JP3002585B2 - Welding material for hardfacing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding material for hardfacing, and more particularly to a welding material for hardfacing a Co-based alloy which is preferably used when performing arc overlay welding under an inert gas shield. Things.

[0002]

2. Description of the Related Art As a means for increasing the wear resistance of various parts, there is a method of overlay welding a Co-based alloy welding material (a filler material). For example, the valve faces of the intake and exhaust valves of diesel and gas engines have less soot and scum in the exhaust gas compared to gasoline engines, so that the metals directly rub against each other. High abrasion resistance is required in order to prevent a decrease or the like. C (carbon): about 0.04% by weight, Si (silicon): about 2.0% by weight, Cr (chromium): about 8% by weight, Mo (Molybdenum): about 28% by weight, Co (cobalt): Cobalt alloy tribaloy 400 composed of the balance
(Trademark of Deloro Stellite) or the like. As such a build-up welding method, an oxygen acetylene gas welding method using a rod-shaped tribaloy is generally used.

[0003]

However, in the oxygen acetylene gas welding method, since the material to be welded (base material) is heated in advance, and then the overlay welding is manually performed by the operator, and then gradually cooled, In addition to low productivity, there are problems that welding work in a high-temperature environment imposes a heavy burden on an operator and requires skill. When an austenitic heat-resistant stainless steel such as SUH36 is used as a material to be welded, such as the exhaust valve, since N (nitrogen) is contained at about 0.4% by weight, the tribaloy 4 is used.
Since direct blow welding of 00 causes many blowholes, stellite (trademark of Deloro Stellite, Inc.) containing about 30% by weight of Cr for fixing N ₂ is previously welded to the material to be welded. After that, it is necessary to cut the surface and overlay weld the tribaloy, which further reduces the productivity.

On the other hand, it is conceivable to employ a plasma powder welding method (PPW method) in which arc build-up welding is performed under an inert gas shield of argon or helium, a TIG welding method, or the like. According to such a welding method, there are advantages such as high productivity being obtained, automation being possible, and the burden on the operator being greatly improved. , The precipitation of an intermetallic compound Mo ₃ Si having a hardness Hv of about 2000, which contributes to the improvement of wear resistance, is hardly recognized.
The effect of improving the wear resistance cannot be obtained sufficiently. That is, in the oxygen acetylene gas welding method, C in the atmosphere enters the molten metal and rises to about 0.2 to 0.8% by weight, which is a temperature range between the solid and liquid phases during solidification of the welding material. To facilitate the precipitation of the intermetallic compound Mo ₃ Si, combined with the slow cooling rate,
A large amount of o ₃ Si precipitates to improve wear resistance. In the case where tribaloy is overlay-welded to SUH36 or the like containing N, there is no change in the circumstances in which stellite must be overlay-welded in advance even in the above-mentioned plasma powder welding method or TIG welding method. is there.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a Co-based alloy capable of obtaining excellent wear resistance even in overlay welding by a high productivity plasma powder welding method or the like. An object of the present invention is to provide an alloy welding material.

[0006]

According to a first aspect of the present invention, there is provided a welding material for hardfacing a Co-based alloy, comprising 0.1 to 0.5% by weight of C and 2%. 0.0-5.0
Wt% Si, 0.01 to 1.0 wt% Mn (manganese), 7.0 to 15.0 wt% Cr, 26 to 3 wt%
3 viewed contains a weight% of Mo, the balance being Co and inevitable not
It is characterized by consisting of a pure substance . The second invention is a Co-based compound.
A welding material for hardfacing of gold, 0.1 to 0.5 weight
% C, 2.0 to 5.0% by weight of Si, 0.01 to
1.0% by weight of Mn and 7.0 to 15.0% by weight of Cr
And 26 to 33% by weight of Mo, and Ti,
One or more of Nb, Zr, and Al are combined in a total amount of 0.1%.
-5.0% by weight, the balance being Co and inevitable impurities
Characterized by comprising: The third invention relates to a Co-based alloy.
A welding material for hardfacing, comprising 0.1 to 0.5% by weight.
C, 2.0-5.0% by weight of Si, and 0.01-1.
0 wt% Mn, 7.0-15.0 wt% Cr,
26 to 33% by weight of Mo and 0.02% by weight or less of B
And the balance consists of Co and inevitable impurities
It is characterized by. The fourth invention is a solution for hardfacing a Co-based alloy.
A contact material comprising 0.1 to 0.5% by weight of C and 2.0% by weight;
-5.0 wt% Si and 0.01-1.0 wt% M
n, 7.0-15.0% by weight of Cr, and 26-33 weights
% Mo and 0.02% by weight or less of B
And one or more of Ti, Nb, Zr and Al
0.1 to 5.0% by weight in total, the balance being Co and impossible
It is characterized by being composed of evasive impurities.

