DE10259141A1 - Material system for thermally coating metallic components subjected to wear and/or corrosion comprises a metallic sleeve made from nickel or nickel alloy and a filler made from vanadium carbides - Google Patents

Abstract

Material system comprises a metallic sleeve made from nickel or nickel alloy and a filler made from vanadium carbides formed as coarse sintered carbides and/or very fine granular aggregates in an amount of 10-35 wt.% and containing (in wt.%) 0.3-0.4 carbon, 1.0-1.5 silicon, 1.5-2.5 molybdenum, 0.5-1.5 vanadium, 0.5-4.0 boron, 0.2-0.4 titanium, and up to 1 iron.

Description

The invention relates to a material system for thermal coating, preferably by thermal spraying, Plasma surfacing or arc welding, to produce a protective layer with high wear or Wear- and corrosion resistance with high mechanical strength for improvement the surface properties.

Have welded coatings their importance especially in the case of heavy wear. Through the metallurgical bond to the substrate becomes high adhesive strength the shift guaranteed. Layer thicknesses up to 6 are used mm possible. The wear resistance conventional filler metals based on iron, nickel and cobalt results from the training species-specific hard phases such as carbides, borides or silicides. By Another addition of mostly alien hard materials creates so-called pseudo-alloys with significantly increased Wear resistance.

usual Pseudo alloys for Wear protective coatings use tungsten carbide or tungsten carbide (WSC) or chromium carbide as hard materials, mainly in nickel or iron-based materials, as well as with increased claims to the heat resistance, are embedded in cobalt base materials. Vanadium carbide (VC) is relatively rare in welding technology usually used in conjunction with other hard materials, though Vanadium carbide for highly wear-resistant powder metallurgy manufactured steels due to its high hardness and wear resistance plays a dominant role.

Such material systems are predominantly in cored wire or Filling tapes used.

Cored wires or Filling bands can in Inside in addition to arc stabilizing, shielding gas forming as well slag-forming components also have metallic components. Cored wires and Filling bands will be for connection and Cladding used. With them you can Alloys are created based on hardness and / or composition cannot be drawn as solid wire.

The composition of the cored wire shapes properties and welding behavior.

For the production of cored wire the most varied combinations of powder mixtures used. For example, FeMn, FeCrC, Ni, Fe, etc. come as metal powder. and their combinations for use. The metal powder can by Gas or water atomization be generated.

The cored wires are produced by shaking the filler powder into a tube with a defined diameter and then reducing it to a specified final diameter by pulling or rolling ( CH-PS 483 290 ).

The object of the invention is material systems to provide for thermal coating with those used for on Wear, Strength or wear, Strength and corrosion stress functional surfaces due to the improved properties open up wider areas of application or a much higher one Tool life compared to conventional additives is achieved thus gives a significant economic advantage.

According to the invention the task is thereby solved, that this Material system for thermal coating for wear and / or Corrosion stressed metallic components, the material system a cored wire or a filling tape is made of a metallic sheath made of nickel, a nickel alloy, Iron or an iron alloy and a filling of embedded vanadium carbides (VC) used as coarse cemented carbides and / or fine grain agglomerates with 10 to 35 percent by weight and other components in percent by weight based on the total mass contains consists.

The layers can be applied by MSG, MIG, open arc build-up welding or done by thermal spraying.

The interior filling contains as components additions on C (carbon), Cr (chromium), B (boron), W (tungsten), Mo (molybdenum), V (vanadium), Co (cobalt), Mn (manganese), Si (silicon), Ti (titanium), Zr (zirconium), Nb (Niobium), Ni (Nickel) and Fe (Iron) as well as vanadium carbides, which are sintered as coarse carbides or - bound by carbonyl iron - as fine grain agglomerate present in weight percent of 10 to 35% based on the total mass.

In iron and nickel materials Vanadium carbide has metallurgical benefits as it is when overheated is melted and dissolved in the melt due to the high affinity primary to carbon and is finely dispersed again. This also eliminates the kinetics of excretion and does not affect the alloy content of the matrix material, whereby especially no unwanted ones changes the hard phases occur. The carbide nuclei also lead to a fine-grained structure of the matrix material. The carbide formation is always fine crystalline. Embrittling eutectic Carbide nets are largely suppressed. Compared to surfacing with Conventional hard materials are also used with high alloys VC contents still crack-proof Coatings possible. This also increases the risk of disruption with superimposed dynamic load reduced.

Because of the low density of vanadium carbide (see Table 1), no segregation occurs compared to the tungsten melting carbides that are often used in wear protection, so that a homogeneous distribution of the vanadium carbides over the layer height ensures very constant wear protection. In addition, in particular with higher carbide contents, the weight per unit area is significantly reduced, which, for example, results in clear advantages in terms of the required drive energy when used in moving systems.

Table 1: Properties different hard materials

The flawless embedding of vanadium carbide in welding metallurgical Coatings based on nickel and iron represent a high potential to improve the properties of wear protection coatings and Cost reduction available. Can be used in thermal coating technology vanadinkarbidverstärkte Material systems based on nickel and iron are particularly advantageous through the cored wire technology use.

Cored wires on NiBSi and NiCrBSi base with vanadium carbide as the main carrier of the wear resistance can be due to the good flow properties of the matrix material excellent processing. Cored wires on Fe base with embedded vanadium carbides in comparison conventional FeCrC cored wire clearly superior wear properties with high crack resistance (single layer) and are therefore also suitable for thermal coating of complex wear and functional surfaces subject to bending stress. Through the material-specific Advantages of vanadium carbide (finely dispersed re-excretion in the event of overheating) is the processing of such cored wire even in larger process windows possible.

