JPS6054294A - Cored wire for build-up by welding - Google Patents

Abstract

PURPOSE:To provide a cored wire which can form a wear resistant build-up layer having secure bond to a base metal by filling ceramic powder or a powder mixture composed of ceramics and metal into a metallic tube. CONSTITUTION:A cored wire for build-up by welding is formed by filling ceramic powder such as chromium carbide or a powder mixture composed of ceramic powder and stainless steel. etc. into a metallic tube. The sectional area ratio of the hole in the tube with respect to the sectional area of such cored wire is made about >=30% and the filling rate of the powder is made preferably >=50%. The same material as the material of the metallic tube is usually used for the metallic powder to be mixed with the ceramic powder. The build-up layer which consists of the composite structure dispersed uniformly with ceramic particles in the metallic matrix and is free from weld crack, etc. is formed by such composite wire.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite wire for melt +1 build-up for forming a wear-resistant build-up layer in which ceramic particles are dispersed in a metal matrix. Conventionally, thermal spraying has been used exclusively as a method for forming ceramic coatings. law is used. Since ceramic sprayed layers have excellent abrasion resistance, they have recently been widely used to improve the wear resistance of rolling rolls, etc. Carbon-based ceramics such as Cr3C2 and Cr7C3 are mainly used as the sprayed material. Composite powders are commercially available. .

However, the bonding of the thermal sprayed layer to the surface of the base material such as a roll is basically nothing more than physical adhesion force that bites into the unevenness of the surface, and the adhesion strength is poor, and it can be peeled off by mechanical insertion. Because it is easy to use, there are problems with stability and durability when used on actual machines, and there is a strong demand for a solution to this problem.

The present invention consists of 1. In order to solve the problem L, a composite wire is provided in which a build-up layer mainly made of ceramic can be formed by a weld build-up method instead of a thermal spraying method.

The composite wire of the present invention is a combination of a metal tube and a ceramic powder filled in the inner hole of the tube, or a mixed powder of ceramic powder and metal powder.

By using the composite wire of the present invention as a filler rod, welding is performed on the six-phase surface by, for example, Kunrasten inert gas arc welding (T J (l welding)), and the metal matrix and
A built-up layer having a composite structure consisting of ceramic particles dispersed in the matrix is formed. The welding conditions need not differ from those for normal weld overlay except for the use of composite wire. The build-up layer has wear resistance equal to or better than that of the sprayed layer, and the boundary with the base material surface is integrated with the welding heat as a fusion shield.
It has a much stronger adhesion strength than the mere physical adhesion strength of a thermally sprayed layer. The mixing ratio of the metal matrix and the ceramic particles in the build-up layer is arbitrary, but from the viewpoint of wear resistance, mechanical strength, etc., the ratio of the ceramic particles is preferably set to a factor of 20 to 80 (area ratio). Of course, this mixing ratio is determined by the ratio of the wall thickness of the metal tube to the cross-sectional area of the inner hole,
This can be easily controlled by adjusting the powder filling rate in the tube hole, the filling mixture ratio of ceramic powder and metal powder, etc.

The composite wire of the present invention has 1. 1 liter obtained by drawing process etc.
It can be manufactured by filling a tube made of II hot steel or the like with ceramic powder or a mixed powder of ceramic powder and metal powder, and then subjecting it to an acing process, drawing it out, and reducing the thickness.

The relationship between the tube internal hole cross-sectional area (ratio of 1 (b/aX100 ratio) (hereinafter simply referred to as "tube cross-sectional area ratio") to the cross-sectional area (a) of the double-tone wire and the powder filling rate in the tube is expressed as follows: An example of the case where the outer diameter is 6 mm is shown in FIG. 1, but from the viewpoint of weldability, it is desirable that the tube cross-sectional area ratio is 30 to 99 widths and the filling rate is 50 widths or more.

FIG. 2 illustrates the relationship between weldability in TiG welding using a composite wire as a filler rod, the tube cross-sectional area ratio, and the powder filling rate in the tube. The meltability was evaluated based on whether there were any weld cracks by color check and the degree of bias in the distribution of ceramic particles in the overlay layer due to the difference in specific gravity between the matrix metal and the ceramic particles. In the figure, the "○" mark means that there is no welding crack and the distribution of ceramic particles is uniform, and the "x" mark means that welding cracking occurs or the distribution of ceramic particles is uneven. In addition,
The material of the test tube is stainless steel, and the filling powder inside the tube is chromium carbide (Cr3C2 and/or Cr7).
C5) A single powder or a mixed powder of chromium carbide and stainless steel powder, and the outer diameter of the tube is 4 to 8 inches. As shown, the tube cross-sectional area ratio is 30 or more, the filling rate is 5
Good weldability is obtained when the coefficient is 0 or higher.

