DE102009008931A1 - Method for producing a fitting, a side grille or a product carrier for high temperature applications and metallic component - Google Patents

Abstract

A method which achieves the manufacture of a fitting, a side rail or a product carrier for high temperature applications with the production of a blank and the application of a metallic coating containing at least one solid lubricant, and a metallic component of a blank and a metallic coating with a solid lubricant.

Description

The Invention describes a method for producing a fitting, a side rail or a food support according to the preamble of claim 1 and a metallic component for use in the high temperature range, according to the preamble of claim 10.

At the Use of components, in particular drawer guides, in Ovens there is the problem of lubrication of moving Components. Fats and oils are used in ovens in pyrolysis operation unsuitable at 500 ° C. Thus, here is the use of solid lubricants necessary. These include graphite, molybdenum disulfide, polytetrafluoroethylene and hexagonal boron nitride.

The The application of these solid lubricants should be as possible evenly. By frequent Actuation of the extracts and sliding mechanisms can a removal of the solid lubricant is not completely prevented become. Already known are material-saving order methods, in which the solid lubricant compound in pasty or dissolved form or applied as a lubricating varnish. Because the Solid lubricant, however, only superficially on a component are applied, it is currently in contact with the component often to the contamination of hands and clothing. To counteract the removal of the solid lubricants were these specifically applied to sliding surfaces of the corresponding components, while other areas of the components corrode Oven conditions were exposed.

The The present invention is therefore based on the previous Methods of applying solid lubricants to the task To provide a component with a coating, which is a ensures lower abrasion of the lubricants and also Corrosion resistant and suitable for high temperature applications is.

The The present invention solves this problem by a method and a metallic component by the characteristics of the license plate of claims 1 and 10.

The Method for producing a fitting, a side rail or a food carrier for high temperature applications includes two consecutive production steps. In one First step, a metallic blank is made or molded and in a subsequent second step becomes a metallic coating applied to the blank. In this metallic coating At least one solid lubricant is incorporated.

By direct incorporation of the solid lubricant into the metal layer of the metallic coating, there are two main ones Advantages.

solid lubricants Mostly have a layered Construction. Their tribologically advantageous properties can be on a shift of the superimposed layers to explain. This results in prolonged use to a sliding wear of the lubricant layer. Metal layers are both removed during friction and each other postponed. But if you build the soft solid lubricants in metal layers material factors such as Vickers hardness and friction coefficients are optimized so that a clear less abrasion of the coating material takes place. This lower abrasion is expressed in abrasion factors, which quadruple to fivefold lower than with pure metal coatings.

One Another advantage is that the solid lubricant is not due to mechanical Cleaning, can be removed from the sliding surface, but firmly connected to the metal surface.

at the preparation according to the invention also remains the metallic gloss of the surface even after the coating of the blank with the metallic coating. The Surface can be added by applying several types of metal surface-refined.

There the application of the metallic coating both partially but also completely over the entire surface of the blank, is a corrosion protection by the metallic coating allows. Therefore, it is no longer absolutely necessary as before, to form the blank from stainless steel, which costs and is energy intensive.

In the method, it is advantageous if the solid lubricant is incorporated as boron nitride during application of the metallic coating in the metal structure. The excellent tribological properties The boron nitride are additionally supplemented by the incorporation into the metallic coating. Hexagonal boron nitride retains most of its tribological properties even at over 600 ° C and is therefore particularly suitable as a lubricant for use in ovens and the like with pyrolysis. It is also extremely pressure resistant, the coefficient of friction under pressure even further decreases, which corresponds to a thixotropic mode of action. By incorporating boron nitride into a metal structure, therefore, a hard but lubricious layer can be formed on the surface of the blank.

ever on the type of metallic coating and metallic Blank, this coating can already in an advantageous manner be achieved by placing a metallic blank in a solution dips with dissolved metal ions. This is done, for example in the cementation of copper to iron fittings.

Around a particularly firmly adhering metallic coating too can achieve an advantageous application of a metallic coating by electrochemical deposition by a galvanic process respectively.

In an advantageous method can be a nickel plating of the metallic Raw material under installation of solid lubricants done. At the nickel plating becomes a large proportion of the supplied current for the deposition of the nickel on the metallic blank used. Therefore, a nickel plating process is very energy efficient in comparison to other galvanic processes. The nickel coating is also chemically resistant to diluted Acids and a lot of alkalis, like them used in aggressive chemical cleaning agents. moreover Nickel is not corrodible and resistant to Water and air.

It is advantageous if the metallic blank after coating with a metallic coating a tempering process passes through, in which an additional curing of the coating takes place. Major disorders In the metal grid are thereby eliminated and the stored solid lubricants are more firmly integrated into the metal structure. It should be the Heating process slowly controlled by a temperature gradient become. Similarly, the cooling should be by a gradient be regulated to miscarriages due to different Thermal expansion coefficient of the individual components too avoid.

Preferably the annealing process is between 300 to 700 ° C, preferably 400-600 ° C operated. In this area are higher Hardness of metal coatings with solid lubricant content to achieve that with comparable untempered metal coatings the case is.