[0007]

In the welding material for hardfacing according to the present invention, since the content of C is larger than that of tribaloy, arc welding is performed under an inert gas shield such as a plasma powder welding method. Also in the method, the C content in the molten metal increases, the temperature range between the solid and liquid phases is expanded, and the intermetallic compound Mo ₃ Si tends to precipitate during solidification. This is because the compound Mo ₃ Si is well precipitated and the wear resistance is improved. In this case, C <
At 0.1% by weight, the effect of expanding the temperature region between the solid and liquid phases is not sufficient, and the intermetallic compound Mo ₃ Si is insufficiently precipitated. On the other hand, when C> 0.5% by weight, the precipitation of Cr carbide increases. And the build-up crack easily occurs.

Since Si is an alloy component of the intermetallic compound Mo ₃ Si and is slightly larger than Tribaloy, it is combined with the increase in the amount of C to form a complex compound of the intermetallic compound Mo ₃ Si. Increase the amount of precipitation. In this case, Si <
At 2.0% by weight, the effect of increasing the amount of precipitation of the intermetallic compound Mo ₃ Si cannot be sufficiently obtained. At Si> 5.0% by weight, the amount of precipitation of the intermetallic compound Mo ₃ Si becomes too large to cause build-up cracking. Occurs, or Si in the matrix increases, and PbO corrosion resistance deteriorates.

Mn acts as a deoxidizing agent, but Mn <
At 0.01% by weight, a sufficient deoxidizing effect cannot be obtained, and Mn>
At 1.0% by weight, the flow of the molten metal is poor and the shape is deteriorated.

[0010] Cr not only improves the oxidation resistance but also improves N ₂
However, when the content of Cr is less than 7.0% by weight, the oxidation resistance and the action of immobilizing N ₂ are not sufficiently obtained, and Cr> 1
At 5.0% by weight, the precipitation of Cr carbide is increased, and overlay cracking is likely to occur. In this case, if Cr ≧ 10% by weight, a sufficient N ₂ fixing effect can be obtained, and even if the member to be welded is SUH36 containing N like the exhaust valve, the stellite is used. Wear resistance can be increased by one-layer overlay welding without overlay welding in advance. However, when Cr is less than about 10% by weight, the N ₂ fixing effect is not always sufficient, and when the member to be welded is such as SUH36, blow holes are easily generated. In this case, one or more of Ti (titanium), Nb (niobium), Zr (zircon), and Al (aluminum) are used in a total of 0.1 to ₂ to fix N _2.
It is desirable to contain 5.0% by weight.
The generation of N ₂ blow holes can be suppressed while reducing the content of expensive Cr. If the total content of Ti, Nb, Zr, and Al is less than 0.1% by weight, a sufficient N ₂ fixing effect cannot be obtained, and if the total content is more than 5.0% by weight, wear resistance deteriorates or viscosity decreases. As a result, the molten metal does not sufficiently flow in the build-up portion, and poor build-up is likely to occur. In addition, SUH3
For a member to be welded that does not contain N, such as SUS or SUH11, the Cr content is about 10% by weight or less,
Even if the contents of i, Nb, Zr, and Al are 0,
Of course, good overlay welding can be performed.

Mo is an alloy component of the intermetallic compound Mo ₃ Si. When Mo <26% by weight, Mo is an intermetallic compound Mo ₃ Si.
Is insufficiently precipitated and the effect of improving wear resistance is not sufficiently obtained.
When o> 33% by weight, the fluidity deteriorates due to the decrease in viscosity,
The molten metal does not sufficiently flow in the build-up portion, and poor build-up is likely to occur.

