JP2007075867A - Ni BRAZING FILLER METAL ALLOY - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an Ni brazing filler metal alloy having satisfactory corrosion resistance and relatively high strength, and having a liquidus temperature low in a degree to braze stainless steel and copper. <P>SOLUTION: The Ni brazing filler metal has a composition comprising, by weight, 5 to 16% Cr, 2 to 9% P, 1 to 6% Si and 0.5 to 2.5% B, and in which the total weight of P, Si and B lies in the range of 8 to 11%, and the balance Ni of 73 to 87% with inevitable impurities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brazing material alloy containing Ni as a main component, which can be brazed at a low temperature as compared with the prior art, has excellent corrosion resistance, and has balanced properties with appropriate strength.

  In Japanese Industrial Standard (JIS Z3265), for example, Ni—Cr—Fe—Si—B (BNi-2), Ni—Cr—Si (BNi-5), Ni—Cr as Ni-based brazing alloy. -P system (BNi-7) and the like are defined.

  However, BNi-2 has a relatively low melting point and no problem with strength, but has a problem of corrosion resistance because it contains a large amount of B. Although BNi-5 has good corrosion resistance, there is a problem that its application is limited because of its high melting point. BNi-7 has a low melting point and good corrosion resistance, but has a problem of low strength because it contains a large amount of P.

Moreover, although the Ni-Cr-P-Si-based brazing material disclosed in Patent Document 1 has a good balance of the above characteristics, the liquidus temperature is somewhat high, so stainless steel and copper may not be brazed. is there. Furthermore, since it contains a large amount of Cr, workability may be inferior when mass-produced in a continuous hydrogen furnace.
Japanese Patent No. 3354922

  The present invention has been made paying attention to the above-mentioned problems, has good corrosion resistance, has a relatively large strength, maintains the advantages of a Ni-based heat-resistant brazing material, and brazes stainless steel and copper. The object is to provide a Ni brazing alloy having a liquidus temperature as low as possible. Furthermore, the Ni brazing alloy provided by the present invention can be used for mass production in a continuous hydrogen furnace, and an object of the present invention is to provide a Ni brazing alloy having a balanced property.

  The Ni brazing alloy of the present invention can be provided by the following constitution.

  (1) 5% to 16% Cr, 2% to 9% P, 1% to 6% Si, 0.5% to 2.5% B, and the balance of Ni containing inevitable impurities is 73% by weight. Ni brazing alloy characterized by ˜87%.

  (2) The Ni brazing alloy according to (1), wherein the total weight of P, Si and B is in the range of 8 to 11%.

  (3) The inevitable impurities include, by weight, Fe 5% or less, Co 1% or less, Cu 1% or less, Mn 1% or less, and C 0.15% or less (1 ) Or (2) Ni brazing alloy.

  In the Ni brazing alloy according to the present invention, Cr has an effect of improving the corrosion resistance. However, if it is less than 5%, the effect is thin, and if it exceeds 16%, the liquidus temperature exceeds 1050 ° C., and copper can be brazed. Since it disappears, it was set as 5 to 16% of range.

  P lowers the melting point of the Ni brazing alloy of the present invention and improves the fluidity. However, if it is less than 2%, the effect cannot be sufficiently exhibited, and if it exceeds 9%, the alloy becomes brittle. It was made the range.

  Si and B lower the melting point of the Ni brazing alloy of the present invention and exhibit a flux action to improve the brazing workability, but the effect is exhibited when Si is less than 1% and B is less than 0.5%. When Si exceeds 6% and B exceeds 2.5%, an intermetallic compound with Ni or Cr is excessively formed, resulting in a decrease in strength and corrosion resistance. Therefore, Si is 1 to 6% and B is 0.5. It was made into the range of -2.5%.

  P, Si, and B are components that similarly affect the melting point and workability of the Ni brazing alloy of the present invention. When the total of the three components is less than 8%, the liquidus temperature is often 1050 ° C. or more, If it exceeds 11%, the strength is often lowered, so the total was made 8 to 11%.

  Ni containing inevitable impurities is a basic component of the Ni brazing alloy of the present invention, and is limited to a range of 73 to 83% depending on the balance with the above-described components. The range of impurities that do not adversely affect the characteristics of the Ni brazing alloy of the present invention is as follows: Fe is 5% or less, Co is 1% or less, Cu is 1% or less, Mn is 1% or less, and C is 0.15%. It is as follows.

The Ni brazing filler metal alloy according to the present invention has a good balance of properties and has the following characteristics, so that it can be applied to a wide range of uses.
(1) Good corrosion resistance.
(2) It has moderate strength.
(3) Brazing can be performed at a relatively low temperature (1050 ° C. or lower).
(4) The flowability of the wax is good.