Around a uniform as possible deposition Obtaining it on the surface of the blank, it is advantageous the blank before applying the metallic coating to smooth.

to additional reduction of the abrasion index and the surface roughness with additional fine distribution of some boron nitride particles on the surface of the coated sheet is post-processing the application of the metallic coating by smoothing the surface of advantage.

moreover The aforementioned object is achieved by an inventive metallic component for use in the high temperature range, in particular ovens solved, which is a molded Blank with a metallic coating provides, which additionally contains at least one solid lubricant.

by virtue of The nature of this component can be anywhere be used where friction in the high temperature region occurs. This applies primarily to devices for preparation of food, but can also be used in appliances such as drying ovens, for example for drying chemical preparations, muffle furnaces, Vacuum furnaces and the like are used, where pullout guides or other fittings are used.

there it is beneficial if the metallic coating is boron nitride contains. Boron nitride has excellent tribological properties Properties on, is also in areas of over 300 ° C can be used and therefore together with the metallic component subjected to an annealing process to increase the coating hardness become.

Another advantageous solid lubricant which is present in or on the metallic coating of the component is polytetrafluoroethylene. This solid lubricant is characterized by its high availability and its low individual particle size. Due to this small particle size, the solid lubricant can be dissolved disperse in an electrolyte solution and then stored finely distributed in the metallic coating become.

Further advantageous solid lubricants which on or in the metallic coating Molybdenum sulphide and are also present Graphite. These solid lubricants have a maximum range of use of 350 ° C and 450 ° C and can in these temperature ranges for ovens as solid lubricant additives be used in coatings.

By Use of a cobalt-nickel alloy as a metallic coating With the aforementioned solid lubricants, the wear resistance the coating be increased again.

at Metallic coatings carries a high Boron nitride usually also to a high phosphorus content, which embedded in the metal structures. In a tempering process may advantageously be a hardening of the metallic coating by removal of phosphides from the metal structure.

The Invention will be described below with reference to an embodiment with reference to the accompanying drawings explained. They show:

1 a front view and a perspective view of a pullout guide according to the invention;

2 an exploded view of the pullout guide;

3a -F several side views, a front view and a perspective view of a further pull-out guide according to the invention; and

4 a schematic temperature diagram for producing a coated component.

A pullout guide 1 for high temperature applications, especially for ovens, includes a guide rail 2 and one relative to the guide rail 2 movable track 3 between which a middle rail 10 is stored. Furthermore, the pullout guide 1 also have more than one middle rail. For the movable mounting of the center rail 10 and the running track 3 are rolling elements 4 , in particular of ceramic, provided. Here are on the guide rail 2 , the middle rail 10 and the running track 3 several tracks each 6 for the spherical rolling elements 4 intended. The rolling elements are arranged in a Wälzkörperkäfig. Other components of the pullout guide are a stop 7 , an attack 10 several brackets 8th for fastening the pullout guide 1 and a panel 9 ,

Another pullout guide 1' for high temperature applications is in 3 shown and shows a guide rail 2 ' and a running rail movable relative to the guide rail 3 ' , which is mounted on the guide rail. For the movable mounting of the track rail 3 ' are rolling elements 4 ' , In particular made of ceramic, provided in raceways 6 ' be guided. Other ingredients like a stop 7 ' , several brackets 8th' and a panel 9 ' are mounted analogous to the previously described embodiment of the pullout guide.

The rails 1 . 2 . 3 . 1' and 2 ' are manufactured for use in ovens made of a stamped and bent sheet steel and provided with a coating. The production of the components of the pullout guide, in particular the rails 1 . 2 . 3 . 1' and 2 ' is done through the following steps:
First, the metallic blanks are produced by punching and bending a steel sheet. The blank can be machined.

After that a metal layer is galvanically deposited on the surface of the Blanks applied, the electrolyte solution boron nitride or any other solid lubricant containing in the application in the deposited on the blank metal layer is stored.

At the galvanic process is via a current flow in one Electrolyte bath with two metal electrodes reaches a mass transfer. The metal electrodes consist of different metals. At the anode metal ions are dissolved, which subsequently walk to the cathode, where they attach themselves. Located in the Electrolyte bath a certain concentration of solid lubricant, which finely distributed and disperse dissolved, this can during depositing the metal layer at the cathode into the metal structure be stored.

Boron nitride can be incorporated in the deposited metal layer up to a volume fraction of 29%, which corresponds to a boron nitride content of about 28-33 g / l in the electrolyte solution. Boron nitride is dispersed in the electrolyte solution. Further process parameters are the current density (at 4-6 A / dm ² ), the pH (at pH 2-4) and the electrolyte temperature (at 40-60 ° C).

The Coated blanks are then heated to a temperature of at least Heated to 400 ° C and for a predetermined period of time annealed before being cooled back to room temperature become.

The Hardness of the metallic coating, in the case NiBN layer (nickel boron nitride) three to four times harder (up to 630 HV) than with a normal nickel coating. In addition, a coefficient of friction of about 0.1 or less, a less wear than pure nickel layers and a low abrasion.

