JPH09323175A - Alloy foil for liquid phase diffusion bonding of Fe-based materials that can be bonded in an oxidizing atmosphere - Google Patents

Abstract

(57) Abstract: The present invention enables liquid-phase diffusion bonding at a relatively high temperature for a Fe-based material as a bonding object, and reduces the thermal effect on the material to be bonded (base material) while maintaining a uniform temperature. (EN) An alloy foil for liquid phase diffusion bonding of Fe-based materials capable of bonding in an oxidizing atmosphere, capable of securing a bonded portion having a structure and having sufficient bonding strength, and shortening the bonding time. SOLUTION: At atomic%, P: 1.0 to 20.0%, S
i: 1.0 to 10.0%, V: 0.1 to 20.0%,
B: 1.0 to 20.0% is contained as an essential component, the balance is composed essentially of Fe and inevitable impurities, and the thickness is 3.0 to 200 μm. . If necessary, one or more of Cr, Ni and Co, or / and one or more of W, Nb and Ti are selectively contained in appropriate amounts. A material having a substantially amorphous crystalline structure is more effective.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended for joining Fe-based materials such as thick steel plates, steel pipes, steel bars (including steel wires and reinforcing bars) in an oxidizing atmosphere at low temperature and in a short time. The present invention relates to a liquid phase diffusion bonding alloy foil that can be bonded to a material to be bonded (base material) with a small thermal effect.

[0002]

2. Description of the Related Art In liquid phase diffusion bonding, an alloy having a eutectic composition having a melting point lower than that of a material to be bonded is interposed between materials to be bonded in the form of foil, powder, plating or the like, and pressure is applied. This is a joining method in which a joining portion is melted and isothermally solidified by heating a joining portion to a temperature just above a liquidus line of an insertion alloy (hereinafter, referred to as “insert metal”), and is considered to be a kind of solid-state joining method.

Since this liquid phase diffusion welding can be performed with a relatively low pressure, it has been conventionally used for welding in which it is necessary to avoid residual stress and deformation due to welding as much as possible. It is applied to heat-resisting steel or joining of these and carbon steel.

On the other hand, as a means for joining general steel materials made of carbon steel, various kinds of welding have hitherto been the mainstream, and there are few cases where liquid phase diffusion joining is applied.

Liquid phase diffusion bonding is often applied to the bonding of materials to be bonded which contain 0.50% or more of Cr in terms of alloy composition. Since this Cr-containing material forms a dense Cr oxide (often Cr ₂ O ₃ ) film on the surface, it is characterized by excellent oxidation resistance and corrosion resistance. Therefore, an oxide film is naturally formed on the bonding surface even by heating at the time of bonding, so that wetting of the molten insert metal is hindered, diffusion of atoms necessary for bonding is significantly prevented, and a good bonded portion is obtained. It was difficult.

Therefore, in the past, Japanese Patent Laid-Open No. 53-81458 has been used.
JP, JP-A-62-34685, and JP-A-6-34685.
As can be seen from JP-A-2-227595, the atmosphere must be kept vacuum, inert, or reducible during liquid phase diffusion bonding, resulting in a significant increase in bonding cost.

The present applicant has found that when applying liquid phase diffusion bonding to stainless steel, high nickel base alloy, heat resistant alloy steel or these alloy steels, an oxide film is formed on the surface of the material to be bonded in the atmosphere. Even if it is, liquid phase diffusion bonding is possible, and as a result of various studies to provide a liquid phase diffusion bonding that can obtain a good joint in a short time while reducing the bonding cost, V is 0.1 to 0.1. Contains 20.0 atom%, Si
It has been found that liquid phase diffusion bonding can be performed even in an oxidizing atmosphere such as the air by using an insert metal with an increased amount.

That is, although V is an element that raises the melting point of the insert metal, it is possible to obtain an insert metal having extremely excellent bondability by appropriately adjusting other elements (in the present invention, exclusively Si). First, the inventors found out Japanese Patent Laid-Open Nos. 2-151377 and 2-1.
JP-A-51378, JP-A-2-185940, JP-A-7-268521, JP-A-7-276066
No., mainly disclosed in stainless steel,
Ni-based V used for liquid phase diffusion bonding of high nickel base alloys, heat resistant alloy steels or these alloy steels and carbon steels,
We proposed an alloy foil for liquid phase diffusion bonding that can be bonded in an oxidizing atmosphere containing Si. However, as described above, these Ni-based alloy foils for liquid phase diffusion bonding are mainly used for bonding stainless steel, high nickel-based alloys, and heat-resistant alloy steels, and are Ni-based. .

