JP7144205B2 - Hard facing forming method, wear resistant material, industrial equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of forming a hard facing using cermet or the like as hard particles, a wear resistant material formed with a hard facing by this method, and industrial equipment using the wear resistant material.

As a conventional method of forming a hard facing, hard particles such as tungsten carbide are dispersed from above into the molten pool to form a hard facing layer with hard particles added inside on the surface of the plate. A method for doing so is known (Patent Literature 1 and Patent Literature 2). According to these forming methods, since hard particles are contained inside the hard facing layer, it is possible to form a hard facing plate having excellent wear resistance.

JP-A-8-47774 Japanese Unexamined Patent Application Publication No. 2008-763

However, in the method of forming a hard facing layer as described above, although the hardness of the hard facing layer can be increased in order to improve wear resistance, there is a problem that cracks are likely to occur if the hardness is improved. However, if the ductility is improved in order to make cracks less likely to occur, the hardness is lowered, which may lead to a decrease in wear resistance. Hard particles such as titanium carbide (TiC) have high hardness, but their specific gravity is smaller than that of the matrix metal. Therefore, with the conventional method of forming a hardfacing layer (reverse method in arc welding, etc.), hard particles are scattered into the molten pool from above. It floats, and the hard particles are distributed only on the surface layer of the hardfacing layer. A material on which a hard facing layer is formed by such a method has a problem that it is not preferable as a wear resistant material.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and the main problem of the present invention is to directly spray hard particles on the mother phase metal, and then to weld while discharging while involving the dispersed hard particles. By performing, even if the hard particles have a small specific gravity relative to the mother phase metal and a high hardness, the hard particles can be uniformly distributed in the hard facing layer. A method for forming a hard facing layer. intended to provide

Means for solving the problems of the present invention are the following (1) to (5).
(1) A first step of scattering hard particles containing carbides and/or carbonitrides on the base material, a second step of generating an arc between the welding torch and the base material to melt the surface of the base material, A method for forming a hard facing layer, comprising a third step of obtaining a hard facing layer by solidifying the base material melted in the second step containing the hard particles in an unmelted state.
(2) The hardfacing layer forming method according to (1), wherein the second step is performed immediately after the first step.
(3) The hard facing layer forming method according to (1) or (2), wherein the hard facing layer is continuously formed by repeating the first step, the second step, and the third step.
(4) A wear resistant material having a hard facing layer formed by the hard facing layer forming method described in (1) to (3).
(5) Industrial equipment using the wear-resistant material on which the hard facing layer is formed.

According to the method for forming a hardfacing layer according to the present invention, even if the hard particles have a small specific gravity relative to the mother phase metal and a high hardness, the hard particles are placed on the hardfacing layer at a constant thickness. Even distribution is possible. As a result, it is possible to provide a wear resistant material that is a member having a hard facing layer with excellent wear resistance formed thereon.

It is a figure which shows the hard facing layer forming apparatus which is one embodiment of this invention. It is a figure which shows the state of the welded part at the time of forming hard facing in embodiment of this invention. It is a figure which shows the flowchart of the hard facing layer formation method implemented by embodiment of this invention. It is a figure which shows the state in each step of the hard facing layer formation method implemented by embodiment of this invention. It is a photograph of the cross section of the hard facing layer formed by the hard facing formation method of an Example. It is a photograph of the cross section of the hard facing layer formed by the comparative example. 1 is a schematic diagram showing the distribution of hard particles; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a hard facing layer forming apparatus 1 used in the hard facing layer forming method according to the present embodiment. FIG. 2 shows a welded portion showing a welded state during hardfacing in this embodiment.

In the welding method of this embodiment, a hard facing layer is formed on the base material 4 by arc welding in a state in which the hard particles 2 are contained in the hard facing layer 3 in an unmelted state.

As the hard particles 2 used in this embodiment, so-called cermet particles are used. The cermet to be used is a composite material obtained by mixing and sintering powders of hard compounds such as metal carbides and nitrides as a metal binder, and has a particle size of about 0.1 mm to 3 mm, preferably 0.2 mm. About 2 mm can be used. Furthermore, it is more preferable to use one that has been pulverized to a particle size of 0.5 mm to 1.5 mm because it is easier to weld and the finished surface is more beautifully finished.
As the cermet particles, for example, titanium-based cermets such as titanium carbide (TiC) and titanium carbonitride (TiCN) alone or mixtures thereof are used. Also, the cermet particles can be titanium carbide and titanium carbonitride alone or a mixture thereof bonded with nickel or cobalt.

