What metals can a silver weld

 

It is made of silver, copper, zinc, cadmium and other metals and rolled into about 20 silks.Used for welding all kinds of small metal, such as band saw blade, marble saw blade and have welding characteristics, with higher regular strength.

 

Classification of silver-based alloy electrodes

 

Silver solder includes (silver electrode, silver wire, silver solder, silver ring, silver flux)

 

Characteristics of silver-based alloy electrodes

 

This indicates that silver-based solders have excellent process properties, low melting point, good wettability and ability to fill gaps, as well as high strength, good plasticity, excellent electrical conductivity and corrosion resistance.It can be used for brazing all ferrous and non-ferrous metals except aluminum, magnesium and other low-melting metals.Silver solder applications

 

Widely used in refrigeration, lighting, hardware electrical appliances, instrumentation, chemical, aerospace and other industrial manufacturing fields.

 

Silver base alloy electrode brand and comprehensive welding industry selection and implementation standards.

 

I. brand and performance of silver-based copper-phosphorus environmental solders (silver-copper-phosphorus solders)

 

(1) hag-2b containing 2% silver is equivalent to AWS bcup-6, GB BCu91PAg and L209 with good liquidity and packing capacity.It is widely used in air conditioning, refrigerator, mechanical and electrical industries, copper and copper alloy brazing.Melting point 645-790 degrees Celsius.

 

The hag-5b contains 5% silver, which is equivalent to the national standard BCu88PAg and L205 of AWS bcu-3.It has a certain plasticity and is suitable for welding copper and its alloy joints that cannot keep a tight fit.Melting point 645-815 degrees Celsius.

 

(3) hag-15b contains 15% silver, which is equivalent to AWS bcu-5 national standard BCu80AgP and L204. It has joints, good plasticity and improved electrical conductivity, especially suitable for occasions with uneven clearance.Brazing melting point of copper and its alloy joints capable of withstands vibration load at 645-800 ° c.

 

2. Introduction to the brand and performance of silver-based environmental solders (silver-based solders)

 

(1) hag-18bsn contains 18% silver, copper, zinc and tin alloy, with a slightly higher melting point range, good wettability and fillability, and economical price.Can weld copper, copper alloy, steel and other materials.Melting point 770-810 degrees Celsius.

 

The hag-25b contains 25% silver, equivalent to the gb BAg25CuZn and L302.It is silver, copper, zinc and alloy.It has good wettability and filling, but has a slightly higher melting point.It can be welded to copper, steel and other materials.The melting point is 700-800 degrees Celsius.

 

Hag-25bsn contains 25% silver equivalent to that of AWS bag-37, which is an alloy of silver, copper, zinc and tin.Its melting point is lower than hag-25b, which improves the wettability and filling performance.It can weld copper, steel and other materials.The melting point is 680-780 degrees Celsius.(4) hag-30b contains 30% silver, which is equivalent to the American standard AWS bag-20 and the national standard BAg30CuZn.It is an alloy of silver, copper and zinc with a slightly higher melting point and good toughness.It can be brazed with copper, copper alloys, steel and other materials.Melting point 677-766 degrees Celsius.

 

(5) hag-35b contains 35% silver, equivalent to AWS bag-35.It is made of an alloy of silver, copper and zinc.It has a moderate melting temperature and good toughness.It can be brazed with copper, copper alloys, steel and other materials.Melting point 621-732 degrees Celsius.

 

(6) hag-35sn contains 35% silver, equivalent to the national standard BAg34CuZnSn.It is an alloy of silver, copper, zinc and tin.Melting temperature moderate, good fluidity, more suitable for welding ferritic and non-ferritic steel.Melting point 620-730 degrees Celsius.

 

(7) hag-40b contains 40% silver, copper, zinc and alloy.With good fluidity, permeability and toughness, melting point is 677-732 degrees Celsius.

 

(8) being HAG - 40 bni contains 40% of silver, copper, zinc and nickel alloy, the equivalent of AWS BAg - 4, have, with good corrosion resistance.Suitable for welding stainless steel, nickel base alloy and tungsten carbide, melting point is 670-780 ℃.