Recently, the present inventors have been able to secure a sufficient bonding strength in a short time with a Fe-based material typified by a steel material such as a steel pipe made of carbon steel, a reinforcing bar and a thick plate in a narrow space in a shorter time. There is an increasing demand for low-cost joining, and based on the recognition that conventional joining by various types of welding cannot sufficiently meet this requirement, the Fe-based material is used as a joining target for liquid bonding in the atmosphere. The application of phase diffusion bonding was examined.

As a result, when liquid-phase diffusion bonding of these Fe-based materials is used and the Ni-based alloy foil for liquid-phase diffusion bonding is used as an insert metal, the Ni-phase intervenes between the materials to be bonded. Therefore, it has been confirmed that it is difficult to sufficiently meet the above requirements because the joint structure becomes heterogeneous, the joint time becomes long, and the joint strength and toughness are affected.

[0011]

DISCLOSURE OF THE INVENTION In the present invention, Fe represented by a steel material such as a steel pipe made of carbon steel, a reinforcing bar, and a thick plate is used.
Bonding of base material and Fe-based material is possible in the oxidizing atmosphere at low temperature and in a short time, and it is possible to bond with less heat effect to the material to be joined (base material). The present invention provides a liquid phase diffusion bonding alloy foil.

[0012]

DISCLOSURE OF THE INVENTION The present invention is based on Fe and contains P, Si, V and B as essential components and is capable of being joined in an oxidizing atmosphere. The first invention is, in atomic%, P: 1.0 to
20.0%, Si: 1.0 to 10.0%, V: 0.1
.About.20.0%, B: 1.0 to 20.0%, and the balance substantially consisting of Fe and unavoidable impurities and having a thickness of 3.0 to 200 .mu.m. And

The second invention is, in atomic%, P: 1.0-
20.0%, Si: 1.0 to 10.0%, V: 0.1
˜20.0%, B: 1.0 to 20.0%, C
r: 0.1 to 20.0%, Ni: 0.1 to 15.0%,
Co: 0.1 to 15.0% of one or more kinds is contained, and the balance has a composition substantially consisting of Fe and inevitable impurities, and has a thickness of 3.0 to 200 μm. And

The third invention is, in atomic%, P: 1.0-
20.0%, Si: 1.0 to 10.0%, V: 0.1
˜20.0%, B: 1.0 to 20.0%,
W: 0.1 to 10.0%, Nb: 0.1 to 10.0%,
Ti: 0.1 to 10.0% of one or more kinds is contained, and the balance has a composition substantially consisting of Fe and inevitable impurities, and has a thickness of 3.0 to 200 μm. And

The fourth invention is, in atomic%, P:
1.0 to 20.0%, Si: 1.0 to 10.0%, V
: 0.1 to 20.0%, B: 1.0 to 20.0%, Cr: 0.1 to 20.0%, Ni: 0.1 to 1
5.0%, Co: 0.1 to 15.0%, and one or more kinds are contained, and W: 0.1 to 10.0%, Nb:
0.1 to 10.0%, Ti: 0.1 to 10.0%, and one or more of them are contained, and the balance has a composition substantially consisting of Fe and inevitable impurities, and has a thickness of 3 .0 to 20
0 μm.

The fifth invention is any one of the first invention, the second invention, the third invention and the fourth invention characterized in that the crystal structure of the structure is substantially amorphous. An alloy foil for liquid phase diffusion bonding of an Fe-based material, which can be bonded in an oxidizing atmosphere as described above.

In the present invention, the "Fe-based material" means steel materials made of various carbon steels containing 50% or more of Fe in atomic%. “Substantially amorphous” means that at least 50% of the crystal structure of the structure is amorphous.

"Liquid phase diffusion bonding" includes diffusion brazing and includes foil, powder, and
Alternatively, by pressing through an alloy having a eutectic composition having a lower melting point than the materials to be joined in the form of plating or the like, and heating the joint to a temperature just above the liquidus of the inserted alloy (hereinafter referred to as insert metal). This is a joining method of melting and isothermally solidifying by means of melting, but melting is not limited to the case of complete melting.
It contains 0% or more of melting.