The application potential of vanadium carbide-containing Cored wires on Nickel base extends to wear and corrosion stress functional surfaces of tools for mining, earthmoving, oil sands processing and general mechanical process engineering, these include in particular Components that are used for conveying, Transporting, breaking and grinding are used, but also conventional linings through, compared to WSC-reinforced build-up welds, weight-reduced wear plates. Vanadium carbide cored wires Iron-based are particularly suitable for applications where in addition to very high abrasive wear resistance, increased toughness (Bending strength) or possibly edge retention required is. In particular, edge-loaded components should be mentioned like wear, Blow, and guide rails, Wipers, guides, Machine knives, but also crusher rollers, mixer blades, screw conveyors, Decanters, grinding plates and wear plates. By varying the Carbon content and the alloying elements chrome and nickel are chrome martensitic materials with corrosion resistance across from Food processing agents or materials with austenitic matrix, which in addition to high wear resistance additionally good corrosion resistance own, achievable.

The invention is intended to be used on the basis of exemplary embodiments described in more detail become.

Example 1:

On edges and surfaces of screw conveyors, which are used, for example, in the cement and brick industry find wear and tear after a certain period of time through erosion attacks.

A thermal coating with the material system according to the invention can eliminate the signs of wear and increase the service life. The material for the material system was a nickel material for the sheath of the cored wire and for the filling vanadium carbide (VC), which is designed as a fine grain agglomerate with 18 percent by weight and 0.35 percent by weight Carbon, 1.25 percent by weight silicon, 2.0 percent by weight molybdenum, 1.0 percent by weight vanadium, 0.75 percent by weight boron, 0.3 percent by weight titanium and 0.75 percent by weight iron based on the total mass.

The components of the filling lie in the form of a metal powder with a maximum grain size of 200 μm.

After filling the nickel jacket of the Cored wire with the filling components are vibrated and the above components subsequently the cored wire pulled down to a diameter of 2 mm.

The cored wire thus created is used for metal shielding gas (MSG) cladding.

When cladding is the surface of the component to be coated with one layer up to several Millimeter layer thickness coated. Hard materials such as vanadium carbide are embedded in the surface. This lead for a significant increase in wear resistance.

Example 2:

To improve wear resistance on guide elements or edges of cutting or forming tools become material systems used on iron basis.

As a composition for such Material system became an iron material for the jacket of the cored wire and for the filling Vanadium carbide (VC) in fine day glomerate form with 20 percent by weight as well as with 0.3 weight percent carbon, 1.5 weight percent silicon, 1.25 Weight percent manganese, 1.25 weight percent molybdenum, 5.0 weight percent Chromium, 2.5% by weight cobalt and 0.25% by weight zirconium, based on the total mass selected.

The components are in powder form with a maximum grain size of 150 μm in the Iron casing of the filling pipe or filling tape filled, vibrated and subsequently becomes the cored wire pulled down to a diameter of 1.8 mm.

Applying the wear protection layer is carried out by thermal application, preferably by arc welding.

Claims (6)

Material system for thermal coating Wear or Wear and tear Corrosion stressed metallic components, the material system a cored wire or a filling tape is composed of a metallic jacket made of nickel or nickel alloy and a filling made of embedded vanadium carbides (VC), which are used as coarse cemented carbides and / or fine grain agglomerates with 10 to 35 percent by weight and the following Components in percent by weight based on the total mass C: 0.3 to 0.4% (carbon), Si: 1.0 to 1.5% (silicon), Mo: 1.5 to 2.5% (molybdenum), V: 0.5 to 1.5% (vanadium), B: 0.5 to 4.0% (boron), Ti: 0.2 to 0.4% (titanium), and contains up to 1% Fe (iron). Material system for thermal coating after Claim 1, characterized in that the filling follows as components Components in percent by weight based on the total mass C: 0.3 to 0.4% (carbon), Si: 1.5 to 2.5% (silicon), Cr: 8.0 to 10.0% (chrome) B: 0.5 to 4.0% (boron) Ti: 0.2 up to 0.4% (titanium) and contains up to 1.5% Fe (iron). Material system for thermal coating, the material system being a cored wire or filler belt, consisting of a metallic sheath made of iron, a low-alloy iron alloy or a high Cr-Ni-containing iron alloy and a filling of embedded vanadium carbides (VC), which are used as coarse cemented carbides and / or fine grain agglomerates with 10 to 25 percent by weight and the following components in percent by weight based on the total mass C: 0.1 to 0.5% (carbon) Si: 0.5 to 2.5% (silicon) Mn: 0.5 to 2 , 0% (manganese) Mo: 0.5 to 2.5% (molybdenum) Cr: 3.0 to 18.0% (chromium) Ni: 0.0 to 9.0% (nickel) and up to 0.5% Zr (zirconium). Material system for thermal coating after Claim 3, characterized in that the filling follows as components Components in percent by weight based on the total mass C: 0.1 to 0.5% (carbon) Cr: 2.0 to 5.0% (chrome) Si: 0.5 to 2.5% (silicon) Mn: 0.5 to 2.0% (manganese) Mo: 0.5 to 2.5% (molybdenum) W: 3.0 to 8.0% (tungsten) Co: 0.0 to 5.0% (cobalt) and contains up to 0.5% Zr (zirconium). Material system for thermal coating after at least one of the preceding claims 1 to 4, characterized in that the cored wire is designed as a round wire with a diameter of 1.2 to 4.0 mm. Material system for thermal coating after at least one of the preceding claims 1 to 4, characterized in that that this filling belt as flat wire with the dimensions 3.5 to 5.5 mm and 0.4 to 0.6 mm executed is.