DE3315920C1 - Process for producing a nickel-based sintered alloy - Google Patents

Abstract

To produce a sintered alloy, the carbon is alloyed by addition of chromium carbide with an alloy of the composition 22 to 27 % by weight of chromium, 2.5 to 2.7 % by weight of boron, 3 to 4 % by weight of silicon, 4 to 4.5 % by weight of iron and 2.5 to 3.5 % by weight of carbon, the remainder being nickel.

Description

When using such hard alloys as a powder Application material for wear protection layers in combination with powdery Hard materials of various other types It is important that they act as a matrix for the hard material particles The hard coating used is sufficient to cope with any stress on the upper hook wear protection layer to withstand impact, shock or vibration and at the same time with relbender stress to bind the embedded hard material particles A hard layer that meets these requirements is essentially fair, is already known from US Pat. No. 2,888,740. These Alloy based on nickel for a welding wire for applying a corrosion and wear-resistant layer contains 15 to 35 wt .-% chromium and up to 4% carbon, as well Iron, boron and stilzlum. The carbon is added in elemental form, so that difficulties arise with regard to the desired with regard to the hardness homogeneous distribution.

The invention is based on the object of specifying a method by means of which a homogeneous distribution

of the components of the alloy responsible for the hardness will.

It has been found, surprisingly, that the same can be achieved with alloys the composition, as it is called "Colmonoy 4" (settlement account of the Wall company Colmonoy) Is given in Table 2 as an example, by adding certain amounts achieved hardness values of IICR 60 or 880 11V 50 on chromium carbide, but at the same time A high toughness of the regulation is achieved, which is expressed by the sum of the crack lengths only results in values of 50 ttm. Compared to the roughly equally hard alloy "Colmonoy 8" in Table 2, this toughness is remarkably high.

It is believed that by adding chromium carbide, the Carbon in an alloy with the composition 22 to 27 wt.% Chromium 3 bis 4% by weight Sllizlum 2.5 to 3.5% by weight carbon 4 to 4.5% by weight iron 2.5 to 2.7 Ge2 .-% boron, remainder nickel is distributed very homogeneously in the alloy, so that the Hardness of the alloy is favorably influenced.

The alloy produced according to the invention is achieved by adding additives corresponding amounts of chromium carbide. preferably Cr3C2, to known hardnesses, as indicated in table 2.

As an application form of the alloy selenium, mention should be made of: alloy powder In pure form or in combination with other substances for thermal spray purposes or spray welding purposes, build-up welds, etc.

The alloys are also suitable as materials for electrodes, Rods, filler wires or cast parts (full cast) as well as for molding and sintering.

The possible applications as a wear or corrosion protection material are very versatile. It is referred to "Stahli-Eisen-Bücher", Volume 20, "Ilartleglerungen to wear protection ", Düsseldorf 1975, pointed out.

A particularly advantageous form of use of those produced according to the invention Alloys concerns the application of the same to base materials. which in general not because of their different thermal expansion behavior can be armored with extremely hard anti-wear layers. In such In some cases, the alloy ensures that the layers are exposed to thermal stress The composite materials had excellent despite their high hardness, which was the case with Ilart alloys is not the case according to the state of the art. Preferably the alloy In Powder or wire form through thermal application spraying (flame spraying or plasma spraying) applied to the substrate and mechanically in the generally usual manner reworked, e.g. 13. by grinding and polishing or the like.

Another preferred form of application are rods that are welded by arc deposition can be applied to the base material.

Instead of wires, the hard alloy powder can also be used in the form of so-called cords (powder strands coated with plastic or metal foils) can be used for thermal spraying. In addition, the use of the alloy in stick form as iloch temperature iot possible.

