SILVER-FLO filler metals

SILVER-FLOTM products can be used to join the common engineering metals such as copper, copper alloys (brass, bronze, nickel silver, aluminium bronze, copper nickel), nickel alloys, steel, stainless steel and tungsten carbide.

SILVER-FLO 55 and 56 are general-purpose cadmium-free filler metals combining low brazing temperatures with short melting ranges. Both are free flowing, produce neat joints and are easy to use. They are used as replacements for cadmium-containing filler metals. SILVER-FLO 40 is a popular general-purpose product with medium melt and flow characteristics. SILVER-FLO 302 is a higher- and longer-melting filler metal and a useful gap-filling alloy.

Standard filler metals

Ag Cu Zn Sn ISO 17672 Melting Range
55 21 22 2 Ag 155 630 - 660oC

 

SILVER-FLO 55 is an easy to use, general purpose silver brazing filler metal. It has a low brazing temperature, short melting range and is free flowing when molten, producing neat joints with small fillets.

SILVER-FLO 55 is a cadmium-free replacement for the high silver (38-50%) cadmium containing filler metals. It can be used on most common engineering metals.

EN1044:1999
AG103

Ag Cu Zn Sn ISO 17672 Melting Range
56 22 17 5 Ag 156 618 - 652oC

 

SILVER-FLO 56 has very similar properties to SILVER-FLO 55. It has a low brazing temperature, short melting range and is free flowing when molten, producing neat joints with small fillets. Originally conforming to the US standard AWS A5.8 BAg-7, it can be used as a cadmium-free replacement for the high silver (38-50%) cadmium containing filler metals.

AMS/AWS A5.8
AMS 4763, AWS Bag-7

EN1044:1999
AG102

Ag Cu Zn Sn ISO 17672 Melting Range
45 27 25.5 2.5 Ag 145 640 - 680oC

 

SILVER-FLO 452 is a general purpose filler metal with 45% silver bridging the gap in properties and cost between high silver 55/56% filler metals and the medium silver 38/40% filler metals. It has the lowest silver content to braze PCD segments below 750˚C without degrading the diamond layer. It has good flow properties, but a slightly higher brazing temperature than the high silver content filler metals.

EN1044:1999
AG104

Ag Cu Zn Sn ISO 17672 Melting Range
40 30 28 2 Ag 140 650 - 710oC

 

SILVER-FLO 40 offers a good combination of properties. It has a medium brazing temperature, melting range, flow characteristics and silver content. SILVER-FLO 40 is widely used as a general purpose silver brazing filler metal as well as for joining copper and its alloys to steel in HVAC&R applications.

AMS/AWS A5.8
BAg-28

EN1044:1999
AG105

Ag Cu Zn Sn ISO 17672 Melting Range
38 31 29 2 Ag 138 660 - 720oC

 

SILVER-FLO 38 has similar properties to SILVER-FLO 40. It has a medium brazing temperature, melting range, flow characteristics and silver content. SILVER-FLO 38 is favoured in different global regions to SILVER-FLO 40 where it is also used in general purpose and HVAC&R applications.

 

Ag Cu Zn Sn ISO 17672 Melting Range
30 36 32 2 Ag 130 665 - 755oC

 

SILVER-FLO 302 has a long melting range and poor flow characteristics, which make it an ideal choice for applications where fillet build ups are required or close tolerance joint gaps are not present. It is used for brazing steel, copper and copper alloy tubes and fittings in HVAC&R and automotive applications. It is a popular choice as a flux coated rod for site work.

EN1044:1999
AG107

Ag Cu Zn Sn ISO 17672 Melting Range
25 40 33 2 Ag 125 680 - 760oC

 

SILVER-FLO 252 has a long melting range and poor flow characteristics, which make it an ideal choice for applications where fillet build ups are required or close tolerance joint gaps are not present. Like SILVER-FLO 302 it may be used for brazing steel, copper and copper alloy tubes and fittings in HVAC&R and automotive applications.

EN1044:1999
AG108

Filler metals for special applications

Ag Cu Zn Melting Range
60 26 14 695 - 730oC

 

SILVER-FLO 60 is a filler metal specified for use on copper nickel and nickel alloys (in particular 70:30 copper nickel). It has a brazing temperature above the stress relieving temperature of many of these types of metals thus preventing liquid metal stress cracking as a result of inter-granular penetration. It is resistant to dezincification.

Ag Cu Zn Sn Si Melting Range
56 22 16.75 5 0.25 618 - 652oC

 

SILVER-FLO 56S is a Johnson Matthey proprietary filler metal which has a small addition of silicon, is very free flowing and produces smooth neat joints with small fillets. It is not recommended on carbon steel components that are subject to high impact or fatigue stress in service.

Ag Cu Zn Sn Si Melting Range
45 25 26.8 3 0.2 640 - 680oC

 

SILVER-FLO 453S has a small addition of silicon and produces smooth neat joints with small fillets making it popular for hand torch brazing of decorative brass components. Like other high silver content silicon containing filler metals it is not recommended for use on carbon steel components that are subject to high impact or fatigue stress in service.