The particle size of the above cermet is, for example, a mixture of particles having a small diameter of 0.2 mm to 0.7 mm, a medium diameter of 0.7 mm to 1.2 mm, and a large diameter of 1.2 mm to 1.8 mm. (Overall, within the above-mentioned range of 0.1 mm to 3 mm), depending on the application of the base material that forms the hardfacing, different particle sizes are used, or different particle sizes are mixed and used. It is preferable to In addition, the hard particles having this particle size are also preferable in that they do not melt and remain in an unmelted state even in the welding of this embodiment.

The hard particles 2 have a hardness of, for example, 500 to 2000 Hv, preferably 1000 to 1800 Hv, in order to maintain sufficient hardness as the hardfacing layer 3 . The amount of the hard particles 2 added is 5 to 55% by volume, preferably 20 to 50% by volume, with respect to the hardfacing layer 3, considering the weldability and the distribution of the hard particles. Furthermore, the specific gravity of the hard particles 2 is 1 to 10 g/cm3, preferably 3 to 8 g/cm3.

The base material 4 used in the present embodiment is, for example, one that is used as a wear-resistant plate provided on both sides of a conveyor belt of a belt conveyor device, and its material is, for example, SS400 (general structural rolled steel). , carbon steel such as S45C, and low alloy steel such as SCM440. The shape of the base material 4 is not limited to a flat plate. Examples of the base material to which hardfacing is applied include sprocket bearings of belt conveyors, linings of mixers, tips of excavator hibits, and the like. Various shapes are conceivable. As the base material 4, metals such as CrMo steel, Cr steel, boron steel, and Mn steel can also be used.

1 used in this embodiment includes a welding torch 5, a hard particle supply nozzle 6, a weaving device 8, a feeder 9, and a traveling carriage . FIG. 1(a) is a view showing the hardfacing forming apparatus 1 and the overall apparatus when performing hardfacing formation, and FIG. 1(b) shows the hardfacing forming apparatus 1 and the hardfacing forming apparatus. FIG. 1(c) is a front view of the hardfacing forming apparatus 1 and the overall apparatus for forming the hardfacing. As shown in (a) to (c) of FIG. 1, the material fixing base 21, the feeder moving beam 22, and the feeder support base 23 are installed on the surface plate 24. As shown in FIG. A feeder support base 23 is installed on the surface plate 24, and the feeder moving beam 22 is placed on the support base. Place 9.
When forming the hard facing, the base material on which the hard facing layer is to be formed is fixed to the material fixing table 21, and the traveling carriage 10 is moved beside the material fixing table 21 while the method of the present embodiment is used. A hardfacing layer is formed.

A welding wire 11 is supplied as a filler material to the welding torch 5 of the present embodiment. The welding wire 11 is mainly composed of carbon steel such as mild steel. The welding wire 11 is let out from a coil (not shown), supplied to the welding torch 5, and protrudes from the welding torch 5 by a predetermined length L1. The welding torch 5 is inclined at an angle θ (torch angle) with respect to the surface of the base material 4, and moves along the surface of the base material 4 at a predetermined speed (see welding progress direction in FIG. 2). Let L2 be the linear distance from the point where the welding wire 11 protrudes from the welding torch 5 to the base material 4 . L2 is 10-30 mm, preferably 15-25 mm. Also, the torch angle θ is suitable for the welding method of this embodiment to be 10° to 25°, preferably 15° to 20°. The welding progress speed is 15 cm/min to 30 cm/min, and the current value, voltage value and welding speed are set according to the plate thickness of the base material. Incidentally, the aforementioned L1 is a distance determined by L2 and the torch angle θ.