The "oxidizing atmosphere" means that the bonding atmosphere contains 0.1% or more by volume of oxygen gas and the oxygen partial pressure is 10%.
^-3 atm or more, ie, reducing gas such as H ₂ , H ₂
Even when S, water vapor, or the like is contained, it means an atmosphere in which the oxidizing power is 0.1% or more corresponding to the oxygen concentration.
In addition, the “melting point” in a binary or more alloy means the solidus line on the phase diagram unless otherwise specified.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to the above-mentioned JP-A-2-15.
Ni-based V and Si as disclosed in JP 1377, JP 2-151378 A, JP 2-185940 A, JP 7-268521 A, JP 7-276066 A, etc. Focusing on the effect obtained with the contained alloy foil for liquid phase diffusion bonding, Fe-based materials are targeted for bonding, and problems such as non-uniformity of the structure due to the Ni phase and deterioration of properties due to thermal effects on the material to be bonded (base material) also occur The present invention has been accomplished through various studies on alloy foils for liquid phase diffusion bonding, which are not present.

In the present invention, when the amount of Ni which causes the problem of grain boundary segregation with respect to the Fe phase is contained, it is 0.1 to 0.1% by atom.
The Fe content is controlled to be 15%, and the Fe base is made to be the same as the Fe-based material to be joined. P that contributes to the lowering of the melting point by the diffusion element, B that is the diffusion element, and Si that contributes to the lowering of the melting point. A liquid phase diffusion bonding alloy foil of an Fe-based material, which contains V as an essential component to reduce the influence of an oxide film and can be bonded in an Fe-based oxidizing atmosphere. , Ni, and C that improve the corrosion resistance of
Cr, N which selectively contains one or more kinds of o, or mainly one or more kinds of W, Nb, and Ti which mainly enhances the joint strength, and further enhances the corrosion resistance of the joints.
One or two or more kinds of i and Co and one or more kinds of W, Nb and Ti which mainly enhance the joint strength are simultaneously contained. These selected components are combined in appropriate amounts according to the composition of the components to be joined, the characteristics required for the joint, and the like, and are contained in appropriate amounts.

B and P are known as diffusing atoms, but in the present invention, B and P are used as diffusing elements,
Compensating each of the shortcomings, the thermal effect on the material to be joined (base material) is reduced even if the joining temperature rises to prevent deterioration of characteristics due to coarsening of crystal grains of the joined material and shorten the joining time. To do.

In the present invention, since B and P are used together as a diffusion element, the complementary effect of P causes the Fe-based material, which is the other material to be joined, to have coarse crystal grains due to the thermal effect and the material characteristics to deteriorate. There is no problem even if it is used in the case of a material having an easy component composition, such as a steel having a ferrite structure, a bainite structure or a martensite structure.

When P is used alone as the diffusing element, the bonding time is longer than when B is used alone. However, when it is used in combination with B, the amorphous forming ability is enhanced. Therefore, the manufacturing time can be facilitated and the bonding time can be significantly shortened as compared with the case of using P alone. Therefore, according to the present invention, it is possible to facilitate the production, use the Fe-based material as a bonding target, in liquid phase diffusion bonding of a wider steel type, and realize bonding with high breaking strength.

The purpose and content of each component used in the present invention will be described below. (1) Fe base (containing 50% or more of Fe in atomic%). The material to be joined is a Fe-based material (a steel material made of carbon steel containing 50% or more of Fe in atomic%, and there is no inhomogeneity of the structure due to the interposition of Ni phase as in the case of Ni base,
The bonding time can be shortened and the bonding strength can be easily secured.

(2) P is 1.0 to 20.0%. P
Is necessary as diffusion atoms for achieving isothermal solidification necessary for achieving liquid phase diffusion bonding, or for lowering the melting point of the material to be welded (P is used in combination with B described later to amorphize). It is an element which is also effective), and it is necessary to contain 1.0% or more for each purpose, but according to the detailed study by the present inventors, it is contained in excess of 20.0%. Then, a coarse metal compound having a crystal grain size of 5 μm or more is generated on the material to be joined side, and the strength of the joined portion is reduced.
It was set to 20.0%. This P depends on the material to be joined, the component composition of the alloy foil of the present invention, the characteristics required for the joint, and the like.
Consider the content of and.

