JPH026097A - Wear resistant overlay layer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a cladding method for coating and maintaining the surfaces of ball mill liners, sand pump impellers and liners, and other members that require wear resistance. Regarding layers.

[Conventional technology]

High speed g (JISG 4403, etc.) has been used as components for ball mill liners, sand pump impellers and liners, sludge granulator paddles and liners, etc.
and stellite alloys (Co-Cr-W series) have been used. These alloy materials have high hardness and wear resistance due to the dispersion strengthening effect of carbide particles etc. precipitated within the metal matrix. In addition, instead of these metal materials, a mixed powder of metal and ceramic is used as a build-up material, and by welding build-up, the surface of the component is coated with a composite structure consisting of a metal matrix and ceramic particles as dispersed phase particles. It is also practiced to form a layer to protect the surface of the member from wear.

[Problem to be solved by the invention]

However, such as ball mills, sand pumps, sludge granulators, etc., coarse powder particles (particle size: a fraction of a mm to several mm)
The wear resistance of the hard alloy and built-up layer is not necessarily sufficient in a usage environment where the parts are repeatedly subjected to severe collisions, and the service life of the parts is unstable. When the surface of the member is observed, it is found that there are many fine depressions on the surface caused by falling of precipitated carbide particles and ceramic particles, which are dispersed phase particles in the matrix metal. In other words, in the above usage environment,
The impact of coarse particles colliding with the surface of the part causes the dispersed phase particles to fall off or break off from the surface of the part, and as a result, the surface layer of the part does not lose its wear-resistance effect due to the dispersed phase particles. It is thought that the surface damage caused by the collision is accelerated.

In view of the above, the present invention provides an improved build-up layer for effectively protecting the surface of a member from abrasion damage in a usage environment where it is subjected to severe collisions of powder and granular materials.

[Means and effects for solving the problem] The build-up layer for protecting the surface of a member of the present invention has three layers in the matrix metal.
Ceramic particles with a particle size of 200 μm or less occupying 0 to 80% by weight, and particle sizes of 0.5 to 200 μm accounting for 10 to 60% by weight
It is characterized by having a composite structure in which 5 mm cemented carbide balls are uniformly mixed.

FIG. 1 schematically shows a composite structure of a built-up layer according to the present invention. (21) is a matrix metal, (22) is a ceramic particle mixed as a dispersed phase particle, and (23) is a cemented carbide ball. (10) is a base material covered and protected by a built-up layer (20). This composite overlay layer (20
) is formed by a powder plasma welding method as described later.

Ceramink particles mixed as dispersed phase particles in the metal matrix may be carbide-based, oxide-based, boride-based, nitride-based, etc., but among these, SiC, WC, TiC
, NbC, CrC, and other carbide-based ceramic particles are extremely hard particles, have high heat resistance, and have excellent thermal stability during overlay construction by powder plasma welding.
In addition, it is a suitable dispersed phase particle because it has good compatibility with the matrix metal.

The reason why the particle size of the ceramic particles is set to 200 μm or less is to ensure the function as dispersion-strengthening particles. Furthermore, the reason why the proportion of the particles in the composite structure of the built-up layer is set to 30% by weight or more is because if the amount is smaller than that, the dispersion strengthening effect will be insufficient and sufficient wear resistance will not be obtained. The reason for setting the upper limit at 80% is that if it exceeds 80%, the relative proportion of the 71-rix metal will be insufficient and the resulting uneven distribution of ceramic particles will cause the build-up layer to become inhomogeneous and the toughness to deteriorate. This is because a decrease etc. will occur.

On the other hand, a cemented carbide ball is a sintered body made of tungsten carbide (WC or/and W2C) particles and a bonding metal. The binding metal is Co.

Cr, Ni, W, Ti, Nb, An, Cu, Ag.

Metals such as MO, or alloys thereof, such as C.

-50%NiXCo-10%Ni-2%Cr-1%V, etc. Further, in order to make the hardness of the cemented carbide ball sufficient, it is preferable that the proportion of tungsten carbide particles in the sintered body is 70% by weight or more.

The particle size of the cemented carbide balls was specified to be 0.5 to 5 mm because, for spheres smaller than 0.5 mm, the effect of improving wear resistance by mixing the balls, especially the dispersed phase particles. If some fine ceramic particles fall off or are missing, the function to prevent them from falling cannot be obtained, while if the coarse spheres exceed 5 bars, it will be difficult to uniformly disperse them in the overlay layer, resulting in the effect of mixing cemented carbide balls. This is because you won't be able to do it.

In addition, the reason why the proportion of the cemented carbide balls in the build-up layer was set at 10% or more was because if it was less than that, the mixing effect would be insufficient, and the reason why the upper limit was set at 60%. This is because if it is added in an amount exceeding this amount, the function as a build-up layer will deteriorate due to a relative decrease in the amount of matrix metal and ceramic particles.

As the cemented carbide balls, it is also possible to use, for example, spherical balls having an appropriate particle size that are commercially available as grinding balls for ball mills. Further, the spherical shape does not necessarily have to be a perfect sphere, and it is perfectly acceptable to have slight deformation or unevenness.