 

Storage of wire requirements

 

1. The welding wire warehouse shall be stored in a dry and ventilated environment to avoid damp;Liquids such as water, acid and alkali are highly volatile.

 

Corrosive substances exist and should not coexist with them in the same warehouse.

 

2. The welding wire should be placed on the wooden pallet, not directly on the floor or against the wall.

 

3. When handling welding wire, be careful not to break the package, especially the inner package "heat shrink film".

 

4, open the wire packaging should be used up as soon as possible (within a week), once the wire is exposed to the air, its anti-rust agent time will be greatly reduced (especially in the humid, corrosive media environment)

 

5. According to the principle of "first in, first out", the distribution of electric wires should minimize the inventory time of product quantity.

 

6. Please store according to the type and specification of welding wire to prevent misuse.

 

Purification and recovery

 

Specialty chemical reaction

 

Fe2 HCl→FEC L2[h]2 GCL 2[h]→2 GCL operation process

 

1. Precipitation silver welding: excessive sodium chloride is added to the waste solution of silver-containing welding to make the silver welding completely precipitate, then it is filtered, cleaned and discharged.

 

2. Silver powder reduction: silver chloride precipitation is put into a beaker, iron plate is buried in silver chloride precipitation, and concentrated hydrochloric acid is added to cover it. Then, while stirring, heat to boil until white silver chloride precipitation turns into gray silver powder (about 1 hour).

 

3. Clean the silver powder: remove the remaining iron, reduce pressure and filter, clean twice with tap water, then clean with distilled water until there are no chlorine ions, and then discharge them.

 

4. Dry silver powder: transfer the obtained silver to the ceramic evaporating dish and place it on the asbestos net for heating and drying to obtain the coarse silver powder.

 

5, the net silver powder: (1) dissolve: coarse silver powder into dilute nitric acid (121), dissolve in several times, the reaction has a large nitrogen dioxide (NO2);When the reaction is slow, add two batches.When the silver powder is almost dissolved, heat the asbestos mesh and stir to completely dissolve the reaction.(2) filtration: dilute the silver nitrate prepared with 1-1.5 times volume of distilled water, then filter, fully clean the beaker and filter paper several times with distilled water, and filter the washing liquid into the same container.(3) purification: dilute the silver nitrate filtrate obtained above with distilled water (make the concentration of silver nitrate solution less than 5%), then add red copper and leave overnight for complete replacement.After stirring, after the silver powder is completely precipitated, pour out the copper nitrate solution in the upper layer, detect the residual copper, wash and decompress with distilled water to no copper ions, then discharge the silver powder, transfer to the evaporating dish, heat and dry on the asbestos network, and obtain the glossy pure silver powder with silver content greater than 99.9%.

 

Matters needing attention

 

1. The iron sheet used should not be too thin, otherwise the remaining iron sheet after the reaction is not easy to detect, do not use nails or iron, otherwise the contact area with hydrochloric acid is small, the reaction is slow, the iron sheet used is 1mm thick, 1-2 cm wide, 4-5 cm long.

 

2. Copper can be made from thick copper wire, but not from fine copper wire, to avoid the inconvenience of detecting residual copper wire after the reaction.

 

3. The prepared silver powder should be thoroughly cleaned, which is the key to improve the purity of silver powder.

 

Silver solder advantages

 

1. Low energy saving cost for silver solder welding

 

2. Small oxidation area during welding

 

3. Beautiful appearance after welding

 

4. Low power consumption and energy saving cost

 

5. Welding can simultaneously weld multiple workpiece, improving the welding effect.

 

6. Small oxidation area

 

7. Uniform heating, no shortage of welding and silver electrode

 

8. The appearance of the welded workpiece is beautiful and firm

 

9. Fast induction heating speed and high efficiency

 

Welding is very convenient.The copper-aluminum flux-cored wire can be set by placing the silver welding piece between the tool head and the matrix.

 

11, uniform heating, no lack of welding and welding spot leakage

Welding Material