

Use of a hot gas corrosion resistant ductile alloy containing 36 to 39% by weight of nickel, 20 to 23% by weight of chromium, 0 to 0.12% by weight of carbon, 0 to 1% by weight of manganese, 1, 3 to 2.2% by weight of silicon, 0 to 0.5% by weight of aluminum, 0.03 to 0.5% by weight of lanthanum, 0 to 0.03% by weight of sulfur, 0 to 0.03 Wt .-% phosphorus, 0 to 0.5 wt .-% copper, remainder iron, the sum of all components does not exceed 100 wt .-%, as a material for protective tubes for sensors.

The use of a hot gas corrosion resistant ductile alloy according to claim 7, wherein said alloy each contains one or more of the elements cerium, yttrium, zirconium, hafnium, titanium at up to 0.5% by weight.

9. Use of a hot gas corrosion resistant ductile alloy according to claim 6 or 7 for use as a protective tube for a lambda probe.

10. Use of a hot gas corrosion resistant ductile alloy containing 36 to 39% by weight nickel, 20 to 23% by weight chromium, 0 to 0.12% by weight carbon, 0 to 1% by weight

Manganese, 1, 3 to 2.2% by weight of silicon, 0 to 0.5% by weight of aluminum, 0.03 to 0.5% by weight of lanthanum, 0 to 0.03% by weight of sulfur, 0 to 0.03 wt .-% phosphorus, 0 to 0.5 wt .-% copper, balance iron, the sum of all components does not exceed 100 wt .-%, as a material for ignition electrodes in oil burners or gas burners.

1 1. Use of a hot gas corrosion resistant ductile alloy according to claim 10, wherein the alloy contains one or more of the elements cerium, yttrium, zirconium, hafnium, titanium at up to 0.5% by weight.