7 Trinks metals are selected as appropriate depending on the application and usage conditions of the parts to be overlaid, but they are suitable for strength, wear resistance, corrosion resistance, and compatibility with ceramic particles and cemented carbide balls (wettability). ) etc., Ni, Co, Fe, C
An alloy containing r as a main component is preferable, and specific examples thereof include Cr: 10-40%, the balance Co, or a part of the Co, Ni: 10-30%, Fe: 40% or less, Nb
: 5% or less, Mo: 10% or less, AP=10% or less, W
: 10% or less, Mn: 10% or less, CO-based alloy substituted with one or more elements selected from 10% or less, Cr
:10-30%, MO=5-20%, remainder substantially Ni
, or a part of the Ni is Co: 30% or less, Nb:
5% or less, Al2 10% or less, W: 10% or less, Y: 5
Ni-based alloy substituted with one or more elements selected from % or less, C: 1.5% or less, Si: 2%
Below, Mn: 10% or less, Cr: 13-40%, Ni:
5 to 30%, the remainder is substantially Fe, or a part of the Fe is Mo: 10% or less, Nb: 5% or less, Aff: 10%
Hereinafter, alloy steels substituted with one or more elements selected from W: 10% or less, Y: 5% or less, Se: 5% or less (for example, SO5304, 5IJS 310, etc.) may be mentioned.

The composite build-up layer of the present invention is typically formed by a powder plasma welding method. The weld build-up may be carried out according to the usual welding procedure except that cemented carbide balls are dispersed and mixed into the molten pool formed on the surface of the base metal. An example is shown in FIG.

(1) is a powder plasma welding torch, and (2) is a cemented carbide ball supply port. The metal powder and ceramic powder are supplied to the plasma flame (3) from the welding torch (1), and the metal powder is melted to form a molten pool (ceramic particles are dispersed in the molten metal) on the base metal (10) surface. A mixed solid-liquid mixing pool (4) is formed, and cemented carbide balls (23) are sprinkled thereon to be mixed and dispersed in the molten pool. By performing the above operation while moving the welding torch (1) at a predetermined speed, a build-up bead (20
), and if necessary, build up beads to a predetermined layer thickness (for example, 2 to 10 a
n) to obtain a composite build-up layer.

〔Example〕

A mixed powder of metal powder and ceramic powder and cemented carbide balls are used as overlay materials, and as shown in Fig. 2, the welding torch (1) is moved at a constant speed using the powder plasma welding method to weld the base material. (Carbon steel plate-like member) By forming a molten pool (a molten metal pool in which ceramic particles are dispersed) (4) on the surface of (10), and scattering cemented carbide balls (23) into this, A build-up bead (20) is formed.

One layer of build-up beads (20) was built up to form a build-up layer with a layer thickness of about 7 mm. This build-up layer is designated as A.

(1) Overlay layer component composition a: Matrix metal S [IS 304 equivalent alloy (18% Cr-8% N1-F
e) b: Ceramic particle material: SiC Average particle size: 5 μm Mixing ratio: 30% by weight C: Cemented carbide ball material: 90%W(, -10%CO sintered body particle size: 1 to 3n
+m (average particle size: 2mm) Mixing ratio: 40% by weight (II) Welding conditions Welding current/voltage: 40OA/50V Working gas: Ar gas Welding torch transfer speed: 80mm/denominator material preheating temperature: 600°C As a comparison material A composite overlay layer was formed under the same welding conditions as above, except that the addition of cemented carbide balls was omitted. Let this be B. Furthermore, a high-speed steel plate member was provided as another comparative material. Let this be C.

[■] Wear Resistance Test For each of the above-mentioned test materials A, B and C, abrasion tests were conducted on powder spraying, and the following results were obtained.

a: Test conditions Spraying medium: Alumina particles with an average particle size of 0.4 mm Spraying pressure 3 kg/ad Spraying angle: 30° Amount of spraying medium: 2 kg Amount of wear (mg) Surface condition Sample material A 15 Smooth (invention) Example) Test material B 70 Uneven rough surface (Comparative example) Test material C200 Uneven rough surface (Comparative example) [Effects of the invention] The composite overlay layer of the present invention is suitable for use in environments where it is subjected to severe collisions of coarse particles. It also exhibits stable wear resistance that exceeds conventional hard alloys and overlay materials.Therefore, it can be used in ball mills, sand pumps, sludge granulators, and other parts that are It is suitable as a protective layer and has a great effect on improving the stability and service life of the member.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing the composite structure of the overlay layer of the present invention, and FIG. 2 is a schematic explanatory diagram of overlay welding. 1: Welding l・-chi, 2: Cemented carbide ball supply I], 4:
't8 molten pool, 20: Overlay layer, 21: Matrix metal, 22: Ceramic resin particles, 23: Cemented carbide ball.

Claims (1)

[Claims] 1. Ceramic particles with a particle size of 200 μm or less accounting for 30 to 80% by weight in the metal matrix, and 10 to 60% by weight
A wear-resistant build-up layer having a composite structure in which cemented carbide balls with a grain size of 0.5 to 5 mm are evenly mixed in the weight percent.