JPH06304781A - Composite wire for build-up welding to surface of ti-base material - Google Patents

Abstract

PURPOSE:To stably obtain a build-up layer having high joinability with a Ti-base material and excellent wear resistance and heat resistance without generating weld defects by using the composite wire, thereby stably supplying a filler metal. CONSTITUTION:This composite wire 3 for build-up welding onto the surface of the Ti-base material is formed by filling iron powder, iron wire materials or iron alloy powder and iron alloy wire materials into the hollow part of a sheath material 1 consisting of the Ti-base material. The composite wire 3 for build-up welding to the surface of the Ti-base material consisting of 10 to 50wt.% Fe by the total weight of the wire, further, contg. <=10% Cr, <=5% Ni, <=2% Mo, <=1% Nb, <=6% Al, <=4% V, <=1% Mn and <=1% Si and having <=15% Cr+Ni+Mo+Nb+Al+V+Mn+Si ratios is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite wire for overlay welding in which a wear-resistant and heat-resistant layer is stably formed on the surface of a Ti-based material and can be economically obtained.

[0002]

2. Description of the Related Art Ti or Ti alloy is lighter (about 60% of iron) and superior in heat resistance and corrosion resistance as compared with steel materials and is therefore used in a wide range of fields including intake and exhaust valves of automobile parts. Is being considered. However, Ti alloys are generally inferior to steel materials in terms of wear resistance.
With the i alloy material as it is, the parts and parts that can be applied as substitute materials for steel materials are limited. Also, already Ti,
Even when a Ti alloy is used, in recent years, as the usage environment becomes more severe, further improvement in durability is required.

As a countermeasure, in addition to the improvement of the Ti alloy itself, a method of forming a wear resistant layer on the surface has been performed. For example, there is a method of forming a thin hard coating layer by PVD or CVD, or a method of forming a relatively thick hard coating layer by thermal spraying. However, the film formed by these methods is very hard, but the adhesion to the base material is weak, resulting in peeling during use.
Poor reliability due to risk of falling off. In addition, PVD,
CVD has a slow film formation rate, and it is difficult to form a thick film. In the case of thermal spraying, there are problems in terms of environment such as generation of noise and light rays, and there is a problem that the adhesion to the substrate is low and peeling occurs during use.

On the other hand, there has been disclosed a method of forming a hard alloy layer by melting an alloying metal together with the surface of a base material using a high-density energy source such as laser or arc. Japanese Laid-Open Patent Publication No. 61-2357 discloses a method of hardfacing welding such a material.
As described in the publication, there is proposed a method of overlaying a face surface of an engine valve made of a titanium-based material by a plasma arc welding method using a mixed powder made of titanium and a metal carbide. In addition, JP-A 1-26
In 2077, an AC plasma arc overlay welding method using metal powder as a overlay material is proposed. However, in these methods, in order to stably supply the powder into the arc, a gas atomized powder having a good fluidity, a plasma rotating electrode method powder and the like are usually used. However, the shapes of the gas atomized powder and the plasma rotary electrode powder are spherical and have good fluidity, and the surface cleanliness is good, but they are expensive.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of alloying treatment. The purpose of the present invention is to stabilize the filler metal by using a composite wire. An inexpensive Ti-based material that does not cause welding defects such as pits and blowholes and can stably obtain a built-up layer with high bondability with Ti base material and excellent heat resistance. It is to provide a composite wire for overlay welding on a surface.

[0006]

In order to achieve the above object, the structure of the Ti-based material according to the present invention as a build-up material on the surface is as follows: iron-based powder or iron-based wire The gist of the composite wire filled with is that the amount of Fe is 10 to 50% with respect to the total weight of the composite wire.

In addition to the iron-based powder or iron-based wire, Cr: 10% or less, N based on the total weight of the composite wire.
i: 5% or less, Mo: 2% or less, Nb: 1% or less, A
1: 6% or less, V: 4% or less, Mn: 1% or less, Si:
1% or less and Cr + Ni + Mo + Nb + Al + V +
The gist of the present invention is a composite wire for overlay welding on the surface of a Ti-based material, which is added and adjusted so that the amount of Mn + Si is 15% or less.

The overlay welding means used for the composite wire of the present invention is a gas shield arc (T
IG welding), and plasma as a heat source for melting.

[0009]

The pure Ti material having good wire drawability is suitable as the Ti material for the outer cover material of the composite wire of the present invention, but a Ti alloy material can also be used. Iron and stainless steel materials are used as the filling material, and typical 18Cr-8Ni steel and 22Cr-12Ni steel are used as the stainless steel material.
Steel, 25Cr-20Ni steel, 18Cr-12Ni-2.
5Mo steel, 18Cr-9Ni-Nb steel, 13Cr steel, 1
8Cr steel etc. are mentioned.

