JPS63157793A - Ni base crystalline rapidly solidified brazing filler metal foil - Google Patents

Abstract

PURPOSE:To improve the strength of a joining part and the corrosion resistance by forming with the fine crystal in a specific size the brazing filler metal foil containing Cr, Si, B in a specific wt.% and the balance Ni by adding Fe, Co, Mo at a specific %, if necessary. CONSTITUTION:The molten alloy 11 containing 10% min., 30% max. Cr, 5% min. 10% max. Si, and 0.001% min. 1% max. B in wt.% and the balance Ni by adding at least more than one kind of 30% max. Fe, 10% max. C and 10% max. Mo so occasion demands is prepared. This molten metal 11 is injected onto a rotary cooling drum 13 from the nozzle port 12 of a molten metal container 10 and cooled for its solidification at the cooling speed of at >=10<3> deg.C/sec to form the brazing filler metal foil having <=10mum crystal grain. The Cr, Si and B components improves the corrosion resistance of the joining part as well as the fluidity improvement of the molten alloy. The strength of the joining part is improved as well because of the crystal grain being fine.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to Ni-based viscous crystal cold solidification: 1"1), especially Ni-based viscous crystalline cold-solidified thin solidified solidified solidified solidified solidified solidified 1"1), which has particularly excellent joint corrosion resistance. Related to obi and its manufacturing method.

The brazing ribbon according to the present invention is particularly effective for brazing various stainless steels and high alloy steels.

(Prior art) Conventionally, a Ni1 alloy brazing material has been used as a brazing material for stainless steel, etc., but in order to lower the melting point, B, Si, etc. are added to about 20 atχ to create a near-eutectic composition. are used. In this way, when a large amount of embrittlement elements such as Si are added, rolling etc.
It is almost impossible to make a plate with a thickness of 100 μm, which is suitable for brazing insert material, by cutting an ingot or other methods.
Even thin plates with a thickness of less than 100 mL are very fragile and break during cutting operations. Therefore, each component is usually powdered and solidified with a binder before use. Therefore, during brazing, voids are generated in the joint due to sublimation of the binder and oxidation of the powder surface, resulting in deterioration of joint strength, corrosion resistance, etc.

Furthermore, in recent years, Ni-based amorphous ribbon produced by the molten metal ultra-quenching method disclosed in Japanese Patent Publication No. 15234/1983 has also been used. According to this method, since the top plate is formed without using a binder, brazing does not generate voids due to sublimation of the binder during joining and the strength of the joint is improved, but it is difficult to join stainless steel. In this case, the corrosion resistance of the joint was not equal to or better than that of the base metal, and when used in a corrosive environment, there was a drawback that the vicinity of the joint would elute and split.

On the other hand, such amorphous ribbons strongly depend on the cooling rate during fabrication, and when attempting to fabricate relatively thick (more than 50μ) ribbons, the cooling rate decreases compared to when fabricating thin ones. , it is difficult to make it amorphous. If it cannot be made amorphous with a high Si content, it will become extremely brittle.
It is difficult to stably produce a ribbon with high ductility on the order of μm. Another drawback was that it was not possible to produce a solder ribbon of 50 to 200 μmF, which was suitable for brazing joints with a relatively wide gap between base materials.

(Problems to be Solved by the Invention) The object of the present invention is to provide a homogeneous and highly ductile brazing ribbon for use in combination with a brazing material, which has excellent joining strength and joint corrosion resistance for high alloys such as stainless steel and Ni-based alloys. An object of the present invention is to provide a manufacturing method.

(Means for Solving the Problems) In order to achieve the above object, the present inventors have repeatedly conducted research on manufacturing wax ribbons using the molten metal super-quenching method, and have obtained the following knowledge.

(1) A thin ribbon with high ductility can be obtained by forming a homogeneous ribbon consisting of fine crystal grains of 10 μm or less, preferably 2 μm or less, more preferably 1 μm or less, from a Ni-based alloy to which appropriate amounts of Cr, Si, and B are added. becomes.

(2) The amounts of B and Cr greatly affect the corrosion resistance of the joint during joining, and by setting B: 1 wt% or less and Cr: 10 wt% or more, the joint corrosion resistance is equal to or higher than that of stainless steel, etc. High bonding strength can be obtained.