(3) Si is 1.0 to 10.0%.
Si is an effective element for lowering the melting point, and by containing a large amount of V, the melting point is prevented from becoming relatively high and the joining time becomes long. If it is less than 1.0%, the effect is slight. If it exceeds 10.0%, a coarse oxide containing Si is generated in the insert metal during liquid phase diffusion bonding in an oxidizing atmosphere, and the joint strength and toughness may be deteriorated.

(4) V is 0.1 to 20.0%. V
, The oxidation film of the welded material surfaces (Fe ₂ O _3), a low-melting composite oxide _{V 2 O 5 -Fe 2 O 3} ( melting point about 800 ° C.)
And Therefore, the bonding temperature (900 to 1200 ° C)
Then, the Fe base material and the molten insert metal are melted and made spherical in the liquid phase due to the difference in surface tension, thereby improving the wettability between the Fe-based material and the molten insert metal. For this reason, the diffusion atoms P and B are extremely important elements that freely diffuse between spheroidized oxides and realize liquid-phase diffusion bonding in an oxidizing atmosphere without being affected by the surface oxide film. . If it is less than 0.1%, it has no effect because it is insufficient to melt the oxide film, and if it is added in excess of 20.0%, the melting point of the insert metal exceeds 1300 ° C and liquid phase diffusion bonding is substantially performed. It will be impossible.

(5) B is 1.0 to 20.0%. B
Is necessary as a diffusing element for achieving the isothermal solidification necessary for achieving liquid phase diffusion bonding, or for lowering the melting point of the material to be bonded (B is used in combination with P above for amorphization). Is also an effective element), and 1.0 or more is necessary for each purpose, but when the material to be joined contains Mo and Cr, coarse boride is generated in the crystal grains and the joining is performed. The part strength is significantly reduced.

(6) Cr is 0.1 to 20.0%.
Cr is mainly for improving corrosion resistance and oxidation resistance. If it is less than 0.1%, the effect is insufficient.
If it exceeds 0%, the melting point of the alloy foil will increase significantly,
This deteriorates manufacturability and raises the liquid phase diffusion bonding temperature to an extremely high temperature outside the practical range, that is, 1400 ° C. or higher.

(7) Ni is 0.1 to 15.0%.
Ni is mainly for enhancing corrosion resistance and oxidation resistance, and if it is less than 0.1%, its effect is insufficient, and 1
If it exceeds 5.0%, the homogeneity of the structure is hindered by the inclusion of the Ni phase. Bonding time becomes long and also causes a decrease in the strength of the bonded portion.

(8) Co is 0.1 to 15.0%.
Co is mainly contained to increase corrosion resistance and oxidation resistance and to impart strength. If it is less than 0.1%, its effect is insufficient, and if it exceeds 15.0%, a coarse intermetallic compound is generated in the insert metal to hinder the toughness of the joint.

(9) W, Nb and Ti are each 0.1 to 0.1
It is 10.0%. W is for increasing the strength of the joint. Less than 0.10% has no effect and 10.0
%, The high-temperature strength of the material is rather lowered due to coarse Laves phase precipitation caused by segregation between dendrites. Nb
Is effective in improving toughness when dispersed in a substrate as carbide, nitride or carbonitride. If it is less than 0.1%, the effect is insufficient, and if it exceeds 10.0%, a coarse Fe—Nb intermetallic compound is generated and the joint is embrittled. Ti
Is for increasing the strength of the joint, and includes carbide,
Uniform dispersion as a nitride enhances toughness. 0.1%
If it is less than 1.0%, the effect is insufficient, and if it exceeds 10.0%, a coarse intermetallic compound is formed to embrittle the joint. The liquid phase diffusion bonding alloy foil of the present invention having the above component composition is required to be melted uniformly during the liquid phase diffusion bonding in order to obtain a good bonded portion.

When the composition of the alloy is non-uniform and the alloy components are segregated, the melting point of the insert metal differs depending on the position of the joint, and a uniform joint interface cannot be obtained, and a good joint cannot be obtained. It will be. It is preferable to make the crystal structure amorphous in consideration of the fact that the alloy composition actually has a non-uniform composition and segregation of alloy components. It is not essential that the crystal structure be amorphous if a uniform composition is easily obtained. The liquid phase diffusion bonding alloy foil of the present invention can be provided in various shapes as insert metal.