When B (boron) is contained in an amount of 0.02% by weight or less, the viscosity and the surface tension are reduced, and the build-up failure such that the molten metal does not flow to the build-up portion is reduced. B> 0.0
If the content is 2% by weight, the flow of the molten metal becomes too good to deteriorate the bead shape, and the hardness increases, so that the build-up cracks easily occur.

[0013] Further, the welding material for hardfacing of the present invention is suitably used for overlay welding of a valve face of an exhaust valve and an intake valve in a diesel engine or a gas engine requiring high wear resistance. However, it can be used not only for overlay welding of other parts requiring wear resistance but also for high temperature corrosion resistance and heat resistance, so such high temperature corrosion resistance and heat resistance are required. It can be similarly used for overlay welding of parts.

When such a hardfacing welding material is used in a plasma powder welding method, a spherical material having a mesh of, for example, about 80 to 350 mesh is preferably used. Such a powder welding material is manufactured by a well-known powder manufacturing method such as a gas atomization method. When used for TIG welding, a rod-shaped welding material having a diameter of, for example, about 2.0 to 3.2 mm is preferably used.

[0015]

As described above, according to the welding material for hardfacing according to the present invention, the intermetallic compound Mo ₃ Si sufficiently precipitates even in the welding method of performing arc overlay welding under an inert gas shield. Since the wear resistance is improved, by adopting the plasma powder welding method or the TIG welding method, etc., high productivity can be obtained and the overlay welding can be automated, greatly reducing the burden on the operator. It is.

For a member to be welded such as SUH36 containing N, the content of Cr having an N ₂ fixing effect is increased, or one or more of Ti, Nb, Zr, and Al are used. Or the like, the occurrence of blow holes due to N ₂ is suppressed, and the wear resistance can be increased by one-layer overlay welding without overlay welding of stellite or the like in advance.

Further, when B is contained in an amount of 0.02% by weight or less, the viscosity and surface tension are reduced, and the build-up defect such that the molten metal does not flow to the build-up portion is reduced, and the yield is improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below.

FIG. 1 shows an example of a plasma powder overlay welding apparatus capable of suitably performing overlay welding using the hardfacing welding material of the present invention. Reference numeral 10 denotes a plasma arc disposed in a vertical direction. It is the tip of a torch (hereinafter simply referred to as a torch). The torch 10 has a tungsten electrode 12 at the center, and a torch inner tube 14 and a torch outer tube 16 are coaxially arranged outside the electrode 12 at a predetermined distance from each other. Between the electrode 12 and the torch inner cylinder 14, and between the torch inner cylinder 14 and the torch outer cylinder 16
Between them are formed annular passages 18 and 20, respectively. The passage 18 is connected to a plasma gas supply device 24 via a pipe 22 so that a plasma gas such as an argon gas is supplied. Then, the plasma gas supplied into the passage 18 is ejected downward from a nozzle 30 provided at the tip of the torch inner cylinder 14. The passage 20 is connected to a carrier gas supply device 34 via a pipe 32, and is supplied with a powder welding material for overlay welding from a powder supply device 36 connected to an intermediate portion of the pipe 32, thereby forming a passage. A carrier gas containing a predetermined amount of powder welding material is supplied to 20, and is ejected downward from a nozzle 38 provided at the tip of the torch outer cylinder 16.
An inert gas such as an argon gas or a helium gas is used as the carrier gas.

The torch inner cylinder 14 and the torch outer cylinder 16
Nozzles 30 and 38 have cooling water passages 40, respectively.
And 42 are formed for cooling.
In addition, a shield gas composed of an inert gas such as an argon gas or a helium gas is supplied from the shield gas supply device 44 to the distal end portion of the torch outer cylinder 16 via a pipe 46. Is blown out in a substantially cylindrical shape in the axial direction of the torch 10, so that the overlay welding portion is shielded from the atmosphere.

