DE102005020611A1 - Workpiece system for thermal coating, e.g. thermal spraying or built-up welding (sic) for deposition of protective layer of high wear and corrosion resistance on metal components useful for production of filler wires - Google Patents

Abstract

A workpiece system for thermal coating, especially thermal spraying or built-up welding (sic, hardfacing) for the deposition of a protective layer of high wear and corrosion resistance on metal components comprises (wt.%) mixed carbide powder (10-80) consisting of 2-4 carbides selected from Ti, V and/or W carbides, for production of filler wires and strips and a metal matrix powder (20-90) on the total weight of Fe, Ni, and/or Co base.

Description

The The invention relates to a material system for thermal coating, preferably by thermal spraying or build-up welding, for the production a protective layer with high wear or corrosion resistance.

From the DE 103 24 713 A1 is a spray material in the form of cored wires or filler tapes to increase the wear resistance of wear and corrosion stressed functional surfaces in lightweight, consisting of a metallic shell and a powdery filler therein, in which the shell material and / or the filler material up to 50 weight percent, Preferably, 5 to 35 weight percent, Si compounds or pure silicon are added, wherein the filler of silicon carbide, boron carbide, titanium carbide, niobium carbide, vanadium carbide, tungsten carbide or chromium carbide with a grain range of 3.5 to 400 microns individually or as a mixture and in the as Si compound ferrosilicon with a Si content greater than 60% is used.

The DE 102 49 125 A1 discloses an alloy system for the thermal coating of powder and flux cores of functional surfaces subject to wear and corrosion in structural lightweight construction by thermal application, in which the alloy system consists of a light metal matrix with embedded carbides of the elements boron, silicon and / or titanium, the proportion of Carbide is singly or mixed from 1 to 30 weight percent and wherein the light metal matrix material is made of pure aluminum, aluminum alloys or aluminum-magnesium alloys.

Furthermore, in the DE 102 59 141 A1 describes a material system for thermal coating of wear and corrosion stressed metallic components, in which the material system is a cored wire or a filling tape, wherein the metallic shell of nickel or nickel alloy and the filling of embedded vanadium carbides (VC), as coarse cemented carbides and / or ultra-fine agglomerates with 10 to 35 weight percent and several other components such as carbon, silicon molybdenum, vanadium, boron, titanium and iron.

The Use of pure carbides have a number of advantages but also disadvantages on which make up certain coating and processing properties to derive.

tungsten carbide (WSC) has a low room temperature compared to titanium and vanadium carbide (RT) hardness on; but has a high heat hardness, good wettability, a good ability with coarse carbides and a high tendency to dissolve in Fe and Ni matrix.

titanium carbide has the highest RT hardness, but poor wettability, low toughness and low tendency to dissolve.

vanadium has a good RT and hot hardness on, but has no solution tendency in Fe and Ni matrix and prone to brittle fracture in coarse particles. Melted carbides do not form mixed carbides. The primary carbide precipitation leads to grain refining the coating.

The Single carbides have the following disadvantages:

tungsten carbide:

• • Gravity segregation at <50% carbide content;
• • Strength solvent and decarburization tendency, therefore only in self-fluxing matrix materials and processable with coarse grain.

titanium carbide:

• • Floating in the molten bath due to lower density;
• • worse wettability;
• • brittle, since none eutectic fine-grained form exists.

vanadium:

• • brittleness in coarse carbide configurations, because of lack of feinfiedriger eutectic arrangement

Of the The present invention is based on the object, an improved Material system for thermal coating, preferably by thermal spraying or build-up welding, for the manufacture of a To provide a protective layer with high wear and / or corrosion resistance.

According to the invention this object is achieved in that the material system of 10 to 80 weight percent mixed carbide powder, based on the total mass, based on titanium, vanadium and / or tungsten carbides and from 20 to 90 weight percent of a metal matrix powder, based on the total mass, on iron -, nickel and / or cobalt base and thereby the grain fraction of Mischkarbidanteils when used as Plas ma-spray powder has a size of 5-50 microns and when used for build-up welding has a size of 45-250 microns.

As one of the main advantages of this solution according to the invention is to be mentioned that the different properties of the carbides can be combined by the combination of carbide types tungsten carbide (eutectic between W ₂ C and WC), vanadium carbide, and titanium carbide, so that coatings with carbide contents of 10 to 80% without carbide segregations, as they occur when using the single carbides, can be generated on the surface to be coated. The formation of mixed carbides between the metals of the single carbides leads to the improvement of the wettability and the strength properties of the coating. The formation of fine-grained intermediate carbide precipitates prevents the washout of the matrix material and increases the wear resistance of the coating.

advantageous Further developments and refinements of the invention are evident from the remaining subclaims and from the following, described in principle embodiments seen.

The listed below Material systems are designed to be suitable for plasma powder buildup welding are.

Example 1:

The Metal matrix powder consists of a nickel-based alloy, are added as the main components boron and silicon. These Alloy has the other constituents carbon, manganese, chromium, Iron, nitrogen and oxygen.

The Production of the metal matrix powder is carried out by gas or water atomization of liquid melt. The metal matrix powder is agglomerated or sintered titanium carbides added in powder form with a grain size of 100 microns.