(3) Although this alloy composition is extremely brittle and cannot be made into a thin strip using conventional casting and rolling methods, it can be easily formed into a thin strip with a thickness of 20 to 200 μm using a molten metal super-quenching method. Furthermore, since the ribbon produced by this method is finely crystalline, it exhibits ductility that would be unimaginable with conventional casting and rolling methods, and has sufficient ductility as a brazing ribbon.

(4) This alloy composition is the amorphous N
The composition is close to that of i-based wax ribbon, but even though it contains B, it is 1w.
Since the amount is as small as t% or less, the molten metal remains completely crystalline even after ultra-quenching, which is essentially different from these patents.

In addition, even if the composition is amorphous, if the plate thickness is 50 μm or more, the cooling rate decreases and the plate becomes amorphous.If it does not become amorphous, it becomes extremely brittle, but in the alloy of the present invention, it is originally crystalline. Therefore, it is not affected by the plate thickness (it is possible to easily produce a ductile ribbon with a thickness of 50 to 200 μm).

Here, the gist of the present invention is, in weight%, Cr: 10% or more and 30% or less, Si: 5% or more, 1
0% or less, B: 0.001% or more, 1% or less, and if desired, Fe: 30% or less, Co: 1
0% or less and Mo: at least 1 of 10% or less
10μ further containing seeds, the remainder being substantially Ni
This is a Ni-based crystalline rapidly solidified wax ribbon consisting of microcrystals of less than m.

In addition, from another aspect, the gist of the present invention is in terms of weight%, Cr: 10% or more and 30% or less, Si: 5% or more, 1
0% or less, B: 0.001% or more, 1% or less, and optionally Fe: 30% or less, Co: 10%
A molten alloy further containing at least one of the following and Mo: 10% or less, the remainder being substantially ll+, is ejected onto a moving and renewing cooling body, and solidified at a cooling rate of 10''C/sec or more. 10μm characterized by cooling
This is a method for producing an Nt-based crystalline rapidly solidified brazing ribbon consisting of the following crystal grains.

(Function) Here, in the present invention, the reason why the alloy composition is limited as described above will be explained in detail.

Cr: Added at least 10 wt% to improve the corrosion resistance of the joint; on the other hand, excessive addition increases the melting point of the alloy.
Further, since the σ phase precipitates in the joint and causes embrittlement, the content should be 30 wt% or less. Preferably it is 15-25-t%.

Si: The melting point of the alloy is lowered, the fluidity during melting is improved,
Further, in order to make it easier for the molten solder during brazing to spread throughout the joint gap, it is added at least 5 wt %, and on the other hand, since the ribbon becomes brittle if added in excess, the amount is set at 19 wt % or less.

Preferably it is 6 to 9&4t%.

B: Preferably added in order to improve the fluidity of the alloy when it is melted and to make it easier for the molten solder during brazing to spread throughout the joint gap. However, if too much is added, the ribbon becomes brittle and the corrosion resistance of the brazed joint deteriorates.
1 stomach (not more than 1%. Preferably not more than Q, 7wt%t%).

Regarding Fe + Co + Mo, at least one kind may be added if desired to improve the strength of the joint, but for example,
Brazing of structural materials is preferred when performing such operations.

Fe: It is preferable to add Fe to improve the strength of the joint or as a substitute for expensive Ni, but if it is added in too large a quantity, the corrosion resistance of the joint will deteriorate and the melting point of the alloy will increase, so Fe should be added at 30wt%. The following shall apply. Preferably it is 10-t% or less.

co=Added to increase the corrosion resistance and high-temperature strength of the joint. However, since it is expensive, it is limited to 10-t% or less.

Mo: As in the case of Co, Mo is added to improve the corrosion resistance and high-temperature strength of the joint, but it is expensive, so it is limited to 10-t% or less.

Next, in the present invention, the crystal grain size is reduced to 1 by rapid solidification.
The grain size is 0 μm or less, but in order to ensure the ductility of the brazing ribbon, the crystal grain size is 10 μm or less, preferably 2 μm or less, and more preferably 1 μm or less. It should be homogeneous without contamination. The crystal grain size can be changed by changing the rapid solidification rate, and by ensuring a cooling rate of 103°C/sec or more, the crystal grain size can be made 10 μm or less.