The ceramic powder used in the composite wire of the present invention is of a wide variety including carbide-based, nitride-based, ferride-based, and oxide-based. For example, carbide-based ceramics, especially Cr3C2
and Cr7C3 are preferably used from the viewpoint of wear resistance. The suitable powder particle size is, for example, 1 to 10 μm.

The material of the metal tube may be ferrous or non-ferrous metals, such as Cr-Fe, 0r-Ni, etc., depending on the usage conditions of the overlay layer.
-Fe system, Cr-Ni-Mo-Fe system, Cr-Ni system,
A metal (alloy) such as Or-Ni-Mo system is selected as the metal.

Furthermore, when a tube is filled with a mixture of metal powder and ceramic powder, the metal powder may be made of any material, but usually the same material as the metal tube is used.

Example 1 Stainless steel (JIS 5US810) Soumrenu tube (outer diameter 6 mm, wall thickness 0.5 mm, length IQOO)
+〃m), Cr 7Ca and Cr with an average particle size of 4 μm
3C2 mixed powder (Cr70370 weight ratio, Cr302
30% by weight) at a weight ratio of 90 to 95%, and was subjected to a rolling and swaging process to obtain an outer diameter of 4 mm.

The wire was drawn and reduced to a thickness of 0.4 mm to obtain a compound wire of the present invention consisting of a metal tube (1) and powder (2) as shown in FIG. The tube cross-sectional area ratio is 64 times, and the filling rate is 70 to 80 times. Use this as a filler rod and TUG
Welded (welding current 20OA) plate-shaped base JA ((J quality:
5CLL22. Width 100+++++++ x length 300mm
A layer thickness of 7 m is applied on one side of the
A build-up layer of m was formed. The overlay layer consists of Cr7C3 and Cr a with an area ratio of about 70 in the metal matrix.
Due to the composite structure in which C2 particles are uniformly dispersed, there are no weld cracks, and it is observed that the boundary with the base material is strongly bonded and integrated by meeting. In addition, the hardness is J (v5
．． 5g, and the conventional wealth layer, such as Cr3C2 and Ni
-It has a wear resistance of 11 J, which is equivalent to a double valley flooded layer (0r3G, area ratio of 75) made of -Cr alloy.

Example 2 Sudens steel (SUS810) tube (outer diameter 1 mm)
, wall thickness 0.5 mm) and ceramic powder (Cr7C3
A length made by filling a mixed powder of ゜Cr5C2) or stainless steel copper powder of the same quality as the tube] A composite wire (tube cross-sectional area ratio of 70 parts, filling rate of 80 parts) is used as a filler rod, Polar base material (material:
SCJ, ♀yu, length 150mm
Table 1 shows the welding conditions and welding results for forming a built-up layer with a length of 1100 r1. The welding results were determined by color checking for the presence or absence of weld cracks, and good results were obtained in all cases. In addition, the distribution of ceramic particles in the build-up layer is uniform, and the proportion of ceramic particles in the matrices is 70 to 80%.
It was observed that the boundary between Z and base (2) was fused and strongly bonded and integrated.The strength u11v of each build-up layer was 460 to 600.

As shown in Table 1, the present invention can be applied using conventional thermal spraying methods. By using the composite wire of the present invention, it is possible to form a coating layer consisting of ceramic or ceramic and one metal as a build-up layer by welding, which was previously impossible to achieve. It is possible to form a built-up layer on parts etc. that has wear resistance equal to or higher than that of the thermally sprayed layer and has a stronger bond to the base material than the thermally sprayed layer.

[Brief explanation of the drawing]

Fig. 1 is a graph illustrating the relationship between tube cross-sectional area ratio and powder filling rate, Fig. 2 is a graph showing the relationship between tube visiting area ratio and powder filling rate, and first welding process, and Fig. 8 is a graph illustrating the relationship between tube visiting area ratio and powder filling rate, and Fig. 8 is a graph illustrating the relationship between the tube cross-sectional area ratio and powder filling rate. FIG. 3 is an external view of an example of a wire. , I: metal tube, 2: powder. Agent Patent Attorney Miyazaki Shinhachibu-+'-I-ni Spirit Exam M Piece F Continued from page 1 7 November 1 Part 8- Migaoka 16-23 17-10

Claims (3)

[Claims] (1) A composite wire for weld overlay, which is made by filling a metal tube with ceramic powder or a mixed powder of ceramic powder and metal powder. (2) Tube inner hole cross section lJ′ relative to wire cross-sectional area
11. The composite wire for weld overlay according to item (1) above, wherein the width ratio is 30 or more, and the powder filling rate in the tube is 50 or more. (3) The composite wire for weld overlay according to item 2, item (1) or item (2), wherein the ceramic powder is chromium carbide powder.