Below the torch 10 configured as described above, a valve 48 of a diesel engine, a gas engine, or the like to be overlaid is arranged. The valve 48 is made of a martensitic stainless steel such as SUH3 or an austenitic stainless steel such as SUH36. The valve 48 includes a shaft portion 50 and an umbrella portion 52. An annular concave portion 54 for application is formed. Such a valve 48 is
An axis A is attached to the mounting shaft 56 provided at an angle θ with respect to the vertical direction via a cooling backing 58 so that the axis A coincides with the axis of the mounting shaft 56. It is driven to rotate around the axis A at a predetermined speed together with the shaft 56. The recess 5 formed in the umbrella portion 52 of the valve 48 when attached to the attachment shaft 56
4 is located directly below the nozzle 38 of the torch 10 and the valve 48 is rotated about the axis A, so that the annular recess 54 has the entire circumference. It is sequentially positioned just below the nozzle 38.

On the other hand, a predetermined pilot current is supplied from a pilot power supply 60 between the electrode 12 of the torch 10 and the torch inner cylinder 14, and a backing 58 to which the electrode 12 and the valve 48 are attached. A predetermined welding current is supplied from the main power supply 62 between the two. The electrode 12 and the torch inner cylinder 14
A high frequency oscillator 64 for ignition is provided in parallel with the pilot power supply 60.

Then, a pilot current is supplied from the pilot power source 60, and the tip of the electrode 12 and the torch inner cylinder 14 are supplied.
When a plasma arc is supplied from the plasma gas supply device 24 into the annular passage 18 at the same time that a pilot arc is generated between the nozzle 12 and the nozzle 30, a plasma arc is formed at the tip of the electrode 12. Next, the electrode 12 and the backing 5
A welding current is supplied from a main power source 62 to the plasma arc between the bulb 4 and the plasma arc formed at the tip of the electrode 12.
8 and the carrier gas containing the powder welding material is supplied from the carrier gas supply device 34 and the powder supply device 36 into the passage 20. The powder welding material supplied into the passage 20 is ejected from the nozzle 38 and melted by the plasma arc, and is welded to the recess 54 of the valve 48 by overlay welding. At this time, a shielding gas is blown from the tip of the torch 10 so that the molten powder welding material and the concave portion 54 are not affected by oxygen in the air or the like. In this state, the valve 48 is moved to its axis A
When it is rotated around, the portion of the recess 54 where the overlay welding is performed moves, and the overlay welding is sequentially performed over the entire circumference of the annular recess 54. A broken line shown in the concave portion 54 indicates a state in which build-up welding has been performed.

Here, as the powder welding material, a welding material for hardfacing of a Co-based alloy shown in Table 1 was used.
Table 2 shows the results of an overlay welding performed on a valve 48 made of SUH3 or SUH36 to check for cracks or blowholes in the overlay, the Ogoshi type abrasion (wear resistance), and the rate of occurrence of overlay failure. Shown in Each of the welding materials in Table 1 has a diameter of 40 μm obtained by gas spraying a molten metal having the chemical components shown in the table.
A rod having a diameter of 4.0 mm produced by a casting method was also prepared for No. 11 of Comparative Example. In the comparative examples, the values with dotted points indicate that the values deviate from the component range of the present invention. Valve 4 as a member to be welded
8, the umbrella 52 has a diameter of 40 mm and the recess 54 has a width of 4 mm. In Table 2, the presence or absence of “cracking in the overlay” is based on color check, and the presence or absence of “blow hole in the overlay” is based on X-ray. It was measured with SUJ2 as the mating material.
“Defective rate (%)” is the rate of occurrence of defective products due to insufficient cladding when 1000 pieces of overlay welding are performed. The unit of “Ogoshi-type wear amount” is mm ³ / (kgf · mm). The build-up welding was performed by an inert gas shielded plasma powder welding method using the above-described plasma powder build-up welding apparatus and the like, except for the welding material of No. 11, and the current was 110 A, and the flow rate of the plasma gas was 10 ^{−. 3} m ³ / min, overlay speed 50 cm
/ Min. The overlay welding of No. 11 welding material is SU
For the H3 valve, direct overlay welding is performed using the oxygen acetylene gas welding method. For the SUH36 valve,
After the stellite # 12 was weld-welded to the recess 54 in advance by oxygen acetylene gas welding, the surface was cut and the surface was cut to form No. 11 by oxygen acetylene gas / plasma powder welding.
Was weld-welded.