  A mixture prepared so that each of Ni, the base, and Cr, P, Si, and B as additive components is in a predetermined weight% is melted to form a liquid alloy, and then powdered by an atomizing method, Ni brazing alloy can be obtained by casting into a mold in the form of a plate or rod. Powder, plate, or rod-like alloy can be used as a brazing material as it is, but a brazing material further processed according to the brazing environment and object may be used. For example, a binder resin can be mixed with the powder to form a paste or a sheet, and the plate can be rolled into a foil and used as a brazing material.

  Table 1 shows the compositions of Examples 1 to 13 of the Ni brazing alloy prepared as described above. Table 1 shows the liquidus temperature (° C.) and the solidus temperature (° C.), which are indicators of the brazing temperature of the alloys of each example, the anti-deposition force (kgf / mm) as an index of the strength of the alloy, and the brazing The results of evaluation of corrosion resistance by the workability and salt spray test are also shown.

  For liquidus and solidus temperatures, melt the Ni brazing alloy in an electric furnace in an argon gas atmosphere, insert a thermocouple into the melted alloy, measure the cooling curve of the alloy, and analyze the curve. I got it.

Electrodeposition force is obtained by melting an alloy to be tested in an argon gas atmosphere in an electric furnace, sucking and solidifying the molten alloy into a quartz tube having an inner diameter of 5 mm, cutting it to a length of about 35 mm, did. A value obtained by placing this test piece on an anti-deposition force test jig (three-point support, distance between fulcrums: 25.4 mm), applying a load with a universal testing machine and breaking the load, and dividing the breaking load by the cross-sectional area of the test piece (Kgf / mm ² ) was calculated as the anti-segregation force.

  Brazing workability is set to 1050 ° C in a continuous hydrogen furnace and pure hydrogen gas atmosphere (open-air -50 ° C), and a test piece for brazing flow installed on a mesh belt is inserted into the furnace. The actual brazed state (spreading and wetting) was determined by visual observation.

  Corrosion resistance was determined by JIS Z2371 “salt water spray test method” after spraying the test piece for which brazing was completed for 48 hours, observing the test piece to observe the state of rust, and determining whether it was good or bad. After spraying with salt water for 48 hours, the sample without rust was evaluated as “good”, and the sample with rust generated during salt spray was determined as “bad”.

  For comparison with the examples according to the present invention, Table 2 also includes values of conventionally used Ni brazing alloy BNi-2 and BNi-7 and alloys outside the composition range of the present invention (comparative examples a to d). Showed.

  From the comparison between Table 1 and Table 2, it can be seen that Examples 1 to 13 according to the present invention have a liquidus temperature of 1040 ° C. or less and an anti-segregation strength of 1.5 times or more that of BNi-7, which is high in strength.

  Further, in the continuous hydrogen furnace at 1050 ° C., the conventional alloy BNi-7 has too large brazing and BNi-2 is too small, whereas the alloy according to the present invention exhibits moderate brazing and good workability. It was also confirmed.

  In the salt spray test, BNi-7 showed good corrosion resistance and BNi-2 showed poor corrosion resistance, but all the alloys according to the present invention showed good corrosion resistance. Comparative Example a had a high liquidus temperature because the amount of Cr was too large, and Comparative Examples b and c had a high liquidus temperature because the total weight of P, Si, and B was small. In Comparative Example d, since the total weight of P, Si, and B was too large, the liquidus temperature was relatively low at 1050 ° C., but the strength was extremely low so that it could not be put to practical use.

  As described above, the Ni brazing alloy according to the present invention has balanced characteristics and can be applied to a wide range of applications. A continuous hydrogen furnace has a core tube that shuts off the interior of the furnace and the atmosphere, and a mesh belt for driving that moves through it. Usually, these members are made of heat-resistant stainless steel or nickel alloy, so that the temperature is 1100 ° C or higher. If used continuously, the service life will be extremely shortened. Therefore, by using the Ni brazing alloy according to the present invention, the brazing operation can be performed at 1050 ° C. or lower, so that the hydrogen furnace can be continuously operated and mass-produced. At this temperature, brazing of stainless steel and pure copper is possible, so that it can be applied to refrigeration and air-conditioning parts, automobile piping parts, and the like.

Claims (3)

  5% to 16% Cr, 2% to 9% P, 1% to 6% Si, 0.5% to 2.5% B, and the remaining Ni containing unavoidable impurities is 73% to 87%. Ni brazing alloy characterized by the above.   2. The Ni brazing alloy according to claim 1, wherein the total weight of P, Si and B is in the range of 8 to 11%.   The inevitable impurities include, by weight, Fe 5% or less, Co 1% or less, Cu 1% or less, Mn 1% or less, and C 0.15% or less. The Ni brazing alloy described.