Table 1 Alloy production form Alloy composition (remainder Nlckel) No.% by weight rods coated cast parts powder rods Cr C SI B Fe further elements x 1.7 1.2 0.5 2 x 2.0 0.9 0.2 3 x 2.3 1.2 <1.5 4 x 2.4 1.4 5 x 2.4 1.5 0 , 3 6 x 2.5 1.5 0.0-1.5 7 x 2.5 2.0 0.3 8 x 2.6 2.0 0.5 9 x 2.7 1.4 0.13 10 x 2 , 7 1.5 0.4 11 x 3.3 2.5 0.4 12 x 3.4 1.35 <3.0 13 x 3.5 1.9 0.4 14 x 4.0 3.3 0.5 15 x 4.5 2.9 16 x 4.5 3.0 17 x 1.0 0.06 2.5 1.5 1.5 18 x 1.2 2.5 1.3 Tabel 1 Continuation of alloy production form Alloying formula (Kesl Nickcl) No. rods encased casting base powder rods Cr (sl B Fe further elements 19 x 5.0 0.25 3.0 1.0 3.5 20 x 5.0 0.25 3.25 1.25 3.0 21 x 5.0 0.25 4.0 1.25 2.0 22 x 5.5 () , 2 2.9 1.5 1.3 23 x 7.0 4.0 2.5 3.0 24 x 7.0 4.5 2.9 3.0 25 x 7p 0.3 4.5 3.2 3 , 0 6 W 26 x 7.3 0.6 3.6 2.7 1.9 27 x x x 7.5 4.0 1.5 1.5 28 x 7.5 0.09 4.52 2.03 2.72 29 x B, 0 0.2 4.6 3.1 3.3 30 x 9.0 0.3 3.25 1.8 3.25 31 x 9.0 0.3 3.5 2.5 3, 5 32 x 9.0 0.45 3.0 2.0 3.75 33 x Logictung 32 + 35 @ (WC + 10Co) 34 x 9.53 0.14 3.29 1.88 3.54 35 x 9.6 0.1 3.7 2.26 0.43 36 x 9.9 0.6 2.5 1.7 2.4 37 xxx 10.0 4.0 1.5 4, 0 38 x 10.0 3 »1.9 4.0 39 x 10.0 0.04 3.5 2.0 0.5 0.3 Mn 40 x 10.0 0.15 2.5 2.5 2, 5 41 x 1 (1.0 0.4 3.5 2.0 3.0 42 x 10.0 0.4 3.5 2.5 3.5 12 W 43 x x 10.0 0.45 2.25 2.0 2.5 44 x 10.0 0.45 2.5 2.0 2.5 45 x 10.0 0.6 4.5 3.2 46 x 10.5 2.0 2.0 3.0 47 x 10.5 (), 1 3.2 2.0 1.5 48 x 11.0 3.0 2.0 4.0 49 x 11.0 4.0 2.0 4.0 50 x 11.0 0, (17th 4.26 2.07 3.75 51 x x 11.0 (1.45 2.25 2.5 2.25 52 x 11.5 0.55 3.25 2.5 3.75 16 W. 53 x x 11.5 0.65 3.75 2.5 4.25 54 x 11.9 0.38 3.54 2.15 3.38 55 x 12.0 0.5 3.6 2.6 3.3 56 x 12.5 0.7 4.0 2.75 4.5 57 x 13.0 0.8 3.7 2.8 3.25 12 W 58 x x 13.5 0.75 4.25 3.0 4.75 59 x 13.5 0.1 4.5 3.5 4.5 60 x 14.0 0.5 4.0 3.0 4.0 61 x 14.0 0, 6th 3.5 2.75 4.0 62 x 14.0 0.65 3.8 2.8 3.75 63 x 14.0 0.65 3.75 2.75 3.75 64 x 14.0 0.66 4.25 3.15 4.5 65 x 14.0 j0, @ 4.5 3.5 4.5 66 x x 14.0 0.75 4.0 3.25 4.0 67 x 14.5 (), 75 4.5 3.5 4.5 68 x x x 15.0 4.5 3.0 4.5 69 x 15.0 0.6 4.2 3.0 3.7 70 x 16.0 4.5 3.0 4.0 71 x 16.0 4.5 3.5 4.0 72 x 16.0 í), 4 4.0 4, () 3.0 2.5 W; 2.5 Mo; 2.5Cu 73 x 16.0 0.5 4.0 4.0 25 3Mo: 3Cu 74 x 16.0 0.7 4.3 3, () 3.9 75 x 16.5 0.9 4.25 3.25 3.75 76 x 17.0 (), 2X 4.25 3.75 0.3 Mn Table I continued Alloy manufacturing standard Alloy composition (remainder Nickcl) No.