The hard particle supply nozzle 6 of this embodiment is arranged above the base material 4 at a location near the welding torch 5 in the traveling direction. The hard particle supply nozzle 6 moves along with the welding torch 5 while weaving a predetermined width to the left and right along the traveling direction of the welding torch 5 (FIG. 2). The weaving width is 10 to 30 mm, preferably 15 to 25 mm. The hard particles 2 are supplied onto the base material 4 by dropping from a hard particle supply nozzle 6 . The linear distance between the hard particle supply nozzle 6 and the base material 4 is L3, and L3 is 15 to 40 mm, preferably 120 to 30 mm.

Next, FIG. 3 shows a flow chart of a method for forming a hard facing layer, and a method for forming a hard facing layer according to the present invention will be described.

First, in the first step STEP 1 , hard particles 2 are dropped from a hard particle supply nozzle 6 and supplied to the base material 4 . This 1st process STEP1 is performed just before the arc welding of 2nd process STEP2. FIG. 4(a) shows the state of STEP1.

In the second step STEP2, arc welding is performed. In this process, the welding wire 11 is melted by generating an arc and supplied as a filler material, thereby forming a molten pool 12 on the base material 4 . At this time, in STEP 2, almost at the same time as the hard particles 2 were dropped onto the base material in STEP 1, an arc was generated in front of the place where the hard particles 2 were dropped to melt the base material 4, forming a molten pool 12. , to form a hard facing layer while entraining the hard particles 2 . FIG. 4B shows the state of STEP2. As for the time from STEP 1 until STEP 2 starts, it is possible that the hard particles are blown away by the shielding gas or the arc force. seconds later).

At this time, the molten pool 12 melts the surfaces of the welding wire 11 and the base material 4, so that the molten pool 12 becomes a molten liquid in which the hard particles 2 are mixed. At this time, the specific gravity of the hard particles 2 is about 5 to 7 g/cm3, which is smaller than the specific gravity (7.85 g/cm3) of the material of the base material 4 (steel material such as SS400). It is conceivable that it floats on the upper surface of the molten pool 12 . However, by welding by the hardfacing forming method of the present embodiment, even if there is a difference in specific gravity, the unmelted cermet particles 2 in the molten pool 12 may float above the hardfacing layer, It is possible to prevent such a state that it appears on the surface, and it is possible to distribute it evenly with a constant thickness in the upper part of the hardfacing layer. The hard particles 2 are evenly distributed at 0.5 to 3 mm, preferably 1 to 2 mm from the surface of the hardfacing layer, so that the wear resistance effect can be improved.

In addition, since the hard particles 2 have a particle size distribution of about 0.1 mm to 3 mm, they can be present in the molten pool 12 in an unmelted state without being melted. Since the hard particles 2 are in an unmelted state, even if a mild steel welding material is used, unmelted hard particles are distributed on the surface or inside the welding material, so it is possible to exhibit characteristics as a wear-resistant material. becomes.

In the third step STEP3, the molten pool 12 is solidified to obtain the hard facing layer 3 formed on the base material 4 and containing the hard particles 2 in an unmelted state. Here, the molten pool 12 is naturally solidified on the locus of movement of the welding torch 5 and the hard particle supply nozzle 6 to form the hardfacing layer 3 .

By repeating the first step S1 to the third step S3 while moving the welding torch 5 and the hard particle supply nozzle 6, the hardfacing layer 3 is formed so as to cover a predetermined region of the base material 4. be done. After that, the hardfacing formed by the welding is solidified, so that the hardfacing layer 3 in which the hard particles 2 are evenly distributed with a constant thickness on the upper part of the hardfacing layer can be formed. . After that, a hard build-up layer is formed on the entire surface of the base material 4 .

Specific examples of the hard facing layer forming method according to the present embodiment will be described below. Table 1 shows the conditions in each example.