According to the present invention, in the arc generated between the Ti base material base material shielded with the inert gas and the non-consumable electrode, the iron-based powder and the iron-based powder are contained in the hollow portion of the Ti outer cover material. By feeding a wire rod, a stainless steel powder or a composite wire filled with a stainless steel wire rod as a build-up welding material, Fe, Cr, Ni, Mo, Nb,
A Ti alloy overlay layer containing Al, V, Mn, and Si can be formed. The hardness of the cladding layer obtained in this case must be Vickers hardness Hv400 or more from the viewpoint of wear resistance.
If it is less than v400, improvement in wear resistance cannot be expected.

That is, the hardness of the build-up layer obtained from the Ti--Fe based composite wire depends on the total weight of the composite wire, Fe.
If the amount is less than 10%, the Hv will be less than 400, and improvement in wear resistance cannot be expected. On the other hand, when the amount of Fe exceeds 50%, a hard and brittle intermetallic compound is generated between Fe and Ti, so that the overlay is cracked. Therefore, the amount of Fe in the Ti-Fe-based composite wire needs to be in the range of 10 to 50% with respect to the total weight of the composite wire.

Further, in addition to the iron-based powder or iron-based wire having the above Fe content range, Cr: 10% or less, Ni: 5% or less,
Mo: 2% or less, Nb: 1% or less, Al: 6% or less,
V: 4% or less, Mn: 1% or less, Si: 1% or less, and Cr + Ni + Mo + Nb + Al + V + Mn + Si amount of 15% or less is added to improve the hardening characteristics without deteriorating the crack resistance of the overlay. To improve
It has been found to be effective in improving heat resistance, high temperature oxidation resistance and corrosion resistance. In this case, Cr + Ni + M
When the amount of o + Nb + Al + V + Mn + Si exceeds 15%, the crack resistance tends to deteriorate and the hardness becomes too high. Therefore, Cr + Ni + Mo + Nb + Al + V + M
The amount of n + Si needs to be 15% or less.

Fe: Fe stabilizes the β phase and is solid.
Build-up as a solution strengthening element or by precipitation of TiFe phase
Increase the hardness of the layer. If the Fe content is less than 10%, the hardness tends to increase.
The upper part is not sufficient, and when it exceeds 50%, the hardness of the overlay is H
Since it becomes higher than v600, cracking occurs, so Fe content
Must be in the range of 10 to 50%. Cr: Cr stabilizes the β phase and acts as a solid solution strengthening element.
Or TiCr ₂The hardness of the buildup layer is increased by the precipitation of the phase.
As well as improving heat resistance. Cr content exceeds 10%
However, the hardness of the overlay is higher than Hv600, but
Therefore, the Cr content needs to be 10% or less.
It

Ni: Ni stabilizes the β phase and acts as a solid solution strengthening element, or has the function of increasing the hardness of the overlay and increasing the toughness by precipitation of the Ti ₂ Ni or TiNi phase. When the Ni content exceeds 5%, T which is vulnerable to the overlay layer
Since a large amount of iNi phase is precipitated and cracks occur, the Ni content needs to be 5% or less. Mo: Mo forms a total solution of β phase solid solution, and as a solid solution strengthening element, it enhances the hardness and heat resistance of the cladding layer and corrosion resistance. Even if the amount of Mo exceeds 2%, it does not contribute so much to the hardness of the overlay and the cost increases, so the amount of Mo is 2%.
Below.

Mn: Mn stabilizes the β phase and
TiMn as a solid-solution strengthening element of α phase and β phase
The phase precipitation serves to increase the hardness of the overlay. Mn
If the amount exceeds 1%, a large amount of fragile TiMn phase precipitates in the buildup layer and cracks occur, so the amount of Mn must be 1% or less. Al: Al stabilizes the α phase, increases the hardness of the cladding layer as a solid solution strengthening element, and enhances the high temperature oxidation resistance. If the Al amount exceeds 6%, the workability is deteriorated, so the Al amount is set to 6% or less.

V: V stabilizes the β phase and, as a solid solution strengthening element, increases the hardness of the overlay. Even if the amount of V exceeds 4%, it does not contribute so much to the hardness of the overlay and the cost increases, so the amount of V was made 4% or less. Si: Si stabilizes the β phase and, as a solid solution strengthening element, increases the hardness of the overlay layer by precipitation of Ti ₅ Si ₃ and TiSi phases. Even if the Si amount exceeds 1%, it does not contribute so much to the hardness of the overlay layer, so the Si amount is set to 1% or less.