The alloy having any of the components of the first invention to the fourth invention can be easily manufactured as an amorphous alloy foil by, for example, a liquid quenching method. As a basic manufacturing method adopted here, the molten metal of the alloy is ejected through a nozzle into a cooling substrate shape, and in the liquid quenching method of cooling and solidifying by thermal contact, one cooling roll is used as a cooling substrate. A simple single roll method is suitable.

Besides, a method of using a centrifugal quenching method using an inner wall of a drum or a method of using an endless type belt, an improved type of these methods, for example, a method in which an auxiliary roll or a roll surface temperature control device is attached, or under reduced pressure or Casting in vacuum or in an inert gas is also included. Further, a twin-roll method in which a molten metal is poured between a pair of rolls and rapidly solidified by cooling is also applicable. It is also possible to melt the alloy in a vacuum and cast it, and then roll and anneal the obtained slab by a usual method to provide it in the form of an alloy foil.

As the thickness of the alloy foil obtained as described above is smaller, the change in mechanical properties in the vicinity of the joint is smaller and the time required for the joint can be shortened, which is advantageous for liquid phase diffusion bonding. If it is less than 3.0 μm, the absolute amount of V is insufficient to render the oxide film on the surface of the materials to be joined harmless, and if it is 200 μm or more, it takes a long time to complete the liquid phase diffusion bonding, which is not practical. It is preferable that the thickness is 0.0 to 200 μm.

The present invention relates to an alloy foil for liquid phase diffusion bonding, but since it can be bonded in the atmosphere,
It is also useful when applied to diffusion brazing.

[0039]

Example Using the alloy for liquid phase diffusion bonding of the present invention, liquid phase diffusion bonding was carried out using a Fe-based material as a material to be bonded. The implementation conditions and implementation results will be described below with reference to the case of the comparative example, using tables and figures. About 100 g of an alloy having the composition (atomic%) of any of the first to fourth inventions of the present invention
A single roll method (cooling roll: Cu alloy 300 mm diameter)
Rapidly cooled to a width of 2 to 215 mm and a thickness of 3.0 to 200
An alloy foil having a substantially amorphous crystal structure of μm was prepared. The peripheral speed of the cooling roll at this time is 5.0 to 15.0 m /
held for s.

The composition (atomic%) of the alloy foil of the present invention in this example is, as shown in Table 1, all using Fe as a base material, and the difference between the sum of each component in Table 1 and 100% is It means the total concentration of Fe and inevitable impurities.

The component composition (atomic%) of the comparative alloy foil with respect to the alloy foil of the present invention is shown in Table 2. Like the alloy foil of the present invention, each of them has Fe as a base material, and the sum of each component in Table 2 and 10
The difference from 0% means the total concentration of Fe and inevitable impurities. The comparative alloy foils in Table 2 were produced in exactly the same manner as the alloy foils of the present invention in Table 1.

No. 1 in Table 1 1 to 199, alloy foils satisfying the first invention to the fifth invention of the present invention (hereinafter referred to as "the insert metal of the present invention") and No. 2 in Table 2.
Liquid phase diffusion bonding was performed using the comparative alloy foils 200 to 212 (including the conventional insert metal, hereinafter referred to as "comparative insert metal").

In this embodiment, the insert metal of the present invention has a disc shape with a thickness of 3.0 to 100 μm and a diameter of 20 mm, and the comparative insert metal has a disk shape of 7.67 to 234.10 μm and a diameter of 20 mm. Material (STK40
0) was prepared and sandwiched between the round steel (diameter 20 mm) and the round steel (diameter 20 mm) as the materials to be joined as shown in FIG. FIG.
In FIG. 1, 1 and 2 are materials to be joined (round steel), and 3 is an alloy for liquid phase diffusion bonding (insert metal).

The liquid-phase diffusion bonding atmosphere is atmospheric air, the bonding temperature is in the range of just above the melting point of each alloy foil to the melting point + 50 ° C., and the target temperature is substantially 900 to 1300 ° C. using a large heating furnace.
Was set to perform liquid phase diffusion bonding. At this time, the material 2 to be joined and the insert metal 3 were pressed with a pressure of 2 megapascals (MPa) in order to improve the adhesion between them.