<Hard particles>
・Titanium-based cermet particles made of a mixture of titanium carbide and titanium carbonitride ・Particle size (particle size): 0.71 mm to 1.18 mm
<Base material>
・Shape: Flat plate with thickness (t) 9mm, height x width 200mm x 100mm ・Material: SS400
<Welding wire>
・Nippon Steel & Sumikin Welding Co., Ltd. Solid wire for mild steel YM-26 (wire diameter: φ1.2 mm)
・θ: 20°
・L2: 25mm
<Movement condition of hard particle supply nozzle 6>
・Weaving waveform: sine wave ・Weaving half amplitude: 10mm
・L3: 30mm
<Welding method>
・MAG welding ・Shield gas: Carbon dioxide gas (25 L/min)
・Welding current: 312A
・Welding voltage: 32.4V
・Welding speed: 25 cm/min

FIG. 5(a) shows a cross-sectional photograph of the hardfacing layer 3 of the plate-like body subjected to hardfacing welding according to the above-described Example 1. As shown in FIG. From this, it can be seen that the hard particles 2 are evenly distributed with a constant thickness in the upper portion inside the hardfacing layer 3 in an unmelted state. The cross-sectional photographs were taken under the following conditions (the same applies to other examples and comparative examples).
<Cross-section photography>
(1) Take an image with a stereoscopic microscope and a USB camera, and (2) measure the distance from the surface using image analysis software based on the image data.
Stereo microscope: Nikon SMZ-745T
USB camera: USB 2.0 model manufactured by Sentech Image analysis software: DIPP-Image manufactured by Detect

<Hard particles>
・Titanium-based cermet particles made of a mixture of titanium carbide and titanium carbonitride ・Particle size (particle size): 1.18 mm to 1.70 mm
<Base material>
・Shape: Flat plate with thickness (t) 9mm, length x width 200mm x 100mm ・Material: SS400
<Welding wire>
・Nippon Steel & Sumikin Welding Co., Ltd. Solid wire for mild steel YM-26 (wire diameter: φ1.2 mm)
・θ: 20°
・L2: 25mm
<Movement condition of hard particle supply nozzle 6>
・Weaving waveform: sine wave ・Weaving half amplitude: 6mm
・L3: 30mm
<Welding method>
・MAG welding ・Shield gas: Carbon dioxide gas (25 L/min)
・Welding current: 310A
・Welding voltage: 32V
・Welding speed: 25 cm/min

FIG. 5(a) shows a cross-sectional photograph of the hardfacing layer 3 of the plate-like body on which hardfacing welding was performed according to Example 2 above. From this, it can be seen that the hard particles 2 are evenly distributed with a constant thickness in the upper portion inside the hardfacing layer 3 in an unmelted state.

<Hard particles>
・Titanium-based cermet particles made of a mixture of titanium carbide and titanium carbonitride ・Particle size (particle size): 0.71 mm to 1.18 mm
<Base material>
・Shape: Thickness (t) 6mm, Length x Width: 200mm x 100mm flat plate ・Material: SS400
<Welding wire>
・Daido Steel solid wire hardfacing DS350 (wire diameter: φ1.2mm)
・θ: 20°
・L2: 25mm
<Movement condition of hard particle supply nozzle 6>
・Weaving waveform: sine wave
・Weaving half amplitude: 8mm
・L3: 30mm
<Welding method>
・MAG welding ・Shield gas: Carbon dioxide gas (25 L/min)
・Welding current: 290A
・Welding voltage: 32.2V
・Welding speed: 26 cm/min

FIG. 5(a) shows a cross-sectional photograph of the hardfacing layer 3 of the plate-like body on which hardfacing welding was performed according to Example 3 above. From this, it can be seen that the hard particles 2 are evenly distributed with a constant thickness in the upper portion inside the hardfacing layer 3 in an unmelted state.
The cross-sectional photographs were taken under the following conditions (the same applies to other examples and comparative examples).

<Hard particles>
・Titanium-based cermet particles made of a mixture of titanium carbide and titanium carbonitride ・Particle size (particle size): 1.18 mm to 1.70 mm
<Base material>
・Shape: Thickness (t) 6mm, length x width 200mm x 100mm flat plate ・Material: SS400
<Welding wire>
・Daido Steel solid wire hardfacing DS350 (wire diameter: φ1.2mm)
・θ: 20°
・L2: 25mm
<Movement condition of hard particle supply nozzle 6>
・Weaving waveform: sine wave ・Weaving half amplitude: 8 mm
・L3: 30mm
<Welding method>
・MAG welding ・Shield gas: Carbon dioxide gas (25 L/min)
・Welding current: 302A
・Welding voltage: 32V
・Welding speed: 26 cm/min

FIG. 5(b) shows a cross-sectional photograph of the hardfacing layer 3 of the plate-like body on which hardfacing welding was performed according to Example 4 above. From this, it can be seen that the hard particles 2 in an unmelted state are evenly distributed in the upper part inside the hardfacing layer 3 with a constant thickness, as in Example 1.