Nb: Nb forms a solid solution in the β phase in all proportions and serves as a solid solution strengthening element to increase the hardness of the overlay. Nb amount is 1%
Even if it exceeds, it does not contribute so much to the hardness of the overlay and the cost increases, so the Nb content is set to 1% or less. In order to manufacture a composite wire in which the hollow portion of the outer sheath material made of Ti material according to the present invention is filled with iron-based powder or iron-based wire, for example, a Ti hoop material or a Ti alloy hoop material is formed into a pipe shape. In the middle of the process, the iron-based powder or iron-based wire containing iron as a main component may be adjusted to a filling rate within an appropriate range, and then the wire drawing may be continuously performed. FIG. 1 shows a horizontal cross section and a vertical cross section of a composite wire in which a hollow portion of an outer cover material made of a Ti material is filled with iron-based powder or iron-based wire.

[0018]

EXAMPLES In order to confirm the effect of the present invention, Ti-6Al
On the surface of the -4V plate (10 ^t x 50 x 150 mm), Table 1
A composite wire in which a wire or powder of an iron-based material is filled in the hollow part of the outer sheath material of the Ti material having the composition shown in
Using 1.2 mm), a bead-on-plate welding test was performed by TIG welding of a non-consumable gas shielded arc welding method, which is a simple arc welding method. Table 2 shows the welding conditions. With respect to the overlay of the overlay obtained by the overlay welding test, the hardness of the overlay, cracks inside the overlay, bead surface cracks, etc. were investigated. The hardness of the overlay layer was investigated by measuring the weld cross-section test piece 1 m from the bead surface as shown in FIG.
The average value of the results (Vickers hardness) obtained by measuring 10 points between AB at the position under m at a 0.5 mm pitch is shown. For cracks inside the overlay, weld cross section with optical microscope (× 100)
For the cracks on the bead surface, the presence or absence of cracks was visually inspected. In addition, for the detection and evaluation of welding defects such as blowholes, a radiographic grading method (JI
S Z 3107-1973).

In Table 3, No. 1-No. Reference numeral 10 is an example of the present invention that satisfies all the requirements of the present invention, in which overlay welding is performed by the TIG welding method. Ti-F of the present invention
The e-based composite wire has sufficient hardness in the build-up layer on the surface of the base material, there are no microcracks inside the build-up layer, and no cracks on the bead surface, and welding defects such as blowholes are a practical problem. It was a range that did not become.

On the other hand, No. Nos. 11 to 15 were out of the range of the present invention, and none of the results was satisfactory in the characteristics of the overlay layer. No. Fe amount of 11 and 13 is 1
In the case of less than 0%, sufficient hardness of the hardfacing layer could not be obtained.
There were no cracks in the built-up layer or on the surface. No.
No. 12 is an example in which the amount of Fe exceeds 50%, and a sufficient hardness of the overlay layer is obtained, but cracks were observed both inside the overlay layer and on the surface.

No. 14 has a proper Fe content,
Cr + Ni + Mo + Nb + Al + V + Mn + Si amount is 1
When the addition upper limit range of 5% was exceeded, sufficient hardness of the overlay was obtained, but cracks were found inside and on the overlay. No. 15 is the amount of Fe and Cr + Ni + Mo
When the amounts of + Nb + Al + V + Mn + Si all exceeded the upper limit range of addition, sufficient hardness of the overlay was obtained, but cracks were found inside and on the overlay.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

According to the present invention, when various skin materials and fillers are combined, filler materials having various component ratios can be easily obtained without passing through the melting step. In addition, the Ti-F of the present invention
If the e-based composite wire is used, cracks do not occur, and a wear resistant and heat resistant alloyed layer having high bondability with the Ti base material can be stably formed at low cost, and its industrial value is great.

[Brief description of drawings]

FIG. 1 (a) is an explanatory view showing a cross section of a Ti—Fe based composite wire of the present invention or a comparative example, and FIG. 1 (b) is a longitudinal section of the composite wire.

FIG. 2 is an explanatory diagram showing a method for measuring the hardness of the overlay metal obtained by the Ti—Fe-based composite wire of the present invention or the comparative example.

[Explanation of symbols]

 1 Ti-based skin 2 Iron-based wire 3 Ti-Fe-based composite wire 4 Ti-6Al-4V plate 5 Overlay layer A, B Hardness measurement position

Claims (2)

[Claims] 1. A composite wire in which a hollow portion of a Ti sheath material is filled with iron-based powder or iron-based wire material, and Fe: 10 to 50% by weight (hereinafter abbreviated as%) based on the total weight of the composite wire. A composite wire for overlay welding on the surface of a Ti-based material, which is characterized in that 2. The wire according to claim 1, wherein, in addition to Fe, Cr: 10% or less, Ni: 5% or less, Mo: 2% or less, Nb: 1% or less, based on the total weight of the composite wire. Al: 6% or less, V: 4% or less, Mn: 1% or less,
Si: 1% or less and satisfying the expression (1), a composite wire for overlay welding on the surface of a Ti-based material. Cr + Ni + Mo + Nb + Al + V + Mn + Si ≦ 15% (1)