[0025]

[Table 1]

[0026]

[Table 2]

As is clear from Table 2 above, in the welding materials No. 1 to No. 10 according to the present invention, the welding material No. 2 was SU
Except for the case of overlay welding on a valve made of H36, a hardfacing with excellent wear resistance was obtained at a low defect rate without any defects such as cracks and blowholes. When the No. 2 welding material was overlay-welded to a SUH36 valve, the occurrence of blow holes due to N ₂ was recognized.
There is no problem in case of overlay welding on the UH3 valve.
No. 3 welding material containing 14.1% by weight of Cr, Ti, N
For No. 4, No. 5, No. 6, No. 7, No. 9 and No. 10 welding materials containing a small amount of one or more of b, Zr, and Al, the hardfacing welding is performed favorably even on SUH36 valves. be able to. In addition, according to the welding materials No. 8 to No. 10 containing a small amount of B, insufficient build-up due to poor flow of molten metal is prevented, the rejection rate is significantly reduced, and a high yield can be obtained.

On the other hand, in the comparative example, the welding material of No. 11 was overlay-welded to the SUH3 valve using the oxygen acetylene gas welding method, and the plasma powder welding method was performed after the stellite was welded to the SUH36 valve in advance. No using
When the weld material No. 11 was overlay-welded, although a good hardfacing was obtained, other than that, sufficient abrasion resistance could not be obtained, cracks were generated in the overlay, and SU
There has been a problem that blow holes frequently occur with the H36 valve. In addition, the thing which the crack had generate | occur | produced in the built-up part was excluded from measurement of abrasion resistance and a defective rate.

The above description is merely an example of the present invention, and the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of a plasma powder build-up welding apparatus capable of suitably performing build-up welding using the hardfacing welding material of the present invention.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Takano 2958 Ishikawa, Fujisawa-shi, Kanagawa Prefecture Fuji Valve Co., Ltd. Fujisawa Plant (72) Inventor Masahito Hirose 2958 Ishikawa, Fujisawa-shi, Kanagawa Prefecture Fujisawa Plant Fujisawa Plant ( 56) References JP-A-57-174431 (JP, A) JP-A-5-84592 (JP, A) JP-A-60-206567 (JP, A) JP-A 1-138095 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B23K 35/30 C22C 19/07

Claims (4)

(57) [Claims] 1. A Co-based alloy comprising 0.1 to 0.5% by weight of C, 2.0 to 5.0% by weight of Si, and 0.01 to 0.5% by weight of Si.
1.0% by weight of Mn and 7.0 to 15.0% by weight of Cr
And, look including a 26-33% by weight of Mo, the balance being Co Hoyo
And a hardfacing welding material comprising an unavoidable impurity . 2. A Co-based alloy having a weight of 0.1 to 0.5.
% C, 2.0 to 5.0% by weight of Si, 0.01 to
1.0% by weight of Mn and 7.0 to 15.0% by weight of Cr
And 26 to 33% by weight of Mo.
One or more of Nb, Zr, and Al are combined in a total amount of 0.1%.
5.0% seen including, the balance being Co and inevitable impurities
A welding material for hardfacing, comprising: 3. A Co-based alloy having a weight of 0.1 to 0.5.
% C, 2.0 to 5.0% by weight of Si, 0.01 to
1.0% by weight of Mn and 7.0 to 15.0% by weight of Cr
, 26 to 33% by weight of Mo, and 0.02% by weight or less of B , and the balance consists of Co and inevitable impurities.
A welding material for hardfacing , characterized in that: (4) Co-based alloy, 0.1-0.5 weight
% C, 2.0 to 5.0% by weight of Si, 0.01 to
1.0% by weight of Mn and 7.0 to 15.0% by weight of Cr
And 26 to 33% by weight of Mo, and 0.02% by weight or less.
B, and at least one of Ti, Nb, Zr, and Al
Or two or more kinds in total of 0.1 to 5.0% by weight, with the balance being
Is composed of Co and unavoidable impurities
Welding material for hardfacing.