Comparative example

A molten pool was formed on the base material by arc welding, which is a conventional method, and a hardfacing layer was formed by a method (retreat method) in which cermet particles were dispersed in the molten pool from above the molten pool. The welding conditions for the backward welding method are shown below.
<Hard particles>
・Titanium-based cermet particles made of a mixture of titanium carbide and titanium carbonitride ・Particle size (particle size): 0.71 mm to 1.18 mm
<Base material>
・Shape: Flat plate with thickness (t) 9mm, height x width 200mm x 100mm ・Material: SS400
<Welding wire>
・Nippon Steel & Sumikin Welding Co., Ltd. Solid wire for mild steel YM-26 (wire diameter: φ1.2 mm)
・θ: 20°
・L2: 25mm
<Movement condition of hard particle supply nozzle 6>
・Weaving waveform: sine wave ・Weaving half amplitude: 10mm
・L3: 30mm
<Welding method>
・MAG welding ・Shield gas: Carbon dioxide gas (25 L/min)
・Welding current: 312A
・Welding voltage: 32.4V
・Welding speed: 25 cm/min

FIG. 6 shows a cross-sectional photograph of the hardfacing layer 3 of the plate-like body subjected to hardfacing welding according to the comparative example. As a result, it can be seen that the hard particles 2 are gathered and floating on the surface of the hardfacing layer 3 . In this state, the hard particles collapse or peel off, making it difficult to exhibit sufficient wear resistance.

FIG. 7 is a conceptual diagram showing the distribution of hard portion particles in the hard facing layers formed by the method of Examples 1 to 4 of the present embodiment and the comparative example. FIG. 7(a) is an example, and FIG. 7(b) is a comparative example. In the examples, the hard particles are dispersed in a constant thickness on the inner side of the upper surface of the hardfacing layer, whereas in the comparative examples, the hard particles are distributed in a floating state on the upper surface of the hardfacing layer. showing. Therefore, as described above, by using the hardfacing layer forming method of the present embodiment, hard particles can be distributed in such a state, and physical properties with high wear resistance can be obtained.

The method of forming a hard facing according to the present invention includes a method of forming a hard facing layer with high wear resistance using hard particles with a small specific gravity such as cermet particles, and a method of forming a hard facing layer with high wear resistance. It is possible to supply a wear-resistant material with The hardfacing layer forming method of the present invention can also be applied to protective plates inside various crushers, protective plates inside hoppers that temporarily store raw materials such as ores, protective plates around casings used in casing rotary excavation methods, and the like. Therefore, it is possible to provide industrial equipment with excellent wear resistance.

[Modification]
(1) In the present embodiment, the hard particles 2 were prepared in advance and used, but the hard particles are fractionated by recycling from waste materials containing hard particles such as cermet particles, and are adjusted to an appropriate particle shape. can also be used in the present invention.
(2) In the present embodiment, the hardfacing layer is formed by MAG welding, but the method is not limited to this, and TIG welding, MIG welding, or the like can also be employed.

1 hard facing forming device 2 hard particles 3 hard facing layer 4 base material 5 welding torch 6 hard particle supply nozzle 7 welding nozzle 8 weaving device 9 feeder 10 traveling carriage 11 welding wire 12 molten pool 20 whole hard facing forming device 21 material fixing base 22 feeder moving beam 23 feeder support base 24 surface plate

Claims (2)

a first step of sprinkling hard particles containing carbides and/or carbonitrides onto the base material;
A second step of generating an arc between the welding torch and the base material to melt the surface of the base material;
A third step for obtaining a hard facing layer by solidifying the base material melted in the second step containing the hard particles in an unmelted state ,
A hard facing layer forming method for continuously forming a hard facing layer by repeating the first step, the second step, and the third step. 2. The hardfacing layer forming method according to claim 1, wherein the second step is performed immediately after the first step.

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