Of the Abrasion was according to the Taber Abraser test according to existing DIN standards and resulted in a Taber Wear Index of 2.5 for a nickel coating with a boron nitride content of 29% and 3.5 for a boron nitride content of 12%, respectively three grinding cycles.

A Another possibility of coating consists in an autocatalytic chemical reduction method, wherein a phosphorus-containing NiBN layer deposited on the metallic surface of the blank becomes. Here, the phosphorus content increases with increasing proportion of boron nitride in the nickel too. At the same time the layer thickness decreases for the same duration of the deposition process.

A Another possibility is the galvanic application a mixture of several metals in which during the Separation process also boron nitride molecules are installed. In this case, the metal mixture, for example a nickel-cobalt mixture, also be phosphorus.

An inventive phosphorus-containing nickel-cobalt coating consists of: - Cobalt: Mass fraction 0.20-0.25 - Phosphorus: Mass fraction 0.06-0.08 Hexagonal boron nitride: Mass fraction 0.03-0.04 - Nickel: Mass fraction 0.63-0.71

The tempering can after the in 4 listed annealing process can be performed.

In 4 schematically is a temperature diagram for the process of tempering of galvanically coated fittings, side rails and food carriers with, embedded in the metallic coating, boron nitride molecules for high temperature applications shown. The coated blank is first heated from ambient temperature θ ₀ . It starts with a temperature gradient of 8-15 K / min, in particular 10 K / min starting from an initial temperature θ ₀ of 25 ° C and then goes at an average temperature of θ ₁ = 100 ° C in a temperature gradient of 25 K / min above. When a target temperature θ ₂ of 500 ° C is reached, a temperature plateau follows for 30 minutes. Finally, a cooling phase follows with 10-20 K / min, in particular 15 K / min back to θ ₀ .

In In the illustrated embodiment, a galvanic-coated Pull-out guide described. It's natural, too possible, other metallic components with an inventive To provide coating. In particular, food carriers, Side rails, fittings or other in ovens usable components are coated.

Further Dispergenzien, which at the surface of the BN particles In addition, adsorb in the metal coating introduced, for example, an agglomeration of the boron nitride particles to prevent. This can be done by charging the particles, which also causes electrostatic interactions with the metal substrate be built of the metallic coating, which is a Storage and distribution of the dispersed boron nitride particles in the facilitate deposited metal coating.

As well a storage of PTFE (polytetrafluoroethylene) is possible into the electroplated metal coatings, but here a corresponding annealing step is omitted and the field of use of such a coated oven partly only a maximum of 250 ° C, otherwise one thermal decomposition of the PTFE is possible.

in principle comes by applying a galvanic or chemical metallic coating under storage of other solid lubricants, also a use of graphite or molybdenum sulfide into consideration.

The lubricants used should also meet the hygiene requirements according to the German version DIN EN ISO 21469: 2006 fulfill.

1

pull-out guide

2

guide rail

3

runner

4

rolling elements

5

Rolling Element

6

career

7

attack

8th

clip

9

cover

10

middle rail

11

attack

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - DIN EN ISO 21469: 2006 [0050]

Claims (15)

Method for producing a fitting, a Side rail or a product carrier for high temperature applications, characterized by the following steps: a) manufacture a blank; and b) applying a metallic coating, which contains at least one solid lubricant. Method according to claim 1, characterized in that that the solid lubricant as boron nitride during application of the metallic coating is stored in the metal structure. Method according to Claims 1 and 2, characterized that the application of the metallic coating by electrochemical Deposition of one or more metals on the surface of the metallic blank. Method according to one of the preceding claims, characterized in that the application of the metallic coating done by a galvanic process. Method according to one of the preceding claims, characterized in that a nickel plating of the metallic Blank is performed. Method according to one of the preceding claims, characterized in that the metallic blank after application of the metallic coating containing at least one solid lubricant contains, is tempered. Method according to Claim 6, characterized that a tempering by a temperature program with at least two temperature gradients is regulated. Process according to claims 6 and 7, characterized characterized in that the annealing at 300 to 700 ° C, preferably 400 to 600 ° C takes place. Method according to one of the preceding claims, characterized in that the surface of the blank before and / or after the application of the metallic coating is smoothed. Metallic component for use in the High temperature range, in particular ovens, characterized that the component comprises a metallic blank, which is a has metallic coating, which in addition contains at least one solid lubricant. Metallic component according to claim 10, characterized that the metallic coating boron nitride as a solid lubricant contains. Metallic component according to claim 10 or 11, characterized characterized in that the metallic coating PTFE (polytetrafluoroethylene) contains as solid lubricant. Metallic component according to one of the preceding claims, characterized in that the metallic coating contains molybdenum sulfite (MoS ₂ ) and / or graphite as solid lubricant. Metallic component according to one of the preceding Claims, characterized in that the metallic coating contains a cobalt-nickel compound. Metallic component according to one of the preceding Claims, characterized in that the metallic coating is phosphorus.