Ag Cu Zn ISO 17672 Melting Range
44 30 26 Ag 244 675 - 735oC

 

SILVER-FLO 44 has a medium brazing temperature, melting range, flow and silver content. Although it is not preferred to the more common SILVER-FLO 40 or 38 it has found use in marine applications because it is resistant to dezincification. It is also used as a medium temperature filler metal for copper alloy tubes where joint gaps are variable and a fillet is desirable.

EN1044:1999
AG203

Ag Cu Zn Melting Range
43 37 20 690 - 775oC

 

SILVER-FLO 43 has a medium brazing temperature, long melting range, and poor flow characteristics. It is not commonly used but has found use in the shipbuilding industry and in marine applications because it is the lowest silver content filler metal, which is resistant to dezincification. It is a good fillet forming and gap filling filler metal.

Ag Cu Zn Melting Range
24 43 33 740 - 800oC

 

SILVER-FLO 24 has been incorporated into aviation / aerospace industry standards and is consequently used in the manufacture of components for applications in this field. It is also used as the first alloy in a two-step silver brazing operation, where the second joint is made with SILVER-FLO 55.

Ag Cu Zn Si Melting Range
20 44 35.85 0.15 776 - 815oC

 

SILVER-FLO 20 is a high melting point silver brazing filler metal that has a comparatively narrow melting range providing reasonable flow properties when molten. It can be used when colour matching to brass is required.

Less common / reference filler metals

Ag Cu Zn Melting Range
45 25 30 680 - 700oC

 

SILVER-FLO 45 is a cadmium free silver brazing alloy originally developed and manufactured to a Johnson Matthey specification. Today this alloy has been largely superseded by SILVER-FLO 452, and is generally only offered where it is included in an old specification.

SILVER-FLO 45 combines a low brazing temperature with a short melting range. It is very free flowing and produces smooth neat joints with small fillets. The alloy is tin and silicon free. The optimum joint gap at brazing temperature is normally 0.05-0.15mm.

Ag Cu Zn Sn ISO 17672 Melting Range
34 36 27.5 2.5 Ag 134 630 - 730oC

 

SILVER-FLO 34 is a cadmium free silver brazing filler metal. It exhibits poor / sluggish flow characteristics melting over a 100°C temperature range. Because of these characteristics SILVER-FLO 34 is not widely used today.

SILVER-FLO 34 has an ability to fill gaps that cannot be tightly controlled and to build fillets. Optimum joint gaps at brazing temperature are 0.075-0.2mm.

EN1044:1999
AG106

Ag Cu Zn Melting Range
33 33.5 33.5 700 - 740oC

 

SILVER-FLO 33 is a cadmium free silver brazing filler metal. It shows free flowing characteristics melting over a short, but comparatively high, temperature range (700-740°C). It is a good brazing filler metal that has been used as the second filler metal in a three step sequential brazing process along with SILVER-FLO 16 and SILVER-FLO 55.

SILVER-FLO

33 is not widely used today. Optimum joint gaps at brazing temperature are 0.075-0.2mm.

Ag Cu Zn ISO 17672 Melting Range
30 38 32 Ag 230 695 - 770oC

 

SILVER-FLO 30 is a cadmium free silver brazing filler metal that has been adopted for a thermal spray coating process used in the aerospace industry. It is supplied as a wire on plastic reels suitable for feeding into a thermal spray gun.

The filler metal itself has a long and high melting range and poor flow characteristics hence it is not used as a brazing filler metal to any extent. Optimum joint gaps at brazing temperature are 0.075-0.2mm.

EN1044:1999
AG204

Ag Cu Zn ISO 17672 Melting Range
25 40 35 Ag 225 700 - 790oC

 

SILVER-FLO 25 is a high melting point cadmium free silver brazing filler metal. It has a high melting temperature(700 to 790°C) with a quoted melting range of 90°C. This melting range suggests medium to sluggish flow properties when molten. The high brazing temperature of the filler metal makes it less easy to use than the high silver content alloys.

Optimum joint gaps at brazing temperature are 0.075-0.2mm.

EN1044:1999
AG205

Ag Cu Zn Si Melting Range
18 45.75 36 0.25 784 - 816oC

 

SILVER-FLO 18 is a high melting point cadmium free silver brazing filler metal. It has a high melting temperature(784 to 816°C) but a narrow melting range of only 32°C providing good flow properties when molten. The high brazing temperature of the filler metal makes it less easy to use than the high silver content alloys. Consequently it is not widely used. This product is a relatively inexpensive filler metal to purchase. However the cost per brazed joint of actually using the alloy may not be favourable in comparison to lower melting point, higher silver content filler metals. Optimum joint gaps at brazing temperature are 0.075-0.2mm.

Ag Cu Zn Melting Range
16 50 34 790 - 830oC

 

SILVER-FLO 16 is a high melting point cadmium free silver brazing filler metal. It has a high melting temperature(790 to 830°C) but a narrow melting range of only 40°C providing good flow properties when molten.The high brazing temperature of the filler metal makes it less easy to use than the high silver content alloys. Consequently it is not widely used. This product is a relatively inexpensive filler metal to purchase. However the cost per brazed joint of actually using the alloy may not be favourable in comparison to lower melting point, higher silver content filler metals. Optimum joint gaps at brazing temperature are 0.075-0.2mm.

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Dalton O’Brien

UK

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    Mario Porta

    Mario Porta

    Switzerland, Austria and Germany

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      Michela Grout

      Michela Grout

      Rest of the world

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