The joining time is 10 minutes in all, and the heat treatment after joining is annealed, quenching + annealing, annealing + tempering, quenching + annealing + tempering to secure the strength, corrosion resistance and toughness of the materials to be joined. Appropriately, alone or in combination. During these heat treatments, interdiffusion of elements between the materials to be joined progressed, and homogenization of the joined portion proceeded, but the formation and increase of precipitates in the insert metal of the present invention,
Little growth was seen. Next, the soundness of the joint was examined by a JIS A No. 2 subsize round steel tensile tester, and the non-joint area ratio was 0% in all the test pieces made of the insert metal of the present invention.

Further, as shown in FIG. 2, from the axial direction of the round steel,
A JIS A No. 2 tensile test piece as shown in FIG. 3 was cut out, and the relative strength at break of the joint was investigated at room temperature using a tensile tester.

The tensile rupture strength of the joint is determined by the material of the material to be joined, the plate thickness, the operating environment conditions, etc. However, in the present embodiment, 400 MPa was provisionally set as the minimum required strength due to practical limitations. It was judged that sufficient joining was realized when a breaking strength equal to or higher than this value was obtained. The experimental results are shown in Tables 1 and 2 together.

As shown in Table 1, all the joints obtained by the liquid phase diffusion bonding using the alloy foil of the present invention showed a very good joint strength of the target level of 400 MPa or more. On the other hand, all the joints obtained by the liquid phase diffusion bonding using the comparative alloy foil which does not satisfy the present invention showed the joint strength of the target level of 400 MPa or less and were not completely satisfactory. The individual results will be described later.

FIGS. 4 to 9 confirm the relationship between the components (atomic%) and the thickness, the joining time and the breaking strength of the joint portion {expressed in MPa} defined in the diffusion bonding alloy foil of the present invention, and FIG.
Is for confirming the toughness of the heat affected zone (base material).

FIG. 4 shows the influence of the concentration of V in the insert metal on the joint breaking strength. When the V concentration is less than 0.1% in atomic%, the oxide film on the surface of the alloy to be joined cannot be made sufficiently harmless, so the fracture strength at the joint is low, but 0.1% to 20.0 in atomic%. In the range of%, the fracture strength at the joint is equal to or higher than that of the base material (material to be joined), and V acts effectively to render the oxide film harmless. However, when V is more than 20.0% in atomic%, the melting point of the insert metal rises, so that the joining time becomes insufficient and the fracture strength at the joint decreases. Similarly, FIG. 5 is a diagram showing the relationship between P and the fracture strength of the joint. When P is less than 1.0% and more than 20.0%, the joint rupture strength is low.
The target joint rupture strength is obtained in the case of 0 to 20.0%.

FIG. 6 is a view showing the relationship between B and the breaking strength of the joint. When B is less than 1.0%, the melting point of the insert metal is high, and when it exceeds 20.0%, the rupture strength of the joint is lowered due to the boride generated near the joint interface. The target joint rupture strength is obtained at 1.0 to 20.0%.

Similarly, FIG. 7 is a diagram showing the relationship between Si and the breaking strength of the bonded portion. Si less than 1.0% and 10.0
%, The rupture strength of the joint is low and 1.0-10.
The target joint breaking strength is obtained at 0%.

FIG. 8 is a diagram showing the relationship between the thickness of the insert metal and the breaking strength of the joint. It is clear that the joint breaking strength is insufficient when the thickness is 200 μm or more.

FIG. 9 is a diagram showing the relationship between the joint tensile strength at break (MPa) and the joint time when P and B are used together as the diffused elements. The bonding time can be made as short as when B is used alone as the diffusion element, and the bonding time can be significantly shortened as compared with the case where P is used alone.

FIG. 10 is a diagram showing the evaluation results of toughness due to the heat effect of the joined parts when P and B are used together. Since the joining temperature is 1050 ° C. or less due to P, the thermal effect on the material to be joined (base material) can be reduced, the toughness of the base material can be increased, and as a result, the fracture strength of the joint can be increased. In addition,
Regarding the toughness, a JIS No. 4 Charpy impact test piece was sampled from a joined round steel test piece, and an impact test was carried out on this test piece to coarsen the crystal grains in the heat-affected zone of the base material (STK400). It was obtained by evaluation, and the toughness threshold value is often required for general structural materials.
J was selected as the evaluation standard value.