Rods encased @ iusstelle powder rods Cr C S @ B Fe elements 77 x Alloy No. 76 + 50% WC 78 x 17.0 0.28 4.25 3.75 2.3 Mo; 2.3 Cu; 0.3 Mn 79 x laying No. 78 + 50% WC 80 x 17.0 0.95 3.9 3.3 2.0 81 x laying No. 80 + 15% (WC + 10 Co) 82 x alloy No. 80 + 50% (WC + 10 Co) 83 x 17.0 1.0 4.0 3.5 4.0 84 x 17.0 1.0 4.5 3.5 4.0 85 x 26.0 0.95 4.0 3.5 1.0 86 x 29.0 2.35 0.6 10 Co; 15 W properties of nickel-based alloy composition Colm.4 Colm.5 Colm.6 Colm.8 invention (43) *) (53) *) (58) *) (85) *)% Ni Bal. Bal. Bal. Bal. 65-70% Cr 10 11.5 13.5 26.0 22-27% B 2.0 2.5 3.0 3.5 approx. 2.5% Si 2.25 3.75 4.25 4.0 3-4% C 0.45 0.65 0.75 0.95 2.5-3.5% Fe 2.5 4.25 4.75 1.0 4 4.5 hardness comparison HRC 30 44 53 55 60 HV 50 80 535 625 690 880 RLS **) 0 23 255 344 50 *) Number of the regulation in table I **) sum of crack lengths In µm as a measure of the toughness.

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Claims (1)

Claim: Method for producing a hardfacing, thereby It counts that the carbon is in an alloy with the composition 22 up to 27% chromium, 2.5 to 2.796 boron, 3 to 4% silicon, 4 to 4.5% iron, 2.5 to 3.5% Carbon, the remainder nickel is added by adding chromium carbide. The invention relates to a method for producing a hard alloy on the basis of an alloy of nickel-chromium-boron-silicon, which is characterized by special has favorable properties in terms of hardness and toughness. The great importance of the nickel-chromium-boron-silicon alloy is documented by a large number of publications, of which an abundance Can be seen from possible applications. They play a special role in this Build-up wear protection layers that are obtained by thermal spraying or build-up welding on certain base materials. A comprehensive overview of the chemical compositions of Liart alloys based on nickel is specified in "Stahl-Eisen-Bücher", Volume 20, "Hartleglerungen zum Verschelßschutz", Düsseldorf 1975, rare 78 and 79 (table 1). In other places in this document there is a large number of possible uses reported. Furthermore, in DE-OS 30 18 007 a powdery additional composite material described, which apart from a nickel-chromium-boron-silicon alloy one with the addition of tungsten, carbon and iron. The content of carbon Is kept as low as possible with these hard adjustments. It is a maximum of 1% by weight. The well-known nickel-chromium-boron-silicon alloys are special those of interest included in the above summary in table 1 with the numbers 43, 53, 58 and 85 are designated. To identify and describe these four types of alloy mentioned reference is made to the following table 2, from which the relationship between the alloy composition and the characteristic properties. This relationship between properties and compositions of the alloys is described below: Characteristic for the alloys mentioned is the Increase in hardness (Rockwell hardness HRC and Vickers hardness HV50) attached to protective layers was measured, which consist of the alloys mentioned. It becomes clear that with increasing contents of chromium, boron, silicon and carbon there is an increase in hardness can be reached. With increasing hardness, however, the brittleness of the alloy also becomes increased, which shows, inter alia, that when performing the hardness measurement According to Vickers, the corners of the indentation pyramids are clear when viewed under the microscope Have cracks, the total length of which is the "crack length sum" RLS - over all four corners - Is indicated in Table 2. The brittleness of the higher alloyed nickel-base alloy has when the alloy is used as a wear protection layer - especially when if additional hard material particles are embedded - the undesirable accompanying property, that such embedded embeddings tend to break out under mechanical stress and this leads to an undesirable shortening of the tent pavilions coated in this way Materials. The alloy with the lowest content of metal golds, boron-silicon-carbon Although there are no cracks, it is insufficiently hard. When using hard coatings of the type mentioned as application materials for wear protection layers, e.g. B. by applying by means of thermal spraying or build-up welding, a large number of types of steel are not used as the base material or only suitable to a limited extent, because during thermal application or a subsequent thermal application Stress due to different thermal expansion coefficients Application layers are destroyed. Such is a whole range of high-level steels, z. B. valve steels, armature steels, spring steels and others, a coating with the known brittle hardenings are not accessible because of the disadvantages mentioned appear.