Figures 1 and 1 are schematic diagrams of an apparatus for manufacturing a crystalline rapidly solidified ribbon according to the present invention. In the figure, the molten metal 11 from the molten metal container 10 moves at high speed through the nozzle port 12 and is renewed. The molten metal is poured onto a rotating cooling drum 3 and rapidly solidified to produce a ribbon 14. The case of ta+ in Fig. 1 is called a single-roll method, and the case of fbl in Fig. 1 is called a double-roll method. There is no particular limitation on the type of ultra-quenching device.In short, it is sufficient as long as it can eject molten metal onto a moving and renewing cooling body, solidify and cool it, and form a ribbon.

The molten metal having the above alloy composition is cooled and solidified at a cooling rate of 103° C./sec or more using a molten metal ultra-quenching device as shown in FIG. 1, preferably into a thin ribbon of 20 to 200 μmW.

If it is thinner than that, it is difficult to produce a crystalline material, so the thickness is set to 20 μm or more, and there is no particular upper limit to -Flu. However, since it reduces the efficient use of brazing filler metal and reduces the cooling rate,
A thickness of 00 μm or less is preferred.

These thin strips have almost no surface oxidation and are useful for brazing as they are, but they have sufficient toughness so they can be used for brazing after being cut and pressed into complex shapes.

The brazing ribbon of the present invention can be applied to various types of austenitic, two-phase, and ferritic stainless steels as well as high alloy steels containing large amounts of Ni, Mo, Co, W, etc. be.

EXAMPLES Below, the present invention will be explained in more detail with reference to Examples.

Example 1 A rectangular nozzle with an opening of 0.5 mm x 14 mm was placed on the surface of a steel roll with a diameter of 300 mm rotating at 3000 r, p, m as shown in Figure 1 (al). A ribbon with a width of 14 mm and a thickness of 35 μm was produced.

For alloy C, 50mm x 50mm x 2
1! 100 μm thicker than the ingot cast into a 0 mm mold!
A plate is cut out and has a diameter of 2 including the wax ribbon according to the present invention.
It was investigated whether it was possible to punch out a circle of 0 mm.

After cutting these thin strips into a size of 14mm x 14mm, two 14mm x 14mm x 60mm
Sandwich the 14mm x 14mm end face of a 511S304 square piece and apply a compressive stress of 1 kg/mm.
The ribbons were melted and bonded by heating at 1250"C for 15 minutes in a 4-air atmosphere. Also, as a comparative example, JIS standard B
Bonding was carried out in the same manner using Ni-14 Ni-based powder sheet solder.

Thereafter, in order to measure the joint strength, a test piece in the shape of Moon SZ2201 was created by cutting the joined square pieces, and a tensile test was conducted. In addition, the joint corrosion resistance test was conducted using a piece of 3 mm thick x 10 mm wide centering on the soldered part from the joined square pieces.
X length 40mm, thickness 2mm X diameter 11mm
A test piece was processed and a stainless steel sulfuric acid-copper sulfate corrosion test (JiS GO575° or less, referred to as the "Strauss test") and pitting potential measurement were performed.

The test piece for the Strauss test was finished by wet polishing with No. 600 emery paper, and after the test, U-bend bending was performed and the presence or absence of cracks was determined using a microscope.

Pitting corrosion potential was measured using 0.01M NaCQ aqueous solution at 60°C.
Measurement was performed by potentiodynamic method at a sweep rate of 20 mV/min under Ar degassing.

The number n is 3.

The above results are summarized in Table 2.

In addition, the structure of the ribbon made from Alloy C is extremely fine (0.3μ
The solder ribbons of the present invention were all flexible and could be easily punched out.

However, all of the thin plates of Alloy C produced by the conventional method were broken during punching.

FIG. 3 (al) is an X-ray diffraction diagram of the ribbon of the base metal C, and it can be seen that sharp peaks characteristic of crystalline materials are observed.