Table 2 shows the chemical composition of the comparative alloy foil with respect to the alloy foil of the present invention and the tensile rupture strength of the obtained joint.

As shown in Table 2, the comparative alloy foil No. 200
Has a melting point exceeding 1300 ° C due to lack of P content,
As a result, an example in which the breaking strength was extremely low, No. 201
Is an example in which the P content is high and a coarse metal compound is generated in the vicinity of the joint to lower the joint rupture strength.

No. 202 has an insufficient amount of B and has a melting point of 130.
The temperature was higher than 0 ° C, the liquid phase diffusion was insufficient, and as a result, the joint rupture strength was remarkably low, No. 203 is an example in which the amount of B is excessive and coarse borides are generated at the time of joining to lower the fracture strength at the joint.

No. 204 has a shortage of Si and a melting point of 13
No. 100 ° C. or higher, and as a result, the joint breaking strength was significantly reduced. Reference numeral 205 is an example in which the amount of Si was excessive and coarse SiO-based oxide was generated at the time of joining to lower the fracture strength at the joint.

No. No. 206 is an example in which the amount of V was insufficient and the oxide film formed on the surface of the alloy to be joined was not sufficiently detoxified and the breaking strength of the joint was low. Reference numeral 207 is an example in which the V content is excessive and the melting point becomes extremely high, so that the liquid-phase diffusion bonding is not sufficiently performed and the joint breaking strength is low.

No. No. 208, which contains a large amount of Cr, has a remarkably high melting point, so that the liquid-phase diffusion bonding is not sufficiently performed and the joint breaking strength is low. 209 is N
This is an example in which since a large amount of i is contained, the Ni phase intervenes in the Fe phase to cause nonuniformity of the structure, lower the toughness, and the fracture strength at the joint part is lowered.

No. No. 210 is an example in which the Co content is excessive, a coarse intermetallic compound is formed, the toughness is lowered, and the joint rupture strength is lowered. No. 211 is an example in which the W content is excessive, a coarse intermetallic compound is formed, the toughness is lowered, and the joint rupture strength is lowered, No. 211. 212 has too much Nb,
This is an example in which a Fe—Nb-based intermetallic compound coarsely precipitates, becomes brittle, and the joint rupture strength becomes low.

No. 213 has an excessive amount of Ti, excessive coarse formation of a coarse intermetallic compound produces a coarse intermetallic compound, lowers toughness, and has a low joint rupture strength,
No. Reference numeral 214 is an example in which the alloy foil thickness was too thick and the joining was insufficient, resulting in a low joint rupture strength.

As described above, although the requirements of the present invention are partially satisfied, but all the requirements of the present invention are not satisfied, the target joint rupture strength may be increased depending on the liquid phase diffusion bonding using the comparative insert metal. It was not possible to achieve 400 MPa.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

[Table 6]

[0071]

[Table 7]

[0072]

[Table 8]

[0073]

[Table 9]

[0074]

INDUSTRIAL APPLICABILITY According to the present invention, P and B are used together as a diffusion element, and various Fe-based materials (thick steel plates, steel pipes, bar steels, steel bars, etc.) are used for joining, and liquid phase diffusion bonding is performed in an oxidizing atmosphere. Even if it is carried out at a high temperature, it is possible to secure a joint part that has a small thermal effect on the material to be joined (base material) and high fracture strength in a short time. , Fe
It can also be effectively used for joining base materials, and it has become possible to significantly reduce the construction period of joining work compared to welding.

[Brief description of drawings]

FIG. 1 is an explanatory plan view showing an example of liquid phase diffusion bonding using an alloy foil for liquid phase diffusion bonding (insert metal) using a round steel bonding test piece as a material to be bonded.

FIG. 2 is an explanatory plan view showing a sample state of a round steel test piece and a tensile test piece obtained by liquid phase diffusion bonding.

FIG. 3 is an explanatory plan view showing an example of a tensile test piece collected by a tensile test piece collecting device.

FIG. 4 is an explanatory view showing the relationship between the V content in the Fe-based insert metal and the fracture strength at the joint portion in liquid phase diffusion bonding using an Fe-based material as the material to be bonded.

FIG. 5 is an explanatory diagram showing the relationship between the amount of P in the Fe-based insert metal and the fracture strength at the joint in liquid phase diffusion bonding using a Fe-based material as the material to be bonded.

