CN102601542B - A kind of brazing solder alloy - Google Patents

Abstract

The invention discloses a brass solder alloy, which is composed of Cu, Zn, Sn, Ge, Ag and/or In; the components are calculated by mass percentage: Cu: 58-60%, Sn: 0.5-3.0 %, Ag: 1.0-6.0% and/or In: 1.0-5.0%, Ge: 0.05-0.3%, and the balance is Zn. Brass solder alloy of the present invention compares with existing brass solder, melting temperature is lower, can replace silver solder and be used for the brazing of steel/copper joint, because Ag content is lower, therefore cost is lower Low.

Description

A kind of brass solder alloy

technical field

The invention relates to the technical field of brazing, in particular to a high-reliability brass solder alloy for brazing connecting steel.

Background technique

At present, in various industrial fields, the solder alloys used for brazing steel mainly include silver solder (Ag-Cu-Zn system), brass solder (Cu-Zn system) and the like. Silver solder has been widely used due to its low melting temperature, excellent wetting properties and good comprehensive mechanical properties. However, with the excessive use of non-renewable resources, the price of precious metal silver continues to rise, resulting in the continuous increase of manufacturing costs for manufacturers. In order to rationally allocate non-renewable resources and reduce manufacturing costs, people have begun to pay attention to the feasibility of applying brass solder in various industrial fields.

For a long time, the traditional brass solder has been based on Cu. First, the α-Cu solid solution is formed by adding the alloying element Zn, and the addition range of Zn is generally 38%-42%. , Mn, Ni, Si to improve the brazing process performance and mechanical properties of the filler metal. Adding Sn to the Cu-Zn alloy can reduce the melting temperature of the solder alloy and improve wettability; adding Mn, Fe and Ni can improve the wettability of the solder on the cemented carbide; adding Si prevents the brazing process from Evaporation of Zn in the medium. In addition, according to the regulations of the American Welding Society, there is also a small amount of P (such as: RBCuZn-D) added to the above solder alloys to improve the wettability of the solder.

Though existing brass filler metal is applied in some industrial fields, will use brass filler metal to braze steel in some important occasions, it also has many deficiencies. Studies have shown that adding a small amount of Si and P to Cu-Zn alloys will form Fe-Si and Fe-P intermetallic compounds at the steel/brazing filler metal interface during brazing, and even form microcracks at the interface, and use There is a big difference in the joint when the silver-based solder is brazed (the interface is α-Cu solid solution). Due to the inherent brittleness and microcracks of Fe-Si and Fe-P intermetallic compounds, the reliability of the brazing joint service process (such as: air tightness, electrical conductivity and mechanical properties) will be reduced. Secondly, due to the high melting point of the existing brass solder, when brazing similar steel/copper joints, the copper annealing is severe, causing excessive growth of grains, resulting in a decrease in strength indicators.

Contents of the invention

The purpose of this invention is to provide a kind of brass solder alloy with high reliability, and this solder can replace silver solder to be used for the steel/steel, steel/copper brazing joint etc. that brazing requires high reliability, and solder cost low.

The object of the invention is achieved through the following technical solutions:

A brass solder alloy consisting of Cu, Zn, Sn, Ge and Ag and/or In.

The components are calculated by mass percentage: Cu: 58-60%, Sn: 0.5-3.0%, Ag: 1.0-6.0% and/or In: 1.0-5.0%, Ge: 0.05-0.3%, and the balance is Zn.

Preferably, the Cu: 58-60%, Sn: 1.0-2.0%, Ag: 2.0-5.0% and/or In: 1.0-3.0%, Ge: 0.05-0.1%, and the balance is Zn.

Preferably, the Cu: 60%, Sn: 1.5%, Ag: 5%, In: 1%, Ge: 0.05%, Zn: the rest.

Preferably, the Cu: 58%, Sn: 1.0%, Ag: 2%, Ge: 0.1%, Zn: the rest.

Preferably, the Cu: 58%, Sn: 2.0%, Ag: 4%, In: 3%, Ge: 0.1%, Zn: the rest.

Preferably, the Cu: 60%, Sn: 1.5%, Ag: 5%, Ge: 0.08%, Zn: the rest.

Preferably, the Cu: 59%, Sn: 2.0%, Ag: 3.0%, Ge: 0.06%, Zn: the balance.

Preferably, Cu: 59%, Sn: 1.5%, In: 3.0%, Ge: 0.15%, Zn: the balance.

The above solder alloys can be obtained by conventional solder alloy smelting methods, and can be processed into wires and strips of different specifications according to conventional solder processing methods.

Solder alloy of the present invention has following advantage compared with prior art:

1) When brazing steel, intermetallic compounds will not be formed at the steel/brazing filler metal interface, and the interface can obtain the same α-Cu solid solution interface structure as silver brazing filler metal, thereby improving the reliability of brazing joints.

2) Compared with the existing brass solder, due to the lower melting temperature, it can replace silver solder for brazing of steel/copper joints.

3) The brass solder of the present invention has lower cost due to its lower Ag content.

The effect of each component among the present invention and the principle of content limitation are as follows (contents are all in mass percent):

Cu and Zn: In order to ensure that the solder alloy structure is α-Cu solid solution; the solder has good processability, according to the Cu-Zn binary phase diagram, the ratio of Cu and Zn should be limited to Cu: Zn at 58-60%: 42%-40% range.

Sn: Adding Sn to Cu-Zn alloy can reduce the melting temperature of solder alloy and increase wettability. However, the solid solubility of Sn in Cu and Zn is very small, so the added Sn will form an intermetallic compound with Cu, making the solder brittle, preferably 1.0-2.0%.

Ag and In: It can reduce the melting temperature of the solder alloy; improve the wettability and improve the mechanical properties of the solder. Considering the material cost and the overall performance of the brazed joint, Ag: 2.0-5.0% and/or In: 1.0-3.0% are preferred.

Ge: There is a large solid solubility in Cu, but Ge is an active element (lower than Si), which can prevent the evaporation of Zn, and will not form intermetallic compounds with Fe, and consider the brass brazing filler metal of the present invention The soldering temperature is reduced, so it is preferably 0.05-0.1%.

Detailed ways

Example 1

A brass solder alloy, its alloy formula is Cu: 60%, Sn: 1.5%, Ag: 5%, In: 1.0%, Ge: 0.05%, Zn: balance.

The preparation steps of above-mentioned brass solder alloy are as follows:

1) Prepare a total of 5000 grams of each material according to the above formula;

2) Put Cu into an induction furnace and heat it to above 1100°C and melt it;

3) Add Zn and stir fully, while rapidly reducing the temperature of the molten metal to 920°C;

4) After the molten metal is uniform, add Ag and stir thoroughly;

5) Add Sn, In and Ge and stir evenly, then cast;

6) The brazing alloy is obtained by extruding and wire drawing according to the conventional brazing filler metal processing method.

Example 2

The difference between this embodiment and Example 1 is to adopt the following formula:

Cu: 58%, Sn: 1.0%, Ag: 2%, Ge: 0.1%, Zn: balance.

Example 3

The difference between this embodiment and Example 1 is to adopt the following formula:

Cu: 58%, Sn: 2.0%, Ag: 4%, In: 3%, Ge: 0.1%, Zn: balance.

Example 4

The difference between this embodiment and Example 1 is to adopt the following formula:

Cu: 60%, Sn: 1.5%, Ag: 5%, Ge: 0.08%, Zn: balance.

Example 5

The difference between this embodiment and Example 1 is to adopt the following formula:

Cu: 59%, Sn: 2.0%, Ag: 3.0%, Ge: 0.06%, Zn: balance.

Example 6

The difference between this embodiment and Example 1 is to adopt the following formula:

Cu: 59%, Sn: 1.5%, In: 3.0%, Ge: 0.15%, Zn: balance.

The preparation of brazing samples adopts conventional flame brazing, the grade of base metal is Q195, and the flux is trimethyl borate gas flux. The melting point of the solder was measured by DSC, and the heating rate was 10°C/min; the loading load for the microhardness was 100gf, and the loading time was 15s; the interface morphology of the brazing samples was observed by scanning electron microscopy. The test results are shown in Table 1.

Table 1 embodiment and comparative example detection result comparison

Claims (8)

1. A brass solder alloy, characterized in that, is made up of Cu, Zn, Sn, Ge and Ag and/or In, and each component is by mass percent: Cu: 58-60%, Sn: 0.5 -3.0%, Ag: 1.0-6.0% and/or In: 1.0-5.0%, Ge: 0.05-0.3%, the balance being Zn. 2. The alloy according to claim 1, characterized in that, the Cu: 58-60%, Sn: 1.0-2.0%, Ag: 2.0-5.0% and/or In: 1.0-3.0%, Ge: 0.05 -0.1%, the balance is Zn. 3. The alloy according to claim 2, characterized in that, said Cu: 60%, Sn: 1.5%, Ag: 5%, In: 1%, Ge: 0.05%, Zn: balance. 4. The alloy according to claim 2, characterized in that, said Cu: 58%, Sn: 1.0%, Ag: 2%, Ge: 0.1%, Zn: balance. 5. The alloy according to claim 2, characterized in that, Cu: 58%, Sn: 2.0%, Ag: 4%, In: 3%, Ge: 0.1%, Zn: balance. 6. The alloy according to claim 2, characterized in that, said Cu: 60%, Sn: 1.5%, Ag: 5%, Ge: 0.08%, Zn: balance. 7. The alloy according to claim 2, characterized in that, said Cu: 59%, Sn: 2.0%, Ag: 3.0%, Ge: 0.06%, Zn: balance. 8. The alloy according to claim 1, characterized in that, said Cu: 59%, Sn: 1.5%, In: 3.0%, Ge: 0.15%, Zn: balance.