The mixing ratio of metal matrix powder and titanium carbide powder is in this Example case 50:50.

Example 2:

The Metal matrix powder also consists of an alloy here Nickel base, which is added as the main constituents boron and silicon are. As further constituents, this alloy has carbon, Manganese, chromium, iron, nitrogen and oxygen.

The Production of the metal matrix powder is likewise carried out by gas or water spraying the liquid Melt. The metal matrix powder is agglomerated or sintered Powdered titanium and vanadium carbides with a grain fraction of 100 μm added.

The mixing ratio from metal matrix powder to titanium carbide powder to vanadium carbide powder is 50:25:25.

Example 3:

The Metal matrix powder again consists of an alloy Nickel-based, as the main components boron and silicon and as other ingredients carbon, manganese, chromium, iron, cobalt, Nitrogen and oxygen are added.

The Production of the metal matrix powder is also carried out here by gas or water spraying the liquid Melt. The metal matrix powder is also agglomerated or sintered titanium and tungsten carbide carbides in powder form with a Grain fraction of 100 μm added.

The mixing ratio from metal matrix powder to titanium carbide powder to tungsten carbide powder is 50:20:30.

Example 4:

The Metal matrix powder again consists of an alloy Nickel base, which is added as the main constituents boron and silicon are. As further constituents, this alloy has the constituents Carbon, manganese, chromium, iron, cobalt, nitrogen and oxygen on.

The Production of the metal matrix powder is carried out by gas or water atomization of liquid melt. The metal matrix powder is also agglomerated or sintered Titanium and vanadium and tungsten carbides in powder form with a grain fraction of 100 microns added.

The mixing ratio from metal matrix powder to titanium carbide powder to vanadium carbide powder Tungsten carbide powder is 40: 10: 20: 30th

By the use of mixed carbides and the use of matrix materials different composition and hardness can be protective layers against complex attacks from wear, corrosion and temperature produce, e.g. in the offshore engineering, in the day, mining and civil engineering as well as in the chemical industry.

In particular, the use of cored wires creates new opportunities, carbide-containing addition also to use materials in the repair sector.

In front everything for an insert " Place "are the metal inert gas welding (MSG) and arc spraying cheap suitable.

The Processing of the metal powder alloys is carried out by means of plasma powder build-up welding and of thermal arc and flame spraying, while for the filler wires the metal inert gas welding (MSG) and arc spraying application find.

The Layer is constructed so that on the substrate a well adhering through the matrix material layer is formed in the titanium carbide (TiC), vanadium carbide (VC) and tungsten carbide (WSC) and mixed carbides formed in situ are incorporated.

by virtue of The different density of carbides changes in the layer Concentration continuously. These are gradient layers with triple combination of WSC, TiC and VC and comparable Grain sizes. TiC as cover carbide, WSC as underlay and VC or (Ti, V) C as intermediate carbide. By different grain spectra or by fine-grained Mischkarbidbildungen can the wear protection layers used in coarse and fine abrasives. WSC can be considered crude Grain, TiC and VC are embedded as fine grain in between. The dissolution of Matrix material is prevented by fine interstitial carbides.

Height wear resistance At low total carbide contents allows a better mechanical Post-processing by grinding with the necessary defined geometry. A high level of processing safety is given since TiC and VC are not tend to decarburization / decomposition.

The Layer is constructed so that on the substrate a well adhering through the matrix material layer takes place in which TiC and VC are embedded. While the TiC is near the surface Are embedded, the matrix, especially in the transition region, supported by finely divided VC. basis therefor is the finely tuned grain fraction of vanadium carbides as well also the use of agglomerated carbides.

The Layer is constructed so that on the substrate a well adhering through the matrix material layer takes place, in which TiC and WSC are stored.

While the TiC in the near-surface Are embedded, the matrix, especially in the transition region, reinforced by WSC. Basis for this is the finely tuned grain fraction of tungsten carbides.

Claims (5)

Material system for thermal coating, preferably by thermal spraying or build-up welding, for the production of a Protective layer with high wear or wear and corrosion resistance on metallic components, wherein the material system of 10 up to 80 weight percent mixed carbide powder, based on the total mass Mixed carbide powder of 2 or 3 carbides single carbide carbide types, Vanadium and / or tungsten carbides and from 20 to 90 weight percent a metal matrix powder, based on the total mass, on Iron, nickel and / or cobalt base exists. Material system according to claim 1, characterized that the Grain fraction of mixed carbide content of titanium carbide when used As a plasma spray powder size of 5-50 microns and when used for the Cladding has a size of 45-250 microns. Material system according to claim 1, characterized that the Grain fraction of mixed carbide content of vanadium carbide in use As a plasma spray powder size of 5-50 microns and at Use for surfacing has a size of 45-250 microns. Material system according to claim 1, characterized that the Grain fraction of mixed carbide content of tungsten carbide at Used as a plasma spray powder 5-50 μm in size and when used for build-up welding Size of 45-250 microns has. Material system according to claim 1 to 4, thereby characterized in that the Mixture of metal matrix powder and mixed carbide powder in a cored wire or in a filling belt is introduced or the metal matrix portion of the metal shell of the cored wire or filling tape and synergistic elements of the filling.