In this example, due to its composition, even if the thickness of the ribbon was reduced and the quenching rate was increased, an amorphous ribbon could not be obtained. :5i=4.2%, B-2,0%:C
The X&5i diffractogram for a 10 μm thick amorphous ribbon containing r=19% is shown in FIG. 3 Fb+. Broad peaks characteristic of amorphous materials are observed. When brazing was performed using this amorphous ribbon, penetration cracking occurred in the Strauss test, and the corrosion resistance was lower than the base metal level. In addition, as shown in Table 2, when brazing is performed using the solder ribbon of the present invention, υ in the Strauss test
No pitting corrosion occurred, and the pitting corrosion type (i) was also higher than that of the comparative example, which clearly shows that a joint with excellent corrosion resistance can be achieved.

Table 1 Table 2 Example 2 The molten metal of the C alloy composition of Example 1 was heated using the same equipment shown in Figure 1 (Al) with a diameter of 300 mm rotated at 250 Or, p, m.
mm FI flor surface, opening 0.6 mm x
A wax ribbon with a width of 20 mm and a height of 30 μm was produced by spraying from a 20 mm rectangular nozzle.

SO5304a fissure diameter 25.4mm x j¥S 1.
A pipe with a length of 100 mm x 100 mm was inserted into the joining surface using the C alloy composition brazing ribbon of Example 1 as an insert material, and in an argon atmosphere, the joining temperature was 1250'C, the joining time was 200 seconds, and the compressive stress was 1. kg/mm".

Four plate-shaped tensile test pieces and a corrosion test piece were taken from this joint.

Table 3 Strength and Corrosion Resistance of Pipe Joints There was no problem when the brazed ribbon of the present invention was applied to pipe joints, and joint strength comparable to that of the base metal was obtained.

Furthermore, the corrosion resistance was also evaluated under the same conditions as in Example 1), and as shown in Table 3, good corrosion resistance was confirmed.

(Effects of the Invention) As described above, according to the present invention, it is possible to obtain a solder ribbon for joining stainless steels and high alloys, which is very useful industrially, and a method for manufacturing the solder ribbon therefor. In addition, according to the present invention, a product with a larger thickness can be obtained compared to an amorphous one, and since the content of B and Si can be lowered, seven-fold ductility can be ensured. 1.1 Melt flow during precautions It has excellent corrosion resistance and improves the corrosion resistance of joints.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an apparatus for producing a rapidly solidified solder ribbon according to the present invention; FIG. 2 is a transmission electron microscope metal weave photograph of the solidified solder ribbon according to the present invention; FIG. 3 is a graph showing a comparison of the X-ray diffraction pattern fa+ of the wax ribbon according to the present invention with that of an amorphous ribbon fbl. 10: Molten metal container 11 Near molten metal 12: Nozzle port 13: Rotating cooling drum 14/thin ribbon

Claims (4)

[Claims] (1) In weight%, Cr: 10% or more and 30% or less, Si: 5% or more, 10
% or less, B: 0.001% or more and 1% or less, the balance being substantially Ni, a Ni-based crystalline rapidly solidified brazing ribbon consisting of fine crystals of 10 μm or less. (2) In weight%, Cr: 10% or more and 30% or less, Si: 5% or more, 10
% or less, B: 0.001% or more and 1% or less, and Fe: 30% or less, Co: 10% or less, and Mo
: A Ni-based crystalline rapidly solidified brazing ribbon consisting of fine crystals of 10 μm or less, further containing at least one of the following: 10% or less, the remainder being substantially Ni. (3) In weight%, Cr: 10% or more and 30% or less, Si: 5% or more, 10
% or less, B: 0.001% or more and 1% or less, the balance being substantially Ni, is spouted onto a cooling body that moves and renews it, at a cooling rate of 10^3 ° C / sec or more. A method for producing a rapidly solidified Ni-based crystalline brazing ribbon comprising crystal grains of 10 μm or less, which comprises solidifying and cooling. (4) In weight%, Cr: 10% or more and 30% or less, Si: 5% or more, 10
% or less, B: 0.001% or more and 1% or less, and Fe: 30% or less, Co: 10% or less, and Mo
: Spraying a molten alloy further containing at least one of 10% or less and the remainder being substantially Ni onto a moving and renewing cooling body, and solidifying and cooling at a cooling rate of 10^3°C/sec or more. A method for producing a Ni-based crystalline rapidly solidified brazing ribbon consisting of crystal grains of 10 μm or less, characterized by: