A kind of corrosion-resistant bronze solder and preparation method thereof

Abstract

The invention discloses a corrosion-resistant bronze solder, the components of which include by weight percentage: Sn10-15%, Ni0.30-2.0%, Cr0.10-1.0%, P0.02-0.4%, B0.02-0.40%, Si0.02-0.40%, and the balance is Cu. The invention also discloses a method for preparing the corrosion-resistant bronze solder, comprising the following steps: firstly melting copper, then adding tin and mixing, then adding Ni-Cr-B-Si-P alloy, melting and mixing to obtain a casting liquid, the components of the casting liquid being the same as the corrosion-resistant bronze solder, then casting and molding, and processing to obtain the corrosion-resistant bronze solder. The invention has good welding performance and excellent salt spray corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of brazing, and in particular to a corrosion-resistant bronze solder and a preparation method thereof. Background Art

[0002] At present, the refrigeration system pipe assemblies in the refrigeration field are generally welded by a main pipe with a larger diameter and a branch pipe with a smaller diameter, while the traditional refrigeration system pipe fittings are all made of copper or copper alloy pipes and welded with phosphor copper or silver-based solder.

[0003] With the rising prices of copper and silver-based solder, the cost of pipe assemblies has increased. In order to reduce costs, a large number of pipe assemblies welded together by stainless steel main pipes and copper branch pipes (or stainless steel branch pipes) are currently used. Stainless steel materials replace copper materials, and the welding materials replace silver-copper solder with tin-phosphor bronze solder. The welding method replaces the traditional flame brazing of silver-copper solder with protective atmosphere tunnel furnace welding. The welding method can achieve green and environmentally friendly brazing without flux and harmful emissions, and is now widely used in the refrigeration field.

[0004] Although tin-phosphor bronze solder is low-cost, it has insufficient corrosion resistance. The conventional salt spray test time of stainless steel or copper tube components welded with tin-phosphor bronze solder is about 300-500 hours. As the core component of the refrigeration system, its service life and reliability have serious hidden dangers, which has become a pain point in this field. Summary of the invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a corrosion-resistant bronze solder and a preparation method thereof. The solder of the present invention has excellent welding performance and good corrosion resistance.

[0006] The invention provides a corrosion-resistant bronze solder, the components of which include, by weight percentage, Sn10-15%, Ni0.30-2.0%, Cr0.10-1.0%, P0.02-0.4%, B0.02-0.40%, Si0.02-0.40%, and the balance is Cu.

[0007] The present invention also proposes a method for preparing the above-mentioned corrosion-resistant bronze solder, comprising the following steps: first melting copper, then adding tin and mixing, and then adding Ni-Cr-B-Si-P alloy, melting and mixing to obtain a casting liquid, the composition of the casting liquid is the same as the above-mentioned corrosion-resistant bronze solder, and then casting and molding, and processing to obtain the corrosion-resistant bronze solder.

[0008] The Ni-Cr-B-Si-P alloy can be prepared by vacuum induction melting.

[0009] After the above casting, the corrosion-resistant bronze solder can be further processed to be in various shapes, such as sheet, line, etc. The processing method can be extrusion, rolling, drawing, etc.

[0010] Preferably, the components of the Ni-Cr-B-Si-P alloy include, by weight percentage, Cr 10-30%, B 1-5%, Si 1-5%, P 5-15%, and the balance is Ni.

[0011] Preferably, the melting temperature of the Ni-Cr-B-Si-P alloy is 850-1050°C.

[0012] Preferably, the addition amount of Ni-Cr-B-Si-P alloy is 0.5-2.5% of the total weight of copper and tin.

[0013] Beneficial effects:

[0014] 1. The present invention prepares a Ni-Cr-B-Si-P alloy with a suitable formula so that the melting temperature of the Ni-Cr-B-Si-P alloy is maintained at 850-1050° C., so that the Ni-Cr-B-Si-P alloy can be quickly melted in a copper-tin melt, and the Ni, Cr, B, Si, and P elements can be quickly melted and quickly and evenly dispersed, thereby improving the performance of the solder and avoiding the problem that when Ni, Cr, B, Si, P and other elements are added separately, the melting speed of each element is slow, it is not easy to be evenly dispersed, and the processing performance and use performance of the solder are affected;

[0015] 2. The present invention adjusts the content of each element in the corrosion-resistant bronze solder by controlling the formula and addition amount of the Ni-Cr-B-Si-P alloy. The coexistence of Ni and Cr elements in the solder in an appropriate ratio can significantly improve the corrosion resistance of the solder, the coexistence of B and Si elements in an appropriate ratio can also refine the solder alloy structure, and an appropriate amount of P element can improve the fluidity and welding performance of the solder; therefore, the coexistence of the above elements enables the solder of the present invention to have both good welding performance and good salt spray corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the alloy microstructure of the welding wire in Example 1.

[0017] Figure 2 This is the alloy microstructure of the welding wire in Example 2.

[0018] Figure 3 This is the alloy microstructure of the welding wire in Example 3. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0020] The formulations of Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0021] Table 1 Formulas of Examples 1-3 and Comparative Examples 1-5 (by weight percentage)

[0022]

[0023] Note: The diameter of the welding wire in comparative example 1 is 1.0 mm, and the formula (by weight percentage) of the QSn8-0.3 welding wire is: Sn7.0-9.0%, P0.03-0.35%, Fe0.1%, Pb0.05%, Zn0.20%, the total impurities are 0.85%, and the balance is Cu.

[0024] The preparation methods of the above-mentioned embodiments 1-3 are the same, comprising the following steps: firstly melting copper, then adding a tin block and mixing, then adding a Ni-Cr-B-Si-P alloy at 1100-1200°C, melting and mixing to obtain a casting liquid, wherein the composition of the casting liquid is the same as the above-mentioned corrosion-resistant bronze solder, and then casting, extruding, rolling, and drawing to obtain a corrosion-resistant bronze welding wire with a diameter of 1.0 mm;

[0025] In Example 1, the composition of the Ni-Cr-B-Si-P alloy includes, by weight percentage, Cr15%, B2.5%, Si2.5%, P8%, and the balance is Ni; the amount of the Ni-Cr-B-Si-P alloy added is 1% of the total weight of copper and tin;

[0026] In Example 2, the composition of the Ni-Cr-B-Si-P alloy includes, by weight percentage, Cr 20%, B 2.5%, Si 2.5%, P 10%, and the balance is Ni; the amount of the Ni-Cr-B-Si-P alloy added is 1.2% of the total weight of copper and tin;

[0027] In Example 3, the components of the Ni-Cr-B-Si-P alloy include, by weight percentage: Cr 15%, B 3.0%, Si 3.0%, P 14%, and the balance is Ni; the added amount of the Ni-Cr-B-Si-P alloy is 1.5% of the total weight of copper and tin.

[0028] Comparative Example 2

[0029] In the preparation process of bronze solder, copper is first melted, and then tin, nickel, chromium, boron, silicon and phosphorus copper alloy are added in sequence to obtain a molten casting liquid, so that the composition of the casting liquid is as prescribed in Example 3, and then cast, extruded, rolled and drawn to obtain a corrosion-resistant bronze welding wire with a diameter of 1.0 mm.

[0030] The welding wires of Examples 1-3 and Comparative Examples 1-2 were respectively used in an atmosphere protection tunnel furnace, with the welding temperature adjusted to 1000-1040° C. to weld the stainless steel pipe assembly, and then the alloy structure, melting range, processing performance, welding performance and salt spray resistance of the weld were examined. The results are shown in Table 2. Figure 1-3 shown.

[0031] Figure 1 The alloy microstructure of the welding wire of Example 1; Figure 2 The alloy microstructure of the welding wire of Example 2; Figure 3 This is the alloy microstructure of the welding wire in Example 3.

[0032] The test method for salt spray resistance adopts neutral salt spray test. The specific steps are as follows: spray salt water containing (5±0.5)% sodium chloride and pH value of 6.5-7.2 through a spray device to allow the salt spray to settle on the test piece; the test temperature is (35±2)℃, the humidity is greater than 95%, and the fogging amount is 1-2mL / (h·cm 2 ), the nozzle pressure is 78.5-137.3kPa.

[0033] Table 2 Test results

[0034]

[0035] It can be seen from Table 2 that the solder prepared using the formula and preparation process of the present invention has a weld with good salt spray resistance, and good processing performance and welding performance.

[0036] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A corrosion-resistant bronze solder, characterized in that: Its components by weight percentage include: Sn 12%, Ni 0.77%, Cr 0.23%, P 0.12%, B 0.03%, Si 0.03%, and the balance is Cu.

2. A method for preparing the corrosion-resistant bronze solder according to claim 1, characterized in that: The method comprises the following steps: firstly melting copper, then adding tin and mixing, and then adding Ni-Cr-B-Si-P alloy, melting and mixing to obtain a casting liquid, wherein the composition of the casting liquid is the corrosion-resistant bronze solder as claimed in claim 1, and then casting and molding, and processing to obtain the corrosion-resistant bronze solder.

3. The method for preparing the corrosion-resistant bronze solder according to claim 2, characterized in that: The composition of the Ni-Cr-B-Si-P alloy includes, by weight percentage, Cr 10-30%, B 1-5%, Si 1-5%, P 5-15%, and the balance is Ni.

4. The method for preparing the corrosion-resistant bronze solder according to claim 2 or 3, characterized in that: The melting temperature of Ni-Cr-B-Si-P alloy is 850-1050℃.

5. The method for preparing the corrosion-resistant bronze solder according to any one of claims 2 to 4, characterized in that: The addition amount of Ni-Cr-B-Si-P alloy is 0.5-2.5% of the total weight of copper and tin.

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