FIG. 6 is an explanatory view showing the relationship between the amount of B in the Fe-based insert metal and the fracture strength at the joint in liquid phase diffusion bonding using a Fe-based material as the material to be bonded.

FIG. 7 is an explanatory diagram showing the relationship between the amount of Si in the Fe-based insert metal in liquid phase diffusion bonding using a Fe-based material as a material to be bonded and the fracture strength at the bonded portion.

FIG. 8 is an explanatory diagram showing the relationship between the thickness of the Fe-based insert metal and the fracture strength at the joint portion in liquid phase diffusion bonding using an Fe-based material as the material to be bonded.

FIG. 9: Fe in liquid phase diffusion welding using Fe-based material
Explanatory drawing showing the relationship between the joining time and joining part fracture | rupture strength by the insert metal containing P and B of Fe base of a base.

FIG. 10: Fe-based P using Fe-based material as a material to be joined
It is explanatory drawing showing the toughness at the test temperature of 0 degreeC of the heat affected zone base material (material to be joined) after the liquid phase diffusion bonding by the insert metal containing B and B.

[Explanation of symbols]

 1 Material to be welded (round steel) 2 Alloy foil for liquid phase diffusion bonding (insert metal) 3 Joined round steel test piece 4 Joining abutting line 5 JISA No. 2 sub-size round steel tensile test piece sampling point 6 Round steel axis Direction and tensile test piece sampling direction 7 Round steel test piece screw part 8 JISA No. 2 sub-size round steel tensile test piece 9 V groove (notch) processing position

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C22C 38/52 C22C 38/52 (72) Inventor Shigekatsu Ozaki 20-1 Shintomi, Futtsu, Chiba Prefecture Nippon Steel Co., Ltd.

Claims (5)

[Claims] 1. In atomic%, P: 1.0 to 20.0%, Si: 1.0 to 10.0%, V: 0.1 to 20.0%, B: 1.0 to 20. Fe-based material liquid that can be bonded in an oxidizing atmosphere, characterized in that it has a composition of 0% and the balance is substantially Fe and unavoidable impurities and has a thickness of 3.0 to 200 μm. Alloy foil for phase diffusion bonding. 2. In atomic%, P: 1.0 to 20.0%, Si: 1.0 to 10.0%, V: 0.1 to 20.0%, B: 1.0 to 20. 1% or more of Cr: 0.1 to 20.0%, Ni: 0.1 to 15.0%, Co: 0.1 to 15.0%, and the balance is It has a composition consisting essentially of Fe and inevitable impurities, and has a thickness of 3.0.
An alloy foil for liquid phase diffusion bonding of an Fe-based material capable of bonding in an oxidizing atmosphere, characterized in that the alloy foil has a thickness of up to 200 μm. 3. In atomic%, P: 1.0 to 20.0%, Si: 1.0 to 10.0%, V: 0.1 to 20.0%, B: 1.0 to 20. 0% is contained, W: 0.1 to 10.0%, Nb: 0.1 to 10.0%, Ti: 0.1 to 10.0%, and one or more kinds are contained, and the balance is It has a composition consisting essentially of Fe and inevitable impurities, and has a thickness of 3.0.
An alloy foil for liquid phase diffusion bonding of an Fe-based material capable of bonding in an oxidizing atmosphere, characterized in that the alloy foil has a thickness of up to 200 μm. 4. In atomic%, P: 1.0 to 20.0%, Si: 1.0 to 10.0%, V: 0.1 to 20.0%, B: 1.0 to 20. 1% or more of Cr: 0.1 to 20.0%, Ni: 0.1 to 15.0%, Co: 0.1 to 15.0%, and W: : 0.1 to 10.0%, Nb: 0.1 to 10.0% Ti: 0.1 to 10.0%, and the balance is substantially Fe and unavoidable impurities. With a composition of 3.0 and a thickness of 3.0
An alloy foil for liquid phase diffusion bonding of an Fe-based material capable of bonding in an oxidizing atmosphere, characterized in that the alloy foil has a thickness of up to 200 μm. 5. An alloy for liquid phase diffusion bonding of a Fe-based material capable of bonding in an oxidizing atmosphere according to claim 1, wherein the crystal structure of the structure is